engine.go

// Here is the main engine app.
package main

import (
	_ "github.com/go-sql-driver/mysql"
	"bytes"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"github.com/jaytaylor/html2text" // converts HTML to pretty-printed text! (20170807)
	"github.com/spf13/viper"
	"golang.org/x/net/websocket"
	"gopkg.in/guregu/null.v3/zero"
	"html/template"
	"io/ioutil"
	"math"
	"math/rand"
	"net/http"
	"sort"
	"strings"
	"strconv"
	"sync/atomic" // used for sync'ing values across goroutines at a low level
	"time"
)

// Define a communications procotol with the client, so that we can selectively
//	send messages to turn options on and off, etc.
// Messages will be JSON.

type WsMessageType struct {
	Type zero.String `json:"type"`
	SubType zero.String `json:"subtype"`
	Text zero.String `json:"text"`
	Id zero.String `json:"id"`
}

// New creates a new WsMessage out of 4 strings
func (wsM *WsMessageType) New(msgType string, msgSubType string, msgText string, msgId string) *WsMessageType {
	wsM.Type = zero.StringFrom(msgType)
	wsM.SubType = zero.StringFrom(msgSubType)
	wsM.Text = zero.StringFrom(msgText)
	wsM.Id = zero.StringFrom(msgId)

	return wsM
}

// Constants for genetic algorithm. Names are retained from the PHP version.
// TODO(gwyneth): Have these constants as variables which are read from the configuration file.

const OS_NPC_SIT_NOW = "0"
// Constants used in genetic algorithm.
const RADIUS = 10.0 // this is the size of the grid that is thrown around the avatar
const POPULATION_SIZE = 50 // was 50
const GENERATIONS = 20 // was 20 for 20x20 grid
const CHROMOSOMES = 7 // was 28 for 20x20 grid
const CROSSOVER_RATE = 90.0 // = 90%, we use a random number generator for 0-100
const MUTATION_RATE = 5.0	// = 0.005%, we use a random number generator for 0-1000 - TODO(gwyneth): try later with 0.01
const WALKING_SPEED = 3.19 // avatar walking speed in meters per second)
// Weights for Shi & Cui
const W1 = 1.0 // Sub-function of Path Length
const W2 = 10.0 // Sub-function of Path Security
const W3 = 5.0 // Sub-function of Smoothness

// When transposing from the PHP version, we now cannot avoid having a few structs and types, since Go
//	is a strongly-typed language (20170726)
//	This was moved out of the GA code body because some external functions need those types (20170727)

// chromosomeType is just a point in a path, really.
type chromosomeType struct {
	x, y, z, distance, obstacle, angle, smoothness float64
}

// popType represents each population as a list of points (= chromosomes) indicating a possible path; it also includes the fitness for this particular path.
type popType struct {
	Fitness float64
	chromosomes []chromosomeType
}

// movementJob is used in the worker goroutine which processes the points to move the avatars to, which needs to wait until the avatars have moved.
// Go is so quick in recalculating generations that the avatars never get a chance to reach their destination until we wait for them!
// So the commands to move the avatars need to go into a separate goroutine, to wait on avatars, while the main engine continues (20170730).
type movementJob struct {
	agentUUID string				// Agent UUID to move
	masterControllerPermURL string	// masterController to use (note that the engine may pick one of several active ones)
	agentPermURL string				// unfortunately the masterController cannot get or set Energy...
	destPoint chromosomeType		// destination to go to; it's a chromosome so that we get distance information as well to calculate
									//	 for how long we need to sleep until the avatar reaches destination
}
// movementJobChannel is the blocking channel to which we write points for the next bot movement
var movementJobChannel = make(chan movementJob, 1) // for now, we'll try with just 1 point

// Go is tricky. While we send and receive WebSocket messages as it would be expected on a 'normal'
//	programming language, we actually have an insane amount of goroutines all in parallel. So what we do is to
//	send messages to a 'channel' (Go's version of a semaphore) and receive them from a different one; two sets
//	of goroutines will have their fun reading and sending messages to the client and updating the channels,
//	so other goroutines only send and receive to the channels and have no concept of 'WebSocket messages'
//	This is sort of neat because it solves parallelism (goroutines block on sockets) but it also allows
//	us to build in other transfer mechanisms and make them abstract using Go channels (20170703)
var wsSendMessage = make(chan WsMessageType)
var wsReceiveMessage = make(chan WsMessageType)
var webSocketActive atomic.Value // this is an attempt to check if we have an active WebSocket, to avoid too many timeouts (20170728)

// serveWs - this is what is 'called' from the outside, and I need to talk to a socket here.
func serveWs(ws *websocket.Conn) {
	// see also how it is implemented here: http://eli.thegreenplace.net/2016/go-websocket-server-sample/ (20170703)
	var err error // to avoid constant redeclarations in tight loop below

	if ws == nil {
		Log.Panic("Received nil WebSocket — I have no idea why or how this happened!")
	}

	/*
	log.Printf("Client connected from %s", ws.RemoteAddr())
	log.Println("entering serveWs with connection config:", ws.Config())
	*/

	webSocketActive.Store(true)
	defer webSocketActive.Store(false)

	go func() {
	//	log.Println("entering send loop")

		for {
			sendMessage := <-wsSendMessage

			if err = websocket.JSON.Send(ws, sendMessage); err != nil {
				Log.Error("Can't send; error:", err)
				break
			}
		}
	}()

	//log.Println("entering receive loop")
	var receiveMessage WsMessageType

	for {
		if err = websocket.JSON.Receive(ws, &receiveMessage); err != nil {
			Log.Error("Can't receive; error:", err)
			break
		}
		// Log.Debugf("Received back from client: type '%s' subtype '%s' text '%s' id '%s'\n", *receiveMessage.Type.Ptr(), *receiveMessage.SubType.Ptr(), *receiveMessage.Text.Ptr(), *receiveMessage.Id.Ptr())
		wsReceiveMessage <- receiveMessage
	}
}

// convertLocPos converts a SL/OpenSim Location and Position into a single region name and (x,y,z) position coordinates
func convertLocPos(location string, position string) (regionName string, xyz []string) {
	regionName = location[:strings.Index(location, "(")-1]
	coords := strings.Trim(position, "() \t\n\r")
	xyz = strings.Split(coords, ",")
	return regionName, xyz
}

// calcDistance calculates the distance between two points, which are actually arrays of x,y,z string coordinates.
//	TODO(gwyneth): Now that we have a strongly-typed language, we should create real objects for this.
func calcDistance(vec1, vec2 []float64) float64 {
	deltaX := vec2[0] - vec1[0] // using extra variables because multiplication is probably
	deltaY := vec2[1] - vec1[1] //	 simpler than calling the math.Pow() function (20170725)
	deltaZ := vec2[2] - vec1[2]

	return math.Sqrt(deltaX * deltaX + deltaY * deltaY + deltaZ * deltaZ)
}

// engineHandler is still being implemented, it uses the old Go websockets interface to try to keep the page updated.
func backofficeEngine(w http.ResponseWriter, r *http.Request) {
	// start gathering the cubes and agents for the Engine form
	checkSession(w, r)
	// Collect a list of existing bots and their PermURLs for the form

	db, err := sql.Open(PDO_Prefix, GoBotDSN)
	checkErr(err)

	// query for in-world objects that are cubes (i.e. not Bot Controllers)
	rows, err := db.Query("SELECT UUID, Name, ObjectType, ObjectClass, Location, Position FROM Positions WHERE ObjectType <> 'Bot Controller' ORDER BY Name")
	checkErr(err)

	defer rows.Close()

	var (
		cubes, regionName = "", ""
		uuid, name, objType, objClass, location, position = "", "", "", "", "", ""
		xyz []string
	)
	cubes = "\t\t\t\t\t\t\t\t\t\t\t\t\t<option value=\"" + NullUUID + "\">Clean selection (let engine figure out next cube)</option>\n"

	// As on backofficeCommands, but a little more complicated
	for rows.Next() {
		err = rows.Scan(&uuid, &name, &objType, &objClass, &location, &position)
		checkErr(err)
		// parse name of the region and coordinates
		regionName, xyz = convertLocPos(location, position)

		cubes += fmt.Sprintf("\t\t\t\t\t\t\t\t\t\t\t\t\t<option value=\"%s\">%s (%s/%s) [%s (%s,%s,%s)]</option>\n", uuid, name, objType, objClass, regionName, xyz[0], xyz[1], xyz[2])
	}

	rows, err = db.Query("SELECT Name, UUID, Location, Position FROM Agents ORDER BY Name")
	checkErr(err)

	var uuidAgent, agentNames = "", ""
	agentNames = "\t\t\t\t\t\t\t\t\t\t\t\t\t<option value=\"" + NullUUID + "\">Clean selection (let engine figure out next agent)</option>\n"

	// To-Do: Agent options should also have location etc.

	// find all Names and OwnerKeys and create select options for each of them
	for rows.Next() {
		err = rows.Scan(&name, &uuidAgent, &location, &position)
		checkErr(err)
		regionName, xyz = convertLocPos(location, position)
		agentNames += fmt.Sprintf("\t\t\t\t\t\t\t\t\t\t\t\t\t<option value=\"%s\">%s	(%s) [%s (%s,%s,%s)]</option>\n", uuidAgent, name, uuidAgent, regionName, xyz) // not obvious for the Go linter, but xyz is an array of 3 elements (gwyneth 20210711)
	}

	rows.Close() // closing after deferring to close is probably not good, but I'll try it anyway (20170723)
	db.Close()

	tplParams := templateParameters{ "Title": "Gobot Administrator Panel - engine",
			"URLPathPrefix": template.HTML(URLPathPrefix),
			"Host": template.HTML(Host),
			"DestinationOptions": template.HTML(cubes),
			"AgentOptions": template.HTML(agentNames),
			"ServerPort": template.HTML(ServerPort),
			"Content": template.HTML("<hr />"),
	}
	err = GobotTemplates.gobotRenderer(w, r, "engine", tplParams)
	checkErr(err)
}

// EngineRunning is the equivalent of a semaphore which starts or stops the engine.
// OneStep allows the engine to run once, and then it stops.
// These are an exported global (atomic) variables because we need to access it from the configuration function and from the SIGHUP/SIGCONT (20170811, 20170919).
var EngineRunning, OneStep atomic.Value

// engine does everything but the kitchen sink.
// Notably, it does not only run the GA. It also deals on a separate goroutine with message handling for WebSockets, which also includes
//	the ability to start or stop the GA. And it launches another goroutine to deal with buffering commands to the virtual world. It really does
//	a lot, and possibly it ought to be simplified somehow. But this is the core, the essence, the kernel, the locus of all the rest!
func engine() {
	// we use sync/atomic for making sure we can read a value that is set by a different goroutine
	//	 see https://texlution.com/post/golang-lock-free-values-with-atomic-value/ among others (20170704)
	var (
		receiveMessage WsMessageType
		userDestCube atomic.Value // using sync/atomic to make values consistent among goroutines (20170704)
		curAgent atomic.Value
	)

//	EngineRunning.Store(true) // we start by running the engine; note that this may very well happen before we even have WebSockets up (20170704)
								// now we let this be set via configuration file; the default is true; and a SIGHUP will start/stop the engine (20170811)
	userDestCube.Store(NullUUID) // we start to nullify these atomic values, either they will be changed by the user,
	curAgent.Store(NullUUID)	//  or the engine will simply go through all agents (20170725)
	OneStep.Store(false)		// in theory, the engine starts or stops; one step is a special case if the client is connected (20170919)
	webSocketActive.Store(false)	// as soon as we know that we have a connection to the client, we set this to true (20170728)

	sendMessageToBrowser("status", "info", "Entering the engine goroutine", "") // browser might not even know we're sending messages to it, so this will just gracefully timeout and be ignored and just appear on the log; changed message to display that we don't know if the engine is going to run or not (20170811)

	// Launch the movement worker goroutine. This is needed because Go is so fast calculating populations that it keeps giving the agents
	// contradictory movement commands. This uses a blocking channel and calculates how long the avatar needs to reach its destination
	// and sleeps for that time. There was something similar done in PHP as well, but PHP took long enough recalculating everything, so
	// it was deemed not to be necessary. (20170730)
	go movementWorker()

	// Now, this is a message handler to receive messages while inside the engine, we
	//	 block on a message and run a goroutine in the background, so we can safely continue
	//	 to run the engine without blocking or errors
	//	 I have no idea yet if this is a good idea or not (20170703)
	//	 At least it works (20170704)
	go func() {
		var messageType, messageSubType string

		for {
			receiveMessage = <-wsReceiveMessage

			if (receiveMessage.Type.Ptr() != nil) {
				messageType = *receiveMessage.Type.Ptr()
			} else {
				messageType = "empty"
			}
			if (receiveMessage.SubType.Ptr() != nil) {
				messageSubType = *receiveMessage.SubType.Ptr()
			} else {
				messageSubType = "empty"
			}

			switch messageType {
				case "status":
					switch messageSubType {
						case "ready": // this is what we get when WebSockets are established on the client
							webSocketActive.Store(true)
							// check for engine running or not and set the controls
							switch EngineRunning.Load().(bool) {
								case true:
									sendMessageToBrowser("htmlControl", "disable", "", "startEngine")
									sendMessageToBrowser("htmlControl", "disable", "", "oneStep")
									sendMessageToBrowser("htmlControl", "enable", "", "stopEngine")
								case false:
									sendMessageToBrowser("htmlControl", "enable", "", "startEngine")
									sendMessageToBrowser("htmlControl", "enable", "", "oneStep")
									sendMessageToBrowser("htmlControl", "disable", "", "stopEngine")
								default: // should never happen, but turn all buttons off just in case
									sendMessageToBrowser("htmlControl", "disable", "", "startEngine")
									sendMessageToBrowser("htmlControl", "disable", "", "oneStep")
									sendMessageToBrowser("htmlControl", "disable", "", "stopEngine")
							}
						case "gone": // The client has gone, we have no more websocket for this one (20170704)
							Log.Info("Client just told us that it went away, we continue on our own")
							webSocketActive.Store(false)
						default: // no other special functions for now, just echo what the client has sent...
							unknownMessage := "<nil>"
							if receiveMessage.Text.Ptr() != nil {
								unknownMessage = *receiveMessage.Text.Ptr()
							}
							Log.Warning("Received from client unknown status message with subtype",
								messageSubType, "text:", unknownMessage, " — ignoring...")
					}
				case "formSubmit":
					var messageText string
					if receiveMessage.Text.Ptr() != nil {
						messageText = *receiveMessage.Text.Ptr()
					} else {
						messageText = NullUUID + "|" + NullUUID // a bit stupid, we could skip this and do direct assigns, but this way we do a bit more effort wasting CPU cycles for the sake of code clarity (20170704)
					}
					returnValues := strings.Split(messageText, "|")
					userDestCube.Store(returnValues[0])
					curAgent.Store(returnValues[1])

					// Commented out because we know this works and we'll print it out later on anyway (20170730)
					// log.Println("Destination: ", userDestCube.Load().(string), "Agent:", curAgent.Load().(string))
					// sendMessageToBrowser("status", "info", "Received '" + userDestCube.Load().(string) + "|" + curAgent.Load().(string) + "'<br />", "")
				case "engineControl":
					switch messageSubType {
						case "start":
							sendMessageToBrowser("htmlControl", "disable", "", "startEngine")
							sendMessageToBrowser("htmlControl", "disable", "", "oneStep")
							sendMessageToBrowser("htmlControl", "enable", "", "stopEngine")
							EngineRunning.Store(true)
							OneStep.Store(false)
						case "one-step":
							sendMessageToBrowser("htmlControl", "disable", "", "startEngine")
							sendMessageToBrowser("htmlControl", "disable", "", "oneStep")
							sendMessageToBrowser("htmlControl", "enable", "", "stopEngine")
							EngineRunning.Store(true)
							OneStep.Store(true)
							Log.Debug("OneStep is now", OneStep.Load().(bool))
/*
						case "stop":
							sendMessageToBrowser("htmlControl", "enable", "", "startEngine")
							sendMessageToBrowser("htmlControl", "enable", "", "oneStep")
							sendMessageToBrowser("htmlControl", "disable", "", "stopEngine")
							EngineRunning.Store(false)
							OneStep.Store(false)
*/
						default: // anything else will stop the engine!
							sendMessageToBrowser("htmlControl", "enable", "", "startEngine")
							sendMessageToBrowser("htmlControl", "enable", "", "oneStep")
							sendMessageToBrowser("htmlControl", "disable", "", "stopEngine")
							EngineRunning.Store(false)
							OneStep.Store(false)
					}
					sendMessageToBrowser("status", "", "Engine " + messageSubType + "<br />", "")

				default:
					Log.Warning("Unknown message type", messageType)
			}
		}
	}()

	// We continue with engine. Things may happen in the background, and theoretically we
	//	 will be able to catch them. (20170703)

	// load whole database in memory. Really. It's so much faster that way! (20170722)
	var (
		Agent AgentType // temporary way to store what comes from database
		lastAgentToRunUUID string // temporary storage of the last UUID agent that ran, when we pick one randomly, so we give others a chance (20170807)
		// Agents map[string]AgentType // we OUGHT to have a type without those strange zero.String, but it's tough to keep two structs in perfect sync (20170722); this is mapped by Agent UUID (20170725)
		Position PositionType
		Cubes map[string]PositionType // name to be compatible with PHP version; mapped by UUID (20170725).
		Object ObjectType
		Obstacles []ObjectType
		masterController PositionType // set to the most recent Bot Master Controller to send commands (name is the same as in former PHP code).
	)
	// NOTE(gwyneth): The reason why we use maps and not slices (slices may be faster) is just because that way we can
	//	directly address the element by UUID, instead of doing array searches (20170725)

	// prepare data to be saved as a CSV/XML file for later import into Excel and do nice graphics
	var export_rows []string // we place it here because of potential scope issues later on...

	// Theoretically endless loop follows (20170730)
	for {
		// Now, the problem with the approach of going through the list of Agents is that new Agents might appear, old
		//  might be deleted, and then we're stuck! (Remember, the updating of the Agents table is done in parallel to this)
		//  The idea of running goroutines for each Agent will also suffer from the same problem: what if the Agent dies and we don't know
		//  about it? Of course we can check with a ping first. What about *new* Agents? How do we launch new goroutines for them if we
		//  don't know about them beforehand? (20170801)

		// Second approach (20170801): initialise lastAgentRunning with NullUUID; pick one agent from the database; if it's the
		//  same as before, pick a new one; if the user has provided us with an agent, use that one instead. This will at least provide
		//  all agents with a chance of running, while allowing new Agents to appear and old ones to die (20170801). The cost of this
		//  solution is that *some* Agents may not have a chance to run (since they're picked randomly), so we might be a little more
		//  evil and use some magical pseudo-random generators from Go which allow a sequence of non-repeated random numbers to be
		//  generated, and try to follow that order if possible, which means reloading the Agent table every cycle, but it might still be
		//  worth it (20170801).
		// NOTE(gwyneth): From 20170807 onwards, the for loop runs forever, each cycle one Agent is picked to run
		// Note that the Agent table does not get reloaded each cycle, only a list of UUIDs, one of which is picked randomly and just one
		//  Agent is loaded (20170807).

		if EngineRunning.Load().(bool) {
			// Open database
			// sanity check first, I have no idea why this happens sometimes:
			if PDO_Prefix == "" {
				PDO_Prefix = viper.GetString("gobot.PDO_Prefix")
			}
			if GoBotDSN == "" {
				GoBotDSN = viper.GetString("gobot.GoBotDSN")
			}
			db, err := sql.Open(PDO_Prefix, GoBotDSN)
			checkErr(err)

			defer db.Close() // needed?

			// load in Agents! We need them to call the movement algorithm for each one
			// BUG(gwyneth): what if the number of agents _change_ while we're running the engine? We need a way to reset the engine somehow. We have a hack at the moment: send a SIGCONT, it will try to restart the engine in a new goroutine
			// Changes 20170807: we now pick one agent randomly

			// First check if the end-user hasn't sent us an Agent UUID to use:
			userSetAgentUUID := curAgent.Load().(string)
			possibleAgentUUID := NullUUID
			// Log.Debug("userSetAgent is", userSetAgent)
			if userSetAgentUUID == NullUUID {
				// we need to pick one agent at random

				// Since apparenty MySQL is not very efficient at picking a row randomly, we load in a temporary number of UUIDs and
				//	select one randomly in Go; then we just get the row from the database (20170807)
				rows, err := db.Query("SELECT UUID FROM Agents")
				if err != nil { // NOTE(gwyneth): caught that error when the grid is not operational yet! (20170816)
					sendMessageToBrowser("status", "error", fmt.Sprintf("Database error when selecting Agent to run: %v", err)," ")
					time.Sleep(10 * time.Second)
					continue // now we simply wait...
				}
				defer rows.Close() // needed? The problem here is with a continue on the check below...

				var agentUUIDs []string
				tempUUID := ""
				for rows.Next() {
					err = rows.Scan(&tempUUID)
					checkErr(err)
					agentUUIDs = append(agentUUIDs, tempUUID)
				}
				// if we have zero agents, we cannot go on!
				// TODO(gwyneth): be more graceful handling this, because the engine will stop forever this way
				// TODO(gwyneth): Better to randomly pick an agent from the database, and if none is available, skip a cycle (20170730).
				if len(agentUUIDs) == 0 {
					sendMessageToBrowser("status", "error", "Error: no Agents found. Engine cannot run. Aborted. Add an Agent and try sending a <code>SIGCONT</code> to restart engine again<br />"," ")
					time.Sleep(10 * time.Second)
					continue // now we simply wait...
				}
				// Log.Debug("We got a bunch of UUIDs:", agentUUIDs)
				possibleAgentUUID = agentUUIDs[0] // make sure we have at least a valid UUID!!
				// Generate a random index, search for it in agentUUIDs; if it's the same one as last time, try again; test for edge case,
				//	i.e. that we have just 1 Agent in the database. (20170807)
				if len(agentUUIDs) > 1 && lastAgentToRunUUID != NullUUID {	// edge case: on initialisation, both are set to NullID, so both are equal
					for index := 0; lastAgentToRunUUID == possibleAgentUUID; {
						index = rand.Intn(len(agentUUIDs))
						possibleAgentUUID = agentUUIDs[index]
						//if lastAgentToRunUUID != possibleAgentUUID {
						//	break
						//}
						// Log.Debug("Index picked:", index, "possibleAgentUUID", possibleAgentUUID, "Last agent was", lastAgentToRunUUID)
					}
				}
			} else {
				possibleAgentUUID = userSetAgentUUID
				sendMessageToBrowser("status", "info", fmt.Sprintf("Using agent UUID %s set by end-user", possibleAgentUUID), "")
			}
			lastAgentToRunUUID = possibleAgentUUID
			if possibleAgentUUID == NullUUID {
				Log.Critical("My logic is still borked!!") // NOTE(gwyneth): if this situation still happens, I need to revisit this! (20170813)
			}
			err = db.QueryRow("SELECT * FROM Agents where UUID=?", possibleAgentUUID).Scan(
				&Agent.UUID,
				&Agent.Name,
				&Agent.OwnerName,
				&Agent.OwnerKey,
				&Agent.Location,
				&Agent.Position,
				&Agent.Rotation,
				&Agent.Velocity,
				&Agent.Energy,
				&Agent.Money,
				&Agent.Happiness,
				&Agent.Class,
				&Agent.SubType,
				&Agent.PermURL,
				&Agent.LastUpdate,
				&Agent.BestPath,
				&Agent.SecondBestPath,
				&Agent.CurrentTarget,
			)
			if err != nil || !Agent.OwnerKey.Valid {
				sendMessageToBrowser("status", "error", fmt.Sprintf("Error %v: no Agent found for UUID %s, or invalid OwnerKey for this agent. Engine cannot run. Aborted. Fix the database and try sending a <code>SIGCONT</code> to restart engine again<br />", err, possibleAgentUUID)," ")
					time.Sleep(10 * time.Second)
					continue // wait until situation improves...
			}
			// do the magic to extract the actual coords
			Agent.Coords_xyz = strings.Split(strings.Trim(*Agent.Position.Ptr(), "() \t\n\r"), ",")
			// we should extract the region name from Agent.Location, but I'm lazy!

			Log.Info("Starting to manipulate Agent", *Agent.Name.Ptr(), " (", *Agent.UUID.Ptr(), ")")
			// We need to refresh all the data about cubes and positions again!

			// do stuff while it runs, e.g. open databases, search for agents and so forth
			Log.Debug("Reloading database for Cubes (Positions) and Obstacles...")

			// Load in the 'special' objects (cubes). Because the Master Controllers can be somewhere in here, to save code.
			//  and a database query, we simply skip all the Master Controllers until we get the most recent one, which gets saved
			//  The rest of the objects are cubes, so we will need them in the ObjectType array (20170722).
			// BUG(gwyneth): Does not work across regions! We will probably need a map of bot controllers for that and check which one to call depending on the region of the current agent; simple, but I'm lazy (20170722).

			Cubes = make(map[string]PositionType) // clear array, let the Go garbage collector deal with the memory (20170723)
			rows, err := db.Query("SELECT * FROM Positions ORDER BY LastUpdate ASC")
			checkErr(err)

			for rows.Next() {
				err = rows.Scan(
					&Position.PermURL,
					&Position.UUID,
					&Position.Name,
					&Position.OwnerName,
					&Position.Location,
					&Position.Position,
					&Position.Rotation,
					&Position.Velocity,
					&Position.LastUpdate,
					&Position.OwnerKey,
					&Position.ObjectType,
					&Position.ObjectClass,
					&Position.RateEnergy,
					&Position.RateMoney,
					&Position.RateHappiness,
				)
				checkErr(err)
				Position.Coords_xyz = strings.Split(strings.Trim(*Position.Position.Ptr(), "() \t\n\r"), ",")

				// check if we got a Master Bot Controller!
				if (*Position.ObjectType.Ptr() == "Bot Controller") {
					masterController = Position // this will get overwritten until we get the last, most recent one
				} else {
					Cubes[*Position.UUID.Ptr()] = Position // if not a controller, it must be a cube! add it to array!
				}
			}
			// we need at least ONE masterController, this will be nil if got none (20170807).
			if !masterController.PermURL.Valid {
				Log.Error(funcName() + ": Major error with database, we need at least one valid masterController to proceed. Sleeping for 10 seconds for user to correct this...")
				time.Sleep(10 * time.Second)
				continue // go to next iteration, this one has borked data (20170801)
			}

			// load in everything we found out so far on our region(s) but ignore phantom objects
			// end-users ought to set their cubes to phantom as well, or else the agents will think of them as obstacles!
			Obstacles = nil
			rows, err = db.Query("SELECT * FROM Obstacles WHERE Phantom = 0")
			checkErr(err)

			for rows.Next() {
				err = rows.Scan(
					&Object.UUID,
					&Object.Name,
					&Object.BotKey,
					&Object.BotName,
					&Object.Type,
					&Object.Position,
					&Object.Rotation,
					&Object.Velocity,
					&Object.LastUpdate,
					&Object.Origin,
					&Object.Phantom,
					&Object.Prims,
					&Object.BBHi,
					&Object.BBLo,
				)
				checkErr(err)
				Object.Coords_xyz = strings.Split(strings.Trim(*Object.Position.Ptr(), "() \t\n\r"), ",")

				Obstacles = append(Obstacles, Object)
			}

			rows.Close()

			// Do not trust the database with the exact Agent position: ask the master controller directly
			// NOTE(gwyneth): Perhaps it's better to try asking the agent first, and if it refuses answering, try the master controller. (20170813)
			//  I believe we go through the master controller because the agent might be too busy informing the database about sensor data.
			Log.Debug("master controller URL:", *masterController.PermURL.Ptr(), "Agent:", *Agent.Name.Ptr(), "Agent's OwnerKey:", *Agent.OwnerKey.Ptr())
			// WHY Agent.Ownerkey?!?! Why not Agent.UUID?!?!?
			// The answer is NOT obvious: NPCs created by the master controller are owned by the avatar owning the master controller
			//  and somehow to contact them we need the ownerkey, which is weird; newer versions of OpenSim are supposed to have fixed
			//  this by adding a flag for NPCs not to be owned by anyone. Using this might mean to change a lot of code! (20170806)
			curPos_raw, err := callURL(*masterController.PermURL.Ptr(), "npc=" + *Agent.OwnerKey.Ptr() + "&command=osNpcGetPos")

			// NOTE(gwyneth): Apparently the web server will reply to ALL possible requests, even if the Agent doesn't exist any more;
			//  I still don't know what to do in that situation, so we skip this cycle and try the next one (20170730).
			if curPos_raw == "" || curPos_raw == "No response could be obtained" || err != nil {
				Log.Error("Error in figuring out the response for agent", *Agent.Name.Ptr(), "so we will try to skip this cycle...")
				continue
			}

			sendMessageToBrowser("status", "info", "Grid reports that agent '" + *Agent.Name.Ptr() + "' is at position: " + curPos_raw + "...</p>\n", "")

			// update database with new position
			_, err = db.Exec("UPDATE Agents SET Position =? WHERE OwnerKey =?", strings.Trim(curPos_raw, " ()<>"), *Agent.OwnerKey.Ptr())
			checkErr(err)

			db.Close()

			// sanitize
			Agent.Coords_xyz = strings.Split(strings.Trim(curPos_raw, " <>()\t\n\r"), ",")
			curPos := make([]float64, 3) // to be more similar to the PHP version

			Log.Debug("curPos_raw is", curPos_raw)
			_, err = fmt.Sscanf(curPos_raw, "<%f, %f, %f>", &curPos[0], &curPos[1], &curPos[2]) // best way to convert strings to floats! (20170728)
			checkErr(err)

			sendMessageToBrowser("status", "", fmt.Sprintf("Avatar '%s' (%s) raw position was %v; recalculated to: %v<br />", *Agent.Name.Ptr(), *Agent.Name.Ptr(), curPos_raw, curPos), "")

			// Now we select where to go to!
			// This will eventually become more complex and *possibly* part of the GA (20170811).
			// For now, we just see what attribute is more 'urgent' and choose a cube of the appropriate type.

			whatCubeTypeNext := "energy" // by default it will be energy

			// convert to floats, we could actually change that in the database but I'm lazy... (20170811)
			energyAgent, err := strconv.ParseFloat(*Agent.Energy.Ptr(), 64)
			checkErr(err)
			moneyAgent, err := strconv.ParseFloat(*Agent.Money.Ptr(), 64)
			checkErr(err)
			happinessAgent, err := strconv.ParseFloat(*Agent.Happiness.Ptr(), 64)
			checkErr(err)

			// Simple way to make a choice, but this will get much more complicated in the future (I hope!) (20170811)
			if moneyAgent < energyAgent {
				whatCubeTypeNext = "money"
			}
			if (happinessAgent < moneyAgent) && (happinessAgent < energyAgent) {
				whatCubeTypeNext = "happiness"
			}

			Log.Debug(*Agent.Name.Ptr(), "has energy:", energyAgent, "money:", moneyAgent, "happiness:", happinessAgent, "so obviously we will pick a", whatCubeTypeNext, "cube to move to.")

			// calculate distances to nearest obstacles and cubes

			// TODO(gwyneth): these might become globals, outside the loop, so we don't need to declare them
			var smallestDistanceToObstacle = 1024.0 // will be used later on
			var nearestObstacle ObjectType
			var smallestDistanceToCube = 1024.0 // will be used later on
			var nearestCube PositionType
			obstaclePosition := make([]float64, 3)
			cubePosition := make([]float64, 3)

			var distance float64

			// pretty-print some nice tables for nearest obstacles and nearest cubes (20170806).
			outputBuffer := "<div class='table-responsive'><table class='table table-striped table-bordered table-hover'><caption>Obstacles</caption><thead><tr><th>#</th><th>Name</th><th>Position</th><th>Distance</th></tr></thead><tbody>\n"

			for k, point := range Obstacles {
				_, err = fmt.Sscanf(*point.Position.Ptr(), "%f, %f, %f", &obstaclePosition[0], &obstaclePosition[1], &obstaclePosition[2])
				checkErr(err)

				distance = calcDistance(curPos, obstaclePosition)

				outputBuffer += fmt.Sprintf("<tr><td>%v</td><td>%s</td><td>%v</td><td>%.4f</td></tr>\n", k, *point.Name.Ptr(), *point.Position.Ptr(), distance)

				if distance < smallestDistanceToObstacle {
					smallestDistanceToObstacle = distance
					nearestObstacle = point
				}
			}
			outputBuffer += "</tbody><tfoot><tr><th>#</th><th>Name</th><th>Position</th><th>Distance</th></tr></tfoot></table></div>\n"
			sendMessageToBrowser("status", "", outputBuffer, "")
			sendMessageToBrowser("status", "info", fmt.Sprintf("Nearest obstacle to agent %s: '%s' (distance: %.4f m)<br />", *Agent.Name.Ptr(), *nearestObstacle.Name.Ptr(), smallestDistanceToObstacle), "")

			// now pretty-print nearest cubes (20170806).
			outputBuffer = "<div class='table-responsive'><table class='table table-striped table-bordered table-hover'><caption>Cubes (Positions)</caption><thead><tr><th>UUID</th><th>Name</th><th>Position</th><th>ObjectType</th><th>Distance</th></tr></thead><tbody>\n"
			for k, point := range Cubes {
				_, err = fmt.Sscanf(*point.Position.Ptr(), "%f, %f, %f", &cubePosition[0], &cubePosition[1], &cubePosition[2])
				checkErr(err)

				distance = calcDistance(curPos, cubePosition)
				point.DistanceToAgent = distance // hope this works, we're saving the distance so that later on we can use this as a weight

				outputBuffer += fmt.Sprintf("<tr><td>%v</td><td>%s</td><td>%v</td><td>%s</td><td>%.4f</td></tr>\n", k, *point.Name.Ptr(), *point.Position.Ptr(), *point.ObjectType.Ptr(), point.DistanceToAgent)

				if distance < smallestDistanceToCube && *point.ObjectType.Ptr() == whatCubeTypeNext {
					smallestDistanceToCube = distance
					nearestCube = point
				}
			}
			outputBuffer += "</tbody><tfoot><tr><th>UUID</th><th>Name</th><th>Position</th><th>ObjectType</th><th>Distance</th></tr></tfoot></table></div>\n"
			sendMessageToBrowser("status", "", outputBuffer, "")
			sendMessageToBrowser("status", "info", fmt.Sprintf("Nearest %s cube to agent %s: '%s' (distance: %.4f m)<br />", whatCubeTypeNext, *Agent.Name.Ptr(), *nearestCube.Name.Ptr(), smallestDistanceToCube), "")

			/* Idea for the GA:

			1. Start with a 20x20 matrix (based loosely on Cosío and Castañeda) around the bot, which contain sensor data (we just sense up to 10 m around the bot). This might need adjustment (i.e. smaller size).
			- This represents the space of possible solutions
			- Active cube will determine attraction point (see later)
			- Chromosomes: randomly generated points (inside the 20x20 matrix) that the robot has to travel. Start perhaps with 50 with a length of 28 (Castañeda use 7 for 10x10 matrix). Points are bounded within the 20x20 matrix
			Now evaluate each chromosome with fitness function:
			- for each point: see if it's "too near" to an obstacle (potential collision)
				- ray casts are more precise, so give it a highest weight (not implemented yet)
				- normal sensor data give lower weigth
				- we can add modifiers: see number of prims of each obstacle (more prims, more weight, because object might be bigger than predicted); see if the obstacle is an agent (initially: agents might act as deflectors; later: interaction matrix will see if the bot goes nearer to the agent or avoids it)
			- for each point: see if it's closest to the cube. Lowest distance reduces weight. In theory, we wish to find the path with the least distance (less energy wasted)
			- sort chromosomes according to fitness
			- do 20 generations and find next expected point. Move bot to it. Reduce energy calculation on bot. See if it dies!
			- repeat for next bot position

			20130520 — Results don't converge. It's hard to get the 'bot in less than a 10m radius.
			Attempt #2 - use a 10x10 matrix, just 7 points, like Castañeda
			Gotshall & Rylander (2002) suggest a population size of about 100-200 for 7 chromosomes
			Attempt #3 - Algorithm from Ismail & Sheta was badly implemented!!
			Attempt #4 - (to-do) implement Shi & Cui (2010) algorithm for fitness function
			Attempt #5 - Shi & Cui (2010) use a strange way to calculate path smoothness. Attempting Qu, Xing & Alexander (2013) which use angles. Modified mutation function, instead of the classical approach (switching two elements in the path), add random ±x, ±y to point
			André Neubauer (circular schema theorem, cited by Qu et al.) suggest two-point crossover
			Qu et al. suggest sorting path points, after crossover/mutation

			*/

			/*		goal/target/attractor: where the 'bot is going to go next
					at some point, this ought to be included in the chromosome as well
					for now, we'll hard-code it (walk to the nearest cube)
					on stage two, we'll do a simple check:
						- see what attributes are lowest
						- go to the nearest cube that replenishes the attribute
						- since this will be iterated every time the 'bot moves, we hope it won't die from starvation,
							as moving elsewhere becomes prioritary
			*/

			// nearestCube is where we go (20140526 changing it to selected cube by user, named destCube)
			var destCube PositionType

			// BUG(gwyneth): Somehow, the code below will just be valid once! (20170728) - this needs more testing, I think
			// it was a `clear` somewhere at the end of the iteration, but we got to check it. Also, the submit button for
			// changing cube/agent does not go away and the visual feedback is weird (20170806).
			// Still working on it, it somehow works sometimes, but it's hard to debug because the GA does so many things (20170813).
			Log.Info("User-set destination cube for", *Agent.Name.Ptr(), ":", userDestCube.Load().(string), "(NullUUID means no destination manually set)")
			if userDestCube.Load().(string) != NullUUID {
				destCube = Cubes[userDestCube.Load().(string)]
				Log.Info("User has supplied us with a destination cube for", *Agent.Name.Ptr(), "named:", *destCube.Name.Ptr())
			} else {
				destCube = nearestCube
				Log.Info("Automatically selecting nearest cube for", *Agent.Name.Ptr(), "to go:", *destCube.Name.Ptr())
			}

			// This is just a test without the GA (20170725)
			// Commented out in 20170730 — forgot completely about this!!
			/*
			sendMessageToBrowser("status", "info", "GA will attempt to move agent '" + *Agent.Name.Ptr() + "' to cube '" + *destCube.Name.Ptr() + "' at position " + *destCube.Position.Ptr(), "")
			_, err = callURL(*masterController.PermURL.Ptr(), "npc=" + *Agent.OwnerKey.Ptr() + "&command=osNpcMoveToTarget&vector=<" + *destCube.Position.Ptr() + ">&integer=1")
			checkErr(err)
			*/
			time_start := time.Now()

			// Genetic algorithm for movement
			// generate 50 strings (= individuals in the population) with 28 random points (= 1 chromosome) at curpos ± 10m

			population := make([]popType, POPULATION_SIZE) // create a population; unlike PHP, Go has to have a few clues about what is being created (20170726)
			// Log.Debug("population len", len(population))
			// initialise the slices of chromosomes; Go needs this to know how much memory to allocate (unlike PHP)
			for k := range population {
				population[k].chromosomes = make([]chromosomeType, CHROMOSOMES)
				// Log.Debug("Chromosome", k, "population len", len(population[k].chromosomes))
			}

			// We calculate now the distance from each point to the destination
			//  Because this is computationally intensive, we will not repeat it every time during each generation
			//  Works well unless the destination moves! Then our calculations might be wrong
			//  But we will catch up on the _next_ iteration (hopefully, unless it moves too fast)
			//  We also use the best and second best path from a previous run of the GA

			// get from the database the last two 'best paths' (if it makes sense)

			start_pop := 0 // if we have no best paths, we will generate everything from scratch

			// Maybe it makes sense to keep around the last best paths if we're still moving towards the same
			//  cube; so check for this first, and discard the last best paths if the destination changed

			// NOTE(gwyneth): Unlike the PHP version, the Go version deals simultaneously with an automated choice of path as well as manual
			//  setting of destination, through user input; so the code here is slightly different. We *already* have the
			//  destination cube in destCube (20170726).
			// We already have the cubePosition with the correct data (array of 3 float64 values for x,y,z).

			// NOTE(gwyneth): I have a doubt here, when the algorithm runs again, should the agent keep the CurrentTarget in mind? (20170726)
			//  The PHP code seems to assume that, but it wasn't ready yet for automated runs...

			// calculate the center point between current position and target
			// needs to be global for path sorting function (Ruhe's algorithm)
			// NOTE(gwyneth): in PHP we had a global $centerPoint; Go uses capital letters to designate globality (20170726).
			// NOTE(gwyneth): Ruhe's algorithm is not used any more, so we can safely forget this declaration (20170805).
			/*
			CenterPoint := struct {
				x, y, z float64
			}{
				x: 0.5 * (cubePosition[0] + curPos[0]),
				y: 0.5 * (cubePosition[1] + curPos[1]),
				z: 0.5 * (cubePosition[2] + curPos[2]),
			}

			sendMessageToBrowser("status", "", fmt.Sprintf("Center point for this iteration is <%f, %f, %f><br/>", CenterPoint.x, CenterPoint.y, CenterPoint.z), "")
			*/

			// Now generate from scratch the remaining population

			for i := start_pop; i < POPULATION_SIZE; i++ {
				population[i].Fitness = 0.0

				for y := 0; y < CHROMOSOMES; y++ {
					// Ismail & Sheta recommend to use the distance between points as part of the fitness
					// edge cases: first point, which is the distance to the current position of the agent
					// and last point, which is the distance between the last point and the target
					// that's why the first and last point have been inserted differently in the population
					// Log.Debug("i", i, "y", y)
					if y == 0 { // first point is (approx.) current position
						population[i].chromosomes[y].x = math.Trunc(curPos[0])
						population[i].chromosomes[y].y = math.Trunc(curPos[1])
						population[i].chromosomes[y].z = math.Trunc(curPos[2])
					} else if y == (CHROMOSOMES - 1) { // last point is (approx.) position of target
						population[i].chromosomes[y].x = math.Trunc(cubePosition[0])
						population[i].chromosomes[y].y = math.Trunc(cubePosition[1])
						population[i].chromosomes[y].z = math.Trunc(cubePosition[2])
					} else { // others are scattered around the current position
						population[i].chromosomes[y].x = math.Trunc(curPos[0] + (rand.Float64() * 2)*RADIUS - RADIUS)
						if population[i].chromosomes[y].x < 0.0 {
							population[i].chromosomes[y].x = 0.0
						} else if population[i].chromosomes[y].x > 255.0 {
							population[i].chromosomes[y].x = 255.0
						}

						population[i].chromosomes[y].y = math.Trunc(curPos[1] + (rand.Float64() * 2)*RADIUS - RADIUS)
						if population[i].chromosomes[y].y < 0.0 {
							population[i].chromosomes[y].y = 0.0
						} else if population[i].chromosomes[y].y > 255.0 {
							population[i].chromosomes[y].y = 255.0
						}

						population[i].chromosomes[y].z = math.Trunc((cubePosition[2] + curPos[2])/2) // will work for flat terrain but not more
					}

					// To implement Shi & Cui (2010) or Qu et al. (2013) we add these distances to obstacles together
					//	 If there are no obstacles in our radius, then we keep it clear

					population[i].chromosomes[y].obstacle = RADIUS // anything beyond that we don't care
					var point ObjectType
					for _, point = range Obstacles {
						_, err = fmt.Sscanf(*point.Position.Ptr(), "%f, %f, %f", &obstaclePosition[0], &obstaclePosition[1], &obstaclePosition[2])
						checkErr(err)
						distance = calcDistance([]float64 {population[i].chromosomes[y].x,
												population[i].chromosomes[y].y,
												population[i].chromosomes[y].z },
												obstaclePosition)


						// Shi & Cui and Qu et al. apparently just uses the distance to the nearest obstacle
						if distance < population[i].chromosomes[y].obstacle {
							 population[i].chromosomes[y].obstacle = 1/distance
							// we use the inverse here, because if we have many distant obstacles it's
							//  better than a single one that is close by
						}
						// TODO(gwyneth): obstacles flagged as ray-casting are far more precise, so they ought to be
						//  more weighted.

						// TODO(gwyneth): obstacles could also have bounding box calculations: bigger objects should
						//  be more weighted. However, HUGE objects might have holes in it. We ought to
						//  include the bounding box only for ray-casting, or else navigation would be impossible!
						//  Note that probably OpenSim raycasts only via bounding boxes (need confirmation)
						//  so maybe this is never a good approach. Lots of tests to be done here!
						// NOTE(gwyneth): The latest version of llRayCast, v3 on BulletSim, does NOT use bounding boxes. Confirmed 20170730.
					}
					if RADIUS - population[i].chromosomes[y].obstacle < 0.00001 { // we use a delta to deal with rounding errors with floats
						population[i].chromosomes[y].obstacle = 0.0
					}

					// calculate, for this point, its distance to the destination, currently $destCube
					// (exploded to array $cubePosition)
					// might not need this

					population[i].chromosomes[y].distance = calcDistance([]float64 { population[i].chromosomes[y].x,
												population[i].chromosomes[y].y,
												population[i].chromosomes[y].z},
												cubePosition)

					// abandoned: initialize smoothness for Shi & Cui
					// adopted (20140523): smoothness using angles, like Qu et al.
					population[i].chromosomes[y].smoothness = 0.0
					population[i].chromosomes[y].angle = 0.0 // maybe initialize it here
				} // endfor y

				// now sort this path. According to Qu et al. (2013) this gets us a smoother path
				// hope it's true, because it's computationally intensive
				// (20140523) we're using Ruhe's algorithm for sorting according to angle, hope it works
				// (20140524) Abandoned Ruhe, using a simple comparison like Qu et al.
				//echo "Before sorting, point i is: "; var_dump(population[i]); echo "<br />\n";
				/*
				$popsort = substr(population[i], 1, -1);
				$first_individual = population[i][0];
				$last_individual  = population[i][CHROMOSOMES - 1];
				usort($popsort, 'point_cmp');
				population[i] = 	array_merge((array)$first_individual, $popsort, (array)$last_individual);
				*/

				pop := population[i].chromosomes

				sort.Slice(pop, func(a, b int) bool {
					// NOTE(gwyneth): these is still the old PHP comments, kept here for historical reasons
					// global $centerPoint;

					/* Attempt #1: Ruhe's algorithm

					$theta_a = atan2($a.y - $centerPoint.y, $a.x - $centerPoint.x);
					$angle_a = fmod(M_PI - M_PI_4 + $theta_a, 2 * M_PI);

					$theta_b = atan2($b.y - $centerPoint.y, $b.x - $centerPoint.x);
					$angle_b = fmod(M_PI - M_PI_4 + $theta_a, 2 * M_PI);

					if ($angle_a == $angle_b)
						return 0;

					return ($angle_a < $angle_b) ? -1 : 1;
					*/

					/*
					// Attempt #2: just angles

					if ($a.angle == $b.angle)
						return 0;

					return (abs($a.angle) < abs($b.angle)) ? -1 : 1;
					*/
					// Attempt #3: Just compare x,y! This is a terrible solution but better than nothing
					// using algorithm from Anonymous on http://www.php.net/manual/en/function.usort.php
					/*
					if ($a.x == $b.x)
					{
						if ($a.y == $b.y)
						{
							return 0;
						}
						elseif ($a.y > $b.y)
						{
							return 1;
						}
						elseif ($a.y < $b.y)
						{
							return -1;
						}
					}
					elseif ($a.x > $b.x)
					{
						return 1;
					}
					elseif ($a.x < $b.x)
					{
						return -1;
					}
					*/

					// Attempt #4: order by shortest distance to the target?
					return pop[a].distance < pop[b].distance
				})
			} // endfor i

			// testing printing the current population (with json we get strange results!)
			// showPopulation(population, "Current population")

			// We're not finished yet! We need to calculate angles between all points (duh!) to establish smoothness
			// Let's do it from scratch:

			for i := 0; i < POPULATION_SIZE; i++ {
				population[i].chromosomes[0].angle = 0.0 // curPos has (obviously) angle 0

				for j := 1; j < CHROMOSOMES; j++ {
					population[i].chromosomes[j].angle =
						math.Atan2(population[i].chromosomes[j].y - population[i].chromosomes[j-1].y,
						population[i].chromosomes[j].x - population[i].chromosomes[j-1].x)
					// sendMessageToBrowser("status", "", fmt.Sprintf("Pop %v, Chromosome %v - Angle is %v<br />", i, j, population[i].chromosomes[j].angle), "")
				}
			}

		// Initial population done; now loop over generations

		for generation := 0; generation < GENERATIONS; generation++	{
			// Calculate fitness
			// Log.Debug("Generating fitness for generation ", generation, " (out of ", GENERATIONS, ") for agent", *Agent.Name.Ptr(), "...")

			// When calculating a new population, each element will have its chromosomes reordered
			//  So we have no choice but to calculate fitness for all population elements _again_
			for i := 0; i < POPULATION_SIZE; i++	{
				fitnessW1 := 0.0
				fitnessW2 := 0.0
				fitnessW3 := 0.0

				// note that first point is current location; we start from the second point onwards
				for y := 1; y < CHROMOSOMES; y++ {
					// Sub-function of Path Length (using Shi & Cui)
					distLastPoint := calcDistance([]float64 {
								population[i].chromosomes[y].x,
								population[i].chromosomes[y].y,
								population[i].chromosomes[y].z,
							},
							[]float64 {
								population[i].chromosomes[y-1].x,
								population[i].chromosomes[y-1].y,
								population[i].chromosomes[y-1].z,
							})

					// Eduardo: suggests using square distance, means path will have more
					//	 distributed points. (20140704 - 2004)
					fitnessW1 += distLastPoint * distLastPoint

					// Sub-function of Path Security (using Shi & Cui) — obstacle proximity
					fitnessW2 += population[i].chromosomes[y].obstacle

					// Sub-function of Smoothness (using Shi & Cui)
					// This measures how zig-zaggy the path is, namely, if points are pointing back etc.
					// We want a smooth path towards the goal
					// Possibly here is where the weight will be added
					// Attempt #5: Qu et al. suggest the angle between line segments
					// used http://stackoverflow.com/questions/20395547/sorting-an-array-of-x-and-y-vertice-points-ios-objective-c

					/* Shi & Cui; abandoned
					population[i][$y]["smoothness"] =
						(
							(population[i][$y-1].y - population[i][$y].y) /
							(population[i][$y-1].x - population[i][$y].x)
						)
						-
						(
							(population[i][$y].y - population[i][$y-1].y) /
							(population[i][$y].x - population[i][$y-1].x)
						);
					*/
					// even though Shi & Cui was abandoned, we calculate smoothness nevertheless, only to make sure these calculations work!
					//	 (20170806)
					population[i].chromosomes[y].smoothness = ( population[i].chromosomes[y-1].y - population[i].chromosomes[y].y /
						population[i].chromosomes[y-1].x - population[i].chromosomes[y].x ) -
						( population[i].chromosomes[y].y - population[i].chromosomes[y-1].y /
							population[i].chromosomes[y].x - population[i].chromosomes[y-1].x )

					fitnessW3 += population[i].chromosomes[y].angle // clever, huh? check if abs makes sense
					// I don't think abs of an angle is a good idea (20170806)

					// and we'll also use the overall distance to the attractor
					//population[i]["fitness"] += population[i][$y]["distance"];
				} // end for y
				population[i].Fitness = W1 * fitnessW1 + W2 * fitnessW2 + W3 * fitnessW3
			} // end for i

			// note that the most critical point is the first: it's the one the 'bot will try to walk to. But we need
			//  to calculate the rest of the path, too, which is "the best path so far which the bot plans to travel"
			//  even if at every iteration, it will get calculated over and over again

			Log.Debug("CPU time used after fitness calculations for generation ", generation, ": ", time.Since(time_start))
			/*
			showPopulation(population, fmt.Sprintf("Generation %v] - Before ordering:", generation))
			*/

			// Now we do genetics!

			// To pick the 'best' population elements, we need to sort this by fitness, so that the best
			//  elements are at the top

			// order by fitness
			sort.Slice(population, func(a, b int) bool {
					return population[a].Fitness < population[b].Fitness
				})

			// TODO(gwyneth): to comment out later (20170727)
			showPopulation(population, fmt.Sprintf("Population for agent '%s' [generation %v] after calculating fitness and ordering by fitness follows:", *Agent.Name.Ptr(), generation))

			sendMessageToBrowser("status", "", fmt.Sprintf("CPU time used after sorting generation %v for agent '%s': %v<br />\n", generation, *Agent.Name.Ptr(), time.Since(time_start)), "")

			// Selection step. We're using fitness rank
			newPopulation := make([]popType, POPULATION_SIZE) // create a new population; see comments above
			for k := range newPopulation {
				newPopulation[k].chromosomes = make([]chromosomeType, CHROMOSOMES)
			}
			// To introduce elitism, we will move the first 2 elements to the new population:
			newPopulation[0] = population[0]
			newPopulation[1] = population[1]
			// we could also delete the remaining two

			// for the remaining population:
			for i := 2; i < POPULATION_SIZE; i += 2 {
				// establish if we do crossover
				if rand.Float64() * 100 < CROSSOVER_RATE {
					// find a crossover point; according to André Neubauer, we might need two crossover points
					crossover_point := int(math.Trunc(rand.Float64() * CHROMOSOMES))
					child0 := make([]chromosomeType, CHROMOSOMES)
					child1 := make([]chromosomeType, CHROMOSOMES)

					// Log.Debug("Generation ", generation, " - Crossover for ", i, " and ", (i + 1), " happening at crossover point: ", crossover_point)

					// now copy the chromosomes from the first parent, up to the crossover point, to child0
					//	 and the remaining chromosomes go to the second child
					// simultaneously, do the reverse for the second parent

					// there are probably better/faster string manipulation techniques but this is easy to debug
					for chromosome := 0; chromosome < CHROMOSOMES; chromosome++ {
						if chromosome <= crossover_point {
							child0[chromosome] = population[i].chromosomes[chromosome]
							child1[chromosome] = population[i+1].chromosomes[chromosome]
						} else {
							child0[chromosome] = population[i+1].chromosomes[chromosome]
							child1[chromosome] = population[i].chromosomes[chromosome]
						}
						/*
						Log.Debug("Pop ", i, ", chromosome: ", chromosome, " Original chromosome: ", population[i].chromosomes[chromosome],
							"Child 0 chromosome: ", child0[chromosome])
						*/
					} // endif chromosomes

					// test for mutation; note that this is permille and not percent
					if rand.Float64() * 1000 < MUTATION_RATE {
						/*
							Abandoned mutation implementation, which was a classical formulation
							for value-based GA (as opposed to bit-based)

						// pick two chromosomes for first child, two for second child
						//  see http://obitko.com/tutorials/genetic-algorithms/crossover-mutation.php

						first_chromosome = mt_rand(0, CHROMOSOMES-1);
						second_chromosome = mt_rand(0, CHROMOSOMES-1);
						// exchange them, by using a temporary holder (this is mostly because
						//  the exchange might be for the same chromosome!
						$temp_first_chromosome = child0[first_chromosome];
						$temp_second_chromosome = child0[second_chromosome];

						child0[first_chromosome] = $temp_second_chromosome;
						child0[second_chromosome] = $temp_first_chromosome;

						// echo "Generation " . $generation . " - Mutation happening for child " . i . " — exchanging chromosomes " . first_chromosome . " and " . second_chromosome . "</br>\n";

						// same for second child

						first_chromosome = mt_rand(0, CHROMOSOMES-1);
						second_chromosome = mt_rand(0, CHROMOSOMES-1);
						// exchange them, by using a temporary holder (this is mostly because
						//  the exchange might be for the same chromosome!
						$temp_first_chromosome = child1[first_chromosome];
						$temp_second_chromosome = child1[second_chromosome];

						child1[first_chromosome] = $temp_second_chromosome;
						child1[second_chromosome] = $temp_first_chromosome;

						// echo "Generation " . $generation . " - Mutation happening for child " . (i + 1) . " — exchanging chromosomes " . first_chromosome . " and " . second_chromosome . "</br>\n";

						*/

						/*
							(20140523) Instead, as Qu et al. do, just pick a point and add some
							random distance to it
						*/
						first_chromosome	:= int(math.Trunc(rand.Float64() * (CHROMOSOMES-1)))
						second_chromosome	:= int(math.Trunc(rand.Float64() * (CHROMOSOMES-1)))

						child0[first_chromosome].x += (rand.Float64() * 2)*RADIUS/2 - RADIUS/2
						if child0[first_chromosome].x < 0 {
							child0[first_chromosome].x = 0
						} else if child0[first_chromosome].x > 255 {
							child0[first_chromosome].x = 255
						}
						child0[first_chromosome].y += (rand.Float64() * 2)*RADIUS/2 - RADIUS/2
						if child0[first_chromosome].y < 0 {
							child0[first_chromosome].y = 0
						} else if child0[first_chromosome].y > 255 {
							child0[first_chromosome].y = 255
						}
						child1[second_chromosome].x += (rand.Float64() * 2)*RADIUS/2 - RADIUS/2
						if child1[second_chromosome].x < 0 {
							child1[second_chromosome].x = 0
						} else if child1[second_chromosome].x > 255 {
							child1[second_chromosome].x = 255
						}
						child1[second_chromosome].y += (rand.Float64() * 2)*RADIUS/2 - RADIUS/2
						if child1[second_chromosome].y < 0 {
							child1[second_chromosome].y = 0
						} else if child1[second_chromosome].y > 255 {
							child1[second_chromosome].y = 255
						}
					} // endif mutation

					/*
					Log.Debug("Generation ", generation, " - New children for population ", i, ": ", child0, "\nand ",
						(i + 1), ": ", child1)
					*/

					/* we need to sort the points on the two childs AGAIN. Duh. And recalculate the angles.
						Duh, duh, duh */
					/*
					child0sort = substr(child0, 1, -1);
					child1sort = substr(child1, 1, -1);

					$first_individual_child0 = child0[0];
					$first_individual_child1 = child1[0];

					$last_individual_child0 = child0[CHROMOSOMES - 1];
					$last_individual_child1 = child1[CHROMOSOMES - 1];

					usort(child0sort, 'point_cmp');
					usort(child1sort, 'point_cmp');

					child0 = array_merge((array)$first_individual_child0, child0sort,
						(array)$last_individual_child0);
					child1 = array_merge((array)$first_individual_child1, child1sort,
						(array)$last_individual_child1);
					*/

					sort.Slice(child0, func(a, b int) bool {
						return child0[a].distance < child0[b].distance
						})
					sort.Slice(child1, func(a, b int) bool {
						return child1[a].distance < child1[b].distance
						})

					child0[0].angle = 0.0;
					child0[1].angle = 0.0;

					for j := 1; j < CHROMOSOMES; j++ {
						child0[j].angle = math.Atan2(child0[j].y - child0[j-1].y,
								child0[j].x - child0[j-1].x)
						child1[j].angle = math.Atan2(child1[j].y - child1[j-1].y,
								child1[j].x - child1[j-1].x)
					}
					// add the two children to the new population; fitness will be calculated on next iteration
					newPopulation[i].chromosomes	= child0
					newPopulation[i+1].chromosomes	= child1

					// endif crossover
				} else {
					// no crossover, just move them directly
					newPopulation[i].chromosomes	= population[i].chromosomes
					newPopulation[i+1].chromosomes	= population[i+1].chromosomes
					// echo "No crossover for " . i . " and " . (i + 1) . " - moving parents to new population<br />\n";
				}
				// Log.Debug("Pop ", i, "finished")

			}
			Log.Debug("Generation ", generation, " finished")

			population = newPopulation; // prepare population
//			Log.Debug("CPU time used after crossover and mutation up to generation ", generation, ": ", time.Since(time_start))

		}	 // for generation

		//showPopulation(population, fmt.Sprintf("Final result (%v generation(s)):", GENERATIONS))

			// at the end, the first point (after the current position) for the last population should give us the nearest point to move to
		//  ideally, the remaining points should also have converged
		//  obviously, as the avatar moves and finds about new obstacles etc. the population will change


		// move to target; integer=1 means "walking" (never "flying")
		//

		// Solution by Eduardo 20140704 — if we're close to the destination, within its radius, then we should
		//  move to the last point — which is our current destination!

		// Calculate where we are before we move
		distanceToTarget := calcDistance(curPos, cubePosition)

		var target int // declared here for scope issues (PHP has the ternary operator for dealing with that, Go hasn't)

		if distanceToTarget < RADIUS {
			target = CHROMOSOMES
		} else {
			target = CHROMOSOMES -1
		}

		sendMessageToBrowser("status", "info", fmt.Sprintf("Solution: move agent %s first to (%v, %v, %v) [and follow with %v points]. Distance is %.4f m", *Agent.Name.Ptr(), population[0].chromosomes[1].x, population[0].chromosomes[1].y, population[0].chromosomes[1].z, target - 1, distanceToTarget), "")

		// BUG(gwyneth): Major bug here! Possibly corrected with new approach. (20170805)
		// Basically, we generate the path for the next CHROMOSOME points. But we just need to move the avatar to the NEXT point
		// (i.e. chromosomes[1], because we will recalculate the whole path from then on. On the other hand, we need to print out
		// what the best path was so far, etc. and this will enter the calculations for the next batch of generations and so forth.
		// Nevertheless, the command to move the avatar is just for the NEXT point. (20170805) This should eliminate the 'quirks' of
		// the avatar moving in zig-zag and sometimes even backwards... and hopefully it will avoid them to move towards 0,0,Z...

		// Possibly Go is much faster at calculating new paths than the avatar is in moving to the next one.

		// because Go is so fast at calculating generations, we need to push the commands to give on a separate goroutine
		//  which acts as a worker to consume points and wait on them until the avatar has finished walking to the point.
		// We begin with a channel with the capacity of allowing CHROMOSOMES points, maybe this needs to be adjusted in the future
		// Possibly we just need to move to the NEXT point, so the channel capacity would be just one! (20170805)
		movementJobChannel <- movementJob {
					agentUUID: *Agent.OwnerKey.Ptr(),
					masterControllerPermURL: *masterController.PermURL.Ptr(),
					agentPermURL: *Agent.PermURL.Ptr(),
					destPoint: population[0].chromosomes[1],
		}

		for p := 1; p < target; p++ { // (skip first point — current location)
			// This is added for the CSV export, but I don't know if it makes more sense here or in the movementWorker goroutine
			export_rows = append(export_rows, fmt.Sprintf("%f,%f,%f;", population[0].chromosomes[p].x, population[0].chromosomes[p].y, population[0].chromosomes[p].z))
		}

 		// Save two best solutions for next iteration; attempts to avoid to recalculate always from scratch
 		// We do it after moving because the avatar needs a few seconds to reach destination

		// Reopen database, we need to write out the new Agent data
		db, err = sql.Open(PDO_Prefix, GoBotDSN)
		checkErr(err)

 		// now update our database with the best paths and the target
		stmt, err := db.Prepare("UPDATE Agents SET BestPath=?, SecondBestPath=?, CurrentTarget=? WHERE UUID=?")
		if err != nil {
			sendMessageToBrowser("status", "error", fmt.Sprintf("%v: Updating database with best path, second best path, and current target for agent %s - prepare failed: %s",
				funcName(), *Agent.Name.Ptr(), err), "")
		}

		marshalled0, err := json.Marshal(population[0])
		checkErr(err)
		marshalled1, err := json.Marshal(population[1])
		checkErr(err)

		_, err = stmt.Exec(marshalled0,
					marshalled1,
					strings.Trim(*destCube.Position.Ptr(), " \t"),
					*Agent.UUID.Ptr())
		if err != nil {
			sendMessageToBrowser("status", "error", fmt.Sprintf("%v: Updating database with best path, second best path, and current target for agent %s failed: %s",
				funcName(), *Agent.Name.Ptr(), err), "")
		}

		stmt.Close()
		db.Close()

		// See if we're close to the target; absolute precision might be impossible
		// first, read position again, just to see what we get
		curposResult, err := callURL(*masterController.PermURL.Ptr(), "npc=" + *Agent.OwnerKey.Ptr() + "&command=osNpcGetPos")
		if err == nil {
			sendMessageToBrowser("status", "info", fmt.Sprintf("Grid reports that agent %s is at position: %v",
				*Agent.Name.Ptr(), curposResult), "")
		} else {
			sendMessageToBrowser("status", "error", "We cannot get report from the grid for the position of agent " + *Agent.Name.Ptr(), "")
		}
/*
		echo "This is how Destination Cube looks like: <br \>\n";
		var_dump($destCube);
		echo "<br />\n";
*/
		currentPosition := make([]float64, 3) // see comment above for doing the same to curPos (20170728)

		_, err = fmt.Sscanf(strings.Trim(curposResult, " ()<>"), "%f,%f,%f", &currentPosition[0], &currentPosition[1], &currentPosition[2])
		checkErr(err)

/*
		echo "Distance comparison: Current Position:<br />\n";
		var_dump($currentPosition);
		echo "Target Cube<br />\n";
		var_dump($targetCube);
		echo "<br />\n";
*/
		distance = calcDistance(cubePosition, currentPosition) // this is how much is missing to reach destination

		if distance < 1.1 { // we might never get closer than this due to rounding errors
			sendMessageToBrowser("status", "info", fmt.Sprintf("Within rounding errors of %s, distance is merely %.4f m; let's sit %s down", *destCube.Name.Ptr(), distance, *Agent.Name.Ptr()), "")

			// if we're close enough, sit on it
			sitResult, err := callURL(*masterController.PermURL.Ptr(), "npc=" + *Agent.OwnerKey.Ptr() + "&command=osNpcSit&key=" + *destCube.UUID.Ptr() + "&integer=" + OS_NPC_SIT_NOW)
			if (err == nil) {
				sendMessageToBrowser("status", "info", "Result from " + *Agent.Name.Ptr() + " sitting: " + sitResult, "")
			} else {
				sendMessageToBrowser("status", "error", "Grid error when trying to sit " + *Agent.Name.Ptr(), "")
			}
		} else if distance < 2.5 {
			sendMessageToBrowser("status", "warning", fmt.Sprintf("%s is very close to %s, distance is now %.4f m", *Agent.Name.Ptr(), *destCube.Name.Ptr(), distance), "")
		} else {
			sendMessageToBrowser("status", "warning", fmt.Sprintf("%s is still %.4f m away from %s (%v, %v, %v)",
				*Agent.Name.Ptr(),
				distance,
				*destCube.Name.Ptr(),
				cubePosition[0],
				cubePosition[1],
				cubePosition[2]), "")
		}

		// Now place a button to save/export to CSV or XML
		// TODO(gwyneth): this was on the original code but no button was there; need to see where it is (20170728)

			// If the user had set agent + cube, clean them up for now
			//  They never get cleaned! That's the whole point! Unless of course the user WANTS them cleaned (20170729)
			//userDestCube.Store(NullUUID)
			//curAgent.Store(NullUUID)

			sendMessageToBrowser("status", "info", fmt.Sprintf("CPU time used: %v", time.Since(time_start)), "")

			// output something to console so that we know this is being run in parallel
			/*
				 fmt.Print("\r|")
				 time.Sleep(1000 * time.Millisecond)
				 fmt.Print("\r/")
				 time.Sleep(1000 * time.Millisecond)
				 fmt.Print("\r-")
				 time.Sleep(1000 * time.Millisecond)
				 fmt.Print("\r\\")
				 time.Sleep(1000 * time.Millisecond)
				 */
					// if we're set to run only once then stop, change atomic values accordingly
			if OneStep.Load().(bool) {
				OneStep.Store(false)
				EngineRunning.Store(false)
				sendMessageToBrowser("htmlControl", "enable", "", "startEngine")
				sendMessageToBrowser("htmlControl", "enable", "", "oneStep")
				sendMessageToBrowser("htmlControl", "disable", "", "stopEngine")
			}
		} else {
			// stop everything!!!
			// in theory this is used to deal with reconfigurations etc.
				 fmt.Print("\r𝔷")
				 time.Sleep(1000 * time.Millisecond)
				 fmt.Print("\rz")
				 time.Sleep(1000 * time.Millisecond)
				 fmt.Print("\rZ")
				 time.Sleep(1000 * time.Millisecond)
				 fmt.Print("\rℤ")
				 time.Sleep(1000 * time.Millisecond)
		}
	} // end for (endless loop here)

	// Why should we ever stop? :)
	sendMessageToBrowser("status", "success", "this is the engine <i>stopping</i>", "")
}

// sendMessageToBrowser sends a string to the internal, global channel which is picked up by the websocket handling goroutine.
// In the case of special status messages (info, success, warning, error) we also send the same message to the log.
// If no WebSocket is active (and we check that in two different ways!) the message simply goes to the log instead.
func sendMessageToBrowser(msgType string, msgSubType string, msgText string, msgId string) {
	text, err := html2text.FromString(msgText, html2text.Options{PrettyTables: true}) // prettify eventual HTML inside msgText
	checkErr(err)
	if webSocketActive.Load() != nil && webSocketActive.Load().(bool) { // no point in sending if nobody is there to receive
		var msgToSend WsMessageType

		msgToSend.New(msgType, msgSubType, msgText, msgId)

		// Go idiomatic programming: 'select' parallels the output of the two cases and picks the one which finishes; in this case, either
		// we are able to send a message via the channel, or there is a timeout, and Go picks what happens first
		select {
			case wsSendMessage <- msgToSend:
				// we use this so often as info/warning/error message that we may better send it also to the log
				if msgType == "status" && msgSubType != "" {
					switch msgSubType {
						case "info":
							Log.Info("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
						case "notice":
							Log.Notice("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
						case "success":
							Log.Notice("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
						case "warning":
							Log.Warning("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
						case "error":
							Log.Error("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
						case "critical":
							Log.Critical("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
						default:
							Log.Debug("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
					}
				} else {
					Log.Debug("(connected via WebSocket)", msgType, "-", msgSubType, "-", text, "-", msgId)
				}
			// 'common' messages have the nil string subtype, so we ignore these and don't log them
			//	we might have a Debug facility in the future which allows for more verbosity!
			case <-time.After(time.Second * 10):
				// this case exists only if we failed to figure out if the WebSocket is active or not; in most cases, we will
				//	be able to know that in advance, but here we catch the edge cases.
				Log.Warning("WebSocket timeout after 10 seconds; coudn't send message:", msgType, "-", msgSubType, "-", text, "-", msgId)
		}
	} else {
		// No active WebSocket? Just dump it to the log. Note that this will be the most usual case, since we hardly expect users to be 24/7 in
		//  front of their browsers...
		if msgType == "status" && msgSubType != "" {
			switch msgSubType {
				case "info":
					Log.Info("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
				case "notice":
					Log.Notice("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
				case "success":
					Log.Notice("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
				case "warning":
					Log.Warning("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
				case "error":
					Log.Error("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
				case "critical":
					Log.Critical("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
				default:
					Log.Debug("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
			}
		} else {
			Log.Debug("(no WebSocket connection)", msgType, "-", msgSubType, "-", text, "-", msgId)
		}
	}
}

// callURL encapsulates a call to an URL. It exists as an analogy to the PHP version (20170723).
func callURL(url string, encodedRequest string) (string, error) {
	//	 HTTP request as per http://moazzam-khan.com/blog/golang-make-http-requests/
	body := []byte(encodedRequest)
	// Log.Debugf("%s: URL: %s Encoded Request: %s\n", funcName(), url, encodedRequest)

	rs, err := http.Post(url, "application/x-www-form-urlencoded", bytes.NewBuffer(body))

	if err != nil {		errMsg := fmt.Sprintf("HTTP call to %s failed; error was: '%v'", url, err)
		Log.Error(errMsg)
		return errMsg, err
	}
	defer rs.Body.Close()

	rsBody, err := ioutil.ReadAll(rs.Body)
	// Check for errors; if errors found, then send the error message back to the caller
	if err != nil {
		errMsg := fmt.Sprintf("error response from in-world object: '%v'", err)
		Log.Error(errMsg)
		return errMsg, err
	} else {
		if string(rsBody) == "No response could be obtained" { // weird case, but apparently it can happen!
			err = errors.New("No response could be obtained")
		}
		Log.Debugf("Reply from in-world object: '%s'; error was %v\n", rsBody, err)
		return string(rsBody), err
	}
}

// showPopulation is adapted from the PHP code to pretty-print a whole population
// new version creates HTML tables
func showPopulation(popul []popType, popCaption string) {
	if !ShowPopulation { // this might be the beginning of a debug level configuration type; currently we have the options from the go-logging pkg (20170813).
		return
	}

	outputBuffer := "<div class='table-responsive'><table class='table table-striped table-bordered table-hover'><caption>" + popCaption + "</caption><thead><tr><th>Pop #</th><th>Fitness</th><th>Chromossomes</th></tr></thead><tbody>\n"

	for p, pop := range popul {
		outputBuffer += fmt.Sprintf("<tr><td>%v</td><td>%.4f</td>", p, pop.Fitness)
		for _, chr := range pop.chromosomes {
			outputBuffer += fmt.Sprintf("<td>(%v, %v, %v)<br />Distance: %.4f<br />Obstacle: %.4f<br />Angle: %.4f<br />Smoothness %.4f</td>",
				chr.x, chr.y, chr.z, chr.distance, chr.obstacle, chr.angle, chr.smoothness)
		}
		outputBuffer += "</tr>\n"
	}
	outputBuffer += "</tbody><tfoot><tr><th>Pop #</th><th>Fitness</th><th>Chromossomes</th></tr></tfoot></table></div>\n"
	sendMessageToBrowser("status", "", outputBuffer, "")
}

// movementWorker reads one point from the movementJobChannel and sends a command to the avatar to move to it, and recalculates energy.
// Then it blocks for the necessary amount of estimated time for the avatar to reach that destination until it reads the next
// point. Right now, the channel accepts CHROMOSOME jobs at a time (20170730).
// Finally, it calculates how much energy the avatar has spent for the distance travelled (20170811).
// TODO(gwyneth): probably happiness is also affected, we have to think about a new formula for that (20170811).
func movementWorker() {
	var nextPoint movementJob
	curPos := make([]float64, 3) // no need to allocate this over and over again
	newPos := make([]float64, 3) // this is the position that the avatar managed to travel to after this iteration
	for { // once started, never stops?
		nextPoint = <-movementJobChannel // consume one point from the channel

		// these must be set, nothing like a bit of error checking for eventual bugs elsewhere
		if nextPoint.masterControllerPermURL == "" || nextPoint.agentUUID == "" || nextPoint.agentPermURL == "" {
			continue	// either the next job comes valid, or we continue to consume points until a valid one comes along
		}

		// The code below was commented in the PHP code, but we reuse it here as it was because it makes sense! (20170730)

		// How much should we wait? Well, we calculate the distance to the next point! And since avatars move pretty much
		//  at the same speed all the time, we can make a rough estimate of the time they will take.

		// ask the avatar where it is
		curPosResult, err := callURL(nextPoint.agentPermURL, "command=osNpcGetPos")
		checkErr(err)
		if err != nil {
			// we have to assume this will never work, so we skip to the next case
			continue
		}

		// convert string result to array of floats
		_, err = fmt.Sscanf(strings.Trim(curPosResult, " ()<>"), "%f,%f,%f", &curPos[0], &curPos[1], &curPos[2])
		checkErr(err)

		walkingDistance := calcDistance(
			curPos, []float64 {	nextPoint.destPoint.x, nextPoint.destPoint.y, nextPoint.destPoint.z })
		timeToTravel := walkingDistance / WALKING_SPEED // we might adjust this to assume the in-world calls took some time as well
		// do not wait too long, though!
		if timeToTravel > 5.0 {
			timeToTravel = 5.0
		}
		sendMessageToBrowser("status", "", fmt.Sprintf("[%s]: Next point at %.4f metres; waiting %.4f secs for avatar %s to go to next point...<br />",
			funcName(), walkingDistance, timeToTravel, nextPoint.agentUUID), "")

		moveResult, err := callURL(nextPoint.agentPermURL,
					fmt.Sprintf("command=osNpcMoveToTarget&vector=<%v,%v,%v>&integer=1",
					nextPoint.destPoint.x, nextPoint.destPoint.y, nextPoint.destPoint.z))
		checkErr(err)
		if err != nil {
			// we lost the ability to send messages; what to do now? Well, we can ignore this, the GA will
			//  just require a new cycle
			continue
		}

		sendMessageToBrowser("status", "", fmt.Sprintf("[%s]: In-world result call from moving %s to (%v, %v, %v): %s<br />",
			funcName(), nextPoint.agentUUID, nextPoint.destPoint.x, nextPoint.destPoint.y, nextPoint.destPoint.z, moveResult), "")
		time.Sleep(time.Second * time.Duration(timeToTravel))

		// ask the avatar AGAIN where it is, since it MIGHT not have reached the destination we expect it to reach (20170811).
		newPosResult, err := callURL(nextPoint.agentPermURL, "command=osNpcGetPos")
		checkErr(err)
		// convert string result to array of floats
		_, err = fmt.Sscanf(strings.Trim(newPosResult, " ()<>"), "%f,%f,%f", &newPos[0], &newPos[1], &newPos[2])
		checkErr(err)

		travelled := calcDistance(newPos, curPos) // see how much we've actually travelled
		// calculate how much energy we've lost so far
		energyLost := travelled / WALKING_SPEED // some stupid formula, it doesn't matter, it's just to affect the counters
		// let the bloody avatar subtract some energy!

		energyResult, err := callURL(nextPoint.agentPermURL, "command=getEnergy")
		checkErr(err)

		energyAgent, err := strconv.ParseFloat(energyResult, 64)
		checkErr(err)
		sendMessageToBrowser("status", "", fmt.Sprintf("[%s]: %s had %f energy; lost %f on movement<br />", funcName(), nextPoint.agentUUID, energyAgent, energyLost), "")

		energyAgent -= energyLost
		energyResult, err = callURL(nextPoint.agentPermURL, fmt.Sprintf("command=setEnergy&float=%f", energyAgent))
		checkErr(err)
		sendMessageToBrowser("status", "", fmt.Sprintf("[%s]: %s updated to new energy level %f; in.world reply: %v<br />", funcName(), nextPoint.agentUUID, energyAgent, energyResult), "")

		// update on database as well
		db, err := sql.Open(PDO_Prefix, GoBotDSN)
		checkErr(err)

		defer db.Close()
		stmt, err := db.Prepare("UPDATE Agents SET `Energy`=? WHERE OwnerKey=?")
		 if (err != nil) {
			  sendMessageToBrowser("status", "error", fmt.Sprintf("Agent '%s' could not be prepared in database with new energy settings; database reply was: '%v'", nextPoint.agentUUID, err), "")
		}
		defer stmt.Close()

		execResult, err := stmt.Exec(energyAgent, nextPoint.agentUUID)
		 if (err != nil) {
			  sendMessageToBrowser("status", "error", fmt.Sprintf("Agent '%s' could not be updated in database with new energy settings; database reply was: '%v'", nextPoint.agentUUID, err), "")
		} else {
			id, err := execResult.LastInsertId()
			rowsAffected, err2 := execResult.RowsAffected()
			Log.Debug("Result from executing the energy update was:", id, err, "Rows affected:", rowsAffected, err2)
		}

		Log.Debug("Agent", nextPoint.agentUUID, "updated database with new energy:", energyAgent)
		stmt.Close()
		db.Close()
	}
}