message.go

package main

import (
	"fmt"
	"log"
	"math/rand"
	"time"
)

type trackedMessage struct {
	ID            string          `json:"id"`             //The unique message id that is used to identify the slack message
	Submitted     int64           `json:"submitted"`      //Time the request was submitted in epoch
	CallbackURL   string          `json:"callback_url"`   //URL to send event stream of emoji usage
	ValidEmojis   []string        `json:"valid_emojis"`   //List of emojis to alert on
	AuthToken     string          `json:"auth_token"`     //Auth token given by app to auth on callback
	MessageEvents []*messageEvent `json:"message_events"` //A list of messages events as they come in
	Expire        int             `json:"expire"`         //Length of time messages can be tracked. Limited to 24h
}

type messageEvent struct {
	ID             string `json:"id"`               //The unique message ID
	Submitted      int64  `json:"submitted"`        //Epoch time when event happened
	EmojiUsed      string `json:"emoji_used"`       //EmojiUsed in event
	SlackUserEmail string `json:"slack_user_email"` //Slack email of the user who used the emoji
	SlackUserName  string `json:"slack_user_name"`  //Slack username of the user who used the emoji
}

func (app *app) getMessage(messageID string) (*trackedMessage, error) {

	if _, ok := app.messages[messageID]; !ok {
		return &trackedMessage{}, errMessageNotFound
	}

	message := app.messages[messageID]

	return message, nil
}

func (app *app) createMessage(callbackURL, authToken string, validEmojs []string) trackedMessage {

	messageID := app.generateNewMessageID()

	newMessage := &trackedMessage{
		ID:          messageID,
		Submitted:   time.Now().Unix(),
		CallbackURL: callbackURL,
		AuthToken:   authToken,
		ValidEmojis: validEmojs,
	}

	app.messages[messageID] = newMessage

	return *newMessage
}

func (app *app) deleteMessage(messageID string) error {
	if _, ok := app.messages[messageID]; !ok {
		return errMessageNotFound
	}

	delete(app.messages, messageID)
	log.Printf("message %s deleted", messageID)

	return nil
}

func generateRandomString(length int) string {

	rand.Seed(time.Now().UTC().UnixNano())
	token := make([]byte, length)
	rand.Read(token)

	return fmt.Sprintf("%x", token)
}

func (app *app) generateNewMessageID() string {

	var messageID string

	for {
		messageID = generateRandomString(10)

		if _, exists := app.messages[messageID]; !exists {
			break
		}
	}

	return messageID
}