Add Discount Management and Application to Billing System

app/Http/Controllers/DiscountController.php

@@ -0,0 +1,86 @@
+
+
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\Discount;
+use Illuminate\Http\Request;
+
+class DiscountController extends Controller
+{
+    public function index()
+    {
+        $discounts = Discount::paginate(10);
+        return view('discounts.index', compact('discounts'));
+    }
+
+    public function create()
+    {
+        return view('discounts.create');
+    }
+
+    public function store(Request $request)
+    {
+        $validated = $request->validate([
+            'code' => 'required|unique:discounts',
+            'name' => 'required|string',
+            'description' => 'nullable|string',
+            'type' => 'required|in:percentage,fixed',
+            'value' => 'required|numeric|min:0',
+            'currency' => 'required_if:type,fixed',
+            'start_date' => 'required|date',
+            'end_date' => 'required|date|after:start_date',
+            'max_uses' => 'nullable|integer|min:1',
+        ]);
+
+        Discount::create($validated);
+
+        return redirect()->route('discounts.index')
+            ->with('success', 'Discount created successfully');
+    }
+
+    public function edit(Discount $discount)
+    {
+        return view('discounts.edit', compact('discount'));
+    }
+
+    public function update(Request $request, Discount $discount)
+    {
+        $validated = $request->validate([
+            'name' => 'required|string',
+            'description' => 'nullable|string',
+            'type' => 'required|in:percentage,fixed',
+            'value' => 'required|numeric|min:0',
+            'currency' => 'required_if:type,fixed',
+            'start_date' => 'required|date',
+            'end_date' => 'required|date|after:start_date',
+            'max_uses' => 'nullable|integer|min:1',
+            'is_active' => 'boolean'
+        ]);
+
+        $discount->update($validated);
+
+        return redirect()->route('discounts.index')
+            ->with('success', 'Discount updated successfully');
+    }
+
+    public function destroy(Discount $discount)
+    {
+        $discount->delete();
+        return redirect()->route('discounts.index')
+            ->with('success', 'Discount deleted successfully');
+    }
+
+    public function validateCode(Request $request)
+    {
+        $code = $request->input('code');
+        $discount = Discount::where('code', $code)->first();
+
+        if (!$discount || !$discount->isValid()) {
+            return response()->json(['valid' => false]);
+        }
+
+        return response()->json(['valid' => true, 'discount' => $discount]);
+    }
+}

app/Models/Discount.php

@@ -0,0 +1,48 @@
+
+
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use App\Traits\HasTeam;
+
+class Discount extends Model
+{
+    use HasFactory;
+    use HasTeam;
+
+    protected $fillable = [
+        'code',
+        'name',
+        'description',
+        'type', // percentage or fixed
+        'value',
+        'currency',
+        'start_date',
+        'end_date',
+        'max_uses',
+        'used_count',
+        'is_active'
+    ];
+
+    protected $casts = [
+        'start_date' => 'datetime',
+        'end_date' => 'datetime',
+        'is_active' => 'boolean'
+    ];
+
+    public function invoices()
+    {
+        return $this->hasMany(Invoice::class);
+    }
+
+    public function isValid()
+    {
+        return $this->is_active &&
+            $this->start_date <= now() &&
+            $this->end_date >= now() &&
+            ($this->max_uses === null || $this->used_count < $this->max_uses);
+    }
+}

app/Models/Invoice.php

@@ -22,9 +22,16 @@ class Invoice extends Model
         'total_amount',
         'currency',
         'status',
+        'discount_id',
+        'discount_amount',
         'invoice_template_id',
     ];
 
+    protected $casts = [
+        'issue_date' => 'datetime',
+        'due_date' => 'datetime',
+    ];
+
     public function currency()
     {
         return $this->belongsTo(Currency::class, 'currency', 'code');
@@ -35,6 +42,20 @@ public function customer()
         return $this->belongsTo(Customer::class);
     }
 
+    public function discount()
+    {
+        return $this->belongsTo(Discount::class);
+    }
+
+    public function getSubtotalAttribute()
+    {
+        return $this->items->sum('total_price');
+    }
+
+    public function getFinalTotalAttribute()
+    {
+        return $this->subtotal - ($this->discount_amount ?? 0);
+    }
     public function template()
     {
         return $this->belongsTo(InvoiceTemplate::class, 'invoice_template_id');

app/Services/BillingService.php

@@ -31,6 +31,49 @@ public function convertCurrency($amount, $fromCurrency, $toCurrency)
         return $this->currencyService->convert($amount, $fromCurrency, $toCurrency);
     }
 
+    public function applyDiscount(Invoice $invoice, string $discountCode)
+    {
+        $discount = Discount::where('code', $discountCode)
+            ->where('is_active', true)
+            ->first();
+
+        if (!$discount || !$discount->isValid()) {
+            return ['success' => false, 'message' => 'Invalid or expired discount code'];
+        }
+
+        $discountAmount = $this->calculateDiscountAmount($invoice, $discount);
+
+        $invoice->update([
+            'discount_id' => $discount->id,
+            'discount_amount' => $discountAmount,
+            'total_amount' => $invoice->subtotal - $discountAmount
+        ]);
+
+        $discount->increment('used_count');
+
+        return ['success' => true, 'discount_amount' => $discountAmount];
+    }
+
+    private function calculateDiscountAmount(Invoice $invoice, Discount $discount)
+    {
+        if ($discount->type === 'percentage') {
+            return $invoice->subtotal * ($discount->value / 100);
+        }
+
+        if ($discount->type === 'fixed') {
+            if ($discount->currency !== $invoice->currency) {
+                return $this->convertCurrency(
+                    $discount->value,
+                    $discount->currency,
+                    $invoice->currency
+                );
+            }
+            return $discount->value;
+        }
+
+        return 0;
+    }
+
     public function generateInvoice(Subscription $subscription)
     {
         $customer = $subscription->customer;

database/migrations/2024_01_10_000000_create_discounts_table.php

@@ -0,0 +1,43 @@
+
+
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up()
+    {
+        Schema::create('discounts', function (Blueprint $table) {
+            $table->id();
+            $table->string('code')->unique();
+            $table->string('name');
+            $table->text('description')->nullable();
+            $table->enum('type', ['percentage', 'fixed']);
+            $table->decimal('value', 10, 2);
+            $table->string('currency')->nullable();
+            $table->timestamp('start_date');
+            $table->timestamp('end_date');
+            $table->integer('max_uses')->nullable();
+            $table->integer('used_count')->default(0);
+            $table->boolean('is_active')->default(true);
+            $table->timestamps();
+        });
+
+        Schema::table('invoices', function (Blueprint $table) {
+            $table->foreignId('discount_id')->nullable()->constrained()->onDelete('set null');
+            $table->decimal('discount_amount', 10, 2)->nullable();
+        });
+    }
+
+    public function down()
+    {
+        Schema::table('invoices', function (Blueprint $table) {
+            $table->dropForeign(['discount_id']);
+            $table->dropColumn(['discount_id', 'discount_amount']);
+        });
+        Schema::dropIfExists('discounts');
+    }
+};