<?php

namespace App\Http\Controllers\Api;

use App\Models\DiscountCode;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\ValidationException;

class DiscountCodeController
{
    public function index(): JsonResponse
    {
        $codes = DiscountCode::where('is_active', true)
            ->where(function ($q) {
                $q->whereNull('expires_at')->orWhere('expires_at', '>=', now());
            })
            ->where(function ($q) {
                $q->whereNull('usage_limit')->orWhereColumn('used_count', '<', 'usage_limit');
            })
            ->get(['code', 'type', 'value', 'min_order_amount', 'expires_at']);

        return response()->json(['codes' => $codes]);
    }

    public function validate(Request $request): JsonResponse
    {
        try {
            $validated = $request->validate([
                'code' => ['required', 'string'],
                'total_price' => ['required', 'numeric', 'min:0'],
            ]);
        } catch (ValidationException $e) {
            return response()->json([
                'message' => 'Validation failed',
                'errors' => $e->errors(),
            ], 422);
        }

        $code = DiscountCode::where('code', $validated['code'])->first();

        if (!$code) {
            return response()->json([
                'valid' => false,
                'message' => 'کد تخفیف نامعتبر است.',
            ]);
        }

        if (!$code->is_active) {
            return response()->json([
                'valid' => false,
                'message' => 'این کد تخفیف غیرفعال شده است.',
            ]);
        }

        if ($code->expires_at && $code->expires_at->isPast()) {
            return response()->json([
                'valid' => false,
                'message' => 'این کد تخفیف منقضی شده است.',
            ]);
        }

        if ($code->usage_limit && $code->used_count >= $code->usage_limit) {
            return response()->json([
                'valid' => false,
                'message' => 'ظرفیت استفاده از این کد تخفیف به پایان رسیده است.',
            ]);
        }

        if ($code->min_order_amount > 0 && $validated['total_price'] < $code->min_order_amount) {
            return response()->json([
                'valid' => false,
                'message' => "حداقل مبلغ سفارش برای استفاده از این کد " . number_format($code->min_order_amount) . " ریال است.",
            ]);
        }

        $discountAmount = 0;

        if ($code->type === 'percentage') {
            $discountAmount = ($validated['total_price'] * $code->value) / 100;
        } elseif ($code->type === 'fixed') {
            $discountAmount = $code->value;
        }

        $discountAmount = min($discountAmount, $validated['total_price']);
        $finalPrice = $validated['total_price'] - $discountAmount;

        return response()->json([
            'valid' => true,
            'code' => $code->code,
            'type' => $code->type,
            'value' => $code->value,
            'discount_amount' => $discountAmount,
            'final_price' => $finalPrice,
        ]);
    }
}