<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Cache;
use App\Models\Plan;

class PayPalService
{
    private ?string $clientId;
    private ?string $clientSecret;
    private string $baseUrl;
    private bool $sandbox;

    public function __construct()
    {
        $this->clientId = config('services.paypal.client_id');
        $this->clientSecret = config('services.paypal.client_secret');
        $this->sandbox = config('services.paypal.mode', 'sandbox') === 'sandbox';
        $this->baseUrl = $this->sandbox 
            ? 'https://api-m.sandbox.paypal.com'
            : 'https://api-m.paypal.com';
    }

    /**
     * Get PayPal access token (cached for 8 hours)
     */
    public function getAccessToken(): ?string
    {
        if (!$this->isConfigured()) {
            Log::warning('PayPal not configured');
            return null;
        }

        return Cache::remember('paypal_access_token', 28800, function () {
            try {
                $response = Http::withBasicAuth($this->clientId, $this->clientSecret)
                    ->asForm()
                    ->post("{$this->baseUrl}/v1/oauth2/token", [
                        'grant_type' => 'client_credentials',
                    ]);

                if ($response->successful()) {
                    return $response->json('access_token');
                }

                Log::error('PayPal auth failed', ['response' => $response->json()]);
                return null;
            } catch (\Exception $e) {
                Log::error('PayPal auth exception', ['error' => $e->getMessage()]);
                return null;
            }
        });
    }

    /**
     * Create a PayPal Product (required before creating plans)
     */
    public function createProduct(): ?array
    {
        $token = $this->getAccessToken();
        if (!$token) return null;

        try {
            $response = Http::withToken($token)
                ->post("{$this->baseUrl}/v1/catalogs/products", [
                    'name' => 'WEBMoney Pro',
                    'description' => 'WEBMoney - Control de Finanzas Personales',
                    'type' => 'SERVICE',
                    'category' => 'SOFTWARE',
                    'home_url' => config('app.url'),
                ]);

            if ($response->successful()) {
                return $response->json();
            }

            Log::error('PayPal create product failed', ['response' => $response->json()]);
            return null;
        } catch (\Exception $e) {
            Log::error('PayPal create product exception', ['error' => $e->getMessage()]);
            return null;
        }
    }

    /**
     * Create a PayPal billing plan
     */
    public function createBillingPlan(Plan $plan, string $productId): ?array
    {
        $token = $this->getAccessToken();
        if (!$token) return null;

        $billingCycles = [];

        // Trial period (if plan has trial)
        if ($plan->trial_days > 0) {
            $billingCycles[] = [
                'frequency' => [
                    'interval_unit' => 'DAY',
                    'interval_count' => $plan->trial_days,
                ],
                'tenure_type' => 'TRIAL',
                'sequence' => 1,
                'total_cycles' => 1,
                'pricing_scheme' => [
                    'fixed_price' => [
                        'value' => '0',
                        'currency_code' => $plan->currency,
                    ],
                ],
            ];
        }

        // Regular billing cycle
        $billingCycles[] = [
            'frequency' => [
                'interval_unit' => $plan->billing_period === 'annual' ? 'YEAR' : 'MONTH',
                'interval_count' => 1,
            ],
            'tenure_type' => 'REGULAR',
            'sequence' => $plan->trial_days > 0 ? 2 : 1,
            'total_cycles' => 0, // Infinite
            'pricing_scheme' => [
                'fixed_price' => [
                    'value' => (string) $plan->price,
                    'currency_code' => $plan->currency,
                ],
            ],
        ];

        try {
            $response = Http::withToken($token)
                ->post("{$this->baseUrl}/v1/billing/plans", [
                    'product_id' => $productId,
                    'name' => $plan->name,
                    'description' => $plan->description ?? "Suscripción {$plan->name}",
                    'status' => 'ACTIVE',
                    'billing_cycles' => $billingCycles,
                    'payment_preferences' => [
                        'auto_bill_outstanding' => true,
                        'setup_fee' => [
                            'value' => '0',
                            'currency_code' => $plan->currency,
                        ],
                        'setup_fee_failure_action' => 'CONTINUE',
                        'payment_failure_threshold' => 3,
                    ],
                ]);

            if ($response->successful()) {
                $data = $response->json();
                
                // Update plan with PayPal plan ID
                $plan->update(['paypal_plan_id' => $data['id']]);
                
                return $data;
            }

            Log::error('PayPal create plan failed', ['response' => $response->json()]);
            return null;
        } catch (\Exception $e) {
            Log::error('PayPal create plan exception', ['error' => $e->getMessage()]);
            return null;
        }
    }

    /**
     * Create a subscription for a user
     */
    public function createSubscription(Plan $plan, string $returnUrl, string $cancelUrl): ?array
    {
        $token = $this->getAccessToken();
        if (!$token) return null;

        if (!$plan->paypal_plan_id) {
            Log::error('Plan has no PayPal plan ID', ['plan_id' => $plan->id]);
            return null;
        }

        try {
            $response = Http::withToken($token)
                ->post("{$this->baseUrl}/v1/billing/subscriptions", [
                    'plan_id' => $plan->paypal_plan_id,
                    'application_context' => [
                        'brand_name' => 'WEBMoney',
                        'locale' => 'es-ES',
                        'shipping_preference' => 'NO_SHIPPING',
                        'user_action' => 'SUBSCRIBE_NOW',
                        'payment_method' => [
                            'payer_selected' => 'PAYPAL',
                            'payee_preferred' => 'IMMEDIATE_PAYMENT_REQUIRED',
                        ],
                        'return_url' => $returnUrl,
                        'cancel_url' => $cancelUrl,
                    ],
                ]);

            if ($response->successful()) {
                return $response->json();
            }

            Log::error('PayPal create subscription failed', ['response' => $response->json()]);
            return null;
        } catch (\Exception $e) {
            Log::error('PayPal create subscription exception', ['error' => $e->getMessage()]);
            return null;
        }
    }

    /**
     * Get subscription details
     */
    public function getSubscription(string $subscriptionId): ?array
    {
        $token = $this->getAccessToken();
        if (!$token) return null;

        try {
            $response = Http::withToken($token)
                ->get("{$this->baseUrl}/v1/billing/subscriptions/{$subscriptionId}");

            if ($response->successful()) {
                return $response->json();
            }

            Log::error('PayPal get subscription failed', ['response' => $response->json()]);
            return null;
        } catch (\Exception $e) {
            Log::error('PayPal get subscription exception', ['error' => $e->getMessage()]);
            return null;
        }
    }

    /**
     * Cancel a subscription
     */
    public function cancelSubscription(string $subscriptionId, string $reason = 'User requested cancellation'): bool
    {
        $token = $this->getAccessToken();
        if (!$token) return false;

        try {
            $response = Http::withToken($token)
                ->post("{$this->baseUrl}/v1/billing/subscriptions/{$subscriptionId}/cancel", [
                    'reason' => $reason,
                ]);

            if ($response->status() === 204) {
                return true;
            }

            // Check if subscription is already cancelled - treat as success
            $responseData = $response->json();
            if (isset($responseData['details'][0]['issue']) && 
                $responseData['details'][0]['issue'] === 'SUBSCRIPTION_STATUS_INVALID') {
                Log::info('PayPal subscription already cancelled', ['subscription_id' => $subscriptionId]);
                return true;
            }

            Log::error('PayPal cancel subscription failed', ['response' => $responseData]);
            return false;
        } catch (\Exception $e) {
            Log::error('PayPal cancel subscription exception', ['error' => $e->getMessage()]);
            return false;
        }
    }

    /**
     * Suspend a subscription
     */
    public function suspendSubscription(string $subscriptionId, string $reason = 'Suspended by system'): bool
    {
        $token = $this->getAccessToken();
        if (!$token) return false;

        try {
            $response = Http::withToken($token)
                ->post("{$this->baseUrl}/v1/billing/subscriptions/{$subscriptionId}/suspend", [
                    'reason' => $reason,
                ]);

            if ($response->status() === 204) {
                return true;
            }

            Log::error('PayPal suspend subscription failed', ['response' => $response->json()]);
            return false;
        } catch (\Exception $e) {
            Log::error('PayPal suspend subscription exception', ['error' => $e->getMessage()]);
            return false;
        }
    }

    /**
     * Verify webhook signature
     */
    public function verifyWebhookSignature(array $headers, string $body, string $webhookId): bool
    {
        $token = $this->getAccessToken();
        if (!$token) return false;

        try {
            $response = Http::withToken($token)
                ->post("{$this->baseUrl}/v1/notifications/verify-webhook-signature", [
                    'auth_algo' => $headers['PAYPAL-AUTH-ALGO'] ?? '',
                    'cert_url' => $headers['PAYPAL-CERT-URL'] ?? '',
                    'transmission_id' => $headers['PAYPAL-TRANSMISSION-ID'] ?? '',
                    'transmission_sig' => $headers['PAYPAL-TRANSMISSION-SIG'] ?? '',
                    'transmission_time' => $headers['PAYPAL-TRANSMISSION-TIME'] ?? '',
                    'webhook_id' => $webhookId,
                    'webhook_event' => json_decode($body, true),
                ]);

            if ($response->successful()) {
                return $response->json('verification_status') === 'SUCCESS';
            }

            return false;
        } catch (\Exception $e) {
            Log::error('PayPal verify webhook exception', ['error' => $e->getMessage()]);
            return false;
        }
    }

    /**
     * Get transactions for a subscription
     */
    public function getSubscriptionTransactions(string $subscriptionId, string $startTime, string $endTime): ?array
    {
        $token = $this->getAccessToken();
        if (!$token) return null;

        try {
            $response = Http::withToken($token)
                ->get("{$this->baseUrl}/v1/billing/subscriptions/{$subscriptionId}/transactions", [
                    'start_time' => $startTime,
                    'end_time' => $endTime,
                ]);

            if ($response->successful()) {
                return $response->json();
            }

            return null;
        } catch (\Exception $e) {
            Log::error('PayPal get transactions exception', ['error' => $e->getMessage()]);
            return null;
        }
    }

    /**
     * Refund a capture (payment)
     */
    public function refundCapture(string $captureId, ?float $amount = null, ?string $currency = 'EUR', string $note = 'Refund within 7-day guarantee period'): ?array
    {
        $token = $this->getAccessToken();
        if (!$token) return null;

        try {
            $body = [
                'note_to_payer' => $note,
            ];

            // If amount specified, do partial refund; otherwise full refund
            if ($amount !== null) {
                $body['amount'] = [
                    'value' => number_format($amount, 2, '.', ''),
                    'currency_code' => $currency,
                ];
            }

            $response = Http::withToken($token)
                ->post("{$this->baseUrl}/v2/payments/captures/{$captureId}/refund", $body);

            if ($response->successful()) {
                Log::info('PayPal refund successful', ['capture_id' => $captureId, 'response' => $response->json()]);
                return $response->json();
            }

            Log::error('PayPal refund failed', ['capture_id' => $captureId, 'response' => $response->json()]);
            return null;
        } catch (\Exception $e) {
            Log::error('PayPal refund exception', ['error' => $e->getMessage()]);
            return null;
        }
    }

    /**
     * Get the last transaction/capture for a subscription to refund
     */
    public function getLastSubscriptionCapture(string $subscriptionId): ?string
    {
        $token = $this->getAccessToken();
        if (!$token) return null;

        try {
            // Get transactions from last 30 days
            $startTime = now()->subDays(30)->toIso8601String();
            $endTime = now()->toIso8601String();

            $response = Http::withToken($token)
                ->get("{$this->baseUrl}/v1/billing/subscriptions/{$subscriptionId}/transactions", [
                    'start_time' => $startTime,
                    'end_time' => $endTime,
                ]);

            if ($response->successful()) {
                $transactions = $response->json('transactions') ?? [];
                
                // Find the most recent COMPLETED transaction
                foreach ($transactions as $transaction) {
                    if (($transaction['status'] ?? '') === 'COMPLETED' && !empty($transaction['id'])) {
                        Log::info('Found capture for refund', ['subscription_id' => $subscriptionId, 'capture_id' => $transaction['id']]);
                        return $transaction['id'];
                    }
                }
            }

            Log::warning('No capture found for subscription', ['subscription_id' => $subscriptionId]);
            return null;
        } catch (\Exception $e) {
            Log::error('PayPal get capture exception', ['error' => $e->getMessage()]);
            return null;
        }
    }

    /**
     * Cancel subscription and refund if within guarantee period
     */
    public function cancelAndRefund(string $subscriptionId, string $reason = 'Refund within 7-day guarantee'): array
    {
        $result = [
            'canceled' => false,
            'refunded' => false,
            'refund_id' => null,
            'refund_amount' => null,
            'error' => null,
        ];

        // First, get capture ID for refund
        $captureId = $this->getLastSubscriptionCapture($subscriptionId);
        
        // Cancel the subscription
        $canceled = $this->cancelSubscription($subscriptionId, $reason);
        $result['canceled'] = $canceled;

        if (!$canceled) {
            $result['error'] = 'Failed to cancel subscription';
            return $result;
        }

        // Process refund if we have a capture
        if ($captureId) {
            $refund = $this->refundCapture($captureId, null, 'EUR', $reason);
            if ($refund) {
                $result['refunded'] = true;
                $result['refund_id'] = $refund['id'] ?? null;
                $result['refund_amount'] = $refund['amount']['value'] ?? null;
            } else {
                $result['error'] = 'Subscription canceled but refund failed';
            }
        } else {
            $result['error'] = 'Subscription canceled but no payment found to refund';
        }

        return $result;
    }

    /**
     * Check if PayPal is configured
     */
    public function isConfigured(): bool
    {
        return !empty($this->clientId) && !empty($this->clientSecret);
    }

    /**
     * Get client ID for frontend
     */
    public function getClientId(): ?string
    {
        return $this->clientId;
    }

    /**
     * Check if in sandbox mode
     */
    public function isSandbox(): bool
    {
        return $this->sandbox;
    }
}