<?php

namespace App\Core\Flows;

use App\Models\ConversationState;
use App\Models\MessageLog;

/**
 * ConversationFlowEngine
 * Orchestrates multi-stage interactive conversation flows.
 */
class ConversationFlowEngine
{
    /**
     * Map of registered flow names to their classes
     */
    private static array $flows = [
        'test_flow' => TestFlow::class,
    ];

    /**
     * Map of keyword triggers to start a specific flow
     */
    private static array $startTriggers = [
        'test' => 'test_flow',
        'اختبار' => 'test_flow',
    ];

    /**
     * Process incoming message.
     * Returns true if handled by the flow engine, false otherwise.
     */
    public static function processMessage(array $session, array $msgData): bool
    {
        // 1. Housekeeping: remove expired sessions
        ConversationState::cleanExpired();

        $phone = $msgData['phone'];
        $companyId = $session['company_id'];
        $text = isset($msgData['body']) ? trim($msgData['body']) : '';

        // 2. Lookup existing active flow
        $state = ConversationState::findActive($companyId, $phone);

        $flowName = '';
        $currentStep = '';
        $context = [];

        if ($state) {
            $flowName = $state['flow_name'];
            $currentStep = $state['current_step'];
            $context = json_decode($state['context_data'] ?: '{}', true) ?: [];
        } else {
            // Check if message is a starting trigger for a new flow
            $normalizedText = strtolower(trim($text));
            if (isset(self::$startTriggers[$normalizedText])) {
                $flowName = self::$startTriggers[$normalizedText];
                $currentStep = 'start';
                $context = [];
            }
        }

        // If no active flow and no trigger matches, pass control back to normal bot rules
        if (empty($flowName) || !isset(self::$flows[$flowName])) {
            return false;
        }

        // 3. User cancel flow option
        $normalizedCancel = strtolower(trim($text));
        if (in_array($normalizedCancel, ['إلغاء', 'خروج', 'cancel', 'exit'])) {
            if ($state) {
                ConversationState::deleteState($state['id']);
                $cancelMsg = in_array($normalizedCancel, ['cancel', 'exit']) 
                    ? 'Interactive flow cancelled.' 
                    : 'تم إلغاء المحادثة التفاعلية.';
                self::sendReply($session, $phone, $cancelMsg);
                return true;
            }
        }

        // 4. Instantiate and execute the flow
        $flowClass = self::$flows[$flowName];
        /** @var BaseFlow $flowInstance */
        $flowInstance = new $flowClass();

        try {
            $result = $flowInstance->handleStep($currentStep, $msgData, $context);

            if ($result->isFinished()) {
                // Flow has reached terminal state: clean up DB record
                if ($state) {
                    ConversationState::deleteState($state['id']);
                }
            } else {
                // Flow has next step: save or update state record (TTL: 1 hour)
                ConversationState::saveState([
                    'company_id' => $companyId,
                    'contact_phone' => $phone,
                    'flow_name' => $flowName,
                    'current_step' => $result->getNextStep(),
                    'context_data' => json_encode($context, JSON_UNESCAPED_UNICODE),
                    'expires_at' => date('Y-m-d H:i:s', strtotime('+1 hour'))
                ]);
            }

            // 5. Send reply if one is provided
            if ($result->getReplyText() !== '') {
                self::sendReply($session, $phone, $result->getReplyText());
            }

            return true;
        } catch (\Exception $e) {
            error_log("[ConversationFlowEngine Exception] Flow '{$flowName}' failed: " . $e->getMessage());
            return false;
        }
    }

    /**
     * Send outbound message reply via the Baileys Gateway
     */
    private static function sendReply(array $session, string $phone, string $message): void
    {
        $gatewayUrl = rtrim(getenv('WHATSAPP_GATEWAY_URL') ?: 'http://localhost:3722', '/');
        if (substr($gatewayUrl, -4) === '/api') {
            $sendUrl = $gatewayUrl . '/messages/send';
        } else {
            $sendUrl = $gatewayUrl . '/api/messages/send';
        }

        $payload = json_encode([
            'session_key' => $session['session_key'],
            'phone' => $phone,
            'message' => $message
        ]);

        $ch = curl_init($sendUrl);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $payload);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Content-Type: application/json',
            'X-Webhook-Secret: ' . getenv('WEBHOOK_SECRET')
        ]);
        curl_setopt($ch, CURLOPT_TIMEOUT, 10);
        
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        $status = 'failed';
        $errorMsg = null;
        $waMsgId = null;

        if ($httpCode === 200) {
            $status = 'sent';
            $resData = json_decode($response, true);
            $waMsgId = $resData['data']['key']['id'] ?? null;
        } else {
            $resData = json_decode($response, true);
            $errorMsg = $resData['error'] ?? 'HTTP Code ' . $httpCode;
            error_log("[Flow Engine Gateway Error] Failed to send: " . $errorMsg);
        }

        // Log the outbound auto-reply message
        MessageLog::logMessage([
            'company_id' => $session['company_id'],
            'session_id' => $session['id'],
            'contact_phone' => $phone,
            'direction' => 'outbound',
            'message_type' => 'text',
            'message_body' => $message,
            'whatsapp_message_id' => $waMsgId,
            'status' => $status,
            'error_message' => $errorMsg
        ]);
    }
}