<?php

declare(strict_types=1);

namespace App\Controllers;

use Core\Request;
use Core\Response;
use Core\Database;
use PDO;

class GatewayController
{
    private string $configuredAppKey;

    public function __construct()
    {
        $this->configuredAppKey = getenv('GATEWAY_APP_KEY') ?: 'uruk_gateway_secret_2026';
    }

    /**
     * Authenticate gateway device app_key
     */
    private function authenticate(string $appKey): bool
    {
        return hash_equals($this->configuredAppKey, $appKey);
    }

    /**
     * GET /api/v1/gateway/pending-call or /pending-call.php
     */
    public function pendingCall(Request $request): void
    {
        $deviceId = (string)$request->get('device_id');
        $appKey = (string)$request->get('app_key');

        if (!$this->authenticate($appKey) || empty($deviceId)) {
            Response::json([
                'task_id' => null,
                'phone' => null,
                'caller_id' => null,
                'otp' => null,
                'timeout_seconds' => null,
                'error' => 'Unauthorized or missing device_id'
            ], 401);
            return;
        }

        $pdo = Database::getConnection();

        // Update device heartbeat
        $this->heartbeat($pdo, $deviceId);

        // Fetch oldest pending FLASH_CALL task
        $stmt = $pdo->prepare('
            SELECT id, target_phone, otp_code, timeout_seconds 
            FROM gateway_tasks 
            WHERE task_type = "FLASH_CALL" 
              AND (assigned_device_id = :dev OR assigned_device_id IS NULL)
              AND status = "PENDING"
              AND created_at >= NOW() - INTERVAL 60 SECOND
            ORDER BY id ASC 
            LIMIT 1
        ');
        $stmt->execute([':dev' => $deviceId]);
        $task = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($task) {
            // Lock task to this device
            $upd = $pdo->prepare('UPDATE gateway_tasks SET status = "PROCESSING", assigned_device_id = :dev WHERE id = :id');
            $upd->execute([':dev' => $deviceId, ':id' => $task['id']]);

            Response::json([
                'task_id' => (int)$task['id'],
                'phone' => $task['target_phone'],
                'caller_id' => null,
                'otp' => $task['otp_code'],
                'timeout_seconds' => (int)($task['timeout_seconds'] ?: 25),
            ]);
            return;
        }

        Response::json([
            'task_id' => null,
            'phone' => null,
            'caller_id' => null,
            'otp' => null,
            'timeout_seconds' => null,
        ]);
    }

    /**
     * GET /api/v1/gateway/pending-sms or /pending-sms.php
     */
    public function pendingSms(Request $request): void
    {
        $deviceId = (string)$request->get('device_id');
        $appKey = (string)$request->get('app_key');

        if (!$this->authenticate($appKey) || empty($deviceId)) {
            Response::json([
                'task_id' => null,
                'phone' => null,
                'caller_id' => null,
                'otp' => null,
                'timeout_seconds' => null,
                'error' => 'Unauthorized or missing device_id'
            ], 401);
            return;
        }

        $pdo = Database::getConnection();
        $this->heartbeat($pdo, $deviceId);

        $stmt = $pdo->prepare('
            SELECT id, target_phone, otp_code, timeout_seconds 
            FROM gateway_tasks 
            WHERE task_type = "SMS" 
              AND (assigned_device_id = :dev OR assigned_device_id IS NULL)
              AND status = "PENDING"
              AND created_at >= NOW() - INTERVAL 120 SECOND
            ORDER BY id ASC 
            LIMIT 1
        ');
        $stmt->execute([':dev' => $deviceId]);
        $task = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($task) {
            $upd = $pdo->prepare('UPDATE gateway_tasks SET status = "PROCESSING", assigned_device_id = :dev WHERE id = :id');
            $upd->execute([':dev' => $deviceId, ':id' => $task['id']]);

            Response::json([
                'task_id' => (int)$task['id'],
                'phone' => $task['target_phone'],
                'caller_id' => null,
                'otp' => $task['otp_code'],
                'timeout_seconds' => (int)($task['timeout_seconds'] ?: 30),
            ]);
            return;
        }

        Response::json([
            'task_id' => null,
            'phone' => null,
            'caller_id' => null,
            'otp' => null,
            'timeout_seconds' => null,
        ]);
    }

    /**
     * POST /api/v1/gateway/call-done or /call-done.php
     */
    public function callDone(Request $request): void
    {
        $taskId = (int)$request->get('task_id');
        $deviceId = (string)$request->get('device_id');
        $appKey = (string)$request->get('app_key');
        $result = (string)$request->get('result');

        if (!$this->authenticate($appKey)) {
            Response::json(['success' => false, 'message' => 'Unauthorized'], 401);
            return;
        }

        $pdo = Database::getConnection();
        $newStatus = (strtoupper($result) === 'SUCCESS' || strtoupper($result) === 'DONE') ? 'COMPLETED' : 'FAILED';

        $stmt = $pdo->prepare('
            UPDATE gateway_tasks 
            SET status = :st, completed_at = NOW() 
            WHERE id = :id AND assigned_device_id = :dev
        ');
        $stmt->execute([':st' => $newStatus, ':id' => $taskId, ':dev' => $deviceId]);

        Response::json([
            'success' => true,
            'message' => "Call task {$taskId} recorded as {$newStatus}.",
            'device_id' => $deviceId,
        ]);
    }

    /**
     * POST /api/v1/gateway/sms-done or /sms-done.php
     */
    public function smsDone(Request $request): void
    {
        $taskId = (int)$request->get('task_id');
        $deviceId = (string)$request->get('device_id');
        $appKey = (string)$request->get('app_key');
        $result = (string)$request->get('result');

        if (!$this->authenticate($appKey)) {
            Response::json(['success' => false, 'message' => 'Unauthorized'], 401);
            return;
        }

        $pdo = Database::getConnection();
        $newStatus = (strtoupper($result) === 'SUCCESS' || strtoupper($result) === 'SENT') ? 'COMPLETED' : 'FAILED';

        $stmt = $pdo->prepare('
            UPDATE gateway_tasks 
            SET status = :st, completed_at = NOW() 
            WHERE id = :id AND assigned_device_id = :dev
        ');
        $stmt->execute([':st' => $newStatus, ':id' => $taskId, ':dev' => $deviceId]);

        Response::json([
            'success' => true,
            'message' => "SMS task {$taskId} recorded as {$newStatus}.",
            'device_id' => $deviceId,
        ]);
    }

    /**
     * POST /api/v1/gateway/register-device or /register-device.php
     */
    public function registerDevice(Request $request): void
    {
        $deviceId = (string)$request->get('device_id');
        $phoneNumber = (string)$request->get('phone_number');
        $simSlot = (int)$request->get('sim_slot', 1);
        $appKey = (string)$request->get('app_key');

        if (!$this->authenticate($appKey) || empty($deviceId)) {
            Response::json(['success' => false, 'message' => 'Unauthorized or missing device_id'], 401);
            return;
        }

        $pdo = Database::getConnection();
        $stmt = $pdo->prepare('
            INSERT INTO gateway_devices (device_id, phone_number, sim_slot, status, last_heartbeat)
            VALUES (:did, :phone, :slot, "ACTIVE", NOW())
            ON DUPLICATE KEY UPDATE 
                phone_number = VALUES(phone_number),
                sim_slot = VALUES(sim_slot),
                status = "ACTIVE",
                last_heartbeat = NOW()
        ');
        $stmt->execute([
            ':did' => $deviceId,
            ':phone' => $phoneNumber,
            ':slot' => $simSlot,
        ]);

        Response::json([
            'success' => true,
            'message' => 'Gateway device registered and active.',
            'device_id' => $deviceId,
        ]);
    }

    private function heartbeat(PDO $pdo, string $deviceId): void
    {
        try {
            $stmt = $pdo->prepare('
                INSERT INTO gateway_devices (device_id, status, last_heartbeat) 
                VALUES (:did, "ACTIVE", NOW())
                ON DUPLICATE KEY UPDATE status = "ACTIVE", last_heartbeat = NOW()
            ');
            $stmt->execute([':did' => $deviceId]);
        } catch (\Throwable $e) {
            // Ignore heartbeat failures if table schema is pending
        }
    }
}