<?php
/**
 * STOP REPORT API - Vehicle Stop Duration Analysis (Big Data Optimized)
 * =====================================================================
 * 
 * DESKRIPSI:
 * ==========
 * API untuk menganalisis durasi berhenti kendaraan dengan optimasi khusus
 * untuk dataset besar (100+ miliar records). Fitur:
 * - Deteksi start/stop berdasarkan status engine
 * - Filter durasi minimum berhenti (interval)
 * - Support single TID atau all TIDs dari session user
 * - Memory-efficient processing untuk big data
 * - Coordinate-based stop location detection
 * 
 * METHOD: GET
 * ENDPOINT: /api/stop_report
 * AUTHENTICATION: Required (Bearer token atau session)
 * 
 * QUERY PARAMETERS:
 * =================
 * - awal: Start datetime (format: YYYY-MM-DD HH:MM:SS)
 * - akhir: End datetime (format: YYYY-MM-DD HH:MM:SS)
 * - tid: Tracking ID kendaraan atau "all" untuk semua TID user
 * - interval: Minimum stop duration dalam menit (default: 5)
 * - license: License plate (optional, untuk display)
 * 
 * CONTOH REQUEST:
 * ===============
 * GET /api/stop_report?awal=2026-01-19 00:00:00&akhir=2026-01-19 23:59:59&tid=123456789&interval=10
 * GET /api/stop_report?awal=2026-01-19 00:00:00&akhir=2026-01-19 23:59:59&tid=all&interval=5
 * 
 * RESPONSE SUCCESS (200):
 * =======================
 * [
 *   [
 *     "license_plate",
 *     "coordinates",
 *     "start_time",
 *     "end_time", 
 *     "duration"
 *   ]
 * ]
 * 
 * RESPONSE ERROR (400/401/500):
 * =============================
 * {
 *   "error": "string"
 * }
 * 
 * BUSINESS LOGIC:
 * ===============
 * - Status < 260000 = Engine OFF (start stop)
 * - Status > 260000 = Engine ON (end stop)
 * - Hanya stop dengan durasi >= interval yang dilaporkan
 * - Data diurutkan berdasarkan receiveTime ASC
 * - GMT timezone adjustment sesuai user setting
 * 
 * BIG DATA OPTIMIZATIONS:
 * =======================
 * - Selective column retrieval
 * - Time-based filtering dengan index hints
 * - Memory-efficient state machine processing
 * - Chunked processing untuk multiple TIDs
 * - Early termination untuk invalid ranges
 * 
 * AUTHOR: Rodhi
 * DATE: 2026-01-19
 * VERSION: 1.0 (Big Data Optimized)
 */

require_once __DIR__.'/../models/database.php';
require_once __DIR__.'/../helpers/session_helper.php';
require_once __DIR__.'/../auth/middleware.php';

if (!headers_sent()) {
    header('Access-Control-Allow-Origin: *');
    header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
    header('Access-Control-Allow-Headers: Content-Type, Authorization, X-Auth-Token');
    header('Access-Control-Allow-Credentials: true');
    header('Content-Type: application/json');
}

// Set memory limit untuk big data processing
ini_set('memory_limit', '512M');

// Require authentication
$user = authRequired();

// Start session untuk GMT setting dan license data
if (session_status() == PHP_SESSION_NONE) {
    session_start();
}

// Start performance monitoring
$startTime = microtime(true);
$startMemory = memory_get_usage(true);

// Debug: Log API access
// error_log("Stop Report API accessed by user: " . $user);
// error_log("Query parameters: " . json_encode($_GET));

try {
    // Validasi required parameters
    if (!isset($_GET['awal']) || !isset($_GET['akhir']) || !isset($_GET['tid'])) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Missing required parameters: awal, akhir, tid',
            'required_format' => [
                'awal' => 'YYYY-MM-DD HH:MM:SS',
                'akhir' => 'YYYY-MM-DD HH:MM:SS',
                'tid' => 'tracking_id or "all"',
                'interval' => 'minimum_stop_minutes (optional, default: 5)'
            ]
        ]);
        exit;
    }

    // Sanitize input parameters
    $awal = trim($_GET['awal']);
    $akhir = trim($_GET['akhir']);
    $tid = trim($_GET['tid']);
    $interval = isset($_GET['interval']) ? (int)$_GET['interval'] : 5;
    $license = isset($_GET['license']) ? trim($_GET['license']) : '';

    // Debug: Log sanitized parameters
    // error_log("Stop Report API - Params: awal={$awal}, akhir={$akhir}, tid={$tid}, interval={$interval}");

    // Validasi format datetime
    $awalTime = DateTime::createFromFormat('Y-m-d H:i:s', $awal);
    $akhirTime = DateTime::createFromFormat('Y-m-d H:i:s', $akhir);
    
    if (!$awalTime || !$akhirTime) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Invalid datetime format. Use: YYYY-MM-DD HH:MM:SS',
            'received' => ['awal' => $awal, 'akhir' => $akhir]
        ]);
        exit;
    }

    // Validasi range waktu (maksimal 7 hari untuk big data protection)
    $diffDays = $akhirTime->diff($awalTime)->days;
    if ($diffDays > 7) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Date range too large for big data processing. Maximum 7 days allowed.',
            'requested_days' => $diffDays,
            'suggestion' => 'Use smaller date ranges for better performance'
        ]);
        exit;
    }

    // Validasi interval (maksimal 1440 menit = 24 jam)
    if ($interval < 1 || $interval > 1440) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Invalid interval. Must be between 1 and 1440 minutes.',
            'received_interval' => $interval
        ]);
        exit;
    }

    // Get GMT setting
    $gmt = isset($_SESSION['GMT']) ? $_SESSION['GMT'] : 7;

    // Determine TIDs to process
    $tidsToProcess = array();
    
    if (strtolower($tid) === 'all') {
        // Load license data jika belum ada
        if (!isset($_SESSION['license']) || empty($_SESSION['license'])) {
            if (!isset($_SESSION['username'])) {
                $_SESSION['username'] = $user;
            }
            SessionHelper::dbLicenseToSession();
        }

        // Get all TIDs dari session user
        if (isset($_SESSION['license']) && !empty($_SESSION['license'])) {
            foreach ($_SESSION['license'] as $licenseData) {
                $tidsToProcess[] = [
                    'tid' => $licenseData[2], // TID
                    'license' => $licenseData[1] // License plate
                ];
            }
        }

        if (empty($tidsToProcess)) {
            http_response_code(403);
            echo json_encode([
                'error' => 'No vehicle licenses available for this user',
                'user' => $user
            ]);
            exit;
        }
    } else {
        // Single TID
        $tidsToProcess[] = [
            'tid' => $tid,
            'license' => $license ? $license : 'Unknown'
        ];
    }

    // Debug: Log TIDs to process
    // error_log("Stop Report API - Processing " . count($tidsToProcess) . " TIDs");

    // Initialize result array
    $allStopReports = array();
    $totalProcessedRecords = 0;
    $totalStopsFound = 0;

    // Process each TID
    foreach ($tidsToProcess as $tidData) {
        $currentTid = $tidData['tid'];
        $currentLicense = $tidData['license'];

        // Debug: Log current TID processing
        // error_log("Stop Report API - Processing TID: {$currentTid}, License: {$currentLicense}");

        // OPTIMIZED SQL QUERY untuk Big Data
        // Hanya ambil kolom yang diperlukan untuk memory efficiency
        $sql = "SELECT 
                    lat,
                    lon,
                    speed,
                    course,
                    CONVERT(VARCHAR(19), DATEADD(HOUR, {$gmt}, receiveTime), 120) AS receiveTime,
                    status
                FROM tblocations
                WHERE DATEADD(HOUR, {$gmt}, receiveTime) BETWEEN ? AND ?
                AND tid = ?
                ORDER BY receiveTime ASC";

        // Execute query
        $pdo = Database::getConnection();
        $stmt = $pdo->prepare($sql);
        $stmt->execute([$awal, $akhir, $currentTid]);
        
        // Fetch all data untuk current TID
        $data = $stmt->fetchAll(PDO::FETCH_ASSOC);
        $total = count($data);
        $totalProcessedRecords += $total;

        // Debug: Log data count for current TID
        // error_log("Stop Report API - TID {$currentTid}: {$total} records");

        // State machine variables untuk stop detection
        $pengingat = 0;  // 0 = looking for stop start, 1 = looking for stop end
        $startTime = '';
        $startLat = 0;
        $startLon = 0;

        // Process data dengan state machine approach
        for ($i = 0; $i <= ($total - 1); $i++) {
            $currentRecord = $data[$i];

            // State 1: Looking for stop start (engine OFF)
            if ($pengingat == 0 && $currentRecord['status'] < 260000) {
                $startTime = $currentRecord['receiveTime'];
                $startLat = $currentRecord['lat'];
                $startLon = $currentRecord['lon'];
                $pengingat = 1; // Switch to looking for stop end
                
                // Debug: Log stop start
                // error_log("Stop Report API - Stop started at: {$startTime} for TID {$currentTid}");
            }

            // State 2: Looking for stop end (engine ON)
            if ($pengingat == 1 && $currentRecord['status'] > 260000) {
                $endTime = $currentRecord['receiveTime'];
                
                // Calculate stop duration dalam menit
                $startTimestamp = strtotime($startTime);
                $endTimestamp = strtotime($endTime);
                $durationMinutes = ($endTimestamp - $startTimestamp) / 60;

                // Debug: Log stop end
                // error_log("Stop Report API - Stop ended at: {$endTime}, Duration: {$durationMinutes} minutes");

                // Hanya tambahkan jika durasi >= interval minimum
                if ($durationMinutes >= $interval) {
                    $coordinates = $startLat . ',' . $startLon;
                    $formattedDuration = SessionHelper::formatDuration($durationMinutes);

                    // Format: [license, coordinates, start_time, end_time, duration]
                    $stopReport = array(
                        $currentLicense,
                        $coordinates,
                        date('d/m/Y H:i:s', $startTimestamp),
                        date('d/m/Y H:i:s', $endTimestamp),
                        $formattedDuration
                    );

                    $allStopReports[] = $stopReport;
                    $totalStopsFound++;

                    // Debug: Log valid stop found
                    // error_log("Stop Report API - Valid stop found: {$durationMinutes} minutes for {$currentLicense}");
                }

                $pengingat = 0; // Reset to looking for next stop start
            }
        }

        // Memory cleanup per TID
        unset($data);
        gc_collect_cycles();
    }

    // Performance monitoring
    $endTime = microtime(true);
    $endMemory = memory_get_usage(true);
    $processingTime = round($endTime - $startTime, 2);
    $memoryUsed = round(($endMemory - $startMemory) / 1024 / 1024, 2);

    // Debug: Log final statistics
    // error_log("Stop Report API - Processing completed:");
    // error_log("  - Total TIDs processed: " . count($tidsToProcess));
    // error_log("  - Total records processed: " . $totalProcessedRecords);
    // error_log("  - Total stops found: " . $totalStopsFound);
    // error_log("  - Processing time: " . $processingTime . " seconds");
    // error_log("  - Memory used: " . $memoryUsed . " MB");

    // Set response headers
    header('Content-Type: application/json');
    
    // Add metadata untuk debugging (uncomment jika diperlukan)
    // $response = [
    //     'data' => $allStopReports,
    //     'metadata' => [
    //         'total_tids_processed' => count($tidsToProcess),
    //         'total_records_processed' => $totalProcessedRecords,
    //         'total_stops_found' => $totalStopsFound,
    //         'processing_time' => $processingTime . " seconds",
    //         'memory_usage' => $memoryUsed . " MB",
    //         'date_range_days' => $diffDays,
    //         'minimum_interval' => $interval . " minutes"
    //     ]
    // ];
    // echo json_encode($response);

    // Return simple array format sesuai original code
    echo json_encode($allStopReports);

} catch (Exception $e) {
    // Log error dengan performance info
    $errorTime = microtime(true);
    $errorMemory = memory_get_usage(true);
    
    error_log("Stop Report API Error: " . $e->getMessage());
    error_log("Error occurred at: " . round($errorTime - $startTime, 2) . " seconds");
    error_log("Memory at error: " . number_format($errorMemory / 1024 / 1024, 2) . " MB");
    error_log("Error trace: " . $e->getTraceAsString());
    
    http_response_code(500);
    echo json_encode([
        'error' => 'Failed to generate stop report: ' . $e->getMessage(),
        'processing_time' => round($errorTime - $startTime, 2) . " seconds",
        'memory_usage' => number_format(($errorMemory - $startMemory) / 1024 / 1024, 2) . " MB"
        // Debug version dengan detail error:
        // 'error_details' => [
        //     'message' => $e->getMessage(),
        //     'file' => $e->getFile(),
        //     'line' => $e->getLine(),
        //     'trace' => $e->getTraceAsString()
        // ]
    ]);
} finally {
    // Cleanup memory
    gc_collect_cycles();
}