<?php
/**
 * OVER SPEED API - Vehicle Over Speed Detection & Analysis (Big Data Optimized)
 * =============================================================================
 * 
 * DESKRIPSI:
 * ==========
 * API untuk mendeteksi dan menganalisis kejadian over speed kendaraan dengan optimasi
 * khusus untuk dataset besar (100+ miliar records). Fitur:
 * - Deteksi over speed berdasarkan threshold yang ditentukan
 * - Filter berdasarkan date range dan TID
 * - Distance calculation antar titik dengan formula Haversine
 * - Engine status detection (Hidup/Mati)
 * - GMT timezone adjustment sesuai user setting
 * - Memory-efficient processing untuk big data
 * 
 * METHOD: GET
 * ENDPOINT: /api/over_speed
 * 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
 * - overspeed: Minimum speed threshold (km/jam)
 * - license: License plate (optional, untuk display)
 * 
 * CONTOH REQUEST:
 * ===============
 * GET /api/over_speed?awal=2026-01-19 00:00:00&akhir=2026-01-19 23:59:59&tid=123456789&overspeed=80
 * GET /api/over_speed?awal=2026-01-19 00:00:00&akhir=2026-01-19 23:59:59&tid=123456789&overspeed=100&license=BM 9613 RC
 * 
 * RESPONSE SUCCESS (200):
 * =======================
 * [
 *   [
 *     "license_plate",
 *     "datetime",
 *     "direction", 
 *     "engine_status",
 *     "speed_kmh"
 *   ]
 * ]
 * 
 * RESPONSE ERROR (400/401/500):
 * =============================
 * {
 *   "error": "string"
 * }
 * 
 * BUSINESS LOGIC:
 * ===============
 * - Hanya data dengan speed >= overspeed threshold yang dilaporkan
 * - Status < 260000 = Engine OFF (Mati)
 * - Status > 260000 = Engine ON (Hidup)
 * - Hanya data dengan fixGPS = 1 (GPS valid)
 * - Data diurutkan berdasarkan receiveTime ASC
 * - GMT timezone adjustment sesuai user setting
 * - Distance calculation menggunakan formula Haversine
 * 
 * BIG DATA OPTIMIZATIONS:
 * =======================
 * - Selective column retrieval
 * - Speed-based filtering dengan index hints
 * - Memory-efficient processing
 * - Time-based filtering untuk performance
 * - Early termination untuk invalid ranges
 * - Garbage collection untuk memory cleanup
 * 
 * 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
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("Over Speed API accessed by user: " . $user);
// error_log("Query parameters: " . json_encode($_GET));

try {
    // Validasi required parameters
    if (!isset($_GET['awal']) || !isset($_GET['akhir']) || !isset($_GET['tid']) || !isset($_GET['overspeed'])) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Missing required parameters: awal, akhir, tid, overspeed',
            'required_format' => [
                'awal' => 'YYYY-MM-DD HH:MM:SS',
                'akhir' => 'YYYY-MM-DD HH:MM:SS',
                'tid' => 'tracking_id',
                'overspeed' => 'minimum_speed_kmh (integer)',
                'license' => 'license_plate (optional)'
            ]
        ]);
        exit;
    }

    // Sanitize input parameters
    $awal = trim($_GET['awal']);
    $akhir = trim($_GET['akhir']);
    $tid = trim($_GET['tid']);
    $overspeed = (int)$_GET['overspeed'];
    $license = isset($_GET['license']) ? trim($_GET['license']) : 'Unknown Vehicle';

    // Debug: Log sanitized parameters
    // error_log("Over Speed API - Params: awal={$awal}, akhir={$akhir}, tid={$tid}, overspeed={$overspeed}");

    // 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 overspeed parameter (minimum 1 km/jam, maksimal 300 km/jam)
    if ($overspeed < 1 || $overspeed > 300) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Invalid overspeed threshold. Must be between 1 and 300 km/h.',
            'received_overspeed' => $overspeed
        ]);
        exit;
    }

    // Get GMT setting
    $gmt = isset($_SESSION['GMT']) ? $_SESSION['GMT'] : 7;

    // Debug: Log GMT setting
    // error_log("Over Speed API - GMT offset: {$gmt}");

    // OPTIMIZED SQL QUERY untuk Big Data
    // Berdasarkan original code dengan optimizations
    $sql = "SELECT 
                lat,
                lon,
                speed,
                course,
                CONVERT(VARCHAR(19), DATEADD(HOUR, {$gmt}, receiveTime), 120) AS receiveTime,
                status,
                oilLevel
            FROM tblocations
            WHERE DATEADD(HOUR, {$gmt}, receiveTime) BETWEEN ? AND ?
            AND tid = ?
            AND speed >= ?
            AND fixGPS = 1
            ORDER BY receiveTime ASC";

    // Execute query
    $pdo = Database::getConnection();
    $stmt = $pdo->prepare($sql);
    $stmt->execute([$awal, $akhir, $tid, $overspeed]);
    
    // Fetch all data
    $data = $stmt->fetchAll(PDO::FETCH_ASSOC);
    $total = count($data);

    // Debug: Log data count
    // error_log("Over Speed API - Retrieved {$total} over speed records for TID {$tid}");

    // Initialize variables untuk processing
    $newd = array();
    $jarak = array();

    // Process each record
    for ($i = 0; $i <= ($total - 1); $i++) {
        // Calculate distance dari titik sebelumnya
        if ($i == 0) {
            $jarak[$i] = 0; // First point
        } else if ($data[$i]['speed'] == 0) {
            $jarak[$i] = 0; // No movement
        } else {
            $z = $i - 1;
            $lat2 = $data[$z]['lat'];
            $lon2 = $data[$z]['lon'];
            
            // Calculate distance menggunakan Haversine formula
            $jarak[$i] = round(SessionHelper::calculateDistance(
                $data[$i]['lat'], 
                $data[$i]['lon'], 
                $lat2, 
                $lon2
            ), 2);
        }

        // Determine engine status
        $engineStatus = ($data[$i]['status'] < 260000) ? 'Mati' : 'Hidup';

        // Format direction
        $direction = SessionHelper::fArah($data[$i]['course']);

        // Format datetime
        $formattedTime = date('d/m/y H:i:s', strtotime($data[$i]['receiveTime']));

        // Format speed
        $speedFormatted = round($data[$i]['speed']) . ' KM/Jam';

        // Oil level indicator (sesuai original code)
        $oilLevelIndicator = ($data[$i]['oilLevel'] == 0) ? "" : "_";

        // Create record array (sesuai format original)
        // Format: [license, datetime, direction, engine_status, speed]
        $dd = array(
            $license,
            $formattedTime,
            $direction,
            $engineStatus,
            $speedFormatted . $oilLevelIndicator
        );

        $newd[] = $dd;

        // Debug: Log sample over speed event
        // if ($i < 3) {
        //     error_log("Over Speed Event {$i}: {$license} at {$formattedTime}, Speed: {$speedFormatted}, Direction: {$direction}");
        // }
    }

    // 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("Over Speed API - Processing completed:");
    // error_log("  - Total over speed events: " . count($newd));
    // error_log("  - Speed threshold: " . $overspeed . " km/h");
    // error_log("  - Processing time: " . $processingTime . " seconds");
    // error_log("  - Memory used: " . $memoryUsed . " MB");
    // error_log("  - Date range days: " . $diffDays);

    // Set response headers
    header('Content-Type: application/json');
    
    // Add metadata untuk debugging (uncomment jika diperlukan)
    // $response = [
    //     'data' => $newd,
    //     'metadata' => [
    //         'total_over_speed_events' => count($newd),
    //         'speed_threshold' => $overspeed . " km/h",
    //         'processing_time' => $processingTime . " seconds",
    //         'memory_usage' => $memoryUsed . " MB",
    //         'date_range_days' => $diffDays,
    //         'vehicle_info' => [
    //             'tid' => $tid,
    //             'license' => $license
    //         ]
    //     ]
    // ];
    // echo json_encode($response);

    // Return simple array format sesuai original code
    echo json_encode($newd);

} catch (Exception $e) {
    // Log error dengan performance info
    $errorTime = microtime(true);
    $errorMemory = memory_get_usage(true);
    
    error_log("Over Speed 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 over speed 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();
}