<?php
/**
 * MSPE Dashboard Stats API
 */

require_once 'config.php';

$method = $_SERVER['REQUEST_METHOD'];

if ($method !== 'GET') {
    jsonResponse(['success' => false, 'message' => 'Method not allowed'], 405);
}

// Require authentication for stats
requireAuth();

$action = $_GET['action'] ?? 'all';
$forceRefresh = !empty($_GET['refresh']);

switch ($action) {
    case 'all':
        getAllStats();
        break;
    case 'bookings':
        getBookingStats();
        break;
    case 'messages':
        getMessageStats();
        break;
    case 'news':
        getNewsStats();
        break;
    default:
        getAllStats();
}

function getAllStats() {
    $cacheKey = 'stats_all_v1';
    if (!$GLOBALS['forceRefresh']) {
        $cached = getStatsCache($cacheKey, 30);
        if ($cached !== null) {
            jsonResponse($cached);
        }
    }

    $bookingStats = calculateBookingStats();
    $messageStats = calculateMessageStats();
    $newsStats = calculateNewsStats();
    $subscriberStats = calculateSubscriberStats();

    $payload = [
        'success' => true,
        'data' => [
            'bookings' => $bookingStats,
            'messages' => $messageStats,
            'news' => $newsStats,
            'subscribers' => $subscriberStats
        ]
    ];

    setStatsCache($cacheKey, $payload);
    jsonResponse($payload);
}

function calculateBookingStats() {
    global $db;

    $today = date('Y-m-d');
    $weekStart = date('Y-m-d', strtotime('monday this week'));
    $weekEnd = date('Y-m-d', strtotime('sunday this week'));

    $totalBookings = $db->count('bookings');
    $thisWeekCount = $db->countByDateRange('bookings', 'booking_date', $weekStart, $weekEnd);

    // Last week's bookings (for trend)
    $lastWeekStart = date('Y-m-d', strtotime('monday last week'));
    $lastWeekEnd = date('Y-m-d', strtotime('sunday last week'));
    $lastWeekCount = $db->countByDateRange('bookings', 'booking_date', $lastWeekStart, $lastWeekEnd);

    $pendingCount = $db->count('bookings', ['status' => 'pending']);
    $confirmedCount = $db->count('bookings', ['status' => 'confirmed']);

    // JSON boolean true is compared as string "true" after JSON_UNQUOTE
    $availableSlotsCount = $db->countByFieldComparison('availability_slots', 'date', '>=', $today, [
        'is_available' => 'true'
    ]);

    $confirmationRate = $totalBookings > 0 ? round(($confirmedCount / $totalBookings) * 100) : 0;

    // Calculate trend percentages
    $bookingTrend = $lastWeekCount > 0 ? round((($thisWeekCount - $lastWeekCount) / $lastWeekCount) * 100) : ($thisWeekCount > 0 ? 100 : 0);

    return [
        'this_week' => $thisWeekCount,
        'pending' => $pendingCount,
        'confirmed' => $confirmedCount,
        'available_slots' => $availableSlotsCount,
        'confirmation_rate' => $confirmationRate,
        'trend' => $bookingTrend,
        'total' => $totalBookings
    ];
}

function calculateMessageStats() {
    global $db;

    $total = $db->count('messages');
    $unread = $db->count('messages', ['status' => 'unread']);

    $weekStart = date('Y-m-d', strtotime('monday this week'));
    $weekEnd = date('Y-m-d', strtotime('sunday this week'));
    $thisWeek = $db->countByDateRange('messages', 'created_at', $weekStart . ' 00:00:00', $weekEnd . ' 23:59:59');

    return [
        'total' => $total,
        'unread' => $unread,
        'this_week' => $thisWeek
    ];
}

function calculateNewsStats() {
    global $db;

    return [
        'total' => $db->count('news'),
        'published' => $db->count('news', ['status' => 'published']),
        'draft' => $db->count('news', ['status' => 'draft'])
    ];
}

function calculateSubscriberStats() {
    global $db;

    return [
        'total' => $db->count('subscribers'),
        'active' => $db->count('subscribers', ['status' => 'active'])
    ];
}

function getBookingStats() {
    $cacheKey = 'stats_bookings_v1';
    if (!$GLOBALS['forceRefresh']) {
        $cached = getStatsCache($cacheKey, 30);
        if ($cached !== null) {
            jsonResponse($cached);
        }
    }

    $payload = [
        'success' => true,
        'data' => calculateBookingStats()
    ];

    setStatsCache($cacheKey, $payload);
    jsonResponse($payload);
}

function getMessageStats() {
    $cacheKey = 'stats_messages_v1';
    if (!$GLOBALS['forceRefresh']) {
        $cached = getStatsCache($cacheKey, 30);
        if ($cached !== null) {
            jsonResponse($cached);
        }
    }

    $payload = [
        'success' => true,
        'data' => calculateMessageStats()
    ];

    setStatsCache($cacheKey, $payload);
    jsonResponse($payload);
}

function getNewsStats() {
    $cacheKey = 'stats_news_v1';
    if (!$GLOBALS['forceRefresh']) {
        $cached = getStatsCache($cacheKey, 30);
        if ($cached !== null) {
            jsonResponse($cached);
        }
    }

    $payload = [
        'success' => true,
        'data' => calculateNewsStats()
    ];

    setStatsCache($cacheKey, $payload);
    jsonResponse($payload);
}

function getStatsCache($cacheKey, $ttlSeconds) {
    $cacheDir = DATA_DIR . 'cache/';
    $cacheFile = $cacheDir . 'stats_' . md5($cacheKey) . '.json';

    if (!file_exists($cacheFile)) {
        return null;
    }

    $age = time() - (int)filemtime($cacheFile);
    if ($age > (int)$ttlSeconds) {
        return null;
    }

    $content = @file_get_contents($cacheFile);
    if ($content === false || $content === '') {
        return null;
    }

    $decoded = json_decode($content, true);
    return is_array($decoded) ? $decoded : null;
}

function setStatsCache($cacheKey, $payload) {
    $cacheDir = DATA_DIR . 'cache/';
    if (!is_dir($cacheDir)) {
        @mkdir($cacheDir, 0755, true);
    }

    $cacheFile = $cacheDir . 'stats_' . md5($cacheKey) . '.json';
    @file_put_contents($cacheFile, json_encode($payload), LOCK_EX);
}