<?php
require_once __DIR__ . '/../db/config.php';
require_once __DIR__ . '/../helpers.php';

header('Content-Type: application/json');

$db = db();
$lang = $_SESSION['lang'] ?? 'en';
$method = $_SERVER['REQUEST_METHOD'];

if ($method === 'GET') {
    $id = $_GET['id'] ?? null;
    if ($id) {
        // Fetch single appointment
        $stmt = $db->prepare("SELECT * FROM appointments WHERE id = ?");
        $stmt->execute([$id]);
        $appointment = $stmt->fetch(PDO::FETCH_ASSOC);
        echo json_encode($appointment);
        exit;
    }

    $startStr = $_GET['start'] ?? null;
    $endStr = $_GET['end'] ?? null;
    $doctor_id = $_GET['doctor_id'] ?? null;

    $events = [];
    $businessHours = [];

    // Fetch Appointments
    $query = "
        SELECT 
            a.id, a.start_time as start, a.end_time as end, a.reason as title, a.status,
            a.patient_id, a.doctor_id,
            p.name as patient_name,
            d.name_$lang as doctor_name
        FROM appointments a
        JOIN patients p ON a.patient_id = p.id
        JOIN doctors d ON a.doctor_id = d.id
        WHERE 1=1";

    $params = [];
    if ($startStr) { $query .= " AND a.start_time >= ?"; $params[] = $startStr; }
    if ($endStr) { $query .= " AND a.start_time <= ?"; $params[] = $endStr; }
    if ($doctor_id) { $query .= " AND a.doctor_id = ?"; $params[] = $doctor_id; }

    $stmt = $db->prepare($query);
    $stmt->execute($params);
    $appointments = $stmt->fetchAll(PDO::FETCH_ASSOC);

    foreach ($appointments as $a) {
        $color = '#0d6efd'; // blue
        if ($a['status'] === 'Completed') $color = '#198754'; // green
        if ($a['status'] === 'Cancelled') $color = '#dc3545'; // red
        
        $events[] = [
            'id' => $a['id'],
            'title' => $a['patient_name'] . ' (' . $a['doctor_name'] . ')',
            'start' => $a['start'],
            'end' => $a['end'],
            'color' => $color,
            'extendedProps' => [
                'type' => 'appointment',
                'patient_id' => $a['patient_id'],
                'doctor_id' => $a['doctor_id'],
                'patient_name' => $a['patient_name'],
                'doctor_name' => $a['doctor_name'],
                'status' => $a['status'],
                'reason' => $a['reason']
            ]
        ];
    }

    // Fetch Holidays
    $holidayQuery = "SELECT holiday_date as start, name_$lang as title FROM holidays WHERE 1=1";
    $holidayParams = [];
    if ($startStr) { $holidayQuery .= " AND holiday_date >= ?"; $holidayParams[] = date('Y-m-d', strtotime($startStr)); }
    if ($endStr) { $holidayQuery .= " AND holiday_date <= ?"; $holidayParams[] = date('Y-m-d', strtotime($endStr)); }

    $stmt = $db->prepare($holidayQuery);
    $stmt->execute($holidayParams);
    $holidays = $stmt->fetchAll(PDO::FETCH_ASSOC);

    foreach ($holidays as $h) {
        $events[] = [
            'id' => 'hol_' . $h['start'],
            'title' => 'Holiday: ' . $h['title'],
            'start' => $h['start'],
            'allDay' => true,
            'color' => '#ffc107', // yellow
            'textColor' => '#000',
            'display' => 'background',
            'extendedProps' => ['type' => 'holiday']
        ];
        
        $events[] = [
            'title' => $h['title'],
            'start' => $h['start'],
            'allDay' => true,
            'color' => '#ffc107',
            'textColor' => '#000',
            'extendedProps' => ['type' => 'holiday']
        ];
    }

    // Fetch Doctor Business Hours
    if ($doctor_id) {
        $scheduleStmt = $db->prepare("SELECT day_of_week as day, start_time as start, end_time as end FROM doctor_schedules WHERE doctor_id = ?");
        $scheduleStmt->execute([$doctor_id]);
        $schedules = $scheduleStmt->fetchAll(PDO::FETCH_ASSOC);
        
        $bhMap = [];
        foreach ($schedules as $s) {
            $key = $s['start'] . '-' . $s['end'];
            if (!isset($bhMap[$key])) {
                $bhMap[$key] = [
                    'daysOfWeek' => [],
                    'startTime' => $s['start'],
                    'endTime' => $s['end']
                ];
            }
            $bhMap[$key]['daysOfWeek'][] = (int)$s['day'];
        }
        $businessHours = array_values($bhMap);
    } else {
        $businessHours = [
            [
                'daysOfWeek' => [0, 1, 2, 3, 4, 5, 6],
                'startTime' => '08:00',
                'endTime' => '17:00'
            ]
        ];
    }

    echo json_encode([
        'events' => $events,
        'businessHours' => $businessHours
    ]);
    exit;
}

if ($method === 'POST') {
    $input = json_decode(file_get_contents('php://input'), true) ?? $_POST;
    $action = $input['action'] ?? '';

    if ($action === 'create') {
        $patient_id = $input['patient_id'] ?? '';
        $doctor_id = $input['doctor_id'] ?? '';
        $start_time = $input['start_time'] ?? '';
        $reason = $input['reason'] ?? '';
        
        if ($patient_id && $doctor_id && $start_time) {
            $stmt = $db->prepare("INSERT INTO appointments (patient_id, doctor_id, start_time, end_time, reason) VALUES (?, ?, ?, DATE_ADD(?, INTERVAL 30 MINUTE), ?)");
            $stmt->execute([$patient_id, $doctor_id, $start_time, $start_time, $reason]);
            echo json_encode(['success' => true, 'id' => $db->lastInsertId()]);
        } else {
            echo json_encode(['success' => false, 'error' => 'Missing fields']);
        }
    } elseif ($action === 'update') {
        $id = $input['id'] ?? '';
        $patient_id = $input['patient_id'] ?? '';
        $doctor_id = $input['doctor_id'] ?? '';
        $start_time = $input['start_time'] ?? '';
        $status = $input['status'] ?? 'Scheduled';
        $reason = $input['reason'] ?? '';

        if ($id && $patient_id && $doctor_id && $start_time) {
            $stmt = $db->prepare("UPDATE appointments SET patient_id = ?, doctor_id = ?, start_time = ?, end_time = DATE_ADD(?, INTERVAL 30 MINUTE), status = ?, reason = ? WHERE id = ?");
            $stmt->execute([$patient_id, $doctor_id, $start_time, $start_time, $status, $reason, $id]);
            echo json_encode(['success' => true]);
        } else {
            echo json_encode(['success' => false, 'error' => 'Missing fields']);
        }
    } elseif ($action === 'delete') {
        $id = $input['id'] ?? '';
        if ($id) {
            $stmt = $db->prepare("DELETE FROM appointments WHERE id = ?");
            $stmt->execute([$id]);
            echo json_encode(['success' => true]);
        } else {
            echo json_encode(['success' => false, 'error' => 'Missing ID']);
        }
    }
    exit;
}