<?php
/**
 * AJAX API voor Dagplanning & Taken
 */

require_once __DIR__ . '/../includes/auth.php';
require_once __DIR__ . '/../includes/integrations/microsoft.php';
$user = require_auth();
$db = get_db_connection();

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

$action = $_GET['action'] ?? ($_POST['action'] ?? '');
$today = date('Y-m-d');

try {
    // 1. Dagdoel of notities opslaan
    if ($action === 'save_goal') {
        $data = json_decode(file_get_contents('php://input'), true);
        $date = $data['date'] ?? $today;
        $focusGoal = $data['focus_goal'] ?? '';
        $notes = $data['notes'] ?? '';

        $stmt = $db->prepare("
            INSERT INTO daily_plans (user_id, plan_date, focus_goal, notes)
            VALUES (?, ?, ?, ?)
            ON DUPLICATE KEY UPDATE focus_goal = VALUES(focus_goal), notes = VALUES(notes)
        ");
        $stmt->execute([$user['id'], $date, $focusGoal, $notes]);

        echo json_encode(['success' => true]);
        exit;
    }

    // 2. Taak toevoegen
    if ($action === 'add_task') {
        $data = json_decode(file_get_contents('php://input'), true);
        $title = trim($data['title'] ?? '');
        $priority = in_array($data['priority'] ?? '', ['P1', 'P2', 'P3']) ? $data['priority'] : 'P2';
        $timeBlockStart = !empty($data['time_block_start']) ? trim($data['time_block_start']) : null;
        $timeBlockEnd = !empty($data['time_block_end']) ? trim($data['time_block_end']) : null;
        $durationMinutes = (int)($data['duration_minutes'] ?? 0);
        $date = !empty($data['date']) ? trim($data['date']) : $today;
        $syncOutlook = !empty($data['sync_to_outlook']);

        if (empty($title)) {
            echo json_encode(['error' => 'Titel is verplicht']);
            exit;
        }

        // Als zowel start- als eindtijd zijn opgegeven, bereken exact de minuten
        if (!empty($timeBlockStart) && !empty($timeBlockEnd)) {
            $t1 = strtotime("2000-01-01 {$timeBlockStart}");
            $t2 = strtotime("2000-01-01 {$timeBlockEnd}");
            if ($t1 !== false && $t2 !== false && $t2 > $t1) {
                $durationMinutes = (int)(($t2 - $t1) / 60);
            }
        }

        if ($durationMinutes <= 0) {
            $durationMinutes = 30;
        }

        // Als starttijd bekend is maar eindtijd nog niet, bereken eindtijd
        if (!empty($timeBlockStart) && empty($timeBlockEnd)) {
            try {
                $dtEnd = new DateTime("{$date} {$timeBlockStart}:00", new DateTimeZone('Europe/Amsterdam'));
                $dtEnd->modify("+{$durationMinutes} minutes");
                $timeBlockEnd = $dtEnd->format('H:i');
            } catch (Throwable $e) {
                // negeer
            }
        }

        // Haal of maak daily plan op
        $stmtPlan = $db->prepare("
            INSERT INTO daily_plans (user_id, plan_date)
            VALUES (?, ?)
            ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id)
        ");
        $stmtPlan->execute([$user['id'], $date]);
        $planId = $db->lastInsertId();

        $source = !empty($data['source']) ? substr(trim($data['source']), 0, 50) : 'FOCIZ';
        $externalId = !empty($data['external_id']) ? substr(trim($data['external_id']), 0, 255) : null;
        $externalUrl = !empty($data['external_url']) ? trim($data['external_url']) : null;
        $outlookSyncError = null;

        // Als synchronisatie naar Outlook gewenst is (of source is OUTLOOK) en nog geen extern ID heeft
        if (($syncOutlook || $source === 'OUTLOOK') && empty($externalId)) {
            // Als er geen starttijd is ingevuld maar wel sync gewenst is, gebruik 09:00 als veilige standaard
            if (empty($timeBlockStart)) {
                $timeBlockStart = '09:00';
            }

            $msResult = microsoft_create_event($user['id'], [
                'subject'          => $title,
                'description'      => "Gepland via Fociz Dagplanning ({$priority})",
                'date'             => $date,
                'start_time'       => $timeBlockStart,
                'end_time'         => $timeBlockEnd,
                'duration_minutes' => $durationMinutes,
            ]);

            if (!empty($msResult['success']) && !empty($msResult['event_id'])) {
                $source = 'OUTLOOK';
                $externalId = $msResult['event_id'];
                $externalUrl = $msResult['web_link'] ?? 'https://outlook.office.com';
                $timeBlockStart = $msResult['start_time'] ?? $timeBlockStart;
                $timeBlockEnd = $msResult['end_time'] ?? $timeBlockEnd;
            } else {
                $outlookSyncError = $msResult['error'] ?? 'Kon afspraak niet aanmaken in Microsoft Outlook';
            }
        }

        $stmt = $db->prepare("
            INSERT INTO tasks (user_id, daily_plan_id, title, priority, time_block_start, time_block_end, duration_minutes, status, source, external_id, external_url)
            VALUES (?, ?, ?, ?, ?, ?, ?, 'TODO', ?, ?, ?)
        ");
        $stmt->execute([$user['id'], $planId, $title, $priority, $timeBlockStart, $timeBlockEnd, $durationMinutes, $source, $externalId, $externalUrl]);
        $taskId = (int)$db->lastInsertId();

        echo json_encode([
            'success' => true,
            'task' => [
                'id' => $taskId,
                'title' => $title,
                'priority' => $priority,
                'time_block_start' => $timeBlockStart,
                'time_block_end' => $timeBlockEnd,
                'duration_minutes' => $durationMinutes,
                'source' => $source,
                'external_id' => $externalId,
                'external_url' => $externalUrl
            ],
            'outlook_synced' => ($source === 'OUTLOOK' && !empty($externalId)),
            'outlook_error' => $outlookSyncError
        ]);
        exit;
    }

    // 2b. Taak bewerken (titel, prioriteit, starttijd, eindtijd, duur)
    if ($action === 'update_task') {
        $data = json_decode(file_get_contents('php://input'), true);
        $taskId = (int)($data['task_id'] ?? 0);
        $title = trim($data['title'] ?? '');
        $priority = in_array($data['priority'] ?? '', ['P1', 'P2', 'P3']) ? $data['priority'] : 'P2';
        $timeBlockStart = !empty($data['time_block_start']) ? trim($data['time_block_start']) : null;
        $timeBlockEnd = !empty($data['time_block_end']) ? trim($data['time_block_end']) : null;
        $durationMinutes = (int)($data['duration_minutes'] ?? 0);

        if (empty($title)) {
            echo json_encode(['error' => 'Titel mag niet leeg zijn']);
            exit;
        }

        // Haal bestaande taak op
        $stmtTask = $db->prepare("SELECT * FROM tasks WHERE id = ? AND user_id = ?");
        $stmtTask->execute([$taskId, $user['id']]);
        $existingTask = $stmtTask->fetch();

        if (!$existingTask) {
            echo json_encode(['error' => 'Taak niet gevonden']);
            exit;
        }

        if (!empty($timeBlockStart) && !empty($timeBlockEnd)) {
            $t1 = strtotime("2000-01-01 {$timeBlockStart}");
            $t2 = strtotime("2000-01-01 {$timeBlockEnd}");
            if ($t1 !== false && $t2 !== false && $t2 > $t1) {
                $durationMinutes = (int)(($t2 - $t1) / 60);
            }
        }

        if ($durationMinutes <= 0) {
            $durationMinutes = (int)($existingTask['duration_minutes'] ?: 30);
        }

        if (!empty($timeBlockStart) && empty($timeBlockEnd)) {
            try {
                $dtEnd = new DateTime("2000-01-01 {$timeBlockStart}:00", new DateTimeZone('Europe/Amsterdam'));
                $dtEnd->modify("+{$durationMinutes} minutes");
                $timeBlockEnd = $dtEnd->format('H:i');
            } catch (Throwable $e) {}
        }

        // Indien gekoppeld aan Outlook, werk afspraak bij via Graph API
        if (!empty($existingTask['external_id']) && $existingTask['source'] === 'OUTLOOK') {
            try {
                $stmtPlan = $db->prepare("SELECT plan_date FROM daily_plans WHERE id = ?");
                $stmtPlan->execute([$existingTask['daily_plan_id']]);
                $planDate = $stmtPlan->fetchColumn() ?: date('Y-m-d');

                microsoft_update_event($user['id'], $existingTask['external_id'], [
                    'subject'    => $title,
                    'date'       => $planDate,
                    'start_time' => $timeBlockStart ?: '09:00',
                    'end_time'   => $timeBlockEnd ?: '09:30',
                ]);
            } catch (Throwable $t) {
                error_log("Fout bij bijwerken Outlook event: " . $t->getMessage());
            }
        }

        $stmtUpdate = $db->prepare("
            UPDATE tasks 
            SET title = ?, priority = ?, time_block_start = ?, time_block_end = ?, duration_minutes = ?
            WHERE id = ? AND user_id = ?
        ");
        $stmtUpdate->execute([$title, $priority, $timeBlockStart, $timeBlockEnd, $durationMinutes, $taskId, $user['id']]);

        echo json_encode([
            'success' => true,
            'time_block_start' => $timeBlockStart,
            'time_block_end' => $timeBlockEnd,
            'duration_minutes' => $durationMinutes
        ]);
        exit;
    }

    // 3. Bestaande taak handmatig naar Microsoft Outlook synchroniseren
    if ($action === 'sync_task_to_outlook') {
        $data = json_decode(file_get_contents('php://input'), true);
        $taskId = (int)($data['task_id'] ?? 0);

        if (!$taskId) {
            echo json_encode(['error' => 'Geen taak-ID opgegeven']);
            exit;
        }

        // Haal taak inclusief plan datum op
        $stmtTask = $db->prepare("
            SELECT t.*, dp.plan_date
            FROM tasks t
            LEFT JOIN daily_plans dp ON t.daily_plan_id = dp.id
            WHERE t.id = ? AND t.user_id = ?
        ");
        $stmtTask->execute([$taskId, $user['id']]);
        $task = $stmtTask->fetch();

        if (!$task) {
            echo json_encode(['error' => 'Taak niet gevonden']);
            exit;
        }

        // Als al gesynchroniseerd
        if (!empty($task['external_id']) && $task['source'] === 'OUTLOOK') {
            echo json_encode([
                'success' => true,
                'already_synced' => true,
                'external_id' => $task['external_id'],
                'external_url' => $task['external_url']
            ]);
            exit;
        }

        $planDate = $task['plan_date'] ?: $today;
        $startTime = !empty($task['time_block_start']) ? $task['time_block_start'] : ($data['time_block_start'] ?? '09:00');
        $endTime = !empty($task['time_block_end']) ? $task['time_block_end'] : null;
        $duration = (int)($task['duration_minutes'] ?: 30);

        $msResult = microsoft_create_event($user['id'], [
            'subject'          => $task['title'],
            'description'      => "Gepland via Fociz Dagplanning (" . $task['priority'] . ")",
            'date'             => $planDate,
            'start_time'       => $startTime,
            'end_time'         => $endTime,
            'duration_minutes' => $duration,
        ]);

        if (empty($msResult['success']) || empty($msResult['event_id'])) {
            echo json_encode(['error' => $msResult['error'] ?? 'Kon afspraak niet aanmaken in Microsoft Outlook']);
            exit;
        }

        // Sla Outlook ID en bron op in de taak
        $stmtUp = $db->prepare("
            UPDATE tasks 
            SET source = 'OUTLOOK', 
                external_id = ?, 
                external_url = ?, 
                time_block_start = COALESCE(time_block_start, ?),
                time_block_end = ?
            WHERE id = ? AND user_id = ?
        ");
        $stmtUp->execute([
            $msResult['event_id'],
            $msResult['web_link'] ?? 'https://outlook.office.com',
            $msResult['start_time'],
            $msResult['end_time'],
            $taskId,
            $user['id']
        ]);

        echo json_encode([
            'success' => true,
            'external_id' => $msResult['event_id'],
            'external_url' => $msResult['web_link'] ?? 'https://outlook.office.com',
            'start_time' => $msResult['start_time'],
            'end_time' => $msResult['end_time'],
        ]);
        exit;
    }

    // 4. Taak status toggelen (voltooid / open)
    if ($action === 'toggle_task') {
        $data = json_decode(file_get_contents('php://input'), true);
        $taskId = (int)($data['task_id'] ?? 0);
        $isCompleted = !empty($data['is_completed']) ? 1 : 0;
        $status = $isCompleted ? 'DONE' : 'TODO';

        $stmt = $db->prepare("
            UPDATE tasks SET is_completed = ?, status = ?
            WHERE id = ? AND user_id = ?
        ");
        $stmt->execute([$isCompleted, $status, $taskId, $user['id']]);

        echo json_encode(['success' => true]);
        exit;
    }

    // 5. Taak verwijderen (verwijder ook eventueel gekoppelde Outlook afspraak)
    if ($action === 'delete_task') {
        $data = json_decode(file_get_contents('php://input'), true);
        $taskId = (int)($data['task_id'] ?? 0);

        // Haal eerst op of deze taak aan Outlook was gekoppeld
        $stmtCheck = $db->prepare("SELECT external_id, source FROM tasks WHERE id = ? AND user_id = ?");
        $stmtCheck->execute([$taskId, $user['id']]);
        $taskToDelete = $stmtCheck->fetch();

        if ($taskToDelete && !empty($taskToDelete['external_id']) && $taskToDelete['source'] === 'OUTLOOK') {
            try {
                microsoft_delete_event($user['id'], $taskToDelete['external_id']);
            } catch (Throwable $t) {
                error_log("Fout bij verwijderen Outlook afspraak voor taak {$taskId}: " . $t->getMessage());
            }
        }

        $stmt = $db->prepare("DELETE FROM tasks WHERE id = ? AND user_id = ?");
        $stmt->execute([$taskId, $user['id']]);

        echo json_encode(['success' => true]);
        exit;
    }

    // 6. Realtime Outlook synchronisatie & controle op gewijzigde/gewiste items
    if ($action === 'check_outlook_sync') {
        $rawInput = file_get_contents('php://input');
        $data = !empty($rawInput) ? (json_decode($rawInput, true) ?: []) : [];
        if (empty($data)) {
            $data = $_GET;
        }

        $planDate = !empty($data['plan_date']) ? trim($data['plan_date']) : $today;
        $weekStart = !empty($data['week_start']) ? trim($data['week_start']) : date('Y-m-d', strtotime('monday this week', strtotime($planDate)));
        $weekEnd = !empty($data['week_end']) ? trim($data['week_end']) : date('Y-m-d', strtotime('sunday this week', strtotime($planDate)));
        $lastHash = !empty($data['last_hash']) ? trim($data['last_hash']) : '';

        // Controleer of Outlook gekoppeld is
        $stmtInt = $db->prepare("SELECT * FROM integrations WHERE user_id = ? AND provider = 'OUTLOOK' AND is_enabled = 1");
        $stmtInt->execute([$user['id']]);
        $integration = $stmtInt->fetch();

        if (!$integration || empty($integration['access_token']) || !empty($integration['is_demo_mode'])) {
            echo json_encode([
                'success'     => true,
                'connected'   => false,
                'has_changes' => false,
                'last_sync'   => date('H:i:s'),
            ]);
            exit;
        }

        // Haal live afspraken op voor de hele week
        $weekLiveEvents = microsoft_fetch_events_range($user['id'], $weekStart, $weekEnd);

        // Voer reconciliatie uit met de Fociz tasks tabel
        $reconcileRes = microsoft_reconcile_tasks_with_outlook($user['id'], $weekStart, $weekEnd, $weekLiveEvents);

        // Haal de geactualiseerde taken voor deze dag op
        $stmtPlan = $db->prepare("SELECT id FROM daily_plans WHERE user_id = ? AND plan_date = ?");
        $stmtPlan->execute([$user['id'], $planDate]);
        $planId = $stmtPlan->fetchColumn();

        $tasks = [];
        if ($planId) {
            $stmtTasks = $db->prepare("
                SELECT id, title, priority, time_block_start, time_block_end, duration_minutes, is_completed, status, source, external_id
                FROM tasks
                WHERE user_id = ? AND (daily_plan_id = ? " . ($planDate === $today ? "OR daily_plan_id IS NULL" : "") . ")
                ORDER BY is_completed ASC, priority ASC, time_block_start ASC, created_at DESC
            ");
            $stmtTasks->execute([$user['id'], $planId]);
            $tasks = $stmtTasks->fetchAll();
        }

        // Filter events voor de geselecteerde dag die geen gesynchroniseerde Fociz taak zijn
        $syncedIds = [];
        foreach ($tasks as $t) {
            if (!empty($t['external_id'])) {
                $syncedIds[$t['external_id']] = true;
            }
        }

        $dayEvents = [];
        foreach ($weekLiveEvents as $e) {
            if (($e['date'] ?? '') === $planDate) {
                if (!empty($e['id']) && isset($syncedIds[$e['id']])) {
                    continue;
                }
                $dayEvents[] = [
                    'id'      => $e['id'],
                    'start'   => $e['start'],
                    'end'     => $e['end'],
                    'subject' => $e['subject'],
                ];
            }
        }

        // Bereken status hash voor de dag
        $hashData = [
            'events' => $dayEvents,
            'tasks'  => array_map(function($t) {
                return [
                    'id'               => $t['id'],
                    'title'            => $t['title'],
                    'time_block_start' => $t['time_block_start'],
                    'time_block_end'   => $t['time_block_end'],
                    'is_completed'     => $t['is_completed'],
                ];
            }, $tasks)
        ];
        $currentHash = md5(json_encode($hashData));

        $hasChanges = ($reconcileRes['deleted'] > 0 || $reconcileRes['updated'] > 0);
        if (!empty($lastHash) && $lastHash !== $currentHash) {
            $hasChanges = true;
        }

        echo json_encode([
            'success'       => true,
            'connected'     => true,
            'has_changes'   => $hasChanges,
            'hash'          => $currentHash,
            'deleted_count' => $reconcileRes['deleted'],
            'updated_count' => $reconcileRes['updated'],
            'events_count'  => count($dayEvents),
            'tasks_count'   => count($tasks),
            'last_sync'     => date('H:i:s'),
        ]);
        exit;
    }

    echo json_encode(['error' => 'Onbekende actie']);
} catch (Exception $e) {
    http_response_code(500);
    echo json_encode(['error' => $e->getMessage()]);
}