<?php
/**
 * Watch / Unwatch Ticket API
 *
 * GET  ?ticket_id=N  → returns { watching: bool, watcher_count: int }
 * POST { ticket_id, action: 'watch'|'unwatch' } → toggles watcher row
 */
require_once __DIR__ . '/bootstrap.php';
require_once dirname(__DIR__) . '/models/TicketModel.php';

$ticketId = isset($_GET['ticket_id'])
    ? (int)$_GET['ticket_id']
    : (isset($data['ticket_id']) ? (int)$data['ticket_id'] : 0);

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $data     = json_decode(file_get_contents('php://input'), true) ?? [];
    $ticketId = (int)($data['ticket_id'] ?? 0);
    $action   = $data['action'] ?? '';

    if ($ticketId <= 0 || !in_array($action, ['watch', 'unwatch'], true)) {
        http_response_code(400);
        echo json_encode(['success' => false, 'error' => 'Invalid parameters']);
        exit;
    }

    $ticketModel = new TicketModel($conn);
    $ticket = $ticketModel->getTicketById($ticketId);
    if (!$ticket || !$ticketModel->canUserAccessTicket($ticket, $currentUser)) {
        http_response_code(404);
        echo json_encode(['success' => false, 'error' => 'Ticket not found']);
        exit;
    }

    if ($action === 'watch') {
        $stmt = $conn->prepare(
            "INSERT IGNORE INTO ticket_watchers (ticket_id, user_id) VALUES (?, ?)"
        );
        $stmt->bind_param("ii", $ticketId, $userId);
        $stmt->execute();
        $stmt->close();
    } else {
        $stmt = $conn->prepare(
            "DELETE FROM ticket_watchers WHERE ticket_id = ? AND user_id = ?"
        );
        $stmt->bind_param("ii", $ticketId, $userId);
        $stmt->execute();
        $stmt->close();
    }

    // Return updated state
    $countStmt = $conn->prepare(
        "SELECT COUNT(*) as cnt FROM ticket_watchers WHERE ticket_id = ?"
    );
    $countStmt->bind_param("i", $ticketId);
    $countStmt->execute();
    $count = (int)$countStmt->get_result()->fetch_assoc()['cnt'];
    $countStmt->close();

    apiRespond([
        'success'       => true,
        'watching'      => $action === 'watch',
        'watcher_count' => $count,
    ]);
}

// GET — return current watch state for this user
if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
    http_response_code(405);
    echo json_encode(['success' => false, 'error' => 'Method not allowed']);
    exit;
}

if ($ticketId <= 0) {
    http_response_code(400);
    echo json_encode(['success' => false, 'error' => 'ticket_id required']);
    exit;
}

$watchingStmt = $conn->prepare(
    "SELECT COUNT(*) as cnt FROM ticket_watchers WHERE ticket_id = ? AND user_id = ?"
);
$watchingStmt->bind_param("ii", $ticketId, $userId);
$watchingStmt->execute();
$watching = (bool)$watchingStmt->get_result()->fetch_assoc()['cnt'];
$watchingStmt->close();

// Fetch watcher list (up to 6) with display names for avatar group
$watchersStmt = $conn->prepare(
    "SELECT u.user_id, COALESCE(u.display_name, u.username) AS display_name
       FROM ticket_watchers tw
       JOIN users u ON tw.user_id = u.user_id
      WHERE tw.ticket_id = ?
      ORDER BY tw.created_at ASC
      LIMIT 6"
);
$watchersStmt->bind_param("i", $ticketId);
$watchersStmt->execute();
$watchersResult = $watchersStmt->get_result();
$watchers = [];
while ($row = $watchersResult->fetch_assoc()) {
    $watchers[] = ['user_id' => (int)$row['user_id'], 'display_name' => $row['display_name']];
}
$watchersStmt->close();
$count = count($watchers);

echo json_encode([
    'success'       => true,
    'watching'      => $watching,
    'watcher_count' => $count,
    'watchers'      => $watchers,
]);