<?php
header('Content-Type: application/json');
require_once 'db/config.php';

$response = [
    'status' => 'error',
    'message' => 'Invalid request.'
];

// Get the posted data
$data = json_decode(file_get_contents('php://input'), true);

if (!$data) {
    echo json_encode($response);
    exit();
}

// Basic validation
$session_code = $data['sessionCode'] ?? null;
$track_title = $data['title'] ?? null;
$artist_name = $data['artist'] ?? null;
$album_art_url = $data['albumArt'] ?? null;
$source = $data['source'] ?? null;

if (!$session_code || !$track_title || !$artist_name) {
    $response['message'] = 'Missing required song data.';
    echo json_encode($response);
    exit();
}

try {
    $pdo = db();

    // 1. Get session ID from session code
    $stmt = $pdo->prepare("SELECT id FROM sessions WHERE session_code = ? AND status = 'active'");
    $stmt->execute([$session_code]);
    $session = $stmt->fetch();

    if (!$session) {
        $response['message'] = 'Invalid or inactive session.';
        echo json_encode($response);
        exit();
    }
    $session_id = $session['id'];

    // 2. Check for duplicates
    $stmt = $pdo->prepare("SELECT id FROM queue_items WHERE session_id = ? AND track_title = ? AND artist_name = ?");
    $stmt->execute([$session_id, $track_title, $artist_name]);
    if ($stmt->fetch()) {
        $response['message'] = 'This song is already in the queue.';
        echo json_encode($response);
        exit();
    }

    // 3. Insert the new song
    $sql = "INSERT INTO queue_items (session_id, track_title, artist_name, album_art_url, source, added_by) VALUES (?, ?, ?, ?, ?, ?)";
    $stmt = $pdo->prepare($sql);
    
    // For now, added_by is anonymous. This can be updated later with user profiles.
    $added_by = 'Guest'; 
    
    if ($stmt->execute([$session_id, $track_title, $artist_name, $album_art_url, $source, $added_by])) {
        $new_song_id = $pdo->lastInsertId();
        
        // Fetch the newly added song to return to the client
        $stmt = $pdo->prepare("SELECT * FROM queue_items WHERE id = ?");
        $stmt->execute([$new_song_id]);
        $new_song_data = $stmt->fetch(PDO::FETCH_ASSOC);

        $response['status'] = 'success';
        $response['message'] = 'Song added successfully!';
        $response['data'] = $new_song_data;
    } else {
        $response['message'] = 'Failed to add song to the database.';
    }

} catch (PDOException $e) {
    // In a real app, log this error instead of exposing it.
    $response['message'] = 'Database error: ' . $e->getMessage();
}

echo json_encode($response);