<?php
session_start();
header('Content-Type: application/json');

if (!isset($_SESSION['user_id'])) {
    http_response_code(401);
    echo json_encode(['error' => 'User not authenticated']);
    exit;
}

require_once 'db/config.php';

$project_id = filter_input(INPUT_GET, 'id', FILTER_VALIDATE_INT);
if (!$project_id) {
    http_response_code(400);
    echo json_encode(['error' => 'Project ID is required.']);
    exit;
}

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    echo json_encode(['error' => 'POST method required.']);
    exit;
}

$request_body = file_get_contents('php://input');
$data = json_decode($request_body, true);
if (json_last_error() !== JSON_ERROR_NONE) {
    http_response_code(400);
    echo json_encode(['error' => 'Invalid JSON input.']);
    exit;
}

try {
    $pdo = db();
    
    // Verify project ownership and status
    $stmt = $pdo->prepare("SELECT status FROM projects WHERE id = ? AND user_id = ?");
    $stmt->execute([$project_id, $_SESSION['user_id']]);
    $project = $stmt->fetch(PDO::FETCH_ASSOC);

    if (!$project) {
        http_response_code(404);
        echo json_encode(['error' => 'Project not found or permission denied.']);
        exit;
    }

    if ($project['status'] !== 'draft') {
        http_response_code(403);
        echo json_encode(['error' => 'Project is not in draft status and cannot be edited.']);
        exit;
    }

    // Get new data from request body
    $title = trim($data['title'] ?? '');
    $story_text = trim($data['story_text'] ?? '');
    $style = trim($data['style'] ?? '');
    $target_duration = filter_var($data['target_duration'] ?? null, FILTER_VALIDATE_INT, ['options' => ['default' => 0]]);

    if (empty($title)) {
        http_response_code(400);
        echo json_encode(['error' => 'Title is required.']);
        exit;
    }

    // Update the project
    $stmt = $pdo->prepare("UPDATE projects SET title = ?, story_text = ?, style = ?, target_duration = ? WHERE id = ?");
    $stmt->execute([$title, $story_text, $style, $target_duration, $project_id]);
    
    // Fetch and return the updated project
    $stmt = $pdo->prepare("SELECT * FROM projects WHERE id = ?");
    $stmt->execute([$project_id]);
    $updated_project = $stmt->fetch(PDO::FETCH_ASSOC);

    echo json_encode($updated_project);

} catch (PDOException $e) {
    http_response_code(500);
    // error_log("Database error: " . $e->getMessage());
    echo json_encode(['error' => 'Database error.']);
}