<?php
declare(strict_types=1);

/**
 * Game Maker project API.
 *
 * Routing uses the `r` query parameter (e.g. `index.php?r=projects/abc123`) because the
 * site's nginx configuration does not pass PATH_INFO to PHP.
 *
 *   GET    ?r=projects          → [{id,name,revision,updatedAt}]
 *   POST   ?r=projects          {name}               → {id,name,revision,updatedAt,project}
 *   GET    ?r=projects/{id}     → {id,name,revision,updatedAt,project}
 *   PUT    ?r=projects/{id}     {revision, project}  → {revision,updatedAt} | 409 {error,revision}
 *   DELETE ?r=projects/{id}     → 204
 */

require __DIR__ . '/lib/Response.php';
require __DIR__ . '/lib/Store.php';

const MAX_BODY_BYTES = 8 * 1024 * 1024;

set_error_handler(static function (int $severity, string $message, string $file, int $line): bool {
    throw new ErrorException($message, 0, $severity, $file, $line);
});

try {
    if ((int) ($_SERVER['CONTENT_LENGTH'] ?? 0) > MAX_BODY_BYTES) {
        Response::error('Request body too large', 413);
    }

    $store = new Store(dirname(__DIR__) . '/data/projects');
    $method = $_SERVER['REQUEST_METHOD'] ?? 'GET';
    $route = trim((string) ($_GET['r'] ?? ''), '/');
    $parts = $route === '' ? [] : explode('/', $route);

    if (($parts[0] ?? '') !== 'projects' || count($parts) > 2) {
        Response::error('Not found', 404);
    }

    // Collection: /projects
    if (count($parts) === 1) {
        if ($method === 'GET') {
            Response::json($store->list());
        }
        if ($method === 'POST') {
            $body = Response::body();
            $name = trim((string) ($body['name'] ?? ''));
            if ($name === '' || mb_strlen($name) > 120) {
                Response::error('Project name must be 1–120 characters', 422);
            }
            Response::json($store->create($name), 201);
        }
        Response::error('Method not allowed', 405);
    }

    // Item: /projects/{id}
    $id = $parts[1];
    if (!Store::isValidId($id)) {
        Response::error('Invalid project id', 400);
    }

    if ($method === 'GET') {
        $doc = $store->load($id);
        if ($doc === null) {
            Response::error('Project not found', 404);
        }
        Response::json($doc);
    }

    if ($method === 'PUT') {
        $body = Response::body();
        if (!isset($body['revision']) || !is_int($body['revision']) || !is_array($body['project'] ?? null)) {
            Response::error('Body must contain integer "revision" and object "project"', 422);
        }
        try {
            $result = $store->save($id, $body['revision'], $body['project']);
        } catch (StaleRevisionException $e) {
            Response::error('Project was modified elsewhere', 409, ['revision' => $e->currentRevision]);
        }
        if ($result === null) {
            Response::error('Project not found', 404);
        }
        Response::json(['revision' => $result['revision'], 'updatedAt' => $result['updatedAt']]);
    }

    if ($method === 'DELETE') {
        if (!$store->delete($id)) {
            Response::error('Project not found', 404);
        }
        Response::noContent();
    }

    Response::error('Method not allowed', 405);
} catch (Throwable $e) {
    error_log('[game-maker api] ' . $e->getMessage());
    Response::error('Internal server error', 500);
}