<?php
declare(strict_types=1);

if (session_status() === PHP_SESSION_NONE) {
    session_start();
}

ini_set('display_errors', '0');

define('ROOT_DIR', dirname(__DIR__));
define('DATA_DIR', ROOT_DIR . '/data');
define('CONFIG_FILE', ROOT_DIR . '/config/app.json');
define('SUBMISSIONS_FILE', DATA_DIR . '/submissions.json');

function loadAppConfig(): array
{
    static $config = null;
    if ($config !== null) {
        return $config;
    }
    if (!is_file(CONFIG_FILE)) {
        jsonError('配置文件不存在', 500);
    }
    $raw = file_get_contents(CONFIG_FILE);
    $config = json_decode($raw ?: '{}', true);
    if (!is_array($config)) {
        jsonError('配置文件格式错误', 500);
    }
    return $config;
}

function jsonResponse($data, int $code = 200): void
{
    http_response_code($code);
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode($data, JSON_UNESCAPED_UNICODE);
    exit;
}

function jsonError(string $message, int $code = 400): void
{
    jsonResponse(['ok' => false, 'message' => $message], $code);
}

function readJsonFile(string $path): array
{
    if (!is_file($path)) {
        jsonError('数据文件不存在: ' . basename($path), 500);
    }
    $data = json_decode(file_get_contents($path) ?: '[]', true);
    return is_array($data) ? $data : [];
}

function getRequestBody(): array
{
    $raw = file_get_contents('php://input');
    $data = json_decode($raw ?: '{}', true);
    return is_array($data) ? $data : [];
}

function requireAdmin(): void
{
    if (empty($_SESSION['admin'])) {
        jsonError('未登录或会话已过期', 401);
    }
}

function readSubmissions(): array
{
    if (!is_file(SUBMISSIONS_FILE)) {
        return [];
    }
    $data = json_decode(file_get_contents(SUBMISSIONS_FILE) ?: '[]', true);
    return is_array($data) ? $data : [];
}

function getDataWriteError(): ?string
{
    if (!is_dir(DATA_DIR)) {
        if (!@mkdir(DATA_DIR, 0755, true) && !is_dir(DATA_DIR)) {
            return 'data 目录无法创建。请在宝塔：文件 → data → 权限设为 755，属主 www';
        }
    }

    if (!is_writable(DATA_DIR)) {
        return 'data 目录不可写。请在宝塔：文件 → data → 权限 755，属主 www，勾选「应用到子目录」';
    }

    if (is_file(SUBMISSIONS_FILE) && !is_writable(SUBMISSIONS_FILE)) {
        return 'submissions.json 不可写。请在宝塔：data/submissions.json → 权限 664，属主 www';
    }

    return null;
}

function saveSubmissions(array $submissions): bool
{
    $writeError = getDataWriteError();
    if ($writeError !== null) {
        error_log('[data] ' . $writeError);
        return false;
    }

    $json = json_encode($submissions, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
    $written = @file_put_contents(SUBMISSIONS_FILE, $json, LOCK_EX);

    if ($written === false && !is_file(SUBMISSIONS_FILE)) {
        $written = @file_put_contents(SUBMISSIONS_FILE, $json, LOCK_EX);
    }

    return $written !== false;
}

function getSaveSubmissionsError(): string
{
    $writeError = getDataWriteError();
    if ($writeError !== null) {
        return $writeError;
    }
    return '保存失败，请稍后重试';
}

function validatePhone(string $phone): bool
{
    return (bool) preg_match('/^1[3-9]\d{9}$/', $phone);
}

function getAssetVersion(): string
{
    static $version = null;
    if ($version !== null) {
        return $version;
    }

    try {
        $config = loadAppConfig();
        if (!empty($config['assetVersion'])) {
            $version = (string) $config['assetVersion'];
            return $version;
        }
    } catch (Throwable $e) {
        // 页面未就绪时回退到文件时间戳
    }

    $max = 0;
    foreach (['css', 'js', 'assets', 'assets/avatars'] as $dirName) {
        $dir = ROOT_DIR . '/' . $dirName;
        if (!is_dir($dir)) {
            continue;
        }
        $files = glob($dir . '/*');
        if ($files === false) {
            continue;
        }
        foreach ($files as $file) {
            if (is_file($file)) {
                $max = max($max, (int) filemtime($file));
            }
        }
    }

    $version = $max > 0 ? (string) $max : date('YmdHis');
    return $version;
}

function asset(string $path): string
{
    $path = ltrim($path, '/');
    $sep = str_contains($path, '?') ? '&' : '?';
    return $path . $sep . 'v=' . rawurlencode(getAssetVersion());
}

function sendHtmlNoCacheHeaders(): void
{
    header('Cache-Control: no-cache, no-store, must-revalidate');
    header('Pragma: no-cache');
    header('Expires: 0');
}