<?php

declare(strict_types=1);

function updateServerJsonResponse(int $status, array $payload): void
{
    http_response_code($status);
    header("Content-Type: application/json; charset=utf-8");
    echo json_encode(
        $payload,
        JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE,
    );
    exit;
}

function updateServerTextResponse(int $status, string $message): void
{
    http_response_code($status);
    header("Content-Type: text/plain; charset=utf-8");
    echo $message;
    exit;
}

function updateServerVersionIsValid(string $version): bool
{
    return preg_match('/^v\d+\.\d+\.\d+$/', $version) === 1;
}

function updateServerEnsureDirectory(string $dir): void
{
    if (!is_dir($dir) && !mkdir($dir, 02775, true) && !is_dir($dir)) {
        throw new RuntimeException("Directory cannot be created: " . $dir);
    }

    @chmod($dir, 02775);
}

function updateServerReadManifest(string $manifestFile, bool $allowMissing = false): array
{
    if (!is_file($manifestFile)) {
        if ($allowMissing) {
            return ["latest" => "", "releases" => []];
        }

        throw new RuntimeException("Manifest file is missing.");
    }

    $decoded = json_decode((string) file_get_contents($manifestFile), true);
    if (!is_array($decoded)) {
        throw new RuntimeException("Manifest file is not valid JSON.");
    }

    return [
        "latest" => trim((string) ($decoded["latest"] ?? "")),
        "releases" => isset($decoded["releases"]) && is_array($decoded["releases"])
            ? $decoded["releases"]
            : [],
    ];
}

function updateServerWriteManifest(string $manifestFile, array $manifest): void
{
    $json = json_encode(
        $manifest,
        JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE,
    );
    if ($json === false) {
        throw new RuntimeException("Manifest cannot be encoded.");
    }

    $tmpFile = $manifestFile . ".tmp";
    if (file_put_contents($tmpFile, $json . PHP_EOL, LOCK_EX) === false) {
        throw new RuntimeException("Manifest cannot be written.");
    }

    @chmod($tmpFile, 0664);
    if (!rename($tmpFile, $manifestFile)) {
        @unlink($tmpFile);
        throw new RuntimeException("Manifest cannot be saved.");
    }

    @chmod($manifestFile, 0664);
}

function updateServerLatestRelease(array $manifest): array
{
    $latest = trim((string) ($manifest["latest"] ?? ""));
    $releases = isset($manifest["releases"]) && is_array($manifest["releases"])
        ? $manifest["releases"]
        : [];

    if ($latest === "" || !updateServerVersionIsValid($latest)) {
        throw new RuntimeException("No valid latest release is configured.");
    }

    if (!isset($releases[$latest]) || !is_array($releases[$latest])) {
        throw new RuntimeException("Latest release entry is missing.");
    }

    return updateServerNormalizeRelease($latest, $releases[$latest]);
}

function updateServerReleaseByVersion(array $manifest, string $version): array
{
    if (!updateServerVersionIsValid($version)) {
        throw new InvalidArgumentException("Invalid version.");
    }

    $releases = isset($manifest["releases"]) && is_array($manifest["releases"])
        ? $manifest["releases"]
        : [];
    if (!isset($releases[$version]) || !is_array($releases[$version])) {
        throw new RuntimeException("Release is not configured.");
    }

    return updateServerNormalizeRelease($version, $releases[$version]);
}

function updateServerNormalizeRelease(string $expectedVersion, array $release): array
{
    $version = trim((string) ($release["version"] ?? $expectedVersion));
    $package = trim((string) ($release["package"] ?? ""));
    $sha256 = strtolower(trim((string) ($release["sha256"] ?? "")));
    $publishedAt = trim((string) ($release["published_at"] ?? ""));
    $size = isset($release["size"]) ? (int) $release["size"] : 0;

    if ($version !== $expectedVersion || !updateServerVersionIsValid($version)) {
        throw new RuntimeException("Release version is invalid.");
    }
    if (!preg_match('/^[a-f0-9]{64}$/', $sha256)) {
        throw new RuntimeException("Release checksum is invalid.");
    }
    if ($package === "" || str_contains($package, "\0") || str_starts_with($package, "/")) {
        throw new RuntimeException("Release package path is invalid.");
    }

    return [
        "version" => $version,
        "package" => $package,
        "sha256" => $sha256,
        "size" => $size,
        "published_at" => $publishedAt,
    ];
}

function updateServerPackagePath(string $baseDir, string $package): string
{
    $packagePath = realpath($baseDir . "/" . $package);
    $packagesDir = realpath($baseDir . "/packages");
    if (
        $packagePath === false ||
        $packagesDir === false ||
        !str_starts_with($packagePath, $packagesDir . DIRECTORY_SEPARATOR) ||
        !is_file($packagePath)
    ) {
        throw new RuntimeException("Release package is missing.");
    }

    return $packagePath;
}

function updateServerPackageUrl(string $version): string
{
    $scheme = "http";
    if (
        (!empty($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] !== "off") ||
        (isset($_SERVER["SERVER_PORT"]) && (int) $_SERVER["SERVER_PORT"] === 443) ||
        strtolower((string) ($_SERVER["HTTP_X_FORWARDED_PROTO"] ?? "")) === "https"
    ) {
        $scheme = "https";
    }

    $host = $_SERVER["HTTP_HOST"] ?? "localhost";
    $scriptDir = rtrim(str_replace("\\", "/", dirname($_SERVER["SCRIPT_NAME"] ?? "")), "/");

    return $scheme .
        "://" .
        $host .
        ($scriptDir === "" ? "" : $scriptDir) .
        "/package.php?version=" .
        rawurlencode($version);
}

function updateServerPackageFileName(string $version): string
{
    $prefix = defined("UPDATE_SERVER_PACKAGE_PREFIX")
        ? (string) UPDATE_SERVER_PACKAGE_PREFIX
        : "release";
    $prefix = trim((string) preg_replace('/[^A-Za-z0-9._-]+/', "-", $prefix), ".-_");
    if ($prefix === "") {
        $prefix = "release";
    }

    return $prefix . "-" . $version . ".zip";
}

function updateServerUploadedFileIsZip(array $file): bool
{
    $name = strtolower((string) ($file["name"] ?? ""));
    $tmpName = (string) ($file["tmp_name"] ?? "");

    if (!str_ends_with($name, ".zip") || !is_uploaded_file($tmpName)) {
        return false;
    }

    $handle = fopen($tmpName, "rb");
    if ($handle === false) {
        return false;
    }

    $signature = fread($handle, 4);
    fclose($handle);

    return $signature === "PK\x03\x04" || $signature === "PK\x05\x06" || $signature === "PK\x07\x08";
}

function updateServerPublishUpload(
    string $version,
    array $file,
    string $manifestFile,
    string $packagesDir,
): void {
    if (!updateServerVersionIsValid($version)) {
        throw new RuntimeException("Version must use the format vX.Y.Z.");
    }

    if (($file["error"] ?? UPLOAD_ERR_NO_FILE) !== UPLOAD_ERR_OK) {
        throw new RuntimeException("Upload failed with error code " . (string) ($file["error"] ?? "unknown") . ".");
    }

    if (!updateServerUploadedFileIsZip($file)) {
        throw new RuntimeException("Uploaded file must be a ZIP package.");
    }

    updateServerEnsureDirectory($packagesDir);

    $fileName = updateServerPackageFileName($version);
    $targetPath = $packagesDir . DIRECTORY_SEPARATOR . $fileName;
    if (!move_uploaded_file((string) $file["tmp_name"], $targetPath)) {
        throw new RuntimeException("Uploaded package cannot be stored.");
    }

    @chmod($targetPath, 0664);

    $sha256 = strtolower(hash_file("sha256", $targetPath) ?: "");
    $size = filesize($targetPath);
    if (!preg_match('/^[a-f0-9]{64}$/', $sha256) || $size === false || $size <= 0) {
        @unlink($targetPath);
        throw new RuntimeException("Stored package could not be verified.");
    }

    $manifest = updateServerReadManifest($manifestFile, true);
    $manifest["latest"] = $version;
    $manifest["releases"][$version] = [
        "version" => $version,
        "package" => "packages/" . $fileName,
        "sha256" => $sha256,
        "size" => $size,
        "published_at" => date(DATE_ATOM),
    ];

    ksort($manifest["releases"]);
    updateServerWriteManifest($manifestFile, $manifest);
}

function updateServerSetLatest(string $version, string $manifestFile): void
{
    if (!updateServerVersionIsValid($version)) {
        throw new RuntimeException("Invalid release version.");
    }

    $manifest = updateServerReadManifest($manifestFile, true);
    if (!isset($manifest["releases"][$version])) {
        throw new RuntimeException("Release is not present in the manifest.");
    }

    $manifest["latest"] = $version;
    updateServerWriteManifest($manifestFile, $manifest);
}

function updateServerDeleteRelease(string $version, string $manifestFile, string $baseDir): void
{
    if (!updateServerVersionIsValid($version)) {
        throw new RuntimeException("Invalid release version.");
    }

    $manifest = updateServerReadManifest($manifestFile, true);
    if (!isset($manifest["releases"][$version])) {
        throw new RuntimeException("Release is not present in the manifest.");
    }

    $package = trim((string) ($manifest["releases"][$version]["package"] ?? ""));
    unset($manifest["releases"][$version]);
    if ($manifest["latest"] === $version) {
        $manifest["latest"] = "";
    }

    updateServerWriteManifest($manifestFile, $manifest);

    if ($package === "" || str_contains($package, "\0") || str_starts_with($package, "/")) {
        return;
    }

    try {
        $packagePath = updateServerPackagePath($baseDir, $package);
        unlink($packagePath);
    } catch (Throwable $exception) {
        return;
    }
}