<?php
const VERSION_EXCLUDE = ['nightly', 'beta', 'alpha'];

// Command to fetch the list of versions from upstream
const FETCH_VERSIONS_COMMAND = "git ls-remote -q --tags https://github.com/electron/electron.git | grep -v '\^{}' |cut -f2 | sed -s 's/refs\/tags\///g' ";

// Since our "first-release-to-support-an-architecture-heuristic" isn't perfect, and there have been some old releases without
// all architectures - this is a small exception list for old releases. This list isn't expected to grow any further.
const MISSING_VERSIONS = ["v1.3.11-linux-x64","v1.3.11-darwin-x64","v1.3.11-win32-x64",
    "v1.4.9-linux-x64","v1.4.9-darwin-x64","v1.4.9-win32-x64","v1.8.0-linux-x64",
    "v1.8.0-linux-arm64","v1.8.0-darwin-x64","v1.8.0-win32-x64","v13.6.4-linux-x64",
    "v13.6.4-linux-arm64","v13.6.4-darwin-x64","v13.6.4-darwin-arm64","v13.6.4-win32-x64",
    "v13.6.4-win32-arm64","v13.6.5-linux-x64","v13.6.5-linux-arm64","v13.6.5-darwin-x64",
    "v13.6.5-darwin-arm64","v13.6.5-win32-x64","v13.6.5-win32-arm64","v2.1.0-unsupported-20180809-linux-x64",
    "v2.1.0-unsupported-20180809-linux-arm64","v2.1.0-unsupported-20180809-darwin-x64","v2.1.0-unsupported-20180809-win32-x64",
    "v9.0.6-linux-x64","v9.0.6-linux-arm64","v9.0.6-darwin-x64","v9.0.6-win32-x64","v9.0.6-win32-arm64"
];

const ARCH_LIST = ['x64', 'arm64'];
const OS_LIST = ['linux', 'darwin', 'win32'];

// https://stackoverflow.com/a/54325258/368328
function rsearch($dir) {
    $dir = new RecursiveDirectoryIterator($dir);
    $dir->setFlags(RecursiveDirectoryIterator::SKIP_DOTS);
    $ite = new RecursiveIteratorIterator($dir);

    foreach($ite as $file) {
         yield $file->getPathName();
    }
}

function known_missing_version($version, $os, $arch) {
    return in_array("$version-$os-$arch", MISSING_VERSIONS);
}

function generateFingerprint($version, $output, $hash_file) {
    $manifest = [];
    foreach(rsearch($output) as $file) {
        $path = substr($file, strlen($output) + 1);
        $manifest[$path] = sha1_file($file);
    }
    $json = json_encode($manifest, JSON_PRETTY_PRINT|JSON_UNESCAPED_SLASHES);
    file_put_contents($hash_file, $json);
}

function download_release($url, $output) {
    @unlink($output);
    system("wget --quiet --max-redirect=5 '$url' -O /dev/shm/test.zip", $ret);

    return ($ret === 0);
}

function extract_release($input, $output) {
    $zip = new ZipArchive();
    if (!$zip->open($input)) {
        die("Download failed?");
    }
    `rm -rf $output`;
    mkdir($output);

    if(!$zip->extractTo($output)) {
        die("Failed extraction");
    }

    $zip->close();
}

/**
 * We skip over unstable and atom-shell releases
 */
function get_versions() {
    $versions = [];
    foreach(explode("\n", shell_exec(FETCH_VERSIONS_COMMAND)) as $version) {
        foreach(VERSION_EXCLUDE as $needle) {
            if (stripos($version, $needle) !== false) {
                continue 2;
            }
        }
        // Atom shell was renamed to electron in this release (17th April 2015)
        if (version_compare($version, 'v0.24.0', '<')) {
            continue;
        }

        $versions[] = $version;
    }

    return $versions;
}

function release_exists($url) {
    exec("curl --silent -I -o /dev/null -w '%{http_code}' $url", $output);
    if (trim($output[0]) == '404') {
        return false;
    } else {
        return true;
    }
}

function generate_lookup_hashes() {
    $lookup = [
        'darwin-x64' => [],
        'darwin-arm64' => [],
        'linux-x64' => [],
        'linux-arm64' => [],
        'win32-x64' => [],
        'win32-arm64' => [],
    ];

    foreach(glob('hashes/*.json') as $h) {
        $data = json_decode(file_get_contents($h));
        $name = basename($h, '.json');
        list($os, $arch, $version) = explode('-', $name, 3);
        foreach($data as $file=>$hash) {
            // Including locales increases the file size by too much.
            if (strpos($file, '.pak') !== false and strlen(basename($file, '.pak') < 3)) {
                continue;
            }
            $subTable = "$os-$arch";
            if(!isset($lookup[$subTable][$hash])) {
                $lookup[$subTable][$hash] = [];
            }
            $lookup[$subTable][$hash][] = $version;
        }
    }

    return $lookup;
}

function download_releases() {
    foreach(get_versions() as $version) {
        foreach(OS_LIST as $os) {
            foreach(ARCH_LIST as $arch) {

                // No releases were made for these combinations
                // Apple Silicon support added in v11: https://www.electronjs.org/blog/apple-silicon
                if (version_compare($version, 'v11.0.0', '<') and $os=='darwin' and $arch=='arm64') {
                    continue;
                }

                // https://github.com/electron/electron/pull/10219
                // v1.8.0 was the first arm64 release
                if (version_compare($version, 'v1.8.0', '<') and $os=='linux' and $arch=='arm64') {
                    continue;
                }

                // 6.0.9 was the first ARM64 windows release (backport)
                // https://github.com/electron/electron/pull/20260
                if (version_compare($version, 'v6.0.9', '<') and $os=='win32' and $arch=='arm64') {
                    continue;
                }

                $hash_file = "hashes/$os-$arch-$version.json";
                if (!file_exists($hash_file)) {
                    $zipfile = '/dev/shm/test.zip';
                    $output = '/dev/shm/electron';
                    $url = "https://github.com/electron/electron/releases/download/$version/electron-$version-$os-$arch.zip";

                    if (known_missing_version($version, $os, $arch)) {
                        continue;
                    }

                    echo $url . PHP_EOL;

                    if (!release_exists($url)) {
                        echo "[DL:404] $url\n";
                    } else if (download_release($url, $zipfile)) {
                        extract_release($zipfile, $output);
                        generateFingerprint($version, $output, $hash_file);
                    } else {
                        echo "[DL:FAIL] $version\n";
                    }
                }
            }
        }
    }
}

function save_lookup($lookup) {
    foreach($lookup as $file => $data) {
        $json = json_encode($data);
        file_put_contents("lookup/$file.json", $json);
    }
}

download_releases();
save_lookup(generate_lookup_hashes());