<?php

namespace Toolbox;

/**
 * Autoactualización del instalador global: detecta la última release vía la
 * API de Forgejo/Gitea eligiendo el mayor tag semver de la lista (igual que
 * el core con sus tags), o un directorio plano; descarga el phar, verifica
 * su sha256 contra el publicado y reemplaza el binario de forma atómica.
 */
final class SelfUpdater
{
    public function __construct(private readonly Console $console)
    {
    }

    public function update(string $from, string $target, string $tempDir, bool $force = false): void
    {
        [$source, $sumUrl, $tag] = $this->resolve($from);

        if ($tag !== null) {
            $remote = ltrim($tag, 'vV');
            if (!$force && Semver::compare(Config::VERSION, $remote) >= 0) {
                $this->console->out('  ya está actualizado (v' . Config::VERSION . ')');
                return;
            }
        }

        $this->console->out('  descargando ' . $source);
        $data = @file_get_contents($source);
        if ($data === false) {
            throw new ToolboxException("No se pudo descargar el instalador: {$source}");
        }

        $expected = trim((string) @file_get_contents($sumUrl));
        if ($expected === '') {
            throw new ToolboxException("No se pudo leer el sha256 publicado: {$sumUrl}");
        }

        $actual = hash('sha256', $data);
        if (!hash_equals($expected, $actual)) {
            throw new ToolboxException('sha256 inválido; actualización abortada sin tocar el binario');
        }

        if (!is_dir($tempDir)) {
            mkdir($tempDir, 0777, true);
        }

        $temp = rtrim($tempDir, '/') . '/duckbrain.phar.' . bin2hex(random_bytes(4));
        file_put_contents($temp, $data);
        chmod($temp, 0755);

        if (!rename($temp, $target)) {
            @unlink($temp);
            throw new ToolboxException("No se pudo reemplazar el instalador: {$target}");
        }

        $this->console->ok('instalador actualizado' . ($tag !== null ? ' a v' . ltrim($tag, 'vV') : '') . ' (' . $target . ')');
    }

    public function available(string $from): ?string
    {
        return $this->resolve($from)[2];
    }

    /**
     * @return array{0: string, 1: string, 2: ?string} [URL del phar, URL del sha256, tag o null]
     */
    private function resolve(string $from): array
    {
        if (!preg_match('#/releases(\?|$|/)|\.json$#', $from)) {
            $source = rtrim($from, '/') . '/duckbrain.phar';
            return [$source, $source . '.sha256', null];
        }

        $json = @file_get_contents($from);
        if ($json === false) {
            throw new ToolboxException("No se pudo leer la release: {$from}");
        }

        $data = json_decode($json, true);
        if (!is_array($data)) {
            throw new ToolboxException("Respuesta de release inválida: {$from}");
        }

        $candidates = [];
        foreach (array_is_list($data) ? $data : [$data] as $release) {
            $tag = is_array($release) ? (string) ($release['tag_name'] ?? '') : '';
            if ($tag === '' || (is_array($release) && ($release['draft'] ?? false)) || !is_array($release)) {
                continue;
            }

            try {
                $version = Semver::normalize($tag);
                Semver::parse($version);
            } catch (ToolboxException) {
                continue;
            }

            $assets = $this->assets((array) $release, $from);
            if ($assets === null) {
                continue;
            }

            $candidates[] = ['version' => $version, 'tag' => $tag, 'phar' => $assets[0], 'sum' => $assets[1]];
        }

        if ($candidates === []) {
            throw new ToolboxException("Ninguna release publicada en '{$from}' incluye duckbrain.phar con su sha256");
        }

        usort($candidates, static fn (array $a, array $b): int => Semver::compare($b['version'], $a['version']));

        $best = $candidates[0];

        return [$best['phar'], $best['sum'], $best['tag']];
    }

    /**
     * @return array{0: string, 1: string}|null
     */
    private function assets(array $release, string $from): ?array
    {
        $phar = $sum = null;
        foreach ($release['assets'] ?? [] as $asset) {
            $name = (string) ($asset['name'] ?? '');
            if ($name === 'duckbrain.phar' || $name === 'duckbrain.phar.sha256') {
                $url = $this->absolute((string) ($asset['browser_download_url'] ?? $asset['download_url'] ?? ''), $from);
                if ($url === '') {
                    return null;
                }
                if ($name === 'duckbrain.phar') {
                    $phar = $url;
                } else {
                    $sum = $url;
                }
            }
        }

        return $phar !== null && $sum !== null ? [$phar, $sum] : null;
    }

    private function absolute(string $url, string $base): string
    {
        if ($url === '' || preg_match('#^(https?|file)://#', $url)) {
            return $url;
        }

        $parts = parse_url($base);

        return ($parts['scheme'] ?? 'https') . '://' . ($parts['host'] ?? '') . $url;
    }
}