<?php
declare(strict_types=1);

namespace Core\Services;

use Throwable;

class Updater
{
    private const CACHE_TTL_SECONDS = 21600;
    private const MANIFEST_URL = 'https://lab.codemunkeh.io/codemunkeh/AudioCore/raw/branch/main/update.json';

    public static function currentVersion(): string
    {
        $data = require __DIR__ . '/../version.php';
        if (is_array($data) && !empty($data['version'])) {
            return (string)$data['version'];
        }
        return '0.0.0';
    }

    public static function getStatus(bool $force = false): array
    {
        $current = self::currentVersion();
        $manifestUrl = self::MANIFEST_URL;
        $channel = trim(Settings::get('update_channel', 'stable'));
        if ($channel === '') {
            $channel = 'stable';
        }

        $cache = self::readCache();
        if (
            !$force
            && is_array($cache)
            && (string)($cache['manifest_url'] ?? '') === $manifestUrl
            && (string)($cache['channel'] ?? '') === $channel
            && ((int)($cache['fetched_at'] ?? 0) + self::CACHE_TTL_SECONDS) > time()
        ) {
            return $cache;
        }

        $status = [
            'ok' => false,
            'configured' => true,
            'current_version' => $current,
            'latest_version' => $current,
            'update_available' => false,
            'channel' => $channel,
            'manifest_url' => $manifestUrl,
            'error' => '',
            'checked_at' => gmdate('c'),
            'download_url' => '',
            'changelog_url' => '',
            'notes' => '',
            'fetched_at' => time(),
        ];

        try {
            $raw = self::fetchManifest($manifestUrl);
            $decoded = json_decode($raw, true);
            if (!is_array($decoded)) {
                throw new \RuntimeException('Manifest JSON is invalid.');
            }

            $release = self::pickReleaseForChannel($decoded, $channel);
            $latest = trim((string)($release['version'] ?? ''));
            if ($latest === '') {
                throw new \RuntimeException('Manifest does not include a version for selected channel.');
            }

            $status['ok'] = true;
            $status['latest_version'] = $latest;
            $status['download_url'] = (string)($release['download_url'] ?? '');
            $status['changelog_url'] = (string)($release['changelog_url'] ?? '');
            $status['notes'] = (string)($release['notes'] ?? '');
            $status['update_available'] = version_compare($latest, $current, '>');
        } catch (Throwable $e) {
            $status['error'] = $e->getMessage();
        }

        self::writeCache($status);
        return $status;
    }

    private static function pickReleaseForChannel(array $manifest, string $channel): array
    {
        if (isset($manifest['channels']) && is_array($manifest['channels'])) {
            $channels = $manifest['channels'];
            if (isset($channels[$channel]) && is_array($channels[$channel])) {
                return $channels[$channel];
            }
            if (isset($channels['stable']) && is_array($channels['stable'])) {
                return $channels['stable'];
            }
        }
        return $manifest;
    }

    private static function cachePath(): string
    {
        return __DIR__ . '/../../storage/update_cache.json';
    }

    private static function readCache(): ?array
    {
        try {
            $db = Database::get();
            if ($db) {
                $stmt = $db->query("
                    SELECT checked_at, channel, manifest_url, current_version, latest_version,
                           is_update_available, ok, error_text, payload_json
                    FROM ac_update_checks
                    ORDER BY id DESC
                    LIMIT 1
                ");
                $row = $stmt ? $stmt->fetch() : null;
                if (is_array($row)) {
                    $payload = json_decode((string)($row['payload_json'] ?? ''), true);
                    if (is_array($payload)) {
                        $payload['channel'] = (string)($row['channel'] ?? ($payload['channel'] ?? 'stable'));
                        $payload['manifest_url'] = (string)($row['manifest_url'] ?? ($payload['manifest_url'] ?? ''));
                        $payload['current_version'] = (string)($row['current_version'] ?? ($payload['current_version'] ?? '0.0.0'));
                        $payload['latest_version'] = (string)($row['latest_version'] ?? ($payload['latest_version'] ?? '0.0.0'));
                        $payload['update_available'] = ((int)($row['is_update_available'] ?? 0) === 1);
                        $payload['ok'] = ((int)($row['ok'] ?? 0) === 1);
                        $payload['error'] = (string)($row['error_text'] ?? ($payload['error'] ?? ''));
                        $checkedAt = (string)($row['checked_at'] ?? '');
                        if ($checkedAt !== '') {
                            $payload['checked_at'] = $checkedAt;
                            $payload['fetched_at'] = strtotime($checkedAt) ?: ($payload['fetched_at'] ?? 0);
                        }
                        return $payload;
                    }
                }
            }
        } catch (Throwable $e) {
        }

        $path = self::cachePath();
        if (!is_file($path)) {
            return null;
        }
        $raw = @file_get_contents($path);
        if ($raw === false) {
            return null;
        }
        $decoded = json_decode($raw, true);
        return is_array($decoded) ? $decoded : null;
    }

    private static function writeCache(array $data): void
    {
        try {
            $db = Database::get();
            if ($db) {
                $stmt = $db->prepare("
                    INSERT INTO ac_update_checks
                    (checked_at, channel, manifest_url, current_version, latest_version, is_update_available, ok, error_text, payload_json)
                    VALUES (NOW(), :channel, :manifest_url, :current_version, :latest_version, :is_update_available, :ok, :error_text, :payload_json)
                ");
                $stmt->execute([
                    ':channel' => (string)($data['channel'] ?? 'stable'),
                    ':manifest_url' => (string)($data['manifest_url'] ?? ''),
                    ':current_version' => (string)($data['current_version'] ?? '0.0.0'),
                    ':latest_version' => (string)($data['latest_version'] ?? '0.0.0'),
                    ':is_update_available' => !empty($data['update_available']) ? 1 : 0,
                    ':ok' => !empty($data['ok']) ? 1 : 0,
                    ':error_text' => (string)($data['error'] ?? ''),
                    ':payload_json' => json_encode($data, JSON_UNESCAPED_SLASHES),
                ]);
            }
        } catch (Throwable $e) {
        }

        $path = self::cachePath();
        @file_put_contents($path, json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
    }

    private static function fetchManifest(string $manifestUrl): string
    {
        $ctx = stream_context_create([
            'http' => [
                'method' => 'GET',
                'timeout' => 10,
                'header' => "User-Agent: AudioCore-Updater/1.0\r\nAccept: application/json\r\n",
            ],
            'ssl' => [
                'verify_peer' => true,
                'verify_peer_name' => true,
            ],
        ]);

        $raw = @file_get_contents($manifestUrl, false, $ctx);
        if (is_string($raw) && $raw !== '') {
            return $raw;
        }

        if (!function_exists('curl_init')) {
            throw new \RuntimeException('Unable to fetch manifest (file_get_contents failed and cURL is unavailable).');
        }

        $ch = curl_init($manifestUrl);
        if ($ch === false) {
            throw new \RuntimeException('Unable to fetch manifest (failed to initialize cURL).');
        }

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10);
        curl_setopt($ch, CURLOPT_TIMEOUT, 15);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'User-Agent: AudioCore-Updater/1.0',
            'Accept: application/json',
        ]);

        $body = curl_exec($ch);
        $httpCode = (int)curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $err = curl_error($ch);
        curl_close($ch);

        if (!is_string($body) || $body === '') {
            $detail = $err !== '' ? $err : ('HTTP ' . $httpCode);
            throw new \RuntimeException('Unable to fetch manifest via cURL: ' . $detail);
        }
        if ($httpCode >= 400) {
            throw new \RuntimeException('Manifest request failed with HTTP ' . $httpCode . '.');
        }

        return $body;
    }
}