<?php
/**
 * R0Installer 云端配置 API 入口
 * 
 * Nginx 配置示例:
 *   location /v3/ {
 *       try_files $uri $uri/ /api/index.php?$query_string;
 *   }
 * 
 * Apache .htaccess:
 *   RewriteEngine On
 *   RewriteRule ^v3/(.*)$ api/index.php [QSA,L]
 */

require_once __DIR__ . '/db.php';
require_once __DIR__ . '/helpers.php';

$path = get_request_path();
$db = getDb();

// 路由匹配
if ($path === '/v3/config/projects') {
    handleGetProjects($db);
}
elseif (preg_match('#^/v3/config/project/([a-zA-Z0-9_]+)$#', $path, $m)) {
    handleGetProjectConfig($db, $m[1]);
}
elseif ($path === '/v3/config/installer') {
    handleGetInstallerConfig($db);
}
elseif ($path === '/v3/version/index') {
    $projectId = $_GET['project'] ?? '';
    handleGetVersionIndex($db, $projectId);
}
elseif ($path === '/v3/update/check') {
    $projectId = $_GET['project'] ?? '';
    $version = $_GET['v'] ?? '';
    handleUpdateCheck($db, $projectId, $version);
}
else {
    json_error('Not Found', 404);
}

// ========== API 处理函数 ==========

function handleGetProjects($db) {
    $rows = $db->select('projects', [
        'project_id', 'display_name', 'description', 'icon_url', 'enabled'
    ]);

    $projects = [];
    foreach ($rows as $row) {
        $row['enabled'] = (bool)$row['enabled'];
        $projects[] = $row;
    }

    json_response(['projects' => $projects]);
}

function handleGetProjectConfig($db, $projectId) {
    $row = $db->get('projects', [
        'project_id', 'display_name', 'config_json'
    ], ['project_id' => $projectId]);

    if (!$row) {
        json_error('项目不存在', 1001);
    }

    $config = json_decode($row['config_json'], true);
    if (!$config) {
        json_error('项目配置解析失败', 1003);
    }

    $config['project_id'] = $row['project_id'];
    $config['display_name'] = $row['display_name'];

    json_response($config);
}

function handleGetInstallerConfig($db) {
    $row = $db->get('installer_config', '*', ['config_key' => 'global']);

    if (!$row) {
        json_error('配置不存在', 1003);
    }

    $filenameRules = json_decode($row['filename_rules'], true) ?: [];
    $commandRules = json_decode($row['command_rules'], true) ?: [];

    json_response([
        'installer_version' => $row['installer_version'],
        'min_client_version' => $row['min_client_version'],
        'filename_rules' => $filenameRules,
        'command_rules' => $commandRules,
        'default_project_id' => $row['default_project'],
        'default_install_mode' => $row['default_mode'],
    ]);
}

function handleGetVersionIndex($db, $projectId) {
    if (empty($projectId)) {
        json_error('缺少 project 参数', 1002);
    }

    $row = $db->get('project_versions', '*', [
        'project_id' => $projectId,
        'is_latest' => 1,
    ]);

    if (!$row) {
        $row = $db->get('project_versions', '*', [
            'project_id' => $projectId,
            'ORDER' => ['id' => 'DESC'],
            'LIMIT' => 1,
        ]);
    }

    if (!$row) {
        json_error('未找到版本信息', 1001);
    }

    $data = [
        'project_id' => $row['project_id'],
        'version' => $row['version'],
        'download_url_cdn' => $row['download_url'],
        'threads' => (int)$row['threads'],
        'changelog' => $row['changelog'] ?? '',
    ];

    $extraDownloads = json_decode($row['extra_downloads'] ?? '{}', true);
    if ($extraDownloads) {
        foreach ($extraDownloads as $key => $val) {
            $data[$key] = $val;
        }
    }

    $runtimeUrls = json_decode($row['runtime_urls'] ?? '{}', true);
    if ($runtimeUrls) {
        $data['runtime_download_url'] = $runtimeUrls;
    }

    json_response($data);
}

function handleUpdateCheck($db, $projectId, $currentVersion) {
    if (empty($projectId)) {
        json_error('缺少 project 参数', 1002);
    }
    if (empty($currentVersion)) {
        json_error('缺少 v 参数', 1002);
    }

    $latestRow = $db->get('project_versions', '*', [
        'project_id' => $projectId,
        'is_latest' => 1,
    ]);

    if (!$latestRow) {
        $latestRow = $db->get('project_versions', '*', [
            'project_id' => $projectId,
            'ORDER' => ['id' => 'DESC'],
            'LIMIT' => 1,
        ]);
    }

    if (!$latestRow) {
        json_response([
            'has_update' => false,
            'latest_version' => $currentVersion,
            'current_version' => $currentVersion,
        ]);
        return;
    }

    $latestVersion = $latestRow['version'];

    if (version_compare($currentVersion, $latestVersion, '>=')) {
        json_response([
            'has_update' => false,
            'latest_version' => $latestVersion,
            'current_version' => $currentVersion,
        ]);
        return;
    }

    $patches = $db->select('project_patches', '*', [
        'project_id' => $projectId,
        'ORDER' => ['id' => 'ASC'],
    ]);

    $chain = buildPatchChain($patches, $currentVersion, $latestVersion);

    // 是否静默更新由“目标版本”（即最新版本）决定，云端按版本控制。
    $silent = (bool)($latestRow['silent_update'] ?? 0);

    if ($chain && count($chain) === 1) {
        $p = $chain[0];
        json_response([
            'has_update' => true,
            'latest_version' => $latestVersion,
            'current_version' => $currentVersion,
            'update_type' => 'incremental',
            'download_url' => $p['download_url'],
            'file_size' => (string)$p['file_size'],
            'total_size' => (string)$p['file_size'],
            'changelog' => $p['changelog'] ?? '',
            'threads' => (int)$latestRow['threads'],
            'silent' => $silent,
        ]);
        return;
    }

    if ($chain && count($chain) > 1) {
        $totalSize = 0;
        $updates = [];
        foreach ($chain as $p) {
            $totalSize += (int)$p['file_size'];
            $updates[] = [
                'from_version' => $p['from_version'],
                'to_version' => $p['to_version'],
                'download_url' => $p['download_url'],
                'file_size' => (string)$p['file_size'],
                'changelog' => $p['changelog'] ?? '',
            ];
        }

        json_response([
            'has_update' => true,
            'latest_version' => $latestVersion,
            'current_version' => $currentVersion,
            'update_type' => 'multi_incremental',
            'total_size' => (string)$totalSize,
            'changelog' => '多版本增量更新',
            'threads' => (int)$latestRow['threads'],
            'incremental_updates' => $updates,
            'silent' => $silent,
        ]);
        return;
    }

    json_response([
        'has_update' => true,
        'latest_version' => $latestVersion,
        'current_version' => $currentVersion,
        'update_type' => 'full',
        'download_url' => $latestRow['download_url'],
        'file_size' => (string)$latestRow['file_size'],
        'total_size' => (string)$latestRow['file_size'],
        'changelog' => $latestRow['changelog'] ?? '',
        'threads' => (int)$latestRow['threads'],
        'silent' => $silent,
    ]);
}

function buildPatchChain($patches, $from, $to) {
    $graph = [];
    foreach ($patches as $p) {
        $graph[$p['from_version']][] = $p;
    }

    $visited = [];
    $queue = [[$from, []]];

    while (!empty($queue)) {
        list($current, $path) = array_shift($queue);

        if ($current === $to) {
            return $path;
        }

        if (isset($visited[$current])) continue;
        $visited[$current] = true;

        if (isset($graph[$current])) {
            foreach ($graph[$current] as $edge) {
                if (!isset($visited[$edge['to_version']])) {
                    $newPath = $path;
                    $newPath[] = $edge;
                    $queue[] = [$edge['to_version'], $newPath];
                }
            }
        }
    }

    return null;
}