<?php

namespace app\common\tools\ai;

/**
 * models.dev 数据同步与缓存.
 *
 * 从 https://models.dev/api.json 获取AI模型供应商和模型目录数据,
 * 缓存到 runtime/ai/models_dev_cache.json, 有效期24小时.
 */
class ModelsDevSync
{
    /**
     * @var string models.dev API地址
     */
    protected $apiUrl = 'https://models.dev/api.json';

    /**
     * @var string 缓存文件路径
     */
    protected $cachePath;

    /**
     * @var int 缓存有效期(秒), 默认24小时
     */
    protected $cacheTtl = 86400;

    public function __construct()
    {
        $this->cachePath = app()->getRuntimePath() . 'ai' . DIRECTORY_SEPARATOR . 'models_dev_cache.json';
    }

    /**
     * 同步供应商数据到本地缓存.
     *
     * @return array 同步结果统计
     *
     * @throws \Exception
     */
    public function syncProviders(): array
    {
        $data = $this->fetchApi();

        if ($data === false) {
            throw new \Exception('无法连接 models.dev API');
        }

        $parsed = $this->parseApiData($data);

        $this->writeCache($parsed);

        return $parsed;
    }

    /**
     * 获取所有供应商列表.
     *
     * @return array
     */
    public function getProviders(): array
    {
        $cache = $this->readCache();
        if ($cache === null) {
            return [];
        }

        return $cache['providers'] ?? [];
    }

    /**
     * 获取指定供应商的模型列表.
     *
     * @param string $providerId 供应商标识
     *
     * @return array
     */
    public function getModelsByProvider(string $providerId): array
    {
        $cache = $this->readCache();
        if ($cache === null) {
            return [];
        }

        $models = $cache['models'][$providerId] ?? [];

        return $models;
    }

    /**
     * 获取缓存状态信息.
     *
     * @return array
     */
    public function getCacheStatus(): array
    {
        $exists = file_exists($this->cachePath);
        $mtime = $exists ? filemtime($this->cachePath) : 0;
        $expired = ($mtime + $this->cacheTtl) < time();

        return [
            'exists' => $exists,
            'last_sync' => $mtime > 0 ? date('Y-m-d H:i:s', $mtime) : '从未同步',
            'expired' => $expired,
            'provider_count' => count($this->getProviders()),
        ];
    }

    /**
     * 从API获取原始数据.
     *
     * @return string|false
     */
    protected function fetchApi()
    {
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $this->apiUrl);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_TIMEOUT, 30);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Accept: application/json',
        ]);

        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode !== 200 || $response === false) {
            return false;
        }

        return $response;
    }

    /**
     * 解析API数据为统一格式.
     *
     * @param string $raw JSON原始数据
     *
     * @return array
     */
    protected function parseApiData(string $raw): array
    {
        $data = json_decode($raw, true);
        if (!is_array($data)) {
            return ['providers' => [], 'models' => []];
        }

        $providers = [];
        $models = [];

        foreach ($data as $providerId => $providerData) {
            if (!is_array($providerData)) {
                continue;
            }

            $provider = [
                'id' => $providerId,
                'name' => $providerData['name'] ?? ucfirst($providerId),
                'url' => $providerData['url'] ?? '',
                'docs_url' => $providerData['docs_url'] ?? '',
            ];

            // 提取API基础地址(如果有)
            if (isset($providerData['api_base_url'])) {
                $provider['api_base_url'] = $providerData['api_base_url'];
            }

            $providers[$providerId] = $provider;

            // 提取模型列表
            $providerModels = [];
            if (isset($providerData['models']) && is_array($providerData['models'])) {
                foreach ($providerData['models'] as $modelId => $modelData) {
                    $model = [
                        'id' => $modelId,
                        'name' => $modelData['name'] ?? $modelId,
                        'description' => $modelData['description'] ?? '',
                    ];

                    if (isset($modelData['context_length'])) {
                        $model['context_length'] = (int) $modelData['context_length'];
                    }
                    if (isset($modelData['pricing'])) {
                        $model['pricing'] = $modelData['pricing'];
                    }

                    $providerModels[] = $model;
                }
            }

            $models[$providerId] = $providerModels;
        }

        return [
            'providers' => $providers,
            'models' => $models,
        ];
    }

    /**
     * 写入缓存文件.
     *
     * @param array $data 缓存数据
     */
    protected function writeCache(array $data): void
    {
        $dir = dirname($this->cachePath);
        if (!is_dir($dir)) {
            mkdir($dir, 0755, true);
        }

        file_put_contents($this->cachePath, json_encode($data, JSON_UNESCAPED_UNICODE));
    }

    /**
     * 读取缓存文件(支持过期降级).
     *
     * @return array|null
     */
    protected function readCache(): ?array
    {
        if (!file_exists($this->cachePath)) {
            return null;
        }

        $content = file_get_contents($this->cachePath);
        $data = json_decode($content, true);

        if (!is_array($data)) {
            return null;
        }

        return $data;
    }
}