package ragflow

import (
	"context"
	"net"
	"net/http"
	"net/url"
	"strings"
	"sync"
	"time"

	"github.com/gogf/gf/v2/encoding/gjson"
	"github.com/gogf/gf/v2/errors/gerror"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/gclient"
)

var (
	// globalClient 全局 RAGFlow 客户端（单例，延迟初始化）
	globalClient *Client
	clientOnce   sync.Once
)

// initClient 延迟初始化客户端
func initClient() {
	clientOnce.Do(func() {
		ctx := context.Background()

		// 读取配置
		baseURL, apiKey := loadConfig(ctx)

		// 如果配置不完整，跳过初始化
		if baseURL == "" || apiKey == "" {
			g.Log().Warning(ctx, "⚠️  RAGFlow 配置未找到，请在项目 config.yml 中添加 ragflow.base_url 和 ragflow.api_key")
			return
		}

		// 自定义 Transport（增大连接池，设置超时）
		transport := &http.Transport{
			Proxy: http.ProxyFromEnvironment,
			DialContext: (&net.Dialer{
				Timeout:   30 * time.Second,
				KeepAlive: 30 * time.Second,
			}).DialContext,
			MaxIdleConns:          200,              // 最大空闲连接数
			MaxIdleConnsPerHost:   100,              // 每个 host 最大空闲连接数
			MaxConnsPerHost:       100,              // 每个 host 最大连接数
			IdleConnTimeout:       90 * time.Second, // 空闲连接超时
			TLSHandshakeTimeout:   10 * time.Second,
			ExpectContinueTimeout: 1 * time.Second,
			ResponseHeaderTimeout: 180 * time.Second, // 等待响应头超时
		}

		// 初始化 gclient（不使用链式调用，避免 Transport 被重置）
		httpClient := gclient.New()
		httpClient.Client.Transport = transport
		httpClient.Client.Timeout = 180 * time.Second

		globalClient = &Client{
			BaseURL:    strings.TrimSuffix(baseURL, "/"),
			APIKey:     apiKey,
			HTTPClient: httpClient,
		}

		g.Log().Infof(ctx, "✅ RAGFlow 客户端初始化成功: baseURL=%s, timeout=180s", baseURL)
	})
}

// loadConfig 从配置文件加载 RAGFlow 配置
func loadConfig(ctx context.Context) (baseURL, apiKey string) {
	// 使用 GoFrame 全局配置（从项目的 config.yml 读取）
	baseURL = g.Cfg().MustGet(ctx, "ragflow.base_url", "").String()
	apiKey = g.Cfg().MustGet(ctx, "ragflow.api_key", "").String()
	return
}

// GetGlobalClient 获取全局客户端（延迟初始化）
// 使用示例：client := ragflow.GetGlobalClient()
func GetGlobalClient() *Client {
	initClient()
	return globalClient
}

// Client RAGFlow API 客户端
type Client struct {
	BaseURL    string
	APIKey     string
	HTTPClient *gclient.Client // HTTP 客户端
}

// CommonResponse 通用响应结构
type CommonResponse struct {
	Code    int         `json:"code"`
	Message string      `json:"message"`
	Data    interface{} `json:"data,omitempty"`
}

// IsSuccess 检查响应是否成功
func (r *CommonResponse) IsSuccess() bool {
	return r.Code == 0
}

// request 发送 HTTP 请求（不使用链式调用）
func (c *Client) request(ctx context.Context, method, path string, body interface{}, result interface{}) (err error) {
	fullURL := c.BaseURL + path

	// 序列化请求体
	var reqBody string
	if body != nil {
		jsonData, jsonErr := gjson.Encode(body)
		if jsonErr != nil {
			return gerror.Newf("marshal request body failed: %v", jsonErr)
		}
		reqBody = string(jsonData)
	}

	// 设置请求头
	c.HTTPClient.SetHeader("Authorization", "Bearer "+c.APIKey)
	c.HTTPClient.SetHeader("Content-Type", "application/json")

	// 发送请求
	var resp *gclient.Response
	switch method {
	case "GET":
		resp, err = c.HTTPClient.Get(ctx, fullURL)
	case "POST":
		resp, err = c.HTTPClient.Post(ctx, fullURL, reqBody)
	case "PUT":
		resp, err = c.HTTPClient.Put(ctx, fullURL, reqBody)
	case "DELETE":
		resp, err = c.HTTPClient.Delete(ctx, fullURL, reqBody)
	default:
		return gerror.Newf("unsupported method: %s", method)
	}

	if err != nil {
		return gerror.Newf("request failed: %v", err)
	}
	defer resp.Close()

	respBody := resp.ReadAll()

	if resp.StatusCode != http.StatusOK {
		return gerror.Newf("http status %d: %s", resp.StatusCode, string(respBody))
	}

	if err = gjson.DecodeTo(respBody, result); err != nil {
		return gerror.Newf("unmarshal response failed: %v", err)
	}

	return
}

// buildQueryString 构建查询字符串
func buildQueryString(params map[string]interface{}) string {
	if len(params) == 0 {
		return ""
	}

	parts := make([]string, 0, len(params))
	for k, v := range params {
		parts = append(parts, url.QueryEscape(k)+"="+url.QueryEscape(g.NewVar(v).String()))
	}
	return strings.Join(parts, "&")
}