package service

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"

	"model-asynch/model/entity"
)

// parseHeadMsgHeaders 支持多个 header 绑定，逗号分隔：
// 示例：
// - X-API-Key:qwen3-tts-key,operation:true,count:123
// - X-API-Key:"qwen3-tts-key",operation:"true"
//
// 说明：
// - HTTP Header 最终都是字符串，这里做的是“值的字符串化表达”。
// - 若 value 用双引号包裹，会去掉外层引号再注入，便于在配置中区分字符串/布尔/数字等表达（以及避免值中包含特殊字符时歧义）。
func parseHeadMsgHeaders(headMsg string) map[string]string {
	headMsg = strings.TrimSpace(headMsg)
	if headMsg == "" {
		return nil
	}
	out := map[string]string{}
	parts := strings.Split(headMsg, ",")
	for _, p := range parts {
		p = strings.TrimSpace(p)
		if p == "" {
			continue
		}
		// HeaderName:HeaderValue（推荐） / HeaderName=HeaderValue（兼容）
		if strings.Contains(p, ":") {
			kv := strings.SplitN(p, ":", 2)
			k := strings.TrimSpace(kv[0])
			v := strings.TrimSpace(kv[1])
			v = strings.Trim(v, "\"")
			if k != "" && v != "" {
				out[k] = v
			}
			continue
		}
		if strings.Contains(p, "=") {
			kv := strings.SplitN(p, "=", 2)
			k := strings.TrimSpace(kv[0])
			v := strings.TrimSpace(kv[1])
			v = strings.Trim(v, "\"")
			if k != "" && v != "" {
				out[k] = v
			}
			continue
		}
	}
	if len(out) == 0 {
		return nil
	}
	return out
}

func payloadToQuery(payload any) (url.Values, error) {
	if payload == nil {
		return url.Values{}, nil
	}
	// 统一转成 map[string]any
	b, err := json.Marshal(payload)
	if err != nil {
		return nil, err
	}
	m := map[string]any{}
	if err := json.Unmarshal(b, &m); err != nil {
		return nil, err
	}
	q := url.Values{}
	for k, v := range m {
		if v == nil {
			continue
		}
		// 复杂类型直接 json 字符串化
		switch vv := v.(type) {
		case string:
			q.Set(k, vv)
		case float64, bool, int, int64, uint64:
			q.Set(k, fmt.Sprintf("%v", vv))
		default:
			bs, _ := json.Marshal(v)
			q.Set(k, string(bs))
		}
	}
	return q, nil
}

// InvokeModel 调用模型服务，返回二进制结果
// modelKey 用于覆盖/补充模型配置 head_msg（例如每次请求携带不同的 X-API-Key）。
func InvokeModel(ctx context.Context, m *entity.AsynchModel, payload any, modelKey string) ([]byte, error) {
	if m == nil || m.BaseURL == "" {
		return nil, fmt.Errorf("模型配置不完整")
	}
	url := strings.TrimRight(m.BaseURL, "/") + "/" + strings.TrimLeft(m.Route, "/")
	if strings.TrimSpace(m.Route) == "" {
		url = strings.TrimRight(m.BaseURL, "/")
	}

	timeout := time.Duration(m.TimeoutSeconds) * time.Second
	if timeout <= 0 {
		timeout = 60 * time.Second
	}
	client := &http.Client{Timeout: timeout}

	method := strings.ToUpper(strings.TrimSpace(m.HttpMethod))
	if method == "" {
		method = http.MethodPost
	}

	var (
		req *http.Request
		err error
	)
	switch method {
	case http.MethodGet:
		q, err := payloadToQuery(payload)
		if err != nil {
			return nil, err
		}
		if len(q) > 0 {
			if strings.Contains(url, "?") {
				url = url + "&" + q.Encode()
			} else {
				url = url + "?" + q.Encode()
			}
		}
		req, err = http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	default:
		bodyBytes, err := json.Marshal(payload)
		if err != nil {
			return nil, err
		}
		req, err = http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(bodyBytes))
	}
	if err != nil {
		return nil, err
	}

	// 先注入模型配置 head_msg（静态头部）
	for hk, hv := range parseHeadMsgHeaders(m.HeadMsg) {
		req.Header.Set(hk, hv)
	}
	// 透传必要头部（如 Authorization / X-User-Info）
	for k, v := range forwardHeaders(ctx) {
		if v != "" {
			req.Header.Set(k, v)
		}
	}
	// 最后注入动态 modelKey（覆盖/补充静态 head_msg）
	for hk, hv := range parseHeadMsgHeaders(modelKey) {
		req.Header.Set(hk, hv)
	}
	if method != http.MethodGet {
		req.Header.Set("Content-Type", "application/json")
	}

	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		// 尽量把错误体带回去，方便排查
		msg := string(b)
		if len(msg) > 2000 {
			msg = msg[:2000]
		}
		return nil, fmt.Errorf("模型服务返回非2xx: %d, body=%s", resp.StatusCode, msg)
	}
	return b, nil
}