package service

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

	"model-asynch/model/entity"

	"github.com/gogf/gf/v2/container/gvar"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/tidwall/gjson"
	"github.com/tidwall/sjson"
)

// 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")
	}

	// ============ 新增：请求参数映射 ============
	mappedPayload, err := mapRequestPayload(m.RequestMapping, payload)
	if err != nil {
		return nil, fmt.Errorf("请求参数映射失败: %w", err)
	}

	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
	)
	switch method {
	case http.MethodGet:
		q, err := payloadToQuery(mappedPayload) // 使用映射后的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(mappedPayload) // 使用映射后的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，适合公共模型固定 API Key）
	for hk, hv := range parseHeadMsgHeaders(m.HeadMsg) {
		req.Header.Set(hk, hv)
	}

	// 最后注入动态 modelKey（允许覆盖/补充静态 head_msg），适合按请求动态传密钥。
	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 {
		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)
	}

	// ============ 新增：响应参数映射 ============
	mappedResponse, err := mapResponsePayload(m.ResponseMapping, b)
	if err != nil {
		// 响应映射失败不阻塞，返回原始数据
		g.Log().Warningf(ctx, "响应参数映射失败: %v，返回原始数据", err)
		return b, nil
	}
	// =========================================

	return mappedResponse, nil
}

// ============================================
// 映射相关函数
// ============================================

// mapRequestPayload 将标准请求映射为模型特定格式
func mapRequestPayload(mappingAny any, payload any) (any, error) {
	// 1. 解析请求映射配置（值是any类型，支持bool、number等）
	mapping, err := parseRequestMapping(mappingAny)
	if err != nil {
		return nil, err
	}

	// 如果没有映射配置，直接返回原始payload
	if len(mapping) == 0 {
		return payload, nil
	}

	// 2. 将payload转为map
	var payloadMap map[string]any
	switch v := payload.(type) {
	case map[string]any:
		payloadMap = v
	case []map[string]any:
		// 如果传进来的是纯messages数组，包装成标准格式
		payloadMap = map[string]any{
			"messages": v,
		}
	default:
		// 通过JSON转换
		jsonBytes, err := json.Marshal(payload)
		if err != nil {
			return nil, fmt.Errorf("序列化payload失败: %w", err)
		}
		if err := json.Unmarshal(jsonBytes, &payloadMap); err != nil {
			return nil, fmt.Errorf("反序列化payload失败: %w", err)
		}
	}

	// 3. 用数据库固定参数覆盖/补充
	for key, value := range mapping {
		if existingValue, exists := payloadMap[key]; !exists || isEmptyValue(existingValue) {
			payloadMap[key] = value
		}
	}

	return payloadMap, nil
}

// mapResponsePayload 将模型响应映射为标准格式
func mapResponsePayload(mappingAny any, responseBytes []byte) ([]byte, error) {
	mapping, err := parseResponseMapping(mappingAny)
	if err != nil {
		return nil, err
	}
	if len(mapping) == 0 {
		return responseBytes, nil
	}

	responseStr := string(responseBytes)
	resultStr := `{}`

	for standardField, modelPath := range mapping {
		value := gjson.Get(responseStr, modelPath)
		if !value.Exists() {
			continue
		}

		resultStr, err = sjson.SetRaw(resultStr, standardField, value.Raw)
		if err != nil {
			return nil, fmt.Errorf("提取字段 %s <- %s 失败: %w", standardField, modelPath, err)
		}
	}

	return []byte(resultStr), nil
}

func parseRequestMapping(mappingAny any) (map[string]any, error) {
	if mappingAny == nil {
		return nil, nil
	}

	result := make(map[string]any)

	switch v := mappingAny.(type) {
	case *gvar.Var:
		if v == nil || v.IsNil() || v.IsEmpty() {
			return nil, nil
		}
		// 尝试转成 map
		if m := v.Map(); m != nil {
			for k, val := range m {
				result[k] = val
			}
			return result, nil
		}
		// 尝试转成 string
		if s := v.String(); s != "" && s != "{}" && s != "null" {
			if err := json.Unmarshal([]byte(s), &result); err != nil {
				return nil, fmt.Errorf("解析请求映射字符串失败: %w", err)
			}
			return result, nil
		}
		return nil, nil
	// =======================================================

	case map[string]interface{}:
		result = v

	case string:
		if v == "" || v == "{}" || v == "null" {
			return nil, nil
		}
		if err := json.Unmarshal([]byte(v), &result); err != nil {
			return nil, fmt.Errorf("解析请求映射字符串失败: %w", err)
		}

	case []byte:
		if len(v) == 0 {
			return nil, nil
		}
		if err := json.Unmarshal(v, &result); err != nil {
			return nil, fmt.Errorf("解析请求映射字节失败: %w", err)
		}

	default:
		jsonBytes, err := json.Marshal(mappingAny)
		if err != nil {
			return nil, fmt.Errorf("序列化映射配置失败: %w", err)
		}
		if err := json.Unmarshal(jsonBytes, &result); err != nil {
			return nil, fmt.Errorf("解析映射配置失败: %w", err)
		}
	}

	return result, nil
}

// parseResponseMapping 解析响应映射配置
// 返回值类型为 map[string]string，值都是JSON路径字符串
func parseResponseMapping(mappingAny any) (map[string]string, error) {
	if mappingAny == nil {
		return nil, nil
	}

	mapping := make(map[string]string)

	switch v := mappingAny.(type) {
	case *gvar.Var:
		if v == nil || v.IsNil() || v.IsEmpty() {
			return nil, nil
		}
		if m := v.Map(); m != nil {
			for k, val := range m {
				if strVal, ok := val.(string); ok {
					mapping[k] = strVal
				}
			}
			return mapping, nil
		}
		if s := v.String(); s != "" && s != "{}" && s != "null" {
			if err := json.Unmarshal([]byte(s), &mapping); err != nil {
				return nil, fmt.Errorf("解析响应映射字符串失败: %w", err)
			}
			return mapping, nil
		}
		return nil, nil
	case string:
		if v == "" || v == "{}" || v == "null" {
			return nil, nil
		}
		if err := json.Unmarshal([]byte(v), &mapping); err != nil {
			return nil, fmt.Errorf("解析响应映射字符串失败: %w", err)
		}

	case map[string]interface{}:
		// 数据库JSONB直接返回的map
		for k, val := range v {
			if strVal, ok := val.(string); ok {
				mapping[k] = strVal
			}
		}

	case []byte:
		if len(v) == 0 {
			return nil, nil
		}
		if err := json.Unmarshal(v, &mapping); err != nil {
			return nil, fmt.Errorf("解析响应映射字节失败: %w", err)
		}

	default:
		jsonBytes, err := json.Marshal(mappingAny)
		if err != nil {
			return nil, fmt.Errorf("序列化响应映射配置失败: %w", err)
		}
		if err := json.Unmarshal(jsonBytes, &mapping); err != nil {
			return nil, fmt.Errorf("解析响应映射配置失败: %w", err)
		}
	}

	return mapping, nil
}

// isEmptyValue 判断值是否为空
func isEmptyValue(v any) bool {
	if v == nil {
		return true
	}
	switch val := v.(type) {
	case string:
		return val == ""
	case []any:
		return len(val) == 0
	case map[string]any:
		return len(val) == 0
	default:
		return false
	}
}