package internal

import (
	"bufio"
	"context"
	"encoding/json"
	"fmt"
	"github.com/gogf/gf/util/guid"
	"github.com/gogf/gf/v2/net/ghttp"
	"strings"
	"yx-dataset-server/app/errors"
	"yx-dataset-server/app/model"
	"yx-dataset-server/app/schema"
	"yx-dataset-server/library/ragflow"
)

// NewChatMessage 创建ChatMessage
func NewChatMessage(
	mSession model.IChatSession,
	mChatMessage model.IChatMessage,
	mAssistant model.IChatAssistant,
) *ChatMessage {
	return &ChatMessage{
		ChatMessageModel: mChatMessage,
		sessionModel:     mSession,
		assistantModel:   mAssistant,
	}
}

// ChatMessage 创建ChatMessage对象
type ChatMessage struct {
	ChatMessageModel model.IChatMessage
	sessionModel     model.IChatSession
	assistantModel   model.IChatAssistant
}

// Query 查询数据
func (a *ChatMessage) Query(ctx context.Context, params schema.ChatMessageQueryParam, opts ...schema.ChatMessageQueryOptions) (*schema.ChatMessageQueryResult, error) {
	return a.ChatMessageModel.Query(ctx, params, opts...)
}

// Get 查询指定数据
func (a *ChatMessage) Get(ctx context.Context, recordID string, opts ...schema.ChatMessageQueryOptions) (*schema.ChatMessage, error) {
	item, err := a.ChatMessageModel.Get(ctx, recordID, opts...)
	if err != nil {
		return nil, err
	} else if item == nil {
		return nil, errors.ErrNotFound
	}
	return item, nil
}

func (a *ChatMessage) getUpdate(ctx context.Context, recordID string) (*schema.ChatMessage, error) {
	return a.Get(ctx, recordID)
}

// StreamChatMessage 流式消息
func (a *ChatMessage) StreamChatMessage(ctx context.Context, r *ghttp.Request, item schema.ChatMessage) {
	item.RecordID = guid.S()
	item.CreatorId = GetUserID(ctx)
	//var sessionId string
	if item.SessionId == "" {
		r.Response.Write("data: {\"code\":500,\"message\":\"会话ID不能为空\"}\n\n")
		return
	}

	session, err := a.sessionModel.Get(ctx, item.SessionId)
	if err != nil {
		r.Response.Write("data: {\"code\":500,\"message\":\"%s\"}\n\n", err.Error())
		return
	}
	//sessionId = session.RagSessionId

	assistant, err := a.assistantModel.Get(ctx, item.AssistantId)
	if err != nil {
		r.Response.Write("data: {\"code\":500,\"message\":\"%s\"}\n\n", err.Error())
		return
	}

	stream, err := ragflow.GetHttpClient().ChatCompletionsStream(ctx, assistant.RagChatId, &ragflow.ChatCompletionReq{
		Question:  item.Question,
		SessionID: session.RagSessionId,
	})
	if err != nil {
		r.Response.Write("data: {\"code\":500,\"message\":\"%s\"}\n\n", err.Error())
		return
	}
	defer stream.Close() // 关闭流
	// 用于拼接答案
	var fullAnswer strings.Builder
	//err = a.collectStreamDataAndCreate(ctx, stream, &item)
	//if err != nil {
	//	r.Response.Write("data: {\"code\":500,\"message\":\"%s\"}\n\n", err.Error())
	//	return
	//}
	// ===================== 5. 设置SSE响应头（必须！） =====================
	r.Response.Header().Set("Content-Type", "text/event-stream")
	r.Response.Header().Set("Cache-Control", "no-cache")
	r.Response.Header().Set("Connection", "keep-alive")
	r.Response.Header().Set("X-Accel-Buffering", "no") // 禁用Nginx缓冲
	r.Response.Flush()

	scanner := bufio.NewScanner(stream)
	buf := make([]byte, 1024*1024*10) // 增大缓冲区
	scanner.Buffer(buf, 1024*1024*10)

	for scanner.Scan() {
		line := scanner.Text()
		// 原封不动写给前端
		r.Response.Write(line + "\n")
		r.Response.Flush() // 实时刷新

		//2. 后端收集数据（拼接完整答案）
		if strings.HasPrefix(line, "data:") {
			jsonStr := strings.TrimPrefix(line, "data:")
			jsonStr = strings.TrimSpace(jsonStr)

			if jsonStr != "true" {
				var chunk ragflow.ChatCompletionResp
				if err := json.Unmarshal([]byte(jsonStr), &chunk); err == nil {
					fullAnswer.WriteString(chunk.Data.Answer)
				}
			}
		}
	}

	// 处理流读取错误
	if err := scanner.Err(); err != nil {
		r.Response.Write(fmt.Sprintf("data: {\"code\":500,\"message\":\"读取流失败：%s\"}\n\n", err.Error()))
		r.Response.Flush()
		return
	}

	// ===================== 【业务层：保存完整答案到数据库】 =====================
	item.Answer = fullAnswer.String()
	if err := a.ChatMessageModel.Create(ctx, item); err != nil {
		fmt.Printf("保存聊天记录失败：%v\n", err)
	}

}

func (a *ChatMessage) ChatMessage(ctx context.Context, r *ghttp.Request, item *schema.ChatMessage) (*schema.ChatMessage, error) {
	item.RecordID = guid.S()
	item.CreatorId = GetUserID(ctx)
	//var sessionId string
	if item.SessionId == "" {
		return nil, errors.New400Response("会话ID不能为空")
	}

	session, err := a.sessionModel.Get(ctx, item.SessionId)
	if err != nil {
		return nil, err
	}
	//sessionId = session.RagSessionId

	assistant, err := a.assistantModel.Get(ctx, item.AssistantId)
	if err != nil {
		return nil, err
	}

	stream, err := ragflow.GetHttpClient().ChatCompletionsStream(ctx, assistant.RagChatId, &ragflow.ChatCompletionReq{
		Question:  item.Question,
		SessionID: session.RagSessionId,
	})
	if err != nil {
		return nil, err
	}
	defer stream.Close() // 关闭流

	item, err = CollectStreamDataAndCreate(ctx, stream, item)
	if err != nil {
		return nil, err
	}

	err = a.ChatMessageModel.Create(ctx, *item)
	if err != nil {
		return nil, err
	}

	return item, nil
}

//func (a *ChatMessage) collectStreamDataAndCreate(ctx context.Context, stream io.ReadCloser, item *schema.ChatMessage) error {
//	// 解决 token too long 报错：调大缓冲区到 10MB
//	const maxBufferSize = 10 * 1024 * 1024
//	scanner := bufio.NewScanner(stream)
//	buf := make([]byte, maxBufferSize)
//	scanner.Buffer(buf, maxBufferSize)
//
//	// 用于拼接答案
//	var fullAnswer strings.Builder
//	// 用于存储最终完整结果
//	finalResp := &ragflow.ChatCompletionResp{}
//
//	// 逐行读取流式返回
//	for scanner.Scan() {
//		line := strings.TrimSpace(scanner.Text())
//		if line == "" {
//			continue
//		}
//
//		// 只处理 SSE 格式 data: ...
//		if !strings.HasPrefix(line, "data:") {
//			continue
//		}
//		jsonStr := strings.TrimPrefix(line, "data:")
//		jsonStr = strings.TrimSpace(jsonStr)
//
//		// 流结束标记：data: true
//		if jsonStr == "true" {
//			break
//		}
//
//		// 解析当前分片
//		var chunk ragflow.ChatCompletionResp
//		if err := json.Unmarshal([]byte(jsonStr), &chunk); err != nil {
//			continue
//		}
//		// 拼接回答内容
//		if chunk.Data.Answer != "" {
//			fullAnswer.WriteString(chunk.Data.Answer)
//		}
//		// 保存最后一个分片（包含 reference/session_id 等完整信息）
//		*finalResp = chunk
//	}
//
//	if err := scanner.Err(); err != nil {
//		return errors.New400Response(fmt.Sprintf("读取流式数据失败: %v", err))
//	}
//
//	item.Answer = fullAnswer.String()
//
//	return a.ChatMessageModel.Create(ctx, *item)
//
//}

func (a *ChatMessage) CreateV3(ctx context.Context, r *ghttp.Request, item schema.ChatMessage) {
	item.RecordID = guid.S()
	item.CreatorId = GetUserID(ctx)
	//var sessionId string
	if item.SessionId == "" {
		//return nil, errors.New400Response("会话ID不能为空")
		return
	}

	session, err := a.sessionModel.Get(ctx, item.SessionId)
	if err != nil {
		//return nil, err
		return
	}
	//sessionId = session.RagSessionId

	assistant, err := a.assistantModel.Get(ctx, item.AssistantId)
	if err != nil {
		//return nil, err
		return
	}

	//resp, err := ragflow.GetHttpClient().ChatCompletions(ctx, assistant.RagChatId, &ragflow.ChatCompletionReq{
	//	Question:  item.Question,
	//	SessionID: sessionId,
	//})
	//if err != nil {
	//	return nil, err
	//}
	//item.Answer = resp.Data.Answer
	err = a.ChatMessageModel.Create(ctx, item)
	if err != nil {
		return
	}
	stream, err := ragflow.GetHttpClient().ChatCompletionsStream(ctx, assistant.RagChatId, &ragflow.ChatCompletionReq{
		Question:  item.Question,
		SessionID: session.RagSessionId,
	})
	if err != nil {
		return
	}
	defer stream.Close() // 关闭流

	// ===================== 5. 设置SSE响应头（必须！） =====================
	r.Response.Header().Set("Content-Type", "text/event-stream")
	r.Response.Header().Set("Cache-Control", "no-cache")
	r.Response.Header().Set("Connection", "keep-alive")
	r.Response.Header().Set("X-Accel-Buffering", "no") // 禁用Nginx缓冲
	//r.Response.Flush()
	//
	//_, err = io.Copy(r.Response.Writer, stream)
	//if err != nil {
	//	// 可自定义错误处理
	//	r.Response.Write(fmt.Sprintf("data: {\"code\":500,\"message\":\"%s\"}\n\n", err.Error()))
	//}
	// 实时刷新
	//===================== 6. 逐行转发RAG流给前端 =====================
	scanner := bufio.NewScanner(stream)
	buf := make([]byte, 1024*1024*10) // 增大缓冲区
	scanner.Buffer(buf, 1024*1024*10)

	for scanner.Scan() {
		line := scanner.Text()
		// 原封不动写给前端
		r.Response.Write(line + "\n")
		r.Response.Flush() // 实时刷新
	}

	//// 处理错误
	//if err = scanner.Err(); err != nil {
	//	r.Response.Write(fmt.Sprintf("data: {\"code\":500,\"message\":\"%s\"}\n\n", err.Error()))
	//	r.Response.Flush() // 实时刷新
	//}

}

func (a *ChatMessage) CreateV2(ctx context.Context, item schema.ChatMessage) (*schema.ChatMessage, error) {
	item.RecordID = guid.S()
	item.CreatorId = GetUserID(ctx)

	if item.SessionId == "" {
		return nil, errors.New400Response("会话ID不能为空")
	}

	session, err := a.sessionModel.Get(ctx, item.SessionId)
	if err != nil {
		return nil, err
	}
	assistant, err := a.assistantModel.Get(ctx, item.AssistantId)
	if err != nil {
		return nil, err
	}

	// 调用非流式接口
	resp, err := ragflow.GetHttpClient().ChatCompletions(ctx, assistant.RagChatId, &ragflow.ChatCompletionReq{
		Question:  item.Question,
		SessionID: session.RagSessionId,
	})
	if err != nil {
		return nil, err
	}

	item.Answer = resp.Data.Answer
	// 保存数据库
	err = a.ChatMessageModel.Create(ctx, item)
	if err != nil {
		return nil, err
	}

	return a.getUpdate(ctx, item.RecordID)
}

// Update 更新数据
func (a *ChatMessage) Update(ctx context.Context, recordID string, item schema.ChatMessage) (*schema.ChatMessage, error) {
	oldItem, err := a.ChatMessageModel.Get(ctx, recordID)
	if err != nil {
		return nil, err
	} else if oldItem == nil {
		return nil, errors.ErrNotFound
	}
	err = a.ChatMessageModel.Update(ctx, recordID, item)
	if err != nil {
		return nil, err
	}
	return a.getUpdate(ctx, recordID)
}

// Delete 删除数据
func (a *ChatMessage) Delete(ctx context.Context, recordID string) error {
	oldItem, err := a.ChatMessageModel.Get(ctx, recordID)
	if err != nil {
		return err
	} else if oldItem == nil {
		return errors.ErrNotFound
	}

	return a.ChatMessageModel.Delete(ctx, recordID)
}

// UpdateStatus 更新状态
func (a *ChatMessage) UpdateStatus(ctx context.Context, recordID string, status int) error {
	oldItem, err := a.ChatMessageModel.Get(ctx, recordID)
	if err != nil {
		return err
	} else if oldItem == nil {
		return errors.ErrNotFound
	}
	return a.ChatMessageModel.UpdateStatus(ctx, recordID, status)
}