package internal

import (
	"bufio"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"regexp"
	"strings"
	iContext "yx-dataset-server/app/context"
	"yx-dataset-server/app/errors"
	"yx-dataset-server/app/model"
	"yx-dataset-server/app/schema"
	"yx-dataset-server/library/ragflow"
	"yx-dataset-server/library/utils"
)

// TransFunc 定义事务执行函数
type TransFunc func(context.Context) error

// GetRootUser 获取root用户
func GetRootUser() *schema.User {
	return &schema.User{
		RecordID: utils.GetConfig("root.user_name").String(),
		UserName: utils.GetConfig("root.user_name").String(),
		RealName: utils.GetConfig("root.real_name").String(),
		Photo:    utils.GetConfig("root.photo").String(),
		Password: utils.MD5HashString(utils.GetConfig("root.password").String()),
	}
}

// GetUserID 获取用户ID
func GetUserID(ctx context.Context) string {
	userID, _ := iContext.FromUserID(ctx)
	return userID
}

// CheckIsRootUser 检查是否是root用户
func CheckIsRootUser(ctx context.Context) bool {
	userId := GetUserID(ctx)
	return GetRootUser().RecordID == userId
}

// ExecTrans 执行事务
func ExecTrans(ctx context.Context, transModel model.ITrans, fn TransFunc) error {
	if _, ok := iContext.FromTrans(ctx); ok {
		return fn(ctx)
	}
	trans, err := transModel.Begin(ctx)
	if err != nil {
		return err
	}

	defer func() {
		if r := recover(); r != nil {
			_ = transModel.Rollback(ctx, trans)
			panic(r)
		}
	}()

	err = fn(iContext.NewTrans(ctx, trans))
	if err != nil {
		_ = transModel.Rollback(ctx, trans)
		return err
	}
	return transModel.Commit(ctx, trans)

}

// ExecTransWithLock 执行事务（加锁）
func ExecTransWithLock(ctx context.Context, transModel model.ITrans, fn TransFunc) error {
	if !iContext.FromTransLock(ctx) {
		ctx = iContext.NewTransLock(ctx)
	}
	return ExecTrans(ctx, transModel, fn)
}

func CollectStreamDataAndCreate(ctx context.Context, stream io.ReadCloser, item *schema.ChatMessage) (*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{}

	re := regexp.MustCompile(`\[ID:\d+\]`)

	// 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 != "" {
			cleanAnswer := re.ReplaceAllString(chunk.Data.Answer, "")
			fullAnswer.WriteString(cleanAnswer)
		}
		// 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 nil, errors.New400Response(fmt.Sprintf("读取流式数据失败: %v", err))
	}

	cleanedFullAnswer := re.ReplaceAllString(fullAnswer.String(), "")
	item.Answer = cleanedFullAnswer
	return item, nil
}