package internal

import (
	"context"
	"fmt"
	"sort"
	"strings"
	"time"

	"github.com/gogf/gf/v2/os/glog"
	"github.com/gogf/gf/v2/util/guid"
	"yx-dataset-server/app/errors"
	"yx-dataset-server/app/model"
	"yx-dataset-server/app/schema"
	"yx-dataset-server/library/ragflow"
)

// NewChatAssistant 创建ChatAssistant
func NewChatAssistant(
	mChatAssistant model.IChatAssistant,
	mChatDataset model.IChatDataset,
	mTrans model.ITrans,
	mDataset model.IDataset,
	mUser model.IUser,
	mSession model.IChatSession,
	mMessage model.IChatMessage,
	mRelation model.IDatasetRelation,
	mFile model.IDatasetFile,
) *ChatAssistant {
	return &ChatAssistant{
		ChatAssistantModel: mChatAssistant,
		chatDatasetModel:   mChatDataset,
		transModel:         mTrans,
		datasetModel:       mDataset,
		userModel:          mUser,
		sessionModel:       mSession,
		messageModel:       mMessage,
		relationModel:      mRelation,
		fileModel:          mFile,
	}
}

// ChatAssistant 创建ChatAssistant对象
type ChatAssistant struct {
	ChatAssistantModel model.IChatAssistant
	chatDatasetModel   model.IChatDataset
	transModel         model.ITrans
	datasetModel       model.IDataset
	userModel          model.IUser
	sessionModel       model.IChatSession
	messageModel       model.IChatMessage
	relationModel      model.IDatasetRelation
	fileModel          model.IDatasetFile
}

// Query 查询数据
func (a *ChatAssistant) Query(ctx context.Context, params schema.ChatAssistantQueryParam, opts ...schema.ChatAssistantQueryOptions) (*schema.ChatAssistantQueryResult, error) {
	var userQueryParam schema.UserQueryParam
	userQueryParam.RoleCode = []string{"11", "12"}
	if !CheckIsRootUser(ctx) {
		user, err := a.userModel.Get(ctx, GetUserID(ctx))
		if err != nil {
			return nil, err
		}
		params.OrgId = user.OrgId
		userQueryParam.OrgId = user.OrgId
	}

	result, err := a.ChatAssistantModel.Query(ctx, params, opts...)
	if err != nil {
		return nil, err
	}
	chatDataset, err := a.chatDatasetModel.Query(ctx, schema.ChatDatasetQueryParam{})
	if err != nil {
		return nil, err
	}
	result.Data.FillDatasetId(chatDataset.Data)

	dataset, err := a.datasetModel.Query(ctx, schema.DatasetQueryParam{})
	if err != nil {
		return nil, err
	}
	result.Data.FillDataset(dataset.Data)

	users, err := a.userModel.Query(ctx, userQueryParam)
	if err != nil {
		return nil, err
	}
	result.Data.FillCreator(users.Data)

	sessions, err := a.sessionModel.Query(ctx, schema.ChatSessionQueryParam{})
	if err != nil {
		return nil, err
	}

	result.Data.FillSession(sessions.Data)

	return result, nil
}

// Get 查询指定数据
func (a *ChatAssistant) Get(ctx context.Context, recordID string, opts ...schema.ChatAssistantQueryOptions) (*schema.ChatAssistant, error) {
	item, err := a.ChatAssistantModel.Get(ctx, recordID, opts...)
	if err != nil {
		return nil, err
	} else if item == nil {
		return nil, errors.ErrNotFound
	}
	user, err := a.userModel.Get(ctx, item.CreatorId)
	if err != nil {
		return nil, err
	}
	item.CreatorName = user.RealName

	chatDataset, err := a.chatDatasetModel.Query(ctx, schema.ChatDatasetQueryParam{ChatAssistantId: recordID})
	if err != nil {
		return nil, err
	}

	dataset, err := a.datasetModel.Query(ctx, schema.DatasetQueryParam{RecordIds: chatDataset.Data.ToDatasetIds()})
	if err != nil {
		return nil, err
	}
	users, err := a.userModel.Query(ctx, schema.UserQueryParam{RoleCode: []string{"11", "12"}})
	if err != nil {
		return nil, err
	}
	dataset.Data.FillCreator(users.Data)
	item.Datasets = dataset.Data

	sessions, err := a.sessionModel.Query(ctx, schema.ChatSessionQueryParam{AssistantId: item.RecordID})
	if err != nil {
		return nil, err
	}
	item.Sessions = sessions.Data
	return item, nil
}

// Create 创建数据
func (a *ChatAssistant) Create(ctx context.Context, item schema.ChatAssistant) (*schema.ChatAssistant, error) {
	// root用户不能创建对话助手
	if CheckIsRootUser(ctx) {
		return nil, errors.New400Response("permission denied")
	}

	item.RecordID = guid.S()
	item.CreatorId = GetUserID(ctx)

	var ragDatasetIds []string

	// 获取用户组织id
	user, err := a.userModel.Get(ctx, item.CreatorId)
	if err != nil {
		return nil, err
	}
	item.OrgId = user.OrgId

	name := fmt.Sprintf("%s%s:%s", user.RealName, "对话助手", time.Now().Format("2006-01-02 15:04:05"))
	if item.Name != "" {
		name = item.Name
	}
	item.Name = name

	// 取当前用户（含其所属组织）能访问的全部知识库
	bizIds := []string{GetUserID(ctx)}
	if user.OrgId != "" {
		bizIds = append(bizIds, user.OrgId)
	}
	rel, err := a.relationModel.Query(ctx, schema.DatasetRelationQueryParam{BizIds: bizIds})
	if err != nil {
		return nil, err
	}
	dataset, err := a.datasetModel.Query(ctx, schema.DatasetQueryParam{RecordIds: rel.Data.ToDatasetIds()})
	if err != nil {
		return nil, err
	}

	err = a.CheckFiles(ctx, dataset.Data.ToRecordIds())
	if err != nil {
		return nil, err
	}
	ragDatasetIds = dataset.Data.ToRagDataIds()

	err = ExecTrans(ctx, a.transModel, func(ctx context.Context) error {
		for _, v := range dataset.Data {
			err = a.chatDatasetModel.Create(ctx, schema.ChatDataset{
				RecordID:        guid.S(),
				ChatAssistantId: item.RecordID,
				DatasetId:       v.RecordID,
			})
			if err != nil {
				return err
			}
		}

		resp, err := ragflow.GetHttpClient().CreateChat(ctx, &ragflow.CreateChatReq{
			Name:       name,
			DatasetIDs: ragDatasetIds,
		})
		if err != nil {
			return err
		}
		item.RagChatId = resp.Data.ID

		err = a.ChatAssistantModel.Create(ctx, item)
		if err != nil {
			return err
		}
		if item.Source == 1 {
			user.H5AssistantId = item.RecordID
			err = a.userModel.Update(ctx, user.RecordID, *user)
			if err != nil {
				return err
			}
		}
		return nil
	})
	return a.Get(ctx, item.RecordID)
}

func (a *ChatAssistant) CheckFiles(ctx context.Context, datasetIds []string) error {
	files, err := a.fileModel.Query(ctx, schema.DatasetFileQueryParam{DatasetIds: datasetIds})
	if err != nil {
		return err
	}
	for _, v := range files.Data {
		if v.Enabled && v.ParseStatus == 2 {
			return nil
		}
	}
	return errors.New("用户关联知识库没有已解析的文件，不能使用对话助手，请联系管理员确认。")
}

// Update 更新数据
func (a *ChatAssistant) Update(ctx context.Context, recordID string, item schema.ChatAssistant) error {
	oldItem, err := a.ChatAssistantModel.Get(ctx, recordID)
	if err != nil {
		return err
	} else if oldItem == nil {
		return errors.ErrNotFound
	}
	err = ExecTrans(ctx, a.transModel, func(ctx context.Context) error {
		err = a.ChatAssistantModel.Update(ctx, recordID, item)
		if err != nil {
			return err
		}
		if item.Name != oldItem.Name {
			_, err = ragflow.GetHttpClient().UpdateChat(ctx, item.RagChatId, &ragflow.UpdateChatReq{
				Name: item.Name,
			})
			if err != nil {
				return err
			}
		}
		return nil
	})

	return err
}

// Delete 删除数据
func (a *ChatAssistant) Delete(ctx context.Context, recordID string) error {
	oldItem, err := a.ChatAssistantModel.Get(ctx, recordID)
	if err != nil {
		return err
	} else if oldItem == nil {
		return errors.ErrNotFound
	}
	err = ExecTrans(ctx, a.transModel, func(ctx context.Context) error {
		err = a.ChatAssistantModel.Delete(ctx, recordID)
		if err != nil {
			return err
		}
		_, err = ragflow.GetHttpClient().DeleteChats(ctx, []string{oldItem.RagChatId})
		if err != nil {
			return err
		}
		return nil
	})
	return err
}

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

// loadCurrentUserDatasets 取当前用户（及所属组织）可访问的全部知识库
func (a *ChatAssistant) loadCurrentUserDatasets(ctx context.Context, user *schema.User) (schema.Datasets, error) {
	bizIds := []string{user.RecordID}

	rel, err := a.relationModel.Query(ctx, schema.DatasetRelationQueryParam{BizIds: bizIds})
	if err != nil {
		return nil, err
	}
	if len(rel.Data) == 0 {
		return schema.Datasets{}, nil
	}
	ds, err := a.datasetModel.Query(ctx, schema.DatasetQueryParam{RecordIds: rel.Data.ToDatasetIds()})
	if err != nil {
		return nil, err
	}
	return ds.Data, nil
}

// diffIds 返回 a 相比 b 的差集（按排序后的字符串切片）
func diffIds(a, b []string) []string {
	m := make(map[string]struct{}, len(b))
	for _, v := range b {
		m[v] = struct{}{}
	}
	out := make([]string, 0)
	for _, v := range a {
		if _, ok := m[v]; !ok {
			out = append(out, v)
		}
	}
	sort.Strings(out)
	return out
}

// idsEqual 忽略顺序比较两组 id 是否一致
func idsEqual(a, b []string) bool {
	if len(a) != len(b) {
		return false
	}
	aa := append([]string(nil), a...)
	bb := append([]string(nil), b...)
	sort.Strings(aa)
	sort.Strings(bb)
	for i := range aa {
		if aa[i] != bb[i] {
			return false
		}
	}
	return true
}

// CheckPermissionSync 对比当前登录用户的 KB 权限与其 h5 对话助手绑定的 KB
func (a *ChatAssistant) CheckPermissionSync(ctx context.Context) (*schema.AssistantPermissionStatus, error) {
	if CheckIsRootUser(ctx) {
		return nil, errors.New400Response("permission denied")
	}
	userId := GetUserID(ctx)
	user, err := a.userModel.Get(ctx, userId)
	if err != nil {
		return nil, err
	} else if user == nil {
		return nil, errors.ErrNotFound
	}

	currentDatasets, err := a.loadCurrentUserDatasets(ctx, user)
	if err != nil {
		return nil, err
	}
	currentIds := currentDatasets.ToRecordIds()

	status := &schema.AssistantPermissionStatus{
		AssistantId:       user.H5AssistantId,
		CurrentDatasetIds: currentIds,
		BoundDatasetIds:   []string{},
		Added:             []string{},
		Removed:           []string{},
	}

	// 没有 h5 助手 => 需要创建
	if user.H5AssistantId == "" {
		status.Synced = false
		status.NeedCreate = true
		status.Added = append([]string{}, currentIds...)
		sort.Strings(status.Added)
		return status, nil
	}

	// 助手可能已被删除
	assistant, err := a.ChatAssistantModel.Get(ctx, user.H5AssistantId)
	if err != nil {
		return nil, err
	}
	if assistant == nil {
		status.Synced = false
		status.NeedCreate = true
		status.AssistantId = ""
		status.Added = append([]string{}, currentIds...)
		sort.Strings(status.Added)
		return status, nil
	}

	cd, err := a.chatDatasetModel.Query(ctx, schema.ChatDatasetQueryParam{ChatAssistantId: assistant.RecordID})
	if err != nil {
		return nil, err
	}
	boundIds := cd.Data.ToDatasetIds()
	status.BoundDatasetIds = boundIds
	status.Synced = idsEqual(currentIds, boundIds)
	status.Added = diffIds(currentIds, boundIds)
	status.Removed = diffIds(boundIds, currentIds)
	return status, nil
}

// SyncPermission 按当前用户的 KB 权限重建或创建 h5 对话助手、会话与欢迎消息
// 流程：
//  1. 无助手 => 创建 ragflow chat + 本地助手 + 本地 chat_dataset + 新会话 + 欢迎消息
//  2. 已有助手且权限不一致 => 清理旧会话（含 ragflow）+ 重建 chat_dataset + 更新 ragflow chat + 创建新会话与欢迎消息
//  3. 权限已一致 => 直接返回
func (a *ChatAssistant) SyncPermission(ctx context.Context) (*schema.ChatAssistant, error) {
	if CheckIsRootUser(ctx) {
		return nil, errors.New400Response("permission denied")
	}
	userId := GetUserID(ctx)
	user, err := a.userModel.Get(ctx, userId)
	if err != nil {
		return nil, err
	} else if user == nil {
		return nil, errors.ErrNotFound
	}

	currentDatasets, err := a.loadCurrentUserDatasets(ctx, user)
	if err != nil {
		return nil, err
	}
	if len(currentDatasets) == 0 {
		return nil, errors.New400Response("当前用户没有可用的知识库，无法创建或更新对话助手")
	}
	if err := a.CheckFiles(ctx, currentDatasets.ToRecordIds()); err != nil {
		return nil, err
	}
	ragDatasetIds := currentDatasets.ToRagDataIds()

	// ---------- 1. 无助手：创建 ----------
	if user.H5AssistantId == "" {
		return a.createH5Assistant(ctx, user, currentDatasets, ragDatasetIds)
	}

	assistant, err := a.ChatAssistantModel.Get(ctx, user.H5AssistantId)
	if err != nil {
		return nil, err
	}
	// 助手已被删 => 重建
	if assistant == nil {
		user.H5AssistantId = ""
		return a.createH5Assistant(ctx, user, currentDatasets, ragDatasetIds)
	}

	// ---------- 2. 已有助手：检查是否一致 ----------
	cd, err := a.chatDatasetModel.Query(ctx, schema.ChatDatasetQueryParam{ChatAssistantId: assistant.RecordID})
	if err != nil {
		return nil, err
	}
	if idsEqual(currentDatasets.ToRecordIds(), cd.Data.ToDatasetIds()) {
		return a.Get(ctx, assistant.RecordID)
	}

	// ---------- 3. 已有助手且不一致：重建 ----------
	if err := a.rebuildAssistant(ctx, assistant, currentDatasets, ragDatasetIds); err != nil {
		return nil, err
	}
	return a.Get(ctx, assistant.RecordID)
}

// createH5Assistant 为用户创建一个 h5 对话助手，并同步创建一个新会话+欢迎消息
func (a *ChatAssistant) createH5Assistant(ctx context.Context, user *schema.User, datasets schema.Datasets, ragDatasetIds []string) (*schema.ChatAssistant, error) {
	assistant := schema.ChatAssistant{
		RecordID:  guid.S(),
		OrgId:     user.OrgId,
		UserId:    user.RecordID,
		Source:    1,
		CreatorId: user.RecordID,
		Name:      fmt.Sprintf("%s%s:%s", user.RealName, "对话助手", time.Now().Format("2006-01-02 15:04:05")),
	}
	err := ExecTrans(ctx, a.transModel, func(ctx context.Context) error {
		resp, err := ragflow.GetHttpClient().CreateChat(ctx, &ragflow.CreateChatReq{
			Name:       assistant.Name,
			DatasetIDs: ragDatasetIds,
		})
		if err != nil {
			return err
		}
		assistant.RagChatId = resp.Data.ID

		for _, d := range datasets {
			if err := a.chatDatasetModel.Create(ctx, schema.ChatDataset{
				RecordID:        guid.S(),
				ChatAssistantId: assistant.RecordID,
				DatasetId:       d.RecordID,
				RagDataId:       d.RagDataId,
			}); err != nil {
				return err
			}
		}

		if err := a.ChatAssistantModel.Create(ctx, assistant); err != nil {
			return err
		}

		user.H5AssistantId = assistant.RecordID
		if err := a.userModel.Update(ctx, user.RecordID, *user); err != nil {
			return err
		}

		return a.createWelcomeSession(ctx, &assistant, datasets, user.RecordID)
	})
	if err != nil {
		return nil, err
	}
	return a.Get(ctx, assistant.RecordID)
}

// rebuildAssistant 清空助手的旧会话、旧知识库映射，按最新 KB 重建，并创建新会话与欢迎消息
func (a *ChatAssistant) rebuildAssistant(ctx context.Context, assistant *schema.ChatAssistant, datasets schema.Datasets, ragDatasetIds []string) error {
	return ExecTrans(ctx, a.transModel, func(ctx context.Context) error {
		// 清理旧会话（先删 ragflow 侧再删本地）
		oldSessions, err := a.sessionModel.Query(ctx, schema.ChatSessionQueryParam{AssistantId: assistant.RecordID})
		if err != nil {
			return err
		}
		if len(oldSessions.Data) > 0 && assistant.RagChatId != "" {
			ragSessionIds := make([]string, 0, len(oldSessions.Data))
			for _, s := range oldSessions.Data {
				if s.RagSessionId != "" {
					ragSessionIds = append(ragSessionIds, s.RagSessionId)
				}
			}
			if len(ragSessionIds) > 0 {
				if _, err := ragflow.GetHttpClient().DeleteSessions(ctx, assistant.RagChatId, ragSessionIds); err != nil {
					glog.Errorf(ctx, "删除 ragflow 会话失败: %s", err.Error())
				}
			}
		}
		if err := a.sessionModel.DeleteByAssistantId(ctx, assistant.RecordID); err != nil {
			return err
		}

		// 重建 chat_dataset 映射
		if err := a.chatDatasetModel.DeleteByAssistantId(ctx, assistant.RecordID); err != nil {
			return err
		}
		for _, d := range datasets {
			if err := a.chatDatasetModel.Create(ctx, schema.ChatDataset{
				RecordID:        guid.S(),
				ChatAssistantId: assistant.RecordID,
				DatasetId:       d.RecordID,
				RagDataId:       d.RagDataId,
			}); err != nil {
				return err
			}
		}

		// 同步 ragflow 助手绑定的知识库
		if assistant.RagChatId != "" {
			if _, err := ragflow.GetHttpClient().UpdateChat(ctx, assistant.RagChatId, &ragflow.UpdateChatReq{
				DatasetIDs: ragDatasetIds,
			}); err != nil {
				return err
			}
		}

		return a.createWelcomeSession(ctx, assistant, datasets, assistant.CreatorId)
	})
}

// createWelcomeSession 为助手创建一条新的 ragflow 会话，并写入一条欢迎消息
func (a *ChatAssistant) createWelcomeSession(ctx context.Context, assistant *schema.ChatAssistant, datasets schema.Datasets, userId string) error {
	if assistant.RagChatId == "" {
		return nil
	}
	sessionName := fmt.Sprintf("%s%s", time.Now().Format("2006-01-02 15:04:05 "), "会话")
	resp, err := ragflow.GetHttpClient().CreateSession(ctx, assistant.RagChatId, &ragflow.CreateSessionReq{Name: sessionName})
	if err != nil {
		return err
	}
	session := schema.ChatSession{
		RecordID:     guid.S(),
		Name:         sessionName,
		AssistantId:  assistant.RecordID,
		RagChatId:    assistant.RagChatId,
		RagSessionId: resp.Data.Id,
		Source:       assistant.Source,
		CreatorId:    userId,
	}
	if err := a.sessionModel.Create(ctx, session); err != nil {
		return err
	}

	datasetNames := make([]string, 0, len(datasets))
	for _, d := range datasets {
		datasetNames = append(datasetNames, fmt.Sprintf("《%s》", d.Name))
	}
	answer := fmt.Sprintf("你好，欢迎使用知识库问答助手！关于%s的疑问，我都会尽力为你解答，快来提问吧！", strings.Join(datasetNames, ","))
	message := schema.ChatMessage{
		RecordID:     guid.S(),
		UserId:       userId,
		AssistantId:  assistant.RecordID,
		SessionId:    session.RecordID,
		RagSessionId: resp.Data.Id,
		Question:     "",
		Answer:       strings.ReplaceAll(answer, `\`, ``),
		CreatorId:    userId,
	}
	return a.messageModel.Create(ctx, message)
}