// Copyright © 2023 OpenIM. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package mgo

import (
	"context"
	"github.com/openimsdk/open-im-server/v3/pkg/common/storage/database"
	"github.com/openimsdk/open-im-server/v3/pkg/common/storage/model"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"time"

	"github.com/openimsdk/tools/db/mongoutil"
	"github.com/openimsdk/tools/db/pagination"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

// FriendMgo implements Friend using MongoDB as the storage backend.
type FriendMgo struct {
	coll  *mongo.Collection
	owner database.VersionLog
}

// NewFriendMongo creates a new instance of FriendMgo with the provided MongoDB database.
func NewFriendMongo(db *mongo.Database) (database.Friend, error) {
	coll := db.Collection(database.FriendName)
	_, err := coll.Indexes().CreateOne(context.Background(), mongo.IndexModel{
		Keys: bson.D{
			{Key: "owner_user_id", Value: 1},
			{Key: "friend_user_id", Value: 1},
		},
		Options: options.Index().SetUnique(true),
	})
	if err != nil {
		return nil, err
	}
	owner, err := NewVersionLog(db.Collection(database.FriendVersionName))
	if err != nil {
		return nil, err
	}
	return &FriendMgo{coll: coll, owner: owner}, nil
}

func (f *FriendMgo) friendSort() any {
	return bson.D{{"is_pinned", -1}, {"_id", 1}}
}

// Create inserts multiple friend records.
func (f *FriendMgo) Create(ctx context.Context, friends []*model.Friend) error {
	for i, friend := range friends {
		if friend.ID.IsZero() {
			friends[i].ID = primitive.NewObjectID()
		}
		if friend.CreateTime.IsZero() {
			friends[i].CreateTime = time.Now()
		}
	}
	return mongoutil.IncrVersion(func() error {
		return mongoutil.InsertMany(ctx, f.coll, friends)
	}, func() error {
		mp := make(map[string][]string)
		for _, friend := range friends {
			mp[friend.OwnerUserID] = append(mp[friend.OwnerUserID], friend.FriendUserID)
		}
		for ownerUserID, friendUserIDs := range mp {
			if err := f.owner.IncrVersion(ctx, ownerUserID, friendUserIDs, model.VersionStateInsert); err != nil {
				return err
			}
		}
		return nil
	})
}

// Delete removes specified friends of the owner user.
func (f *FriendMgo) Delete(ctx context.Context, ownerUserID string, friendUserIDs []string) error {
	filter := bson.M{
		"owner_user_id":  ownerUserID,
		"friend_user_id": bson.M{"$in": friendUserIDs},
	}
	return mongoutil.IncrVersion(func() error {
		return mongoutil.DeleteOne(ctx, f.coll, filter)
	}, func() error {
		return f.owner.IncrVersion(ctx, ownerUserID, friendUserIDs, model.VersionStateDelete)
	})
}

// UpdateByMap updates specific fields of a friend document using a map.
func (f *FriendMgo) UpdateByMap(ctx context.Context, ownerUserID string, friendUserID string, args map[string]any) error {
	if len(args) == 0 {
		return nil
	}
	filter := bson.M{
		"owner_user_id":  ownerUserID,
		"friend_user_id": friendUserID,
	}
	return mongoutil.IncrVersion(func() error {
		return mongoutil.UpdateOne(ctx, f.coll, filter, bson.M{"$set": args}, true)
	}, func() error {
		var friendUserIDs []string
		if f.IsUpdateIsPinned(args) {
			friendUserIDs = []string{model.VersionSortChangeID, friendUserID}
		} else {
			friendUserIDs = []string{friendUserID}
		}
		return f.owner.IncrVersion(ctx, ownerUserID, friendUserIDs, model.VersionStateUpdate)
	})
}

// UpdateRemark updates the remark for a specific friend.
func (f *FriendMgo) UpdateRemark(ctx context.Context, ownerUserID, friendUserID, remark string) error {
	return f.UpdateByMap(ctx, ownerUserID, friendUserID, map[string]any{"remark": remark})
}

func (f *FriendMgo) fillTime(friends ...*model.Friend) {
	for i, friend := range friends {
		if friend.CreateTime.IsZero() {
			friends[i].CreateTime = friend.ID.Timestamp()
		}
	}
}

func (f *FriendMgo) findOne(ctx context.Context, filter any) (*model.Friend, error) {
	friend, err := mongoutil.FindOne[*model.Friend](ctx, f.coll, filter)
	if err != nil {
		return nil, err
	}
	f.fillTime(friend)
	return friend, nil
}

func (f *FriendMgo) find(ctx context.Context, filter any) ([]*model.Friend, error) {
	friends, err := mongoutil.Find[*model.Friend](ctx, f.coll, filter)
	if err != nil {
		return nil, err
	}
	f.fillTime(friends...)
	return friends, nil
}

func (f *FriendMgo) findPage(ctx context.Context, filter any, pagination pagination.Pagination, opts ...*options.FindOptions) (int64, []*model.Friend, error) {
	return mongoutil.FindPage[*model.Friend](ctx, f.coll, filter, pagination, opts...)
}

// Take retrieves a single friend document. Returns an error if not found.
func (f *FriendMgo) Take(ctx context.Context, ownerUserID, friendUserID string) (*model.Friend, error) {
	filter := bson.M{
		"owner_user_id":  ownerUserID,
		"friend_user_id": friendUserID,
	}
	return f.findOne(ctx, filter)
}

// FindUserState finds the friendship status between two users.
func (f *FriendMgo) FindUserState(ctx context.Context, userID1, userID2 string) ([]*model.Friend, error) {
	filter := bson.M{
		"$or": []bson.M{
			{"owner_user_id": userID1, "friend_user_id": userID2},
			{"owner_user_id": userID2, "friend_user_id": userID1},
		},
	}
	return f.find(ctx, filter)
}

// FindFriends retrieves a list of friends for a given owner. Missing friends do not cause an error.
func (f *FriendMgo) FindFriends(ctx context.Context, ownerUserID string, friendUserIDs []string) ([]*model.Friend, error) {
	filter := bson.M{
		"owner_user_id":  ownerUserID,
		"friend_user_id": bson.M{"$in": friendUserIDs},
	}
	return f.find(ctx, filter)
}

// FindReversalFriends finds users who have added the specified user as a friend.
func (f *FriendMgo) FindReversalFriends(ctx context.Context, friendUserID string, ownerUserIDs []string) ([]*model.Friend, error) {
	filter := bson.M{
		"owner_user_id":  bson.M{"$in": ownerUserIDs},
		"friend_user_id": friendUserID,
	}
	return f.find(ctx, filter)
}

// FindOwnerFriends retrieves a paginated list of friends for a given owner.
func (f *FriendMgo) FindOwnerFriends(ctx context.Context, ownerUserID string, pagination pagination.Pagination) (int64, []*model.Friend, error) {
	filter := bson.M{"owner_user_id": ownerUserID}
	opt := options.Find().SetSort(f.friendSort())
	return f.findPage(ctx, filter, pagination, opt)
}

func (f *FriendMgo) FindOwnerFriendUserIds(ctx context.Context, ownerUserID string, limit int) ([]string, error) {
	filter := bson.M{"owner_user_id": ownerUserID}
	opt := options.Find().SetProjection(bson.M{"_id": 0, "friend_user_id": 1}).SetSort(f.friendSort()).SetLimit(int64(limit))
	return mongoutil.Find[string](ctx, f.coll, filter, opt)
}

// FindInWhoseFriends finds users who have added the specified user as a friend, with pagination.
func (f *FriendMgo) FindInWhoseFriends(ctx context.Context, friendUserID string, pagination pagination.Pagination) (int64, []*model.Friend, error) {
	filter := bson.M{"friend_user_id": friendUserID}
	opt := options.Find().SetSort(f.friendSort())
	return f.findPage(ctx, filter, pagination, opt)
}

// FindFriendUserIDs retrieves a list of friend user IDs for a given owner.
func (f *FriendMgo) FindFriendUserIDs(ctx context.Context, ownerUserID string) ([]string, error) {
	filter := bson.M{"owner_user_id": ownerUserID}
	return mongoutil.Find[string](ctx, f.coll, filter, options.Find().SetProjection(bson.M{"_id": 0, "friend_user_id": 1}).SetSort(f.friendSort()))
}

func (f *FriendMgo) UpdateFriends(ctx context.Context, ownerUserID string, friendUserIDs []string, val map[string]any) error {
	// Ensure there are IDs to update
	if len(friendUserIDs) == 0 || len(val) == 0 {
		return nil // Or return an error if you expect there to always be IDs
	}

	// Create a filter to match documents with the specified ownerUserID and any of the friendUserIDs
	filter := bson.M{
		"owner_user_id":  ownerUserID,
		"friend_user_id": bson.M{"$in": friendUserIDs},
	}

	// Create an update document
	update := bson.M{"$set": val}

	return mongoutil.IncrVersion(func() error {
		return mongoutil.Ignore(mongoutil.UpdateMany(ctx, f.coll, filter, update))
	}, func() error {
		var userIDs []string
		if f.IsUpdateIsPinned(val) {
			userIDs = append([]string{model.VersionSortChangeID}, friendUserIDs...)
		} else {
			userIDs = friendUserIDs
		}
		return f.owner.IncrVersion(ctx, ownerUserID, userIDs, model.VersionStateUpdate)
	})
}

func (f *FriendMgo) FindIncrVersion(ctx context.Context, ownerUserID string, version uint, limit int) (*model.VersionLog, error) {
	return f.owner.FindChangeLog(ctx, ownerUserID, version, limit)
}

func (f *FriendMgo) FindFriendUserID(ctx context.Context, friendUserID string) ([]string, error) {
	filter := bson.M{
		"friend_user_id": friendUserID,
	}
	return mongoutil.Find[string](ctx, f.coll, filter, options.Find().SetProjection(bson.M{"_id": 0, "owner_user_id": 1}).SetSort(f.friendSort()))
}

func (f *FriendMgo) IncrVersion(ctx context.Context, ownerUserID string, friendUserIDs []string, state int32) error {
	return f.owner.IncrVersion(ctx, ownerUserID, friendUserIDs, state)
}

func (f *FriendMgo) IsUpdateIsPinned(data map[string]any) bool {
	if data == nil {
		return false
	}
	_, ok := data["is_pinned"]
	return ok
}