// Licensed to the LF AI & Data foundation under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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 checkers

import (
	"context"
	"time"

	"github.com/milvus-io/milvus/internal/querycoordv2/balance"
	. "github.com/milvus-io/milvus/internal/querycoordv2/params"
	"github.com/milvus-io/milvus/internal/querycoordv2/task"
)

// BalanceChecker checks the cluster distribution and generates balance tasks.
type BalanceChecker struct {
	baseChecker
	balance.Balance
}

func NewBalanceChecker(balancer balance.Balance) *BalanceChecker {
	return &BalanceChecker{
		Balance: balancer,
	}
}

func (b *BalanceChecker) Description() string {
	return "BalanceChecker checks the cluster distribution and generates balance tasks"
}

func (b *BalanceChecker) Check(ctx context.Context) []task.Task {
	ret := make([]task.Task, 0)
	if !Params.QueryCoordCfg.AutoBalance.GetAsBool() {
		return ret
	}
	segmentPlans, channelPlans := b.Balance.Balance()

	tasks := balance.CreateSegmentTasksFromPlans(ctx, b.ID(), Params.QueryCoordCfg.SegmentTaskTimeout.GetAsDuration(time.Millisecond), segmentPlans)
	task.SetPriority(task.TaskPriorityLow, tasks...)
	ret = append(ret, tasks...)

	tasks = balance.CreateChannelTasksFromPlans(ctx, b.ID(), Params.QueryCoordCfg.ChannelTaskTimeout.GetAsDuration(time.Millisecond), channelPlans)
	ret = append(ret, tasks...)
	return ret
}