// Copyright 2019 Yunion
//
// 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 workqueue

import (
	"sync"

	utilruntime "yunion.io/x/pkg/util/runtime"
)

type DoWorkPieceFunc func(piece int)

// Parallelize is a very simple framework that allow for parallelizing
// N independent pieces of work.
func Parallelize(workers, pieces int, doWorkPiece DoWorkPieceFunc) {
	toProcess := make(chan int, pieces)
	for i := 0; i < pieces; i++ {
		toProcess <- i
	}
	close(toProcess)

	if pieces < workers {
		workers = pieces
	}

	wg := sync.WaitGroup{}
	wg.Add(workers)
	for i := 0; i < workers; i++ {
		go func() {
			defer utilruntime.HandleCrash()
			defer wg.Done()
			for piece := range toProcess {
				doWorkPiece(piece)
			}
		}()
	}
	wg.Wait()
}