package parallel

import (
	"sync"

	"git.tuxpa.in/a/lambda"
)

var routineCount int = 1

func SetRoutineCount(n int) {
	routineCount = n
}
func Foldl[T any](xs []T, fx func(T, T) T) T {
	spl := lambda.Split(xs, routineCount)
	wg := new(sync.WaitGroup)
	wg.Add(len(spl))
	tmp := make([]T, len(spl))
	for i, v := range spl {
		go func(ix int, vx []T) {
			tmp[ix] = lambda.Foldl(vx, fx)
			wg.Done()
		}(i, v)
	}
	wg.Wait()
	return lambda.Foldl(tmp, fx)
}

func Foldr[T any](xs []T, fx func(T, T) T) T {
	spl := lambda.Split(xs, routineCount)
	wg := new(sync.WaitGroup)
	wg.Add(len(spl))
	tmp := make([]T, len(spl))
	for i, v := range spl {
		go func(ix int, vx []T) {
			tmp[ix] = lambda.Foldr(vx, fx)
			wg.Done()
		}(i, v)
	}
	wg.Wait()
	return lambda.Foldr(tmp, fx)
}