package parallel

import (
	"sync"

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

func Map[T any](xs []T, fx func(T) T, n ...int) []T {
	rc := routineCount
	if len(n) > 0 {
		rc = n[0]
	}
	spl := lambda.Split(xs, rc)
	wg := new(sync.WaitGroup)
	wg.Add(len(spl))
	for i, v := range spl {
		go func(ix int, vx []T) {
			spl[ix] = lambda.Map(vx, fx)
			wg.Done()
		}(i, v)
	}
	wg.Wait()
	return lambda.Flatten(spl)
}

func MapV[T, V any](xs []T, fx func(T) V, n ...int) []V {
	rc := routineCount
	if len(n) > 0 {
		rc = n[0]
	}
	spl := lambda.Split(xs, rc)
	wg := new(sync.WaitGroup)
	wg.Add(len(spl))
	tmp := make([][]V, len(spl))
	for i, v := range spl {
		go func(ix int, vx []T) {
			tmp[ix] = lambda.MapV(vx, fx)
			wg.Done()
		}(i, v)
	}
	wg.Wait()
	return lambda.Flatten(tmp)
}

func MapError[T any](xs []T, fx func(T) (T, error), n ...int) ([]T, []error) {
	rc := routineCount
	if len(n) > 0 {
		rc = n[0]
	}
	spl := lambda.Split(xs, rc)
	wg := new(sync.WaitGroup)
	wg.Add(len(spl))
	tmp := make([][]error, len(spl))
	for i, v := range spl {
		go func(ix int, vx []T) {
			spl[ix], tmp[ix] = lambda.MapError(vx, fx)
			wg.Done()
		}(i, v)
	}
	wg.Wait()
	return lambda.Flatten(spl), lambda.Flatten(tmp)
}

func MapErrorV[T, V any](xs []T, fx func(T) (V, error), n ...int) ([]V, []error) {
	rc := routineCount
	if len(n) > 0 {
		rc = n[0]
	}
	spl := lambda.Split(xs, rc)
	wg := new(sync.WaitGroup)
	wg.Add(len(spl))
	tmp := make([][]V, len(spl))
	tmp2 := make([][]error, len(spl))
	for i, v := range spl {
		go func(ix int, vx []T) {
			tmp[ix], tmp2[ix] = lambda.MapErrorV(vx, fx)
			wg.Done()
		}(i, v)
	}
	wg.Wait()
	return lambda.Flatten(tmp), lambda.Flatten(tmp2)
}