package pipe

import (
	"fmt"
	"sync"
)

func Proc[T any, V any](cin <-chan T, count int, proc func(T) (V, error)) <-chan V {
	cout := make(chan V)
	var wg sync.WaitGroup

	for i := 0; i < count; i++ {
		wg.Add(1)
		go func(<-chan T, chan<- V) {
			for i := range cin {
				v, err := proc(i)
				if err == nil {
					cout <- v
				} else {
					fmt.Println("####", err.Error())
				}
			}
			wg.Done()
		}(cin, cout)
	}

	go func() {
		wg.Wait()
		close(cout)
	}()

	return cout
}

func noop[T any](_ T) {}

func Wait[T any](cin <-chan T) {
	for v := range cin {
		noop(v)
	}
}

func TailProc[T any](cin <-chan T, count int, proc func(T) error) {
	var wg sync.WaitGroup

	for i := 0; i < count; i++ {
		wg.Add(1)
		go func(<-chan T) {
			for i := range cin {
				if err := proc(i); err != nil {
					fmt.Println("####", err.Error())
				}
			}
			wg.Done()

		}(cin)
	}
	wg.Wait()
}

func Yield[T any](in []T) <-chan T {
	cout := make(chan T)

	go func(chan<- T) {
		for _, a := range in {
			cout <- a
		}
		close(cout)
	}(cout)

	return cout
}

func Map[T any, V any](m func(T) V, vs []T) []V {
	result := make([]V, len(vs))

	for i, v := range vs {
		result[i] = m(v)
	}

	return result
}