package media

import (
	"errors"
	"fmt"
	"strconv"

	"codeberg.org/danjones000/strip-beats/config"
	ffmpeg "github.com/u2takey/ffmpeg-go"
)

func TrimWithFade(in Probe, out string, start, stop, up, down float64) error {
	// -ss (start) -t (end) -af afade=t=in:st=(start):d=(up),afade=t=out:st=(downstart):d=(down)
	st := in.GetFirstAcceptableAudio()
	if st == nil {
		return errors.New("Can't find an audio stream")
	}
	args := ffmpeg.KwArgs{"c:a": "copy"}
	if start != 0 {
		args["ss"] = start
	}
	if stop != 0 {
		end := stop - start
		args["t"] = end
	} else {
		stop = st.Duration
	}

	input := ffmpeg.Input(in.Format.Path).Get(strconv.Itoa(st.Index))
	if up != 0 {
		args["c:a"] = config.GetConfig().FfEncoder
		input = input.Filter("afade", ffmpeg.Args{
			"t=in",
			fmt.Sprintf("st=%v", start),
			fmt.Sprintf("d=%v", up)})
	}

	if down != 0 {
		args["c:a"] = config.GetConfig().FfEncoder
		downstart := stop - down
		input = input.Filter("afade", ffmpeg.Args{
			"t=out",
			fmt.Sprintf("st=%v", downstart),
			fmt.Sprintf("d=%v", down)})
	}
	output := input.Output(out, args).GlobalArgs("-y")
	// @todo out should be stdout
	return output.Run()
}

func Trim(in Probe, out string, start, stop float64) error {
	return TrimWithFade(in, out, start, stop, 0, 0)
}

func Fade(in Probe, out string, up, down float64) error {
	return TrimWithFade(in, out, 0, 0, up, down)
}