// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later

package sound

import (
	"math"
	"strconv"
	"strings"
	"time"
)

const positionCuePrefix = "generated-position-tone:"

// PositionCueName encodes relative position: zero is first, one is last.
func PositionCueName(position float64) string {
	return positionCuePrefix + strconv.FormatFloat(position, 'g', -1, 64)
}

func set_position(cue string) (float64, bool) {
	if !strings.HasPrefix(cue, positionCuePrefix) {
		return 0, false
	}
	position, err := strconv.ParseFloat(strings.TrimPrefix(cue, positionCuePrefix), 64)
	return position, err == nil && !math.IsNaN(position) && !math.IsInf(position, 0) && position >= 0 && position <= 1
}

func position_tone_wav(position float64) []byte {
	// Two octaves distinguish the ends of a set. Smooth the edges of this
	// short cue; the service supplies the user's volume and stereo position.
	return tone_wav(220*math.Pow(4, position), 60*time.Millisecond, 0.5, 5*time.Millisecond)
}