package effects

import (
	"fmt"
	"git.aiterp.net/lucifer3/server/device"
	"math"
	"time"
)

type Gradient struct {
	States      []device.State `json:"states,omitempty"`
	AnimationMS int64          `json:"AnimationMs,omitempty"`
	Reverse     bool           `json:"backward,omitempty"`
	Interpolate bool           `json:"interpolate,omitempty"`
}

func (e Gradient) State(index, length, round, _ int) device.State {
	if len(e.States) == 0 {
		return device.State{}
	}

	if e.Reverse {
		index = length - (index + 1)
	}

	walkedIndex := (index + round) % length
	indexFactor := math.Min(float64(walkedIndex)/float64(length-1), 1)
	stateIncrement := 1.0 / float64(len(e.States)-1)

	for i := range e.States {
		a := float64(i) * stateIncrement
		if indexFactor >= a {
			si := e.States[i]
			sj := e.States[(i+1)%len(e.States)]
			f := (indexFactor - a) / stateIncrement

			if f < 0 || f > 1 {
				panic(f)
			}

			if e.Interpolate {
				return si.Interpolate(sj, f)
			} else if f < 0.5 {
				return si
			} else {
				return sj
			}
		}
	}

	return e.States[len(e.States)-1]
}

func (e Gradient) Frequency() time.Duration {
	return time.Duration(e.AnimationMS) * time.Millisecond
}

func (e Gradient) EffectDescription() string {
	return fmt.Sprintf("Gradient(states:%s, anim:%dms, int:%t)", statesDescription(e.States), e.AnimationMS, e.Interpolate)
}