package tins2021

import (
	"math/rand"
	"time"

	"opslag.de/schobers/geom"
)

type Animation struct {
	LastUpdate time.Time
	Frame      int
}

type Animations struct {
	Values     map[geom.Point]*Animation
	Interval   time.Duration
	Frames     int
	AutoReset  bool
	RandomInit bool
}

func NewAnimations(interval time.Duration, frames int, autoReset, randomInit bool) *Animations {
	return &Animations{
		Values:     map[geom.Point]*Animation{},
		Interval:   interval,
		Frames:     frames,
		AutoReset:  autoReset,
		RandomInit: randomInit,
	}
}

func (a *Animations) Update() {
	now := time.Now()
	update := now.Add(-a.Interval)
	for _, value := range a.Values {
		if value.Frame == a.Frames {
			break
		}
		for value.LastUpdate.Before(update) {
			value.LastUpdate = value.LastUpdate.Add(a.Interval)
			value.Frame = value.Frame + 1
			if value.Frame == a.Frames {
				if a.AutoReset {
					value.Frame = 0
				} else {
					break
				}
			}
		}
	}
}

func (a *Animations) newAnimation() *Animation {
	if a.RandomInit {
		return &Animation{
			LastUpdate: time.Now().Add(time.Duration(-rand.Int63n(int64(a.Interval)))),
			Frame:      rand.Intn(a.Frames),
		}
	}
	return &Animation{
		LastUpdate: time.Now(),
		Frame:      0,
	}
}

func (a *Animations) Frame(pos geom.Point) int {
	value, ok := a.Values[pos]
	if !ok {
		value = a.newAnimation()
		a.Values[pos] = value
	}
	return value.Frame
}