package main

import (
	"math"

	rl "github.com/gen2brain/raylib-go/raylib"
)

type movementPattern func(*enemy) *enemy

type patternDuration struct {
	duration duration
	move     movementPattern
}

type statePipeline []patternDuration

func shootStill() movementPattern {
	return func(e *enemy) *enemy {
		if e.shoot != nil {
			e.shoot(e)
		}
		return e
	}
}

func (sp statePipeline) MovementPattern(g *game) movementPattern {
	state := -1
	t := newTimer(0)
	return func(e *enemy) *enemy {
		if !t.isTimeout() {
			t.tick(g)
		} else if state < len(sp)-1 {
			state++
			t = newTimer(sp[state].duration)
		}
		sp[state].move(e)
		return e
	}
}

func horizonalPattern(g *game) movementPattern {
	direction := 1

	return func(e *enemy) *enemy {
		if e.shoot != nil {
			e.shoot(e)
		}

		delta := rl.Vector2{
			X: 400,
			Y: 0,
		}

		if e.pos.X < e.hitBoxRadius || e.pos.X > float32(g.arenaWidth-int32(e.hitBoxRadius)) {
			direction = -direction
		}

		e.pos = rl.Vector2Add(
			e.pos,
			rl.Vector2Scale(
				rl.Vector2{X: float32(direction) * delta.X, Y: delta.Y},
				rl.GetFrameTime()*g.gameSpeed,
			),
		)
		return e
	}
}

func descentMove(g *game, y0, y1 float32, d duration) movementPattern {
	t := newTimer(d)
	return func(e *enemy) *enemy {

		if e.shoot != nil {
			e.shoot(e)
		}

		if !t.isTimeout() {
			t.tick(g)
		} else {
			return e
		}

		e.pos.Y = lerp(y0, y1, easeInOutSine(t.unit()))
		return e
	}
}

func sineDescentMove(g *game, y0, y1 float32, d duration) movementPattern {
	t := newTimer(d)
	return func(e *enemy) *enemy {

		if e.shoot != nil {
			e.shoot(e)
		}

		if !t.isTimeout() {
			t.tick(g)
		} else {
			return e
		}

		e.pos.Y = lerp(y0, y1, easeInOutSine(t.unit()))
		e.pos.X += float32(math.Sin(rl.GetTime() * 5 * float64(g.gameSpeed)))

		return e
	}
}

func sineHorizonalPattern(g *game, offset float64) movementPattern {
	direction := 1

	return func(e *enemy) *enemy {
		if e.shoot != nil {
			e.shoot(e)
		}

		sine := math.Sin(rl.GetTime()*5*float64(g.gameSpeed)+offset) * 150

		delta := rl.Vector2{
			X: 400,
			Y: float32(sine),
		}

		if e.pos.X < e.hitBoxRadius || e.pos.X > float32(g.arenaWidth-int32(e.hitBoxRadius)) {
			direction = -direction
		}

		e.pos = rl.Vector2Add(
			e.pos,
			rl.Vector2Scale(
				rl.Vector2{X: float32(direction) * delta.X, Y: delta.Y},
				rl.GetFrameTime()*g.gameSpeed,
			),
		)
		return e
	}
}