package main

import (
	"fmt"
	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
	"github.com/hajimehoshi/ebiten/v2/inpututil"
	"gitlab.com/kbr4/9heroja/collision"
	"gitlab.com/kbr4/9heroja/configuration"
	"gitlab.com/kbr4/9heroja/hero"
	"gitlab.com/kbr4/9heroja/input"
	"gitlab.com/kbr4/9heroja/terrain"
	"gitlab.com/kbr4/9heroja/weapons"
	"gitlab.com/kbr4/9heroja/zombie"
	_ "image/png"
	"log"
)

const (
	screenWidth      = 640
	screenHeight     = 480
	tileSize         = 33
	titleFontSize    = fontSize * 1.5
	fontSize         = 24
	smallFontSize    = fontSize / 2
	pipeWidth        = tileSize * 2
	pipeStartOffsetX = 8
	pipeIntervalX    = 8
	pipeGapY         = 5
)

func floorDiv(x, y int) int {
	d := x / y
	if d*y == x || x >= 0 {
		return d
	}
	return d - 1
}

func floorMod(x, y int) int {
	return x - floorDiv(x, y)*y
}

type Game struct {

	// The gopher's position
	x16  int
	y16  int
	vy16 int

	keys []ebiten.Key

	control *input.Keyboard

	hero    *hero.Hero
	terrain *terrain.Terrain
	zombies []*zombie.Zombie
	world   *collision.World
	bullets []*weapons.Handgun
}

func (g *Game) Update() error {
	g.keys = inpututil.AppendPressedKeys(g.keys[:0])
	GameInstance.hero.ChangeDirection(GameInstance.control.DirectionFromKeys(g.keys))
	GameInstance.terrain.ChangeDirection(GameInstance.control.DirectionFromKeys(g.keys))
	bullet := GameInstance.hero.Fire(GameInstance.control.ShouldFire(g.keys), g.terrain.PositionX, g.terrain.PositionY)
	if bullet != nil {
		GameInstance.world.AddEntity(bullet)
		g.bullets = append(g.bullets, bullet)
	}

	if len(g.keys) <= 0 {
		g.hero.Stop()
	} else {
		g.terrain.Move()
		g.hero.Walk()
	}

	for _, b := range g.bullets {
		if b.IsFlying {
			b.Move()
		}
	}

	g.world.NotifyAboutCollisions()
	return nil
}

func (g *Game) Draw(screen *ebiten.Image) {
	g.terrain.DrawTerrain(screen)
	for _, z := range g.zombies {
		z.OffsetX = g.terrain.PositionX
		z.OffsetY = g.terrain.PositionY
		z.DrawZombie(screen)
	}

	for _, b := range g.bullets {
		b.OffsetX = g.terrain.PositionX
		b.OffsetY = g.terrain.PositionY
		if b.IsFlying {
			b.DrawHandgunBullet(screen)
		}
	}
	g.hero.DrawHero(screen)
	msg := fmt.Sprintf(`TPS: %0.2f
    FPS: %0.2f`, ebiten.ActualTPS(), ebiten.ActualFPS())
	ebitenutil.DebugPrint(screen, msg)

}

func (g *Game) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
	s := ebiten.DeviceScaleFactor()
	return int(float64(outsideWidth) * s), int(float64(outsideHeight) * s)
}

var GameInstance *Game

func init() {

	GameInstance = &Game{}
	GameInstance.world = collision.NewWorld()
	GameInstance.control = &input.Keyboard{}
	GameInstance.hero = hero.NewHero()
	GameInstance.zombies = []*zombie.Zombie{zombie.NewZombie(), zombie.NewZombie(), zombie.NewZombie(), zombie.NewZombie(), zombie.NewZombie()}

	GameInstance.world.AddEntity(GameInstance.hero)
	// put zombies in random places on the screen but not too close to the hero or each other
	for _, z := range GameInstance.zombies {
		z.X = float64(configuration.Random(50, screenWidth-50))
		z.Y = float64(configuration.Random(50, screenHeight-50))
		for z.X > float64(screenWidth/2-64) && z.X < float64(screenWidth/2+64) && z.Y > float64(screenHeight/2-64) && z.Y < float64(screenHeight/2+64) {
			z.X = float64(configuration.Random(0, screenWidth))
			z.Y = float64(configuration.Random(0, screenHeight))
		}
		z.Walk()
		GameInstance.world.AddEntity(z)
	}

	GameInstance.terrain = terrain.NewTerrain()

	GameInstance.hero.ChangeDirection(configuration.North)
	GameInstance.terrain.ChangeDirection(configuration.North)
	GameInstance.hero.Walk()
}

func main() {
	ebiten.SetWindowSize(screenWidth, screenHeight)
	ebiten.SetWindowTitle("Bosanski Zombicid")

	if err := ebiten.RunGame(GameInstance); err != nil {
		log.Fatal(err)
	}
}