package main

import (
	"fmt"
	_ "image/png"
	"log"
	"time"

	"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/input"
	"gitlab.com/kbr4/9heroja/terrain"
	"gitlab.com/kbr4/9heroja/tiles"
	"gitlab.com/kbr4/9heroja/weapons"
	"gitlab.com/kbr4/9heroja/zombie"
)

const (
	screenWidth      = 720
	screenHeight     = 1280
	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 {
	keys []ebiten.Key

	control *input.Keyboard

	terrain  *terrain.Terrain
	zombies  []*zombie.Zombie
	world    *collision.World
	bullets  []*weapons.Handgun
	ending   *tiles.Ending
	starting *tiles.Starting

	gameSpeed         time.Duration
	tickCount         int
	zombiesToSpawn    int
	zombieSpawnTicker *time.Ticker
}

func (g *Game) Update() error {
	g.keys = inpututil.AppendPressedKeys(g.keys[:0])
	GameInstance.terrain.ChangeDirection(GameInstance.control.DirectionFromKeys(g.keys))
	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.ending.DrawEnding(screen)
	g.starting.DrawStarting(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.zombies = []*zombie.Zombie{}
	GameInstance.ending = tiles.NewEnding()
	GameInstance.starting = tiles.NewStarting()

	GameInstance.world.AddEntity(GameInstance.starting)
	GameInstance.world.AddEntity(GameInstance.ending)

	GameInstance.gameSpeed = 100 * time.Millisecond
	GameInstance.zombieSpawnTicker = time.NewTicker(GameInstance.gameSpeed)
	GameInstance.zombiesToSpawn = 20

	GameInstance.terrain = terrain.NewTerrain()

	go func() {
		log.Println("Starting zombie spawn ticker")
		for {
			select {
			case <-GameInstance.zombieSpawnTicker.C:
				GameInstance.tickCount++
				if GameInstance.tickCount%10 == 0 && GameInstance.zombiesToSpawn > 0 {
					z := GameInstance.starting.SpawnZombie(GameInstance.ending.X, GameInstance.ending.Y)
					GameInstance.zombies = append(GameInstance.zombies, z)
					GameInstance.world.AddEntity(z)
					GameInstance.zombiesToSpawn--
				}
			}
			if GameInstance.zombiesToSpawn <= 0 {
				GameInstance.zombieSpawnTicker.Stop()
				break
			}
		}
	}()
}

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

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