package main

import (
	"log"
	stdmath "math"
	"time"

	"github.com/pnx/go-raytracer/graphics"
	"github.com/pnx/go-raytracer/math"
	"github.com/pnx/go-raytracer/render"
	"github.com/pnx/go-raytracer/world"
	"github.com/veandco/go-sdl2/sdl"
)

var (
	gfxContext   *graphics.Context
	player       Player
	level        *world.Level
	startOfFrame time.Time
)

func loadLevel(newLevel *world.Level) {
	level = newLevel

	// Set player start position
	start := level.PlayerStart()

	player.Position = math.Position{
		X: (float64(start.X) + 0.5) * world.TileSize,
		Y: (float64(start.Y) + 0.5) * world.TileSize,
	}
}

func update() bool {
	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
		switch ev := event.(type) {
		case *sdl.QuitEvent:
			return true
		case *sdl.KeyboardEvent:
			if ev.Type == sdl.KEYDOWN {
				switch ev.Keysym.Sym {
				case sdl.K_ESCAPE:
					return true
				}
			}
		}
	}

	keys := sdl.GetKeyboardState()

	if keys[sdl.SCANCODE_UP] != 0 {
		player.MoveForward(level)
	}
	if keys[sdl.SCANCODE_DOWN] != 0 {
		player.MoveBackward(level)
	}
	if keys[sdl.SCANCODE_LEFT] != 0 {
		player.RotateLeft()
	}
	if keys[sdl.SCANCODE_RIGHT] != 0 {
		player.RotateRight()
	}

	return false
}

func main() {
	var err error

	gfxContext, err = graphics.Init("Go Raycaster", 1024, 768)
	if err != nil {
		log.Fatal(err)
	}

	player = Player{
		MoveSpd: 2,
		RotSpd:  0.05,
	}

	loadLevel(&world.Level1)

	for {
		startOfFrame := time.Now()
		if update() {
			break
		}

		render.DrawScene(gfxContext, player.Transform, level)
		render.DrawMiniMap(gfxContext, player.Transform, level)
		gfxContext.Sync()

		elapsed := time.Since(startOfFrame)
		sdl.Delay(uint32(stdmath.Max(16-float64(elapsed.Milliseconds()), 1)))
	}

	gfxContext.Exit()
}