package mainwindow

import (
	"errors"
	"fmt"
	"lab.zaar.be/thefish/alchemyst-go/engine/fov"
	"lab.zaar.be/thefish/alchemyst-go/engine/fov/precomputed_shade"
	"lab.zaar.be/thefish/alchemyst-go/engine/gamemap"
	"lab.zaar.be/thefish/alchemyst-go/engine/types"
)

var NotInViewError = errors.New("not in ViewPort")

type ViewPort struct {
	*types.Rect
	cameraCoords      types.Coords
	level             *gamemap.Level
	layer             *Layer
	Fov               fov.Fov
	PlayerCoords      types.Coords
	PlayerTorchRadius int
}

func NewViewPort(x, y, w, h int, level *gamemap.Level, layer *Layer) *ViewPort {
	//fixme
	fov := precomputed_shade.NewPrecomputedShade(15)
	fov.Init()
	vp := ViewPort{
		Rect:  &types.Rect{x, y, w, h},
		level: level,
		layer: layer,
		Fov:   fov,
	}

	vp.PlayerCoords = types.Coords{10, 10}
	vp.PlayerTorchRadius = 10

	return &vp
}

func (vp *ViewPort) Move(c *types.Coords, state types.GameState) {
	x := c.X - vp.Rect.W/2
	y := c.Y - vp.Rect.H/2

	if x < 0 {
		x = 0
	}
	if y < 0 {
		y = 0
	}
	if x > vp.level.W-vp.W {
		x = vp.level.W - vp.W - 1
	}
	if y > vp.level.H-vp.H {
		x = vp.level.H - vp.H - 1
	}
	if x != vp.cameraCoords.X || y != vp.cameraCoords.Y {
		state.FovRecompute <- struct{}{}
	}
	vp.cameraCoords.X = x
	vp.cameraCoords.Y = y

}

func (vp *ViewPort) ToVPCoords(c types.Coords) (newCoords types.Coords, err error) {
	//coords on map to coords on vp
	x, y := c.X-vp.cameraCoords.X, c.Y-vp.cameraCoords.Y
	if x < 0 || y < 0 || x > vp.W || y > vp.H {
		return types.Coords{-1, -1}, NotInViewError
	}
	return types.Coords{x, y}, nil
}

////call only from main thread
//func (vp *ViewPort) Render() {
//	//fixme get these from state chan(s)
//	var fpsTicker int
//	var fovRecompute bool = true
//	redraw := false
//	//fixme get player instance
//
//	vp.Move(&vp.PlayerCoords)
//	//fixme detect fovRecompute
//	if fovRecompute {
//		vp.layer.ClearRect(vp.Rect)
//		fovRecompute = false
//		redraw = true
//		//fixme
//
//		vp.Fov.ComputeFov(vp.level, vp.PlayerCoords, vp.PlayerTorchRadius)
//	}
//	//increase ticker
//	fpsTicker++
//
//	if redraw || fpsTicker%(FPS_LIMIT/10) == 0 {
//		fpsTicker = 0
//
//		for y := 0; y < vp.H; y++ {
//			for x := 0; x < vp.W; x++ {
//				mapCoords := types.Coords{vp.X + x, vp.Y + y}
//				tile := vp.level.Tiles[mapCoords.X][mapCoords.Y]
//				visible := vp.Fov.IsInFov(mapCoords)
//				if !visible {
//					if tile.MustDraw {
//						//darkened version of landscape
//						vp.layer.WithRawColor(tile.ColorSet.DarkFg()).
//							PutWithRawBackground(mapCoords.X, mapCoords.Y, tile.Char, tile.ColorSet.DarkBg())
//					}
//				} else {
//					if redraw == true || tile.Colordance {
//						vp.layer.WithRawColor(tile.ColorSet.Fg()).
//							PutWithRawBackground(mapCoords.X, mapCoords.Y, tile.Char, tile.ColorSet.Bg())
//						tile.Explored = true
//						tile.MustDraw = true
//					}
//				}
//			}
//		}
//
//	}
//}

var redraw = true
var fovRecompute = true

func (vp *ViewPort) Listen(state types.GameState) {
	for {
		select {
		case <-state.FovRecompute:
			fovRecompute = true
		case <-state.Redraw:
			redraw = true
		}
	}
}

func (vp *ViewPort) Render(state types.GameState) {

	vp.Move(&vp.PlayerCoords, state)

	if fovRecompute {
		vp.layer.ClearRect(vp.Rect)
		fovRecompute = false
		redraw = true
		vp.Fov.ComputeFov(vp.level, vp.PlayerCoords, vp.PlayerTorchRadius)
	}

	if redraw {
		//terrain
		for y := 0; y < vp.H; y++ {
			for x := 0; x < vp.W; x++ {
				mapCoords := types.Coords{vp.cameraCoords.X + x, vp.cameraCoords.Y + y}

				if vp.level.InBounds(mapCoords) {
					tile := vp.level.GetTile(mapCoords)
					if tile.Explored || tile.MustDraw || tile.Visible {
						vp.layer.PutToBase(x + vp.X, y + vp.Y, tile.GetChar(), tile.GetRawColor(), tile.GetRawBgColor())
					}
				}
			}
		}
		//mobs
		pc,err := vp.ToVPCoords(vp.PlayerCoords)
		_ = pc
		if err != nil {
			fmt.Println("error on getting player position")
		} else {
			vp.layer.WithColor("white").Put(pc.X + vp.X, pc.Y + vp.Y, "@")
			//mw.GetLayer("base").WithColor("white").Put(42, 10, "B")
			//mw.GetLayer("overlay").WithColor("white").Put(59, 10, "O")
		}

		redraw = true
		//redraw = false
	}

}