package tins2020

import (
	"fmt"

	"opslag.de/schobers/zntg/play"

	"opslag.de/schobers/geom"
	"opslag.de/schobers/zntg/ui"
)

type terrainRenderer struct {
	ui.ControlBase

	game           *Game
	hover          *geom.Point
	viewBounds     geom.RectangleF32
	interactBounds geom.RectangleF32
	isometric      *play.IsometricProjection

	drag ui.Dragable
}

func NewTerrainRenderer(game *Game) ui.Control {
	renderer := &terrainRenderer{game: game, isometric: play.NewIsometricProjection(geom.PtF32(128, 64), geom.RectF32(0, 0, 100, 100))}

	renderer.game.CenterChanged().AddHandler(func(ctx ui.Context, state interface{}) {
		center := state.(geom.Point)
		renderer.isometric.MoveCenterTo(center.ToF32())
	})
	return renderer
}

func (r *terrainRenderer) Arrange(ctx ui.Context, bounds geom.RectangleF32, _ geom.PointF32, _ ui.Control) {
	r.viewBounds = geom.RectF32(buttonBarWidth, 0, bounds.Dx()-buttonBarWidth, bounds.Dy())
	r.isometric.SetViewBounds(r.viewBounds)
	r.interactBounds = r.viewBounds
	r.interactBounds.Min.Y += 64
}

func isControlKeyDown(ctx ui.Context) bool {
	modifiers := ctx.KeyModifiers()
	return modifiers&(ui.KeyModifierControl|ui.KeyModifierOSCommand) != 0
}

func (r *terrainRenderer) Handle(ctx ui.Context, event ui.Event) bool {
	switch e := event.(type) {
	case *ui.MouseButtonDownEvent:
		pos := e.Pos()
		if pos.In(r.interactBounds) {
			controlKeyDown := isControlKeyDown(ctx)
			if e.Button == ui.MouseButtonMiddle || (e.Button == ui.MouseButtonLeft && controlKeyDown) {
				if _, ok := r.drag.IsDragging(); !ok {
					r.drag.Start(pos)
				}
			}
			if e.Button == ui.MouseButtonLeft && !controlKeyDown {
				pos := r.isometric.ViewToTileInt(pos)
				r.game.UserClickedTile(pos)
			}
			if e.Button == ui.MouseButtonRight {
				r.game.CancelTool(ctx)
			}
		}
	case *ui.MouseButtonUpEvent:
		if _, ok := r.drag.IsDragging(); ok {
			r.game.Terrain.Center = r.isometric.TileInt(r.isometric.Center())
			r.drag.Cancel()
		}
	case *ui.MouseMoveEvent:
		pos := e.Pos()
		if pos.In(r.interactBounds) {
			hover := r.isometric.ViewToTileInt(pos)
			r.hover = &hover
		} else {
			r.hover = nil
		}
		if _, ok := r.drag.IsDragging(); ok {
			delta, _ := r.drag.Move(pos)
			r.isometric.Pan(delta.Invert())
		}
		if r.hover != nil {
			if e.MouseWheel < 0 {
				r.isometric.ZoomOut(r.hover.ToF32())
			} else if e.MouseWheel > 0 {
				r.isometric.ZoomIn(r.hover.ToF32())
			}
		}
	case *ui.MouseLeaveEvent:
		r.hover = nil
	case *ui.KeyDownEvent:
		switch e.Key {
		case ui.KeyPadPlus:
			r.isometric.ZoomIn(r.isometric.Center())
		case ui.KeyMinus:
			r.isometric.ZoomOut(r.isometric.Center())
		case ui.KeyPadMinus:
			r.isometric.ZoomOut(r.isometric.Center())
		case ui.KeyW:
			r.isometric.PanTile(geom.PtF32(-1, -1))
		case ui.KeyA:
			r.isometric.PanTile(geom.PtF32(-1, 1))
		case ui.KeyS:
			r.isometric.PanTile(geom.PtF32(1, 1))
		case ui.KeyD:
			r.isometric.PanTile(geom.PtF32(1, -1))
		}
	}

	tool := r.game.Tool().Type()
	if r.hover != nil {
		if tool != "none" {
			ctx.Renderer().SetMouseCursor(ui.MouseCursorPointer)
		}
		if tool == "plant-flower" {
			terrain := r.game.Terrain
			temp := func() string {
				temp := terrain.Temp.Value(r.hover.X, r.hover.Y)
				switch {
				case temp < .3:
					return "very cold"
				case temp < .4:
					return "cold"
				case temp > .7:
					return "very hot"
				case temp > .6:
					return "hot"
				default:
					return "moderate"
				}
			}()
			humid := func() string {
				humid := terrain.Humid.Value(r.hover.X, r.hover.Y)
				switch {
				case humid < .3:
					return " and very arid"
				case humid < .4:
					return " and arid"
				case humid > .7:
					return " and very damp"
				case humid > .6:
					return " and damp"
				default:
					return ""
				}
			}()
			ctx.ShowTooltip(fmt.Sprintf("It is %s%s over here", temp, humid))
		}
	}
	return false
}

func (r *terrainRenderer) Render(ctx ui.Context) {
	zoom := r.isometric.Zoom()
	terrain := r.game.Terrain
	toTileTexture := func(tile geom.Point) ui.Texture {
		temp := terrain.Temp.Value(tile.X, tile.Y)
		if temp < .35 {
			return ctx.Textures().ScaledByName("tile-snow", zoom)
		}
		if temp > .65 {
			return ctx.Textures().ScaledByName("tile-dirt", zoom)
		}
		return ctx.Textures().ScaledByName("tile-grass", zoom)
	}

	variantToInt := func(variant float64) int {
		if variant < .25 {
			return 1
		}
		if variant < .5 {
			return 2
		}
		if variant < .75 {
			return 3
		}
		if variant < 1 {
			return 4
		}
		return -1
	}

	variantToTexture := func(format string, variant float64) ui.Texture {
		textName := fmt.Sprintf(format, variantToInt(variant))
		return ctx.Textures().ScaledByName(textName, zoom)
	}
	stretch := func(x, from, to float64) float64 { return (x - from) * 1 / (to - from) }

	toPropTexture := func(temp, humid, variant float64) ui.Texture {
		if temp < .35 {
			if humid < .2 {
				return nil
			} else if humid < .7 {
				return variantToTexture("bush-small-%d", variant*5)
			}
			return variantToTexture("tree-pine-%d", variant*5)
		}
		if temp > .65 {
			if humid < .2 {
				return nil
			}
			if humid < .7 {
				return variantToTexture("cactus-short-%d", variant*7)
			}
			return variantToTexture("cactus-tall-%d", variant*2)
		}
		if humid < .2 {
			return nil
		}
		multiplier := 1 - stretch(humid, 0.2, 1)
		if variant < .5 {
			return variantToTexture("tree-fat-%d", stretch(variant, 0, .5)*multiplier*3)
		} else if variant < .8 {
			return variantToTexture("grass-small-%d", stretch(variant, .5, .8)*multiplier*2)
		}
		return variantToTexture("bush-large-%d", stretch(variant, .8, 1)*multiplier)
	}

	toItemTexture := func(x, y int) ui.Texture {
		variant := terrain.Variant.Value(x, y)
		flower, ok := terrain.Flowers[geom.Pt(x, y)]
		if ok {
			desc, _ := r.game.Herbarium.Find(flower.ID)
			return ctx.Textures().ScaledByName(desc.IconTemplate.Variant(variantToInt(variant)), zoom)
		}
		temp := terrain.Temp.Value(x, y)
		humid := terrain.Humid.Value(x, y)
		return toPropTexture(temp, humid, variant)
	}

	// horizontal: [0, 128) = 128
	// vertical (tile): [96,160) = 64
	// vertical (total): [0,160) = 160

	topLeft := geom.PtF32(-64*zoom, -112*zoom)
	bottomRight := geom.PtF32(64*zoom, 48*zoom)
	textureRect := func(center geom.PointF32) geom.RectangleF32 {
		return geom.RectangleF32{Min: center.Add(topLeft), Max: center.Add(bottomRight)}
	}
	hoverTexture := ctx.Textures().ScaledByName("tile-hover", zoom)

	r.isometric.EnumerateInt(func(tile geom.Point, view geom.PointF32) {
		text := toTileTexture(tile)
		rect := textureRect(view)
		ctx.Renderer().DrawTexture(text, rect)
		// if r.game.Debug {
		// 	ctx.Renderer().FillRectangle(view.Add2D(-1, -1).RectRel2D(2, 2), color.White)
		// 	ctx.Fonts().TextAlign("debug", view, color.White, fmt.Sprintf("%d, %d", tile.X, tile.Y), ui.AlignCenter)
		// }
		if r.hover != nil && tile.X == r.hover.X && tile.Y == r.hover.Y {
			ctx.Renderer().DrawTexture(hoverTexture, rect)
		}
	})

	r.isometric.EnumerateInt(func(tile geom.Point, view geom.PointF32) {
		text := toItemTexture(tile.X, tile.Y)
		if text == nil {
			return
		}

		placeX, placeY := terrain.PlaceX.Value(tile.X, tile.Y), terrain.PlaceY.Value(tile.X, tile.Y)
		displaced := r.isometric.TileToView(tile.ToF32().Add2D(-.2+.9*float32(placeX)-.45, -.2+.9*float32(placeY)-.45))
		rect := textureRect(displaced)
		ctx.Renderer().DrawTexture(text, rect)
	})
}