package tins2020

import (
	"fmt"

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

type terrainRenderer struct {
	ui.ControlBase

	game    *Game
	hover   *geom.Point
	project projection

	drag ui.Dragable
}

func NewTerrainRenderer(game *Game) ui.Control {
	renderer := &terrainRenderer{game: game, project: newProjection()}

	renderer.game.CenterChanged().AddHandler(func(ctx ui.Context, state interface{}) {
		center := state.(geom.Point)
		renderer.project.center = center.ToF32()
		renderer.project.update(ctx.Renderer())
	})
	// renderer.project.update(ctx.Renderer)
	return renderer
}

func (r *terrainRenderer) Arrange(ctx ui.Context, _ geom.RectangleF32, _ geom.PointF32, _ ui.Control) {
	r.project.update(ctx.Renderer())
}

func (r *terrainRenderer) Init(ctx ui.Context) error {
	return nil
}

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.ToInt().In(r.project.windowInteractRect) {
			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.project.screenToMapInt(int(e.X), int(e.Y))
				r.game.UserClickedTile(pos)
			}
			if e.Button == ui.MouseButtonRight {
				r.game.CancelTool(ctx)
			}
		}
	case *ui.MouseButtonUpEvent:
		pos := e.Pos().ToInt()
		if pos.In(r.project.windowInteractRect) {
			if _, ok := r.drag.IsDragging(); ok {
				r.game.Terrain.Center = mapToTile(r.project.center)
				r.drag.Cancel()
			}
		}
	case *ui.MouseMoveEvent:
		pos := e.Pos()
		if pos.ToInt().In(r.project.windowInteractRect) {
			hover := r.project.screenToMapInt(int(e.X), int(e.Y))
			r.hover = &hover
		} else {
			r.hover = nil
		}
		if _, ok := r.drag.IsDragging(); ok {
			delta, _ := r.drag.Move(pos)
			r.project.center = r.project.center.Sub(r.project.screenToMapRel(int(delta.X), int(delta.Y)))
			r.project.update(ctx.Renderer())
		}
		if r.hover != nil {
			if e.MouseWheel < 0 {
				r.project.ZoomOut(ctx, r.hover.ToF32())
			} else if e.MouseWheel > 0 {
				r.project.ZoomIn(ctx, r.hover.ToF32())
			}
		}
	case *ui.MouseLeaveEvent:
		r.hover = nil
		r.project.update(ctx.Renderer())
	case *ui.KeyDownEvent:
		switch e.Key {
		case ui.KeyPadPlus:
			r.project.ZoomIn(ctx, r.project.center)
		case ui.KeyMinus:
			r.project.ZoomOut(ctx, r.project.center)
		case ui.KeyPadMinus:
			r.project.ZoomOut(ctx, r.project.center)
		case ui.KeyW:
			r.project.Pan(ctx, geom.PtF32(-1, -1))
		case ui.KeyA:
			r.project.Pan(ctx, geom.PtF32(-1, 1))
		case ui.KeyS:
			r.project.Pan(ctx, geom.PtF32(1, 1))
		case ui.KeyD:
			r.project.Pan(ctx, geom.PtF32(1, -1))
		}
	}
	return false
}

func (r *terrainRenderer) Render(ctx ui.Context) {
	zoom := r.project.zoom
	terrain := r.game.Terrain
	toTileTexture := func(x, y int) ui.Texture {
		temp := terrain.Temp.Value(x, 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

	r.project.visibleTiles(func(x, y int, pos geom.Point) {
		text := toTileTexture(x, y)
		rect := r.project.screenToTileRect(pos)
		ctx.Renderer().DrawTexture(text, rect.ToF32())

		if r.hover != nil && x == r.hover.X && y == r.hover.Y {
			ctx.Renderer().DrawTexture(ctx.Textures().ScaledByName("tile-hover", zoom), rect.ToF32())
		}
	})

	r.project.visibleTiles(func(x, y int, pos geom.Point) {
		text := toItemTexture(x, y)
		if text == nil {
			return
		}

		placeX, placeY := terrain.PlaceX.Value(x, y), terrain.PlaceY.Value(x, y)
		pos = r.project.mapToScreenF(float32(x)-.2+float32(.9*placeX-.45), float32(y)-.2+float32(.9*placeY-.45))
		rect := r.project.screenToTileRect(pos)
		ctx.Renderer().DrawTexture(text, rect.ToF32())
		// ctx.Fonts().Text("debug", pos.ToF32(), color.White, fmt.Sprintf("%d, %d", x, y))
	})
}