package tins2020

import (
	"fmt"

	"github.com/veandco/go-sdl2/sdl"
)

type terrainRenderer struct {
	game    *Game
	hover   *Point
	project projection

	drag Drageable
}

func NewTerrainRenderer(game *Game) Control {
	return &terrainRenderer{game: game, project: newProjection()}
}

func (r *terrainRenderer) Arrange(ctx *Context, _ Rectangle) {
	r.project.update(ctx.Renderer)
}

func (r *terrainRenderer) Init(ctx *Context) error {
	r.game.CenterChanged().RegisterItf(func(state interface{}) {
		center := state.(Point)
		r.project.center = center.ToPtF()
		r.project.update(ctx.Renderer)
	})
	r.project.update(ctx.Renderer)
	return nil
}

func isControlKeyDown() bool {
	state := sdl.GetKeyboardState()
	return state[sdl.SCANCODE_LCTRL] == 1 || state[sdl.SCANCODE_RCTRL] == 1
}

func (r *terrainRenderer) Handle(ctx *Context, event sdl.Event) bool {
	switch e := event.(type) {
	case *sdl.MouseButtonEvent:
		if r.project.windowInteractRect.IsPointInside(e.X, e.Y) {
			if e.Type == sdl.MOUSEBUTTONDOWN {
				if e.Button == sdl.BUTTON_MIDDLE || (e.Button == sdl.BUTTON_LEFT && isControlKeyDown()) {
					if !r.drag.IsDragging() {
						r.drag.Start(Pt(e.X, e.Y))
					}
				}
				if e.Button == sdl.BUTTON_LEFT {
					pos := r.project.screenToMapInt(e.X, e.Y)
					r.game.UserClickedTile(pos)
				}
				if e.Button == sdl.BUTTON_RIGHT {
					if e.Type == sdl.MOUSEBUTTONDOWN {
						r.game.CancelTool()
					}
				}
			}
			if e.Type == sdl.MOUSEBUTTONUP {
				if r.drag.IsDragging() {
					r.game.Terrain.Center = mapToTile(r.project.center)
					r.drag.Cancel()
				}
			}
		}
	case *sdl.MouseMotionEvent:
		if r.project.windowInteractRect.IsPointInside(e.X, e.Y) {
			hover := r.project.screenToMapInt(e.X, e.Y)
			r.hover = &hover
		} else {
			r.hover = nil
		}
		if r.drag.IsDragging() {
			delta := r.drag.Move(Pt(e.X, e.Y))
			r.project.center = r.project.center.Sub(r.project.screenToMapRel(delta.X, delta.Y))
			r.project.update(ctx.Renderer)
		}
	case *sdl.MouseWheelEvent:
		if r.hover != nil {
			zoom := r.project.zoom
			if e.Y < 0 && r.project.zoom > .25 {
				zoom *= .5
			} else if e.Y > 0 && r.project.zoom < 2 {
				zoom *= 2
			}
			if zoom != r.project.zoom {
				hover := r.hover.ToPtF()
				r.project.center = hover.Sub(hover.Sub(r.project.center).Mul(r.project.zoom / zoom))
				r.project.zoom = zoom
				r.project.update(ctx.Renderer)
			}
		}
	case *sdl.WindowEvent:
		if e.Event == sdl.WINDOWEVENT_LEAVE {
			r.hover = nil
			r.project.update(ctx.Renderer)
		}
	}
	return false
}

func (r *terrainRenderer) Render(ctx *Context) {
	terrain := r.game.Terrain
	toTileTexture := func(x, y int32) *Texture {
		temp := terrain.Temp.Value(x, y)
		if temp < .35 {
			return ctx.Textures.Texture("tile-snow")
		}
		if temp > .65 {
			return ctx.Textures.Texture("tile-dirt")
		}
		return ctx.Textures.Texture("tile-grass")
	}

	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) *Texture {
		textName := fmt.Sprintf(format, variantToInt(variant))
		return ctx.Textures.Texture(textName)
	}

	stretch := func(x, from, to float64) float64 { return (x - from) * 1 / (to - from) }

	toPropTexture := func(temp, humid, variant float64) *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 int32) *Texture {
		variant := terrain.Variant.Value(x, y)
		flower, ok := terrain.Flowers[Pt(x, y)]
		if ok {
			desc, _ := r.game.Herbarium.Find(flower.ID)
			return ctx.Textures.Texture(desc.IconTemplate.Variant(variantToInt(variant)))
		}
		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 int32, pos Point) {
		text := toTileTexture(x, y)
		rect := r.project.screenToTileRect(pos)
		text.CopyResize(ctx.Renderer, rect)

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

	r.project.visibleTiles(func(x, y int32, pos 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))
		text.CopyResize(ctx.Renderer, r.project.screenToTileRect(pos))
	})
}