package main

import (
	rl "github.com/gen2brain/raylib-go/raylib"
	"github.com/ojrac/opensimplex-go"
)

type Field interface {
	/**
	 * return a value on the range 0,1
	 */
	Get(x float32, y float32) float32
}

// TRANSFORM FIELDS
type ScaleField struct {
	field Field
	scale float32
}

func (f *ScaleField) Get(x, y float32) float32 {
	return f.field.Get(x / f.scale, y / f.scale)
}

type TranslateField struct {
	field Field
	x, y float32
}

func (f *TranslateField) Get(x, y float32) float32 {
	return f.field.Get(x + f.x, y + f.y)
}

// NOISE FIELDS

type SimplexNoiseField struct {
	Noise opensimplex.Noise32
}

func (f *SimplexNoiseField) Get(x, y float32) float32 {
	return f.Noise.Eval2(x, y)
}

// IMAGE FIELDS

type ImageField struct {
	image *rl.Image
	pixels ImagePixels
	offsetX, offsetY float32
}

type ImagePixels struct {
	w, h int
	colors []rl.Color
}

func (p *ImagePixels) Get(x, y int) rl.Color {
	if x < 0 || x >= p.w {
		return rl.Black
	}
	if y < 0 || y >= p.h {
		return rl.Black
	}
	return p.colors[x + y * p.w]
}

func NewImageField(path string) ImageField {
	image := rl.LoadImage(path)
	colors := rl.LoadImageColors(image)
	pixels := ImagePixels {
		w: int(image.Width),
		h: int(image.Height),
		colors: colors,
	}
	offsetX := float32(image.Width / 2)
	offsetY := float32(image.Height / 2)
	return ImageField {
		image: image,
		pixels: pixels,
		offsetX: offsetX,
		offsetY: offsetY,
	}
}

func (f *ImageField) Get(x, y float32) float32 {
	// todo : blend colors
	c := f.pixels.Get(int(x+f.offsetX), int(y + f.offsetY))
	return Brightness(c)
}