package draw

import (
	"fmt"
	"math"
)

const batchSize = 32

type Plane struct {
	Width  uint
	Height uint
	pixels []uint32
}

func (p *Plane) pixelsValue() []uint32 {
	return p.pixels
}

func New(width uint, height uint) Plane {
	elements := int(math.Ceil(float64(width*height) / batchSize))
	return Plane{Width: width, Height: height, pixels: make([]uint32, elements)}
}

func (p Plane) Mark(x, y int) {
	boundX := (p.Width + uint(x)) % p.Width
	boundY := (p.Height + uint(y)) % p.Height
	p.mark(boundX + boundY*p.Width)

	// p.mark(x + y*p.Width)

	// number := x + y*p.width
	// index := number / batchSize
	// bit := number % batchSize
	// p.pixels[index] |= (0b1 << bit)
}

func (p Plane) mark(number uint) {
	// index := number / batchSize
	// bit := number % batchSize
	p.pixels[number/batchSize] |= (0b1 << (number % batchSize))
}

func (p Plane) Marked(x, y uint) bool {
	return p.marked(x + y*p.Width)
	// number := x + y*p.width
	// index := number / batchSize
	// bit := number % batchSize
	// return p.pixels[index]&(0b1<<bit) > 0
}

func (p Plane) marked(number uint) bool {
	// index := number / batchSize
	// bit := number % batchSize
	return p.pixels[number/batchSize]&(0b1<<(number%batchSize)) > 0
}

func (p Plane) Circle(x, y int, r float64) {
	plotX := 0
	plotY := int(math.Ceil(r))
	delta := 3 - 2*plotY
	lastY := plotY
	for plotX <= plotY {
		p.octant(x, y, plotX, plotY)
		if plotY < lastY {
			for lineX := 0; lineX < plotX; lineX++ {
				p.octant(x, y, lineX, plotY)
			}
			lastY = plotY
		}
		if delta < 0 {
			delta += 4*plotX + 6
		} else {
			delta += 4*(plotX-plotY) + 10
			plotY -= 1
		}
		plotX += 1
	}
	for fillX := 0; fillX < plotX; fillX++ {
		for fillY := 0; fillY <= fillX; fillY++ {
			p.octant(x, y, fillX, fillY)
		}
	}
}

func (p Plane) CircleAdjacent(x, y int, r float64) {
	plotX := 0
	plotY := int(math.Ceil(r))
	delta := 1 - 2*plotY
	err := 0
	for plotX <= plotY {
		p.octant(x, y, plotX, plotY)
		err = 2*(delta+plotY) - 1
		if delta < 0 && err <= 0 {
			plotX += 1
			delta += 2*plotX + 1
			continue
		}
		if delta > 0 && err > 0 {
			plotY -= 1
			delta -= 2*plotY + 1
			continue
		}
		plotX += 1
		plotY -= 1
		delta += 2 * (plotX - plotY)
	}
}

func (p Plane) octant(x, y int, plotX, plotY int) {
	p.Mark(x+plotX, y+plotY)
	p.Mark(x+plotX, y-plotY)
	p.Mark(x-plotX, y+plotY)
	p.Mark(x-plotX, y-plotY)
	p.Mark(x+plotY, y+plotX)
	p.Mark(x+plotY, y-plotX)
	p.Mark(x-plotY, y+plotX)
	p.Mark(x-plotY, y-plotX)
}

func (p Plane) Clear() {
	for i := range p.pixels {
		p.pixels[i] &= 0
	}
}

func (p Plane) String() string {
	px := map[bool]string{true: "x", false: "_"}
	var result string
	// for y := 0; y < int(p.height); y++ {
	// 	for x := 0; x < int(p.width); x++ {
	// 		result += px[p.Marked(uint(x), uint(y))] + " "
	// 	}
	// 	result += "\n"
	// }
	// result += "\n"
	cnt := 0
	for i := 0; i < len(p.pixels); i++ {
		for bit := 0; bit < batchSize && cnt < int(p.Width*p.Height); bit++ {
			result += fmt.Sprintf("%s ", px[p.pixels[i]&(0b1<<bit) > 0])
			cnt++
			if cnt%int(p.Width) == 0 {
				result += "\n"
			}
		}
	}
	return result
}