package generator

import (
	"errors"
	"fmt"
	"math/rand"

	"github.com/iliadenisov/galaxy/pkg/bitmap"
)

type Plotter struct {
	factor              float32
	clearFn             func()
	circleFn            func(x, y int, r float32)
	freeCountFn         func() int
	freeNumberToCoordFn func(int) (int, int)
}

func NewPlotter(width, height uint, factor float32) (Plotter, error) {
	if factor > 1 || factor <= 0 {
		return Plotter{}, fmt.Errorf("factor should be: 0 > F <= 1")
	}
	sectorsX := uint32(float32(width) / factor)
	sectorsY := uint32(float32(height) / factor)
	bm := bitmap.NewBitmap(sectorsX, sectorsY)
	return Plotter{
		factor:      factor,
		clearFn:     bm.Clear,
		circleFn:    func(x, y int, r float32) { bm.Circle(x, y, r, true) },
		freeCountFn: bm.FreeCount,
		freeNumberToCoordFn: func(n int) (x int, y int) {
			x, y, err := bm.GetFreeN(n)
			if err != nil {
				panic(err)
			}
			return
		},
	}, nil
}

func (p Plotter) RandomFreePoint(deadZoneRaduis float32) (float32, float32, error) {
	fsCount := p.freeCountFn()
	if fsCount == 0 {
		return 0, 0, errors.New("no more space for planets")
	}
	next := rand.Intn(fsCount)
	x, y := p.freeNumberToCoordFn(next)
	p.PlotDeadZone(x, y, deadZoneRaduis)
	planetX := float32(x)*p.factor + rand.Float32()*p.factor // TODO: correct shift?
	planetY := float32(y)*p.factor + rand.Float32()*p.factor
	return planetX, planetY, nil
}

func (p Plotter) MarkDeadZone(x, y float32, radius float32) {
	p.PlotDeadZone(int(x/p.factor), int(y/p.factor), radius)
}

func (p Plotter) PlotDeadZone(x, y int, radius float32) {
	p.circleFn(x, y, radius/p.factor)
}