package ui

import (
	"image"
	"image/color"
	"math"
	"time"

	"github.com/llgcode/draw2d/draw2dimg"
	"opslag.de/schobers/galleg/allegro5"
)

var _ Control = &Spinner{}

type Spinner struct {
	ControlBase
	Text  string
	spin  float32
	circs []*allegro5.Bitmap
}

func createCirle(r, w int, startAngle, a float64, c color.Color) *allegro5.Bitmap {
	var width = 2*r + w
	dest := image.NewRGBA(image.Rect(0, 0, width, width))

	gc := draw2dimg.NewGraphicContext(dest)
	gc.SetFillColor(color.Transparent)
	gc.Clear()
	gc.SetFillColor(c)
	gc.SetStrokeColor(c)
	gc.SetLineWidth(float64(w))
	var rad = float64(r)
	var cnt = float64(width) * .5
	var dx1, dy1 = cnt + math.Cos(startAngle)*rad, cnt + math.Sin(startAngle)*rad
	gc.MoveTo(dx1, dy1)
	gc.ArcTo(cnt, cnt, rad, rad, startAngle, a)
	gc.Stroke()

	bmp, err := allegro5.NewBitmapFromImage(dest, false)
	if nil != err {
		return nil
	}
	return bmp
}

func (s *Spinner) Created(ctx Context, p Container) error {
	s.ControlBase.Created(ctx, p)
	const numCircs = 32
	s.circs = make([]*allegro5.Bitmap, numCircs)
	var am = math.Pi * 2 / float64(numCircs)
	for i := range s.circs {
		s.circs[i] = createCirle(8, 3, float64(i)*am, math.Pi, Blue500)
	}
	return nil
}

func (s *Spinner) Destroyed(ctx Context) {
	for _, circ := range s.circs {
		circ.Destroy()
	}
}

func (s *Spinner) Update(ctx Context, dt time.Duration) {
	var spin = float64(s.spin)
	spin += dt.Seconds()
	for spin > 1. {
		spin -= 1.
	}
	s.spin = float32(spin)
}

func (s *Spinner) Render(ctx Context) {
	var disp = ctx.Display()
	var fonts = ctx.Fonts()

	var width = float32(disp.Width())
	var height = float32(disp.Height())

	var fnt = fonts.Get("default")
	var textW = fnt.TextWidth(s.Text)

	allegro5.DrawFilledRectangle(0, 0, width, height, ctx.Palette().Disabled())

	const marginH, marginV float32 = 64, 16
	const textH float32 = 12
	var rectW, rectH float32 = textW + 2*marginH, 3*marginV + textH + 32
	var rectX, rectY = (width - rectW) * .5, (height - rectH) * .5
	allegro5.DrawFilledRectangle(rectX, rectY, rectX+rectW, rectY+rectH, ctx.Palette().White())
	DropShadow(rectX, rectY, rectX+rectW, rectY+rectH)
	fnt.Draw(rectX+marginH, rectY+marginV, ctx.Palette().Black(), allegro5.AlignLeft, s.Text)

	const numCircs = 32
	var i = int(math.Floor(float64(s.spin) * numCircs))
	s.circs[i].DrawOptions(width*.5, rectY+2*marginV+2*textH, allegro5.DrawOptions{Center: true})

	s.ControlBase.Render(ctx)
}