package vumeter

import (
	"image/color"
	"strconv"

	"git.martyn.berlin/martyn/fyne-widgets/internal/cache"
	col "git.martyn.berlin/martyn/fyne-widgets/internal/color"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/data/binding"
	"fyne.io/fyne/v2/theme"
	"fyne.io/fyne/v2/widget"
)

type VUMeter struct {
	widget.BaseWidget
	Min, Max, Value float64
	TextFormatter   func() string

	binder basicBinder
}

type vuMeterRenderer struct {
	objects         []fyne.CanvasObject
	background, bar *canvas.Rectangle
	label           *canvas.Text
	meter           *VUMeter
}

func (p *vuMeterRenderer) MinSize() fyne.Size {
	var tsize fyne.Size
	if text := p.meter.TextFormatter; text != nil {
		tsize = fyne.MeasureText(text(), p.label.TextSize, p.label.TextStyle)
	} else {
		tsize = fyne.MeasureText("100%", p.label.TextSize, p.label.TextStyle)
	}

	return fyne.NewSize(tsize.Width+theme.Padding()*4, tsize.Height+theme.Padding()*2)
}

func (p *vuMeterRenderer) updateBar() {
	if p.meter.Value < p.meter.Min {
		p.meter.Value = p.meter.Min
	}
	if p.meter.Value > p.meter.Max {
		p.meter.Value = p.meter.Max
	}

	delta := float32(p.meter.Max - p.meter.Min)
	ratio := float32(p.meter.Value-p.meter.Min) / delta

	if text := p.meter.TextFormatter; text != nil {
		p.label.Text = text()
	} else {
		p.label.Text = strconv.Itoa(int(ratio*100)) + "%"
	}

	size := p.meter.Size()
	p.bar.Resize(fyne.NewSize(size.Width*ratio, size.Height))
}

func (p *vuMeterRenderer) Layout(size fyne.Size) {
	p.background.Resize(size)
	p.label.Resize(size)
	p.updateBar()
}

func (p *vuMeterRenderer) applyTheme() {
	p.background.FillColor = vuMeterBackgroundColor()
	p.bar.FillColor = theme.PrimaryColor()
	p.label.Color = theme.ForegroundColor()
	p.label.TextSize = theme.TextSize()
}

func (p *vuMeterRenderer) Refresh() {
	p.applyTheme()
	p.updateBar()
	p.background.Refresh()
	p.bar.Refresh()
	p.meter.super()
}

func (r *vuMeterRenderer) Objects() []fyne.CanvasObject {
	return r.objects
}

// SetObjects updates the objects of the renderer.
func (r *vuMeterRenderer) SetObjects(objects []fyne.CanvasObject) {
	r.objects = objects
}

func (r *vuMeterRenderer) Destroy() {

}

func (p *VUMeter) Bind(data binding.Float) {
	p.binder.SetCallback(p.updateFromData)
	p.binder.Bind(data)
}

func (p *VUMeter) SetValue(v float64) {
	p.Value = v
	p.Refresh()
}

func (p *VUMeter) MinSize() fyne.Size {
	p.ExtendBaseWidget(p)
	return p.BaseWidget.MinSize()
}

func (p *VUMeter) CreateRenderer() fyne.WidgetRenderer {
	p.ExtendBaseWidget(p)
	if p.Min == 0 && p.Max == 0 {
		p.Max = 1.0
	}

	background := canvas.NewRectangle(vuMeterBackgroundColor())
	bar := canvas.NewRectangle(theme.PrimaryColor())
	label := canvas.NewText("0%", theme.ForegroundColor())
	label.Alignment = fyne.TextAlignCenter
	return &vuMeterRenderer{[]fyne.CanvasObject{background, bar, label}, background, bar, label, p}
}

func (p *VUMeter) Unbind() {
	p.binder.Unbind()
}

func NewVUMeter() *VUMeter {
	p := &VUMeter{Min: 0, Max: 1}

	cache.Renderer(p).Layout(p.MinSize())
	return p
}

func NewVUMeterWithData(data binding.Float) *VUMeter {
	p := NewVUMeter()
	p.Bind(data)

	return p
}

func vuMeterBackgroundColor() color.Color {
	r, g, b, a := col.ToNRGBA(theme.PrimaryColor())
	faded := uint8(a) / 3
	return &color.NRGBA{R: uint8(r), G: uint8(g), B: uint8(b), A: faded}
}

func (p *VUMeter) updateFromData(data binding.DataItem) {
	if data == nil {
		return
	}
	floatSource, ok := data.(binding.Float)
	if !ok {
		return
	}

	val, err := floatSource.Get()
	if err != nil {
		fyne.LogError("Error getting current data value", err)
		return
	}
	p.SetValue(val)
}