package main

import (
	"fmt"
	"image/color"
	"math"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/widget"
)

// barGraphCanvas is a custom widget that renders a bar graph
type barGraphCanvas struct {
	widget.BaseWidget
	stats *DiceStatistics
}

func newBarGraphCanvas(stats *DiceStatistics) *barGraphCanvas {
	graph := &barGraphCanvas{
		stats: stats,
	}
	graph.ExtendBaseWidget(graph)
	return graph
}

func (b *barGraphCanvas) CreateRenderer() fyne.WidgetRenderer {
	b.ExtendBaseWidget(b)
	return &barGraphCanvasRenderer{
		graph: b,
	}
}

type barGraphCanvasRenderer struct {
	graph   *barGraphCanvas
	objects []fyne.CanvasObject
}

func (r *barGraphCanvasRenderer) Layout(size fyne.Size) {
	r.Refresh()
}

func (r *barGraphCanvasRenderer) MinSize() fyne.Size {
	return fyne.NewSize(800, 500)
}

func (r *barGraphCanvasRenderer) Refresh() {
	r.objects = []fyne.CanvasObject{}

	if r.graph.stats == nil || len(r.graph.stats.Results) == 0 {
		return
	}

	stats := r.graph.stats
	outcomes := stats.GetSortedOutcomes()
	maxPercentage := stats.GetMaxPercentage()

	// Round up maxPercentage to nearest 5%
	roundedMaxPercent := math.Ceil(maxPercentage/5) * 5
	if roundedMaxPercent < 5 {
		roundedMaxPercent = 5
	}

	// Padding
	topPadding := float32(40)
	bottomPadding := float32(80)
	leftPadding := float32(100)
	rightPadding := float32(20)

	graphWidth := float32(800) - leftPadding - rightPadding
	graphHeight := float32(500) - topPadding - bottomPadding

	// Background
	background := canvas.NewRectangle(color.NRGBA{R: 20, G: 20, B: 20, A: 255})
	background.Move(fyne.NewPos(0, 0))
	background.Resize(fyne.NewSize(800, 500))
	r.objects = append(r.objects, background)

	// Y-axis
	yAxisLine := canvas.NewLine(color.White)
	yAxisLine.StrokeWidth = 2
	yAxisLine.Move(fyne.NewPos(leftPadding, topPadding))
	yAxisLine.Resize(fyne.NewSize(0, graphHeight))
	r.objects = append(r.objects, yAxisLine)

	// X-axis
	xAxisLine := canvas.NewLine(color.White)
	xAxisLine.StrokeWidth = 2
	xAxisLine.Move(fyne.NewPos(leftPadding, topPadding+graphHeight))
	xAxisLine.Resize(fyne.NewSize(graphWidth, 0))
	r.objects = append(r.objects, xAxisLine)

	// Title
	title := canvas.NewText(fmt.Sprintf("Probability Distribution: %d to %d (%d total outcomes)", stats.MinValue, stats.MaxValue, stats.Total), color.White)
	title.TextSize = 16
	title.Move(fyne.NewPos(leftPadding, 10))
	r.objects = append(r.objects, title)

	// Y-axis label
	yLabel := canvas.NewText("Probability (%)", color.White)
	yLabel.TextSize = 12
	yLabel.Move(fyne.NewPos(10, topPadding+graphHeight/2-30))
	r.objects = append(r.objects, yLabel)

	// X-axis label
	xLabel := canvas.NewText("Result Value", color.White)
	xLabel.TextSize = 12
	xLabel.Move(fyne.NewPos(leftPadding+graphWidth/2-30, topPadding+graphHeight+50))
	r.objects = append(r.objects, xLabel)

	// Y-axis tick marks and labels
	numYTicks := int(roundedMaxPercent/5) + 1
	for i := 0; i <= numYTicks; i++ {
		percent := float64(i) * 5

		yPos := topPadding + graphHeight - (float32(percent/roundedMaxPercent) * graphHeight)

		// Tick mark
		tick := canvas.NewLine(color.White)
		tick.StrokeWidth = 1
		tick.Move(fyne.NewPos(leftPadding-5, yPos))
		tick.Resize(fyne.NewSize(5, 0))
		r.objects = append(r.objects, tick)

		// Label
		label := canvas.NewText(fmt.Sprintf("%.0f%%", percent), color.White)
		label.TextSize = 10
		label.Move(fyne.NewPos(leftPadding-50, yPos-7))
		r.objects = append(r.objects, label)
	}

	// Draw bars
	numBars := len(outcomes)
	barWidth := (graphWidth - float32(numBars+1)*2) / float32(numBars)
	if barWidth < 2 {
		barWidth = 2
	}

	barSpacing := float32(2)

	for i, value := range outcomes {
		percentage := stats.Percentages[value]

		// Bar height proportional to percentage
		barHeight := (float32(percentage) / float32(roundedMaxPercent)) * graphHeight

		// X position
		xPos := leftPadding + float32(i)*(barWidth+barSpacing*2) + barSpacing

		// Draw bar
		bar := canvas.NewRectangle(color.NRGBA{R: 100, G: 180, B: 255, A: 255})
		bar.Move(fyne.NewPos(xPos, topPadding+graphHeight-barHeight))
		bar.Resize(fyne.NewSize(barWidth, barHeight))
		r.objects = append(r.objects, bar)

		// X-axis label
		label := canvas.NewText(fmt.Sprintf("%d", value), color.White)
		label.TextSize = 10
		label.Move(fyne.NewPos(xPos, topPadding+graphHeight+10))
		r.objects = append(r.objects, label)
	}
}

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

func (r *barGraphCanvasRenderer) Destroy() {
}

// ShowStatisticsWindow creates and shows a statistics window for the given expression
func ShowStatisticsWindow(expression string) {
	stats, err := CalculateDiceStatistics(expression)
	if err != nil {
		fmt.Printf("Error calculating statistics: %v\n", err)
		return
	}

	// Create the bar graph
	graph := newBarGraphCanvas(stats)

	// Create and show the window
	window := fyne.CurrentApp().NewWindow("Statistics: " + expression)
	window.SetContent(graph)
	window.Resize(fyne.NewSize(800, 500))
	window.Show()
}