// Package ui provides the Picocrypt NG graphical user interface using Fyne.
package ui

import (
	"image/color"

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

// PasswordStrengthIndicator is a custom widget that displays password strength
// as a circular arc, colored from red (weak) to green (strong).
// Uses canvas.Arc for efficient GPU-accelerated rendering.
// Matches original Picocrypt behavior: arc from top going clockwise.
type PasswordStrengthIndicator struct {
	widget.BaseWidget
	strength  int  // 0-4 (zxcvbn score)
	visible   bool // whether to show the indicator
	decryMode bool // hide in decrypt mode
}

// NewPasswordStrengthIndicator creates a new password strength indicator.
func NewPasswordStrengthIndicator() *PasswordStrengthIndicator {
	p := &PasswordStrengthIndicator{}
	p.ExtendBaseWidget(p)
	return p
}

// SetStrength updates the strength value (0-4).
func (p *PasswordStrengthIndicator) SetStrength(strength int) {
	p.strength = strength
	p.Refresh()
}

// SetVisible sets whether the indicator should be visible.
func (p *PasswordStrengthIndicator) SetVisible(visible bool) {
	p.visible = visible
	p.Refresh()
}

// SetDecryptMode sets whether in decrypt mode (hides the indicator).
func (p *PasswordStrengthIndicator) SetDecryptMode(decrypt bool) {
	p.decryMode = decrypt
	p.Refresh()
}

// MinSize returns the minimum size of the indicator.
func (p *PasswordStrengthIndicator) MinSize() fyne.Size {
	return fyne.NewSize(24, 24)
}

// CreateRenderer creates the renderer for the widget.
func (p *PasswordStrengthIndicator) CreateRenderer() fyne.WidgetRenderer {
	// Use canvas.Arc for efficient single-object rendering
	// CutoutRatio 0.6 creates a ring appearance similar to the original
	// StartAngle 0 = top (12 o'clock) in Fyne's coordinate system
	arc := canvas.NewArc(0, 0, 0.6, color.Transparent)
	arc.SetMinSize(fyne.NewSize(20, 20))

	r := &passwordStrengthRenderer{
		indicator: p,
		arc:       arc,
	}
	r.updateArc()
	return r
}

type passwordStrengthRenderer struct {
	indicator *PasswordStrengthIndicator
	arc       *canvas.Arc
}

func (r *passwordStrengthRenderer) Layout(size fyne.Size) {
	// Center the arc in the widget area
	arcSize := fyne.NewSize(20, 20)
	offset := fyne.NewPos(
		(size.Width-arcSize.Width)/2,
		(size.Height-arcSize.Height)/2,
	)
	r.arc.Move(offset)
	r.arc.Resize(arcSize)
}

func (r *passwordStrengthRenderer) MinSize() fyne.Size {
	return r.indicator.MinSize()
}

func (r *passwordStrengthRenderer) updateArc() {
	// Hide when not visible or in decrypt mode (matches original behavior)
	if !r.indicator.visible || r.indicator.decryMode {
		r.arc.FillColor = color.Transparent
		return
	}

	// Calculate color based on strength (0-4)
	// Red (weak) to Green (strong): matches original formula exactly
	// strength=0: R=200(0xc8), G=76(0x4c) - red
	// strength=4: R=76, G=200 - green
	// Clamp strength to valid range to prevent overflow
	s := r.indicator.strength
	if s < 0 {
		s = 0
	} else if s > 4 {
		s = 4
	}
	// #nosec G115 -- s is clamped to [0,4], so 31*s is [0,124], result always fits uint8
	col := color.RGBA{
		R: uint8(0xc8 - 31*s),
		G: uint8(0x4c + 31*s),
		B: 0x4b,
		A: 0xff,
	}

	// Arc angle calculation matching original Picocrypt:
	// Original used radians: start=-π/2, end=π*(0.4*strength-0.1)
	// Arc length = π*(0.4*strength-0.1) - (-π/2) = π*(0.4*strength+0.4) = 0.4π*(strength+1)
	// In degrees: 72*(strength+1)
	//
	// Fyne Arc: 0° is top, positive is clockwise
	// strength=0: 72° arc, strength=4: 360° (full circle)
	endAngle := float32(72 * (r.indicator.strength + 1))

	r.arc.StartAngle = 0
	r.arc.EndAngle = endAngle
	r.arc.FillColor = col
}

func (r *passwordStrengthRenderer) Refresh() {
	r.updateArc()
	canvas.Refresh(r.arc)
}

func (r *passwordStrengthRenderer) Destroy() {}

func (r *passwordStrengthRenderer) Objects() []fyne.CanvasObject {
	return []fyne.CanvasObject{r.arc}
}

// ValidationIndicator is a custom widget that displays a circular validation indicator.
// Shows green circle when valid, red circle when invalid, or invisible when not applicable.
// Uses canvas.Circle for efficient GPU-accelerated rendering.
type ValidationIndicator struct {
	widget.BaseWidget
	valid   bool // true = green, false = red
	visible bool // whether to show the indicator
}

// NewValidationIndicator creates a new validation indicator.
func NewValidationIndicator() *ValidationIndicator {
	v := &ValidationIndicator{}
	v.ExtendBaseWidget(v)
	return v
}

// SetValid sets whether the validation passed.
func (v *ValidationIndicator) SetValid(valid bool) {
	v.valid = valid
	v.Refresh()
}

// SetVisible sets whether the indicator should be visible.
func (v *ValidationIndicator) SetVisible(visible bool) {
	v.visible = visible
	v.Refresh()
}

// MinSize returns the minimum size of the indicator.
func (v *ValidationIndicator) MinSize() fyne.Size {
	return fyne.NewSize(24, 24)
}

// CreateRenderer creates the renderer for the widget.
func (v *ValidationIndicator) CreateRenderer() fyne.WidgetRenderer {
	// Use canvas.Circle for efficient single-object rendering
	circle := canvas.NewCircle(color.Transparent)
	circle.StrokeWidth = 2

	r := &validationRenderer{indicator: v, circle: circle}
	r.updateColor()
	return r
}

type validationRenderer struct {
	indicator *ValidationIndicator
	circle    *canvas.Circle
}

func (r *validationRenderer) Layout(size fyne.Size) {
	// Center the circle in the widget area - same size as password strength arc (20x20)
	circleSize := fyne.NewSize(20, 20)
	offset := fyne.NewPos(
		(size.Width-circleSize.Width)/2,
		(size.Height-circleSize.Height)/2,
	)
	r.circle.Move(offset)
	r.circle.Resize(circleSize)
}

func (r *validationRenderer) MinSize() fyne.Size {
	return r.indicator.MinSize()
}

func (r *validationRenderer) updateColor() {
	if !r.indicator.visible {
		r.circle.StrokeColor = color.Transparent
		r.circle.FillColor = color.Transparent
	} else if r.indicator.valid {
		r.circle.StrokeColor = color.RGBA{0x4c, 0xc8, 0x4b, 0xff} // Green
		r.circle.FillColor = color.Transparent
	} else {
		r.circle.StrokeColor = color.RGBA{0xc8, 0x4c, 0x4b, 0xff} // Red
		r.circle.FillColor = color.Transparent
	}
}

func (r *validationRenderer) Refresh() {
	r.updateColor()
	canvas.Refresh(r.circle)
}

func (r *validationRenderer) Destroy() {}

func (r *validationRenderer) Objects() []fyne.CanvasObject {
	return []fyne.CanvasObject{r.circle}
}

// DisabledEntry is an Entry widget that appears disabled but still shows content.
type DisabledEntry struct {
	widget.Entry
}

// NewDisabledEntry creates a new disabled entry.
func NewDisabledEntry() *DisabledEntry {
	e := &DisabledEntry{}
	e.ExtendBaseWidget(e)
	e.Disable()
	return e
}

// SetText sets the text of the disabled entry.
func (e *DisabledEntry) SetText(text string) {
	e.Entry.SetText(text)
}

// PasswordEntry is an Entry widget that can toggle between password and text mode.
type PasswordEntry struct {
	widget.Entry
	hidden bool
}

// NewPasswordEntry creates a new password entry.
func NewPasswordEntry() *PasswordEntry {
	e := &PasswordEntry{hidden: true}
	e.ExtendBaseWidget(e)
	e.Password = true
	return e
}

// SetHidden sets whether the password is hidden.
func (e *PasswordEntry) SetHidden(hidden bool) {
	e.hidden = hidden
	e.Password = hidden
	e.Refresh()
}

// IsHidden returns whether the password is currently hidden.
func (e *PasswordEntry) IsHidden() bool {
	return e.hidden
}

// ColoredLabel is a label with custom text color.
type ColoredLabel struct {
	widget.BaseWidget
	text       string
	color      color.Color
	truncation fyne.TextTruncation
}

// NewColoredLabel creates a new label with custom color.
func NewColoredLabel(text string, col color.Color) *ColoredLabel {
	l := &ColoredLabel{
		text:       text,
		color:      col,
		truncation: fyne.TextTruncateEllipsis, // Default to ellipsis truncation
	}
	l.ExtendBaseWidget(l)
	return l
}

// SetText updates the label text.
func (l *ColoredLabel) SetText(text string) {
	l.text = text
	l.Refresh()
}

// SetColor updates the label color.
func (l *ColoredLabel) SetColor(col color.Color) {
	l.color = col
	l.Refresh()
}

// SetTruncation updates the label truncation mode.
func (l *ColoredLabel) SetTruncation(truncation fyne.TextTruncation) {
	l.truncation = truncation
	l.Refresh()
}

// MinSize returns the minimum size needed to display the label.
// When truncation is enabled, limits width to prevent window resizing.
func (l *ColoredLabel) MinSize() fyne.Size {
	textSize := fyne.MeasureText(l.text, theme.TextSize(), fyne.TextStyle{})

	// If truncation is enabled, don't let the label force window resizing
	// Use a reasonable maximum width (e.g., 600 pixels)
	if l.truncation != fyne.TextTruncateOff && textSize.Width > 600 {
		textSize.Width = 600
	}

	return textSize
}

// CreateRenderer creates the renderer for the colored label.
func (l *ColoredLabel) CreateRenderer() fyne.WidgetRenderer {
	text := canvas.NewText(l.text, l.color)
	text.TextSize = theme.TextSize()
	return &coloredLabelRenderer{label: l, text: text}
}

type coloredLabelRenderer struct {
	label         *ColoredLabel
	text          *canvas.Text
	availableSize fyne.Size
}

func (r *coloredLabelRenderer) Layout(size fyne.Size) {
	r.availableSize = size
	r.text.Move(fyne.NewPos(0, 0))
	r.text.Resize(size)
	r.updateText()
}

func (r *coloredLabelRenderer) MinSize() fyne.Size {
	return r.label.MinSize()
}

func (r *coloredLabelRenderer) Refresh() {
	r.updateText()
}

// updateText updates the displayed text with truncation if needed
func (r *coloredLabelRenderer) updateText() {
	displayText := r.label.text

	// Apply truncation if needed and we have available size
	if r.label.truncation != fyne.TextTruncateOff && r.availableSize.Width > 0 {
		displayText = r.truncateText(displayText, r.availableSize.Width)
	}

	r.text.Text = displayText
	r.text.Color = r.label.color
	canvas.Refresh(r.text)
}

// truncateText truncates text with ellipsis if it exceeds maxWidth
func (r *coloredLabelRenderer) truncateText(text string, maxWidth float32) string {
	if maxWidth <= 0 {
		return text
	}

	textSize := fyne.MeasureText(text, theme.TextSize(), fyne.TextStyle{})
	if textSize.Width <= maxWidth {
		return text
	}

	ellipsis := "..."
	ellipsisWidth := fyne.MeasureText(ellipsis, theme.TextSize(), fyne.TextStyle{}).Width
	availableWidth := maxWidth - ellipsisWidth

	if availableWidth <= 0 {
		return ellipsis
	}

	runes := []rune(text)

	// Binary search for the longest substring that fits with ellipsis
	low, high := 0, len(runes)
	for low < high {
		mid := (low + high + 1) / 2
		candidate := string(runes[:mid]) + ellipsis
		candidateWidth := fyne.MeasureText(candidate, theme.TextSize(), fyne.TextStyle{}).Width

		if candidateWidth <= maxWidth {
			low = mid // This length fits, try longer
		} else {
			high = mid - 1 // This length is too long, try shorter
		}
	}

	if low == 0 {
		return ellipsis
	}
	return string(runes[:low]) + ellipsis
}

func (r *coloredLabelRenderer) Destroy() {}

func (r *coloredLabelRenderer) Objects() []fyne.CanvasObject {
	return []fyne.CanvasObject{r.text}
}
