package main

import (
	"image/color"
	"os/exec"
	"strings"

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

// CustomTheme structure
type CustomTheme struct {
	background color.Color
	primary    color.Color
	isDark     bool
}

var _ fyne.Theme = (*CustomTheme)(nil)

func (t *CustomTheme) Color(name fyne.ThemeColorName, variant fyne.ThemeVariant) color.Color {
	switch name {
	case theme.ColorNameBackground:
		return t.background
	case theme.ColorNamePrimary:
		return t.primary
	default:
		return theme.DefaultTheme().Color(name, variant)
	}
}

func (t *CustomTheme) Font(style fyne.TextStyle) fyne.Resource {
	return theme.DefaultTheme().Font(style)
}

func (t *CustomTheme) Icon(name fyne.ThemeIconName) fyne.Resource {
	return theme.DefaultTheme().Icon(name)
}

func (t *CustomTheme) Size(name fyne.ThemeSizeName) float32 {
	return theme.DefaultTheme().Size(name)
}

func applyThemeToApp(a fyne.App, background, primary [3]uint8, isDark bool) {
	customTheme := &CustomTheme{
		background: color.NRGBA{R: background[0], G: background[1], B: background[2], A: 0xff},
		primary:    color.NRGBA{R: primary[0], G: primary[1], B: primary[2], A: 0xff},
		isDark:     isDark,
	}
	a.Settings().SetTheme(customTheme)
}

// ApplyTheme applies the detected GTK theme to the Fyne app
func ApplyTheme(a fyne.App) {
	// Default light theme settings
	colBackground := [3]uint8{245, 245, 245}
	colTheme := [3]uint8{0, 120, 215}
	isDark := false

	// Detect GTK Theme
	isDarkGTK, err := getGTKTheme()
	if err == nil && isDarkGTK {
		colBackground = [3]uint8{10, 10, 10}
		isDark = true
	}

	applyThemeToApp(a, colBackground, colTheme, isDark)
}

// getGTKTheme detects if the current GTK theme is dark
func getGTKTheme() (bool, error) {
	cmd := exec.Command("dconf", "read", "/org/gnome/desktop/interface/gtk-theme")
	output, err := cmd.Output()
	if err != nil {
		return false, err
	}

	themeName := strings.Trim(string(output), "'\n ")
	return strings.Contains(strings.ToLower(themeName), "dark"), nil
}