package main

import (
	"os"
	"path/filepath"
	"strings"

	"github.com/charmbracelet/lipgloss"
	"github.com/muesli/termenv"
)

// Theme represents a color theme
type Theme struct {
	Name string

	// UI colors
	Base     lipgloss.Color
	Surface  lipgloss.Color
	Overlay  lipgloss.Color
	Text     lipgloss.Color
	Subtext  lipgloss.Color
	Accent   lipgloss.Color
	Blue     lipgloss.Color
	Teal     lipgloss.Color
	Green    lipgloss.Color
	Yellow   lipgloss.Color
	Orange   lipgloss.Color
	Red      lipgloss.Color
	Purple   lipgloss.Color

	// For code highlighting
	ChromaStyle   string
	GlamourStyle  string
	LineNumColor  string
}

var (
	// LightTheme for light terminal backgrounds
	LightTheme = Theme{
		Name:     "light",
		Base:     lipgloss.Color("#f5f5f5"),
		Surface:  lipgloss.Color("#e8e8e8"),
		Overlay:  lipgloss.Color("#c0c0c0"),
		Text:     lipgloss.Color("#1a1a1a"),
		Subtext:  lipgloss.Color("#505050"),
		Accent:   lipgloss.Color("#6366f1"),
		Blue:     lipgloss.Color("#2563eb"),
		Teal:     lipgloss.Color("#0d9488"),
		Green:    lipgloss.Color("#16a34a"),
		Yellow:   lipgloss.Color("#ca8a04"),
		Orange:   lipgloss.Color("#ea580c"),
		Red:      lipgloss.Color("#dc2626"),
		Purple:   lipgloss.Color("#9333ea"),

		ChromaStyle:  "github",
		GlamourStyle: "light",
		LineNumColor: "#888888",
	}

	// DarkTheme for dark terminal backgrounds
	DarkTheme = Theme{
		Name:     "dark",
		Base:     lipgloss.Color("#1e1e2e"),
		Surface:  lipgloss.Color("#313244"),
		Overlay:  lipgloss.Color("#45475a"),
		Text:     lipgloss.Color("#cdd6f4"),
		Subtext:  lipgloss.Color("#a6adc8"),
		Accent:   lipgloss.Color("#b4befe"),
		Blue:     lipgloss.Color("#89b4fa"),
		Teal:     lipgloss.Color("#94e2d5"),
		Green:    lipgloss.Color("#a6e3a1"),
		Yellow:   lipgloss.Color("#f9e2af"),
		Orange:   lipgloss.Color("#fab387"),
		Red:      lipgloss.Color("#f38ba8"),
		Purple:   lipgloss.Color("#cba6f7"),

		ChromaStyle:  "catppuccin-mocha",
		GlamourStyle: "dark",
		LineNumColor: "#6c7086",
	}

	// CurrentTheme is the active theme
	CurrentTheme = LightTheme
)

// DetectTheme tries to detect if terminal has dark or light background
func DetectTheme() Theme {
	// Check for config file override first
	if theme := loadThemePreference(); theme != "" {
		if theme == "dark" {
			return DarkTheme
		}
		return LightTheme
	}

	// Auto-detect from terminal
	if termenv.NewOutput(os.Stdout).HasDarkBackground() {
		return DarkTheme
	}
	return LightTheme
}

// SetTheme sets the current theme and updates all styles
func SetTheme(t Theme) {
	CurrentTheme = t
	updateStyles()
}

// loadThemePreference loads theme from config file
func loadThemePreference() string {
	configDir, err := os.UserConfigDir()
	if err != nil {
		return ""
	}

	configPath := filepath.Join(configDir, "reader", "theme")
	data, err := os.ReadFile(configPath)
	if err != nil {
		return ""
	}

	return strings.TrimSpace(string(data))
}

// SaveThemePreference saves theme preference to config file
func SaveThemePreference(theme string) error {
	configDir, err := os.UserConfigDir()
	if err != nil {
		return err
	}

	readerDir := filepath.Join(configDir, "reader")
	if err := os.MkdirAll(readerDir, 0755); err != nil {
		return err
	}

	configPath := filepath.Join(readerDir, "theme")
	return os.WriteFile(configPath, []byte(theme), 0644)
}

// updateStyles updates all the lipgloss styles based on current theme
func updateStyles() {
	t := CurrentTheme

	activeBorderStyle = lipgloss.NewStyle().
		Border(lipgloss.RoundedBorder()).
		BorderForeground(t.Accent)

	inactiveBorderStyle = lipgloss.NewStyle().
		Border(lipgloss.RoundedBorder()).
		BorderForeground(t.Overlay)

	directoryStyle = lipgloss.NewStyle().
		Foreground(t.Blue).
		Bold(true)

	fileStyle = lipgloss.NewStyle().
		Foreground(t.Text)

	selectedStyle = lipgloss.NewStyle().
		Background(t.Surface).
		Foreground(t.Accent).
		Bold(true)

	statusBarStyle = lipgloss.NewStyle().
		Background(t.Surface).
		Foreground(t.Subtext).
		Padding(0, 1)

	statusKeyStyle = lipgloss.NewStyle().
		Background(t.Overlay).
		Foreground(t.Text).
		Padding(0, 1)

	helpStyle = lipgloss.NewStyle().
		Border(lipgloss.RoundedBorder()).
		BorderForeground(t.Purple).
		Padding(1, 2)

	helpTitleStyle = lipgloss.NewStyle().
		Foreground(t.Purple).
		Bold(true).
		MarginBottom(1)

	helpKeyStyle = lipgloss.NewStyle().
		Foreground(t.Yellow).
		Width(12)

	helpDescStyle = lipgloss.NewStyle().
		Foreground(t.Subtext)

	titleStyle = lipgloss.NewStyle().
		Foreground(t.Accent).
		Bold(true).
		Padding(0, 1)
}