package main

import (
	"fmt"
	"os"
	"time"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"

	"github.com/calmcacil/wg-admin/internal/config"
	"github.com/calmcacil/wg-admin/internal/tui/screens"
)

const version = "0.1.0"

// TickMsg is sent for transition animation frames
type TickMsg time.Time

// Transition settings
const (
	transitionDuration = 200 * time.Millisecond
	transitionFPS     = 60
)


var (
	styleTitle    = lipgloss.NewStyle().Foreground(lipgloss.Color("62")).Bold(true)
	styleSubtitle = lipgloss.NewStyle().Foreground(lipgloss.Color("241"))
	styleSuccess  = lipgloss.NewStyle().Foreground(lipgloss.Color("46"))
	styleError    = lipgloss.NewStyle().Foreground(lipgloss.Color("196"))
	styleHelpKey  = lipgloss.NewStyle().Foreground(lipgloss.Color("63")).Bold(true)
)

type model struct {
	transitionFrom       screens.Screen
	transitionTo         screens.Screen
	transitionProgress   float64
	transitionAnimating  bool
	transitionStartTime  time.Time
	transitionType       screens.TransitionType
	transitionDuration   time.Duration
	currentScreen  screens.Screen
	previousScreen screens.Screen
	quitting       bool
	initialized    bool
	errorScreen    *screens.ErrorScreen
}

func (m model) Init() tea.Cmd {
	if os.Geteuid() != 0 {
		fmt.Println(styleError.Render("ERROR: Must run as root"))
		os.Exit(1)
	}
	_, _ = config.LoadConfig()
	return nil
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	// Handle initialization on first update after Init
	if !m.initialized {
		m.initialized = true
		m.currentScreen = screens.NewListScreen()
		return m, m.currentScreen.Init()
	}

	// Handle transition animation updates
	if m.transitionAnimating {
		switch msg.(type) {
		case TickMsg:
			// Update transition progress
			elapsed := time.Since(m.transitionStartTime)
			m.transitionProgress = float64(elapsed) / float64(m.transitionDuration)

			// Ease-out cubic function for smoother animation
			easeProgress := 1 - ((1 - m.transitionProgress) * (1 - m.transitionProgress) * (1 - m.transitionProgress))

			if m.transitionProgress >= 1 || easeProgress >= 1 {
				// Transition complete
				m.transitionAnimating = false
				m.currentScreen = m.transitionTo
				m.previousScreen = m.transitionFrom
				m.transitionFrom = nil
				m.transitionTo = nil
				return m, nil
			}

			// Continue animation
			return m, tea.Tick(time.Second/time.Duration(transitionFPS), func(t time.Time) tea.Msg {
				return TickMsg(t)
			})
		}
		// During transition, don't process other messages
		return m, nil
	}

	switch msg := msg.(type) {
	case tea.KeyMsg:
		// Only quit on 'q' or ctrl+c when on list screen
		if msg.String() == "q" || msg.String() == "ctrl+c" {
			if _, ok := m.currentScreen.(*screens.ListScreen); ok {
				m.quitting = true
				return m, tea.Quit
			}
		}
		switch msg.String() {
		case "?":
			cmd := m.startTransition(screens.NewHelpScreen(m.previousScreen), screens.TransitionFade)
			return m, cmd
		case "l":
			cmd := m.startTransition(screens.NewListScreen(), screens.TransitionFade)
			return m, cmd
		case "a":
			cmd := m.startTransition(screens.NewAddScreen(), screens.TransitionSlideLeft)
			return m, cmd
		}
	case screens.ClientSelectedMsg:
		cmd := m.startTransition(screens.NewDetailScreen(msg.Client.Client), screens.TransitionSlideLeft)
		return m, cmd
	case screens.ClientDeletedMsg:
		cmd := m.startTransition(screens.NewListScreen(), screens.TransitionFade)
		return m, cmd
	case screens.ClientCreatedMsg:
		cmd := m.startTransition(screens.NewListScreen(), screens.TransitionFade)
		return m, cmd
	case screens.RestoreCompletedMsg:
		cmd := m.startTransition(screens.NewListScreen(), screens.TransitionFade)
		return m, cmd
	case screens.CloseDetailScreenMsg:
		if m.previousScreen != nil {
			cmd := m.startTransition(m.previousScreen, screens.TransitionSlideRight)
			return m, cmd
		}
		cmd := m.startTransition(screens.NewListScreen(), screens.TransitionFade)
		return m, cmd
	case screens.ErrMsg:
		m.previousScreen = m.currentScreen
		m.errorScreen = screens.NewErrorScreen(msg.Err)
		cmd := m.startTransition(m.errorScreen, screens.TransitionFade)
		return m, cmd
	}

	// Pass messages to current screen
	if m.currentScreen != nil {
		newScreen, cmd := m.currentScreen.Update(msg)
		if newScreen == nil {
			if m.previousScreen != nil {
				transitionCmd := m.startTransition(m.previousScreen, screens.TransitionSlideRight)
				return m, tea.Batch(cmd, transitionCmd)
			}
		} else if newScreen != m.currentScreen {
			m.previousScreen = m.currentScreen
			transitionCmd := m.startTransition(newScreen, screens.TransitionSlideLeft)
			return m, tea.Batch(cmd, transitionCmd)
		}
		return m, cmd
	}

	return m, nil
}
}

func (m model) View() string {

func (m model) View() string {
	if m.quitting {
		return "\nGoodbye!\n"
	}

	// If transitioning, render the transition animation
	if m.transitionAnimating {
		return renderTransition(m)
	}

	if m.currentScreen != nil && m.initialized {
		return m.currentScreen.View()
	}

	title := styleTitle.Render("WireGuard Client Manager")
	subtitle := styleSubtitle.Render(fmt.Sprintf("v%s", version))
	bar := fmt.Sprintf("Press %s for help, %s to quit", styleHelpKey.Render("?"), styleHelpKey.Render("q"))

	return title + " " + subtitle + "\n\nInitializing...\n\n" + bar
}
}

func main() {
	p := tea.NewProgram(model{}, tea.WithAltScreen())
	if _, err := p.Run(); err != nil {
		fmt.Printf("Error: %v\n", err)
		os.Exit(1)
	}
}

// startTransition begins a screen transition animation
func (m *model) startTransition(toScreen screens.Screen, ttype screens.TransitionType) tea.Cmd {
	// Initialize new screen
	var initCmd tea.Cmd
	if toScreen != nil {
		initCmd = toScreen.Init()
	}

	// Set up transition
	m.transitionFrom = m.currentScreen
	m.transitionTo = toScreen
	m.transitionType = ttype
	m.transitionDuration = transitionDuration
	m.transitionProgress = 0
	m.transitionAnimating = true
	m.transitionStartTime = time.Now()

	// Return initialization command and tick command
	tickCmd := tea.Tick(time.Second/time.Duration(transitionFPS), func(t time.Time) tea.Msg {
		return TickMsg(t)
	})

	if initCmd != nil {
		return tea.Batch(initCmd, tickCmd)
	}
	return tickCmd
}

func renderTransition(m model) string {
	if m.transitionFrom == nil || m.transitionTo == nil {
		return m.transitionTo.View()
	}

	fromView := m.transitionFrom.View()
	toView := m.transitionTo.View()

	// Apply easing to progress
	easeProgress := 1 - ((1 - m.transitionProgress) * (1 - m.transitionProgress) * (1 - m.transitionProgress))

	switch m.transitionType {
	case screens.TransitionFade:
		return renderFadeTransition(fromView, toView, easeProgress)
	case screens.TransitionSlideLeft:
		return renderSlideTransition(fromView, toView, easeProgress, true)
	case screens.TransitionSlideRight:
		return renderSlideTransition(fromView, toView, easeProgress, false)
	default:
		return toView
	}
}

func renderFadeTransition(fromView, toView string, progress float64) string {
	fromLines := splitLines(fromView)
	toLines := splitLines(toView)

	maxLines := max(len(fromLines), len(toLines))
	for len(fromLines) < maxLines {
		fromLines = append(fromLines, "")
	}
	for len(toLines) < maxLines {
		toLines = append(toLines, "")
	}

	var result []string
	for i := 0; i < maxLines; i++ {
		threshold := progress * float64(maxLines)
		if float64(i) < threshold {
			result = append(result, toLines[i])
		} else {
			result = append(result, fromLines[i])
		}
	}

	return joinLines(result)
}

func renderSlideTransition(fromView, toView string, progress float64, slideLeft bool) string {
	fromLines := splitLines(fromView)
	toLines := splitLines(toView)

	width := 80

	for i := range fromLines {
		fromLines[i] = padLine(fromLines[i], width)
	}
	for i := range toLines {
		toLines[i] = padLine(toLines[i], width)
	}

	offset := int(float64(width) * progress)

	var result []string
	maxLines := max(len(fromLines), len(toLines))

	for i := 0; i < maxLines; i++ {
		var fromLine, toLine string
		if i < len(fromLines) {
			fromLine = fromLines[i]
		} else {
			fromLine = ""
		}
		if i < len(toLines) {
			toLine = toLines[i]
		} else {
			toLine = ""
		}

		if slideLeft {
			fromOffset := -offset
			toOffset := width - offset
			combined := combineSlidingLines(fromLine, toLine, fromOffset, toOffset, width)
			result = append(result, combined)
		} else {
			fromOffset := offset
			toOffset := -width + offset
			combined := combineSlidingLines(fromLine, toLine, fromOffset, toOffset, width)
			result = append(result, combined)
		}
	}

	return joinLines(result)
}

func combineSlidingLines(from, to string, fromOffset, toOffset, width int) string {
	result := make([]byte, width)
	for i := range result {
		result[i] = ' '
	}

	if fromOffset >= -len(from) && fromOffset < width {
		for i := 0; i < len(from) && i+fromOffset < width && i+fromOffset >= 0; i++ {
			if i+fromOffset >= 0 && i+fromOffset < width {
				result[i+fromOffset] = from[i]
			}
		}
	}

	if toOffset >= -len(to) && toOffset < width {
		for i := 0; i < len(to) && i+toOffset < width && i+toOffset >= 0; i++ {
			if i+toOffset >= 0 && i+toOffset < width {
				result[i+toOffset] = to[i]
			}
		}
	}

	return string(result)
}

func splitLines(s string) []string {
	lines := make([]string, 0)
	current := ""
	for _, c := range s {
		if c == '\n' {
			lines = append(lines, current)
			current = ""
		} else {
			current += string(c)
		}
	}
	if current != "" {
		lines = append(lines, current)
	}
	return lines
}

func joinLines(lines []string) string {
	result := ""
	for i, line := range lines {
		if i > 0 {
			result += "\n"
		}
		result += line
	}
	return result
}

func padLine(line string, width int) string {
	if len(line) >= width {
		return line[:width]
	}
	return fmt.Sprintf("%-*s", width, line)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}