package main

import (
	"fmt"
	"os"
	"strings"

	"github.com/charmbracelet/bubbles/textinput"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

// ============================================================================
// STYLING DEFINITIONS (Lipgloss)
// ============================================================================
var (
	focusedStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("205")).Bold(true)
	blurredStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("240"))
	cursorStyle  = focusedStyle.Copy()
	noStyle      = lipgloss.NewStyle()

	// A nice box around the login screen
	dialogBoxStyle = lipgloss.NewStyle().
			Border(lipgloss.RoundedBorder()).
			BorderForeground(lipgloss.Color("87")).
			Padding(1, 4).
			MarginTop(1).
			MarginLeft(2)
)

// ============================================================================
// 1. THE MODEL
// ============================================================================
type loginModel struct {
	focusIndex int
	inputs     []textinput.Model
	cursorMode textinput.CursorMode

	// Flags to return back to the main application
	isSubmitted  bool
	isCanceled   bool
	errorMessage string
}

func initialModell() loginModel {
	m := loginModel{
		inputs: make([]textinput.Model, 2),
	}

	var t textinput.Model
	for i := range m.inputs {
		t = textinput.New()
		t.Cursor.Style = cursorStyle
		t.CharLimit = 32

		switch i {
		case 0:
			t.Placeholder = "Username"
			t.Focus()
			t.PromptStyle = focusedStyle
			t.TextStyle = focusedStyle
		case 1:
			t.Placeholder = "Password"
			t.EchoMode = textinput.EchoPassword // Masks the password with *
			t.EchoCharacter = '•'
		}

		m.inputs[i] = t
	}

	return m
}

// ============================================================================
// 2. THE INIT FUNCTION (Runs once on startup)
// ============================================================================
func (m loginModel) Init() tea.Cmd {
	return textinput.Blink
}

// ============================================================================
// 3. THE UPDATE FUNCTION (Handles keypresses)
// ============================================================================
func (m loginModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "ctrl+c", "esc":
			m.isCanceled = true
			return m, tea.Quit

		// Handle switching between username and password fields
		case "tab", "shift+tab", "enter", "up", "down":
			s := msg.String()

			// If they press Enter on the password field, submit the form
			if s == "enter" && m.focusIndex == len(m.inputs)-1 {
				m.isSubmitted = true
				return m, tea.Quit
			}

			// Cycle through inputs
			if s == "up" || s == "shift+tab" {
				m.focusIndex--
			} else {
				m.focusIndex++
			}

			if m.focusIndex > len(m.inputs)-1 {
				m.focusIndex = 0
			} else if m.focusIndex < 0 {
				m.focusIndex = len(m.inputs) - 1
			}

			// Apply focus states
			cmds := make([]tea.Cmd, len(m.inputs))
			for i := 0; i <= len(m.inputs)-1; i++ {
				if i == m.focusIndex {
					cmds[i] = m.inputs[i].Focus()
					m.inputs[i].PromptStyle = focusedStyle
					m.inputs[i].TextStyle = focusedStyle
					continue
				}
				m.inputs[i].Blur()
				m.inputs[i].PromptStyle = noStyle
				m.inputs[i].TextStyle = noStyle
			}

			return m, tea.Batch(cmds...)
		}
	}

	// Handle character inputs and blinking
	cmd := m.updateInputs(msg)
	return m, cmd
}

func (m *loginModel) updateInputs(msg tea.Msg) tea.Cmd {
	cmds := make([]tea.Cmd, len(m.inputs))
	for i := range m.inputs {
		m.inputs[i], cmds[i] = m.inputs[i].Update(msg)
	}
	return tea.Batch(cmds...)
}

// ============================================================================
// 4. THE VIEW FUNCTION (Renders the UI)
// ============================================================================
func (m loginModel) View() string {
	// Build the UI string
	var b strings.Builder

	b.WriteString(lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("78")).Render("✈️  SKYRAMA TERMINAL LOGIN\n\n"))

	for i := range m.inputs {
		b.WriteString(m.inputs[i].View())
		if i < len(m.inputs)-1 {
			b.WriteRune('\n')
		}
	}

	button := &lipgloss.Style{}
	if m.focusIndex == len(m.inputs) {
		button = &focusedStyle
	} else {
		button = &blurredStyle
	}

	b.WriteString("\n")
	if m.errorMessage != "" {
		b.WriteString(lipgloss.NewStyle().Foreground(lipgloss.Color("9")).Render("⚠️ " + m.errorMessage + "\n"))
	} else {
		b.WriteString("\n")
	}
	b.WriteString(button.Render("[ Submit ]"))
	b.WriteString(blurredStyle.Render("\n\n(esc to quit)"))

	// Wrap the whole thing in our dialog box
	return dialogBoxStyle.Render(b.String()) + "\n"
}

// ============================================================================
// THE WRAPPER FUNCTION (Call this from your app)
// ============================================================================
// RunLoginScreen starts the TUI and returns the username, password, and a boolean
// indicating if the user completed the form (true) or pressed escape (false).
func RunLoginScreen() (username string, password string, submitted bool) {

	p := tea.NewProgram(initialModell())

	// Run the Bubble Tea program synchronously
	finalModel, err := p.Run()
	if err != nil {
		fmt.Printf("Error running login screen: %v", err)
		os.Exit(1)
	}

	// Cast the returned tea.Model back into our specific loginModel
	if m, ok := finalModel.(loginModel); ok {
		if m.isSubmitted {
			return m.inputs[0].Value(), m.inputs[1].Value(), true
		}
	}

	return "", "", false
}