package ui

import (
	"fmt"
	"strings"

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

	"skyrama-tui/internal/service"
	"skyrama-tui/internal/style"
)

// ─── Messages ─────────────────────────────────────────────────────────────────

type LoginSuccessMsg struct {
	UserID   int32
	Username string
}
type LoginErrMsg struct{ Err error }

// ─── Model ────────────────────────────────────────────────────────────────────

type LoginModel struct {
	client *service.GameService
	inputs []textinput.Model // 0=username, 1=password
	focus  int
	mode   string // "login" | "register"
	err    string
	width  int
}

func NewLoginModel(client *service.GameService) LoginModel {
	user := textinput.New()
	user.Placeholder = "username"
	user.Focus()
	user.CharLimit = 64
	user.Width = 30

	pass := textinput.New()
	pass.Placeholder = "password"
	pass.EchoMode = textinput.EchoPassword
	pass.EchoCharacter = '•'
	pass.CharLimit = 128
	pass.Width = 30

	return LoginModel{
		client: client,
		inputs: []textinput.Model{user, pass},
		mode:   "login",
	}
}

func (m LoginModel) Init() tea.Cmd {
	return textinput.Blink
}

func (m LoginModel) Update(msg tea.Msg) (LoginModel, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.width = msg.Width

	case tea.KeyMsg:
		switch msg.String() {
		case "tab", "down":
			m.focus = (m.focus + 1) % len(m.inputs)
			for i := range m.inputs {
				if i == m.focus {
					m.inputs[i].Focus()
				} else {
					m.inputs[i].Blur()
				}
			}
		case "shift+tab", "up":
			m.focus = (m.focus - 1 + len(m.inputs)) % len(m.inputs)
			for i := range m.inputs {
				if i == m.focus {
					m.inputs[i].Focus()
				} else {
					m.inputs[i].Blur()
				}
			}
		case "ctrl+r":
			m.mode = "register"
			m.err = ""
		case "ctrl+l":
			m.mode = "login"
			m.err = ""
		case "enter":
			username := strings.TrimSpace(m.inputs[0].Value())
			password := m.inputs[1].Value()
			if username == "" || password == "" {
				m.err = "username and password required"
				return m, nil
			}
			if m.mode == "login" {
				return m, m.doLogin(username, password)
			}
			return m, m.doRegister(username, password)
		}
	}

	// Forward input events to focused field
	var cmds []tea.Cmd
	for i := range m.inputs {
		var cmd tea.Cmd
		m.inputs[i], cmd = m.inputs[i].Update(msg)
		cmds = append(cmds, cmd)
	}
	return m, tea.Batch(cmds...)
}

func (m LoginModel) View() string {
	banner := style.Title.Render("✈  SKYRAMA  ✈")

	modeLabel := style.PanelHeader.Render("Login")
	if m.mode == "register" {
		modeLabel = style.PanelHeader.Render("Register")
	}

	form := lipgloss.JoinVertical(lipgloss.Left,
		style.Muted.Render("Username"),
		m.inputs[0].View(),
		"",
		style.Muted.Render("Password"),
		m.inputs[1].View(),
	)

	errLine := ""
	if m.err != "" {
		errLine = "\n" + style.Error.String() + style.Muted.Render(m.err)
	}

	hints := "\n" +
		style.HelpKey.Render("enter") + style.HelpDesc.Render(" confirm  ") +
		style.HelpKey.Render("ctrl+r") + style.HelpDesc.Render(" register  ") +
		style.HelpKey.Render("ctrl+l") + style.HelpDesc.Render(" login  ") +
		style.HelpKey.Render("tab") + style.HelpDesc.Render(" next field")

	box := style.Panel.Padding(1, 3).Render(
		lipgloss.JoinVertical(lipgloss.Left, modeLabel, "", form, errLine, hints),
	)

	content := lipgloss.JoinVertical(lipgloss.Center, banner, "", box)

	return lipgloss.Place(m.width, 24, lipgloss.Center, lipgloss.Center, content)
}

// SetErr injects an error string from outside (e.g. from main after a LoginErrMsg).
func (m *LoginModel) SetErr(e string) { m.err = e }

// ─── Commands ─────────────────────────────────────────────────────────────────

func (m LoginModel) doLogin(username, password string) tea.Cmd {
	return func() tea.Msg {
		id, err := m.client.Login(username, password)
		if err != nil {
			return LoginErrMsg{Err: err}
		}
		return LoginSuccessMsg{UserID: id, Username: username}
	}
}

func (m LoginModel) doRegister(username, password string) tea.Cmd {
	return func() tea.Msg {
		_, err := m.client.Register(username, password)
		if err != nil {
			return LoginErrMsg{Err: fmt.Errorf("register: %w", err)}
		}
		// Auto-login after register
		id, err := m.client.Login(username, password)
		if err != nil {
			return LoginErrMsg{Err: err}
		}
		return LoginSuccessMsg{UserID: id, Username: username}
	}
}