package tui

import (
	"tailscale-vpn/internal/styles"

	tea "charm.land/bubbletea/v2"
	lipgloss "charm.land/lipgloss/v2"
)

func footerHint(key, desc string) string {
	return styles.FooterKeyStyle.Render(key) +
		" " +
		styles.FooterDescStyle.Render(desc)
}

func footerSep() string {
	return styles.FooterSepStyle.Render(" · ")
}

func (m TUIInterface) subtitle() string {
	switch m.Page {
	case pageHome:
		return "Secure vpn"
	case pageSettings:
		return "Settings"
	case pageSelectServer:
		return "Select Server"
	default:
		return "Secure vpn"
	}
}

func (m TUIInterface) View() tea.View {
	if m.Quitting {
		return tea.NewView("")
	}

	w := m.WindowWidth
	h := m.WindowHeight
	if w == 0 {
		w = 80
	}
	if h == 0 {
		h = 24
	}

	var body string
	switch m.Page {
	case pageHome:
		body = m.viewHomePage()
	case pageSettings:
		body = m.viewSettingsPage()
	case pageSelectServer:
		body = m.viewSelectServerPage()
	default:
		body = m.viewHomePage()
	}

	header := lipgloss.JoinVertical(lipgloss.Left,
		styles.CardTitleStyle.Render("✦  tailscale vpn"),
		styles.CardSubtitleStyle.Render(m.subtitle()),
	)

	topContent := styles.CardInnerStyle.Render(
		lipgloss.JoinVertical(lipgloss.Left, header, body),
	)

	var footerStr string
	switch m.Page {
	case pageHome:
		footerStr = footerHint("↑↓", "navigate") +
			footerSep() +
			footerHint("enter", "select") +
			footerSep() +
			footerHint("r", "refresh") +
			footerSep() +
			footerHint("esc", "quit")
	case pageSettings:
		if m.SettingsEditMode == "" {
			if m.SettingsConfirmDelete {
				footerStr = footerHint("enter", "confirm") +
					footerSep() +
					footerHint("esc", "cancel")
			} else {
				footerStr = footerHint("↑↓", "navigate") +
					footerSep() +
					footerHint("enter", "select") +
					footerSep() +
					footerHint("a", "add") +
					footerSep() +
					footerHint("d", "delete") +
					footerSep() +
					footerHint("esc", "back")
			}
		} else {
			footerStr = footerHint("↑↓", "navigate") +
				footerSep() +
				footerHint("enter", "select") +
				footerSep() +
				footerHint("esc", "cancel")
		}
	case pageSelectServer:
		footerStr = footerHint("↑↓", "navigate") +
			footerSep() +
			footerHint("enter", "select") +
			footerSep() +
			footerHint("esc", "cancel")
	default:
		footerStr = footerHint("↑↓", "navigate") +
			footerSep() +
			footerHint("enter", "select") +
			footerSep() +
			footerHint("esc", "quit")
	}
	footer := styles.FooterStyle.Render(footerStr)

	card := styles.CardStyle.Render(
		lipgloss.JoinVertical(lipgloss.Left, topContent, footer),
	)

	cardHeight := lipgloss.Height(card)
	topPad := max((h-cardHeight)/2, 0)

	centeredCard := lipgloss.NewStyle().
		Width(w).
		Align(lipgloss.Center).
		PaddingTop(topPad).
		Render(card)

	v := tea.NewView(centeredCard)
	v.AltScreen = true
	return v
}

func (m TUIInterface) viewHomePage() string {
	var status string
	if m.VPNLoading {
		status = styles.VPNStatusLoadingStyle.Render("Checking...")
	} else if m.VPNConnected {
		status = styles.VPNStatusConnectedStyle.Render("● VPN Connected")
	} else {
		status = styles.VPNStatusDisconnectedStyle.Render("○ VPN Disconnected")
	}

	var serverStatus string
	if m.HasSelectedServer {
		serverStatus = styles.ServerSelectedStyle.Render("Server: " + m.SelectedServer.Name)
	} else if m.HasServers {
		serverStatus = styles.ServerNotSelectedStyle.Render("No server selected")
	}

	var menu string
	if !m.VPNLoading && !m.VPNToggleLoading {
		menu = m.renderMenu()
	} else {
		menu = styles.ButtonLoadingStyle.Render("...")
	}

	var errorStr string
	if m.VPNError != nil {
		errorStr = styles.VPNErrorStyle.Render("✗ " + m.VPNError.Error())
	}

	content := lipgloss.JoinVertical(lipgloss.Left, status, serverStatus, menu, errorStr)
	return content
}

func (m TUIInterface) renderMenu() string {
	if len(m.MenuItems) == 0 {
		return ""
	}

	var rows []string
	for i, item := range m.MenuItems {
		if i == m.Selected {
			prefix := "▸ "
			rows = append(rows, styles.ButtonActiveStyle.Render(prefix+item.Label))
		} else {
			prefix := "  "
			rows = append(rows, styles.ButtonInactiveStyle.Render(prefix+item.Label))
		}
	}

	return lipgloss.JoinVertical(lipgloss.Left, rows...)
}

func (m TUIInterface) viewSettingsPage() string {
	if m.SettingsEditMode != "" {
		return m.renderSettingsForm()
	}

	if m.SettingsConfirmDelete {
		return m.renderSettingsDeleteConfirm()
	}

	return m.renderSettingsList()
}

func (m TUIInterface) renderSettingsList() string {
	if len(m.SettingsServers) == 0 {
		return styles.EmptyListStyle.Render("No servers configured")
	}

	var rows []string
	for i, srv := range m.SettingsServers {
		if i == m.SettingsSelected {
			name := styles.ServerItemActiveStyle.Render(srv.Name)
			host := styles.ServerItemActiveStyle.Render(srv.Host)
			rows = append(rows, lipgloss.JoinHorizontal(lipgloss.Top, "▸ ", name, styles.ServerItemInactiveStyle.Render(" · "), host))
		} else {
			name := styles.ServerItemInactiveStyle.Render(srv.Name)
			host := styles.ServerItemInactiveStyle.Render(srv.Host)
			rows = append(rows, lipgloss.JoinHorizontal(lipgloss.Top, "  ", name, styles.ServerItemInactiveStyle.Render(" · "), host))
		}
	}

	return styles.ServerListStyle.Render(lipgloss.JoinVertical(lipgloss.Left, rows...))
}

func (m TUIInterface) renderSettingsForm() string {
	title := styles.FormTitleStyle.Render(
		func() string {
			if m.SettingsEditMode == "add" {
				return "Add Server"
			}
			return "Edit Server"
		}(),
	)

	nameLabel := styles.FormLabelStyle.Render("Name:")
	nameInput := func() string {
		if m.SettingsFormField == 0 {
			return styles.FormInputActiveStyle.Render(m.SettingsFormName + "_")
		}
		return styles.FormInputInactiveStyle.Render(m.SettingsFormName)
	}()

	hostLabel := styles.FormLabelStyle.Render("Host:")
	hostInput := func() string {
		if m.SettingsFormField == 1 {
			return styles.FormInputActiveStyle.Render(m.SettingsFormHost + "_")
		}
		return styles.FormInputInactiveStyle.Render(m.SettingsFormHost)
	}()

	saveBtn := func() string {
		if m.SettingsFormField == 2 {
			return styles.FormButtonActiveStyle.Render("Save")
		}
		return styles.FormButtonInactiveStyle.Render("Save")
	}()

	cancelBtn := func() string {
		if m.SettingsFormField == 3 {
			return styles.FormButtonActiveStyle.Render("Cancel")
		}
		return styles.FormButtonInactiveStyle.Render("Cancel")
	}()

	buttons := lipgloss.JoinHorizontal(lipgloss.Left, saveBtn, "  ", cancelBtn)

	content := lipgloss.JoinVertical(
		lipgloss.Left,
		title,
		"",
		lipgloss.JoinHorizontal(lipgloss.Top, nameLabel, " ", nameInput),
		lipgloss.JoinHorizontal(lipgloss.Top, hostLabel, " ", hostInput),
		"",
		buttons,
	)

	return styles.CardInnerStyle.Render(content)
}

func (m TUIInterface) renderSettingsDeleteConfirm() string {
	if m.SettingsSelected < 0 || m.SettingsSelected >= len(m.SettingsServers) {
		return ""
	}

	srv := m.SettingsServers[m.SettingsSelected]
	title := styles.ConfirmTitleStyle.Render("Delete Server?")
	message := styles.ConfirmStyle.Render("Delete \"" + srv.Name + "\"?")

	content := lipgloss.JoinVertical(
		lipgloss.Left,
		title,
		"",
		message,
	)

	return styles.CardInnerStyle.Render(content)
}

func (m TUIInterface) viewSelectServerPage() string {
	return m.renderSelectServerList()
}

func (m TUIInterface) renderSelectServerList() string {
	if len(m.SelectServerServers) == 0 {
		return styles.EmptyListStyle.Render("No servers available")
	}

	var rows []string
	for i, srv := range m.SelectServerServers {
		isSelected := m.HasSelectedServer && srv.ID == m.SelectedServer.ID
		if i == m.SelectServerSelected {
			prefix := "▸ "
			row := prefix + srv.Name
			if isSelected {
				row += " " + styles.SelectedMarkerStyle.Render("✓")
			}
			rows = append(rows, styles.SelectItemActiveStyle.Render(row))
		} else {
			prefix := "  "
			row := prefix + srv.Name
			if isSelected {
				row += " " + styles.SelectedMarkerStyle.Render("✓")
			}
			rows = append(rows, styles.SelectItemInactiveStyle.Render(row))
		}
	}

	return styles.SelectListStyle.Render(lipgloss.JoinVertical(lipgloss.Left, rows...))
}