bubbletea/examples/help/main.go

package main

import (
	"fmt"
	"os"
	"strings"

	"github.com/charmbracelet/bubbles/help"
	"github.com/charmbracelet/bubbles/key"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

// keyMap defines a set of keybindings. To work for help it must satisfy
// key.Map. It could also very easily be a map[string]key.Binding.
type keyMap struct {
	Up    key.Binding
	Down  key.Binding
	Left  key.Binding
	Right key.Binding
	Help  key.Binding
	Quit  key.Binding
}

// ShortHelp returns keybindings to be shown in the mini help view. It's part
// of the key.Map interface.
func (k keyMap) ShortHelp() []key.Binding {
	return []key.Binding{k.Help, k.Quit}
}

// FullHelp returns keybindings for the expanded help view. It's part of the
// key.Map interface.
func (k keyMap) FullHelp() [][]key.Binding {
	return [][]key.Binding{
		{k.Up, k.Down, k.Left, k.Right}, // first column
		{k.Help, k.Quit},                // second column
	}
}

var keys = keyMap{
	Up: key.NewBinding(
		key.WithKeys("up", "k"),
		key.WithHelp("↑/k", "move up"),
	),
	Down: key.NewBinding(
		key.WithKeys("down", "j"),
		key.WithHelp("↓/j", "move down"),
	),
	Left: key.NewBinding(
		key.WithKeys("left", "h"),
		key.WithHelp("←/h", "move left"),
	),
	Right: key.NewBinding(
		key.WithKeys("right", "l"),
		key.WithHelp("→/l", "move right"),
	),
	Help: key.NewBinding(
		key.WithKeys("?"),
		key.WithHelp("?", "toggle help"),
	),
	Quit: key.NewBinding(
		key.WithKeys("q", "esc", "ctrl+c"),
		key.WithHelp("q", "quit"),
	),
}

type model struct {
	keys       keyMap
	help       help.Model
	inputStyle lipgloss.Style
	lastKey    string
	quitting   bool
}

func newModel() model {
	return model{
		keys:       keys,
		help:       help.New(),
		inputStyle: lipgloss.NewStyle().Foreground(lipgloss.Color("#FF75B7")),
	}
}

func (m model) Init() tea.Cmd {
	return nil
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		// If we set a width on the help menu it can it can gracefully truncate
		// its view as needed.
		m.help.Width = msg.Width

	case tea.KeyMsg:
		switch {
		case key.Matches(msg, m.keys.Up):
			m.lastKey = "↑"
		case key.Matches(msg, m.keys.Down):
			m.lastKey = "↓"
		case key.Matches(msg, m.keys.Left):
			m.lastKey = "←"
		case key.Matches(msg, m.keys.Right):
			m.lastKey = "→"
		case key.Matches(msg, m.keys.Help):
			m.help.ShowAll = !m.help.ShowAll
		case key.Matches(msg, m.keys.Quit):
			m.quitting = true
			return m, tea.Quit
		}
	}

	return m, nil
}

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

	var status string
	if m.lastKey == "" {
		status = "Waiting for input..."
	} else {
		status = "You chose: " + m.inputStyle.Render(m.lastKey)
	}

	helpView := m.help.View(m.keys)
	height := 8 - strings.Count(status, "\n") - strings.Count(helpView, "\n")

	return "\n" + status + strings.Repeat("\n", height) + helpView
}

func main() {
	if os.Getenv("HELP_DEBUG") != "" {
		if f, err := tea.LogToFile("debug.log", "help"); err != nil {
			fmt.Println("Couldn't open a file for logging:", err)
			os.Exit(1)
		} else {
			defer f.Close()
		}
	}

	if _, err := tea.NewProgram(newModel()).Run(); err != nil {
		fmt.Printf("Could not start program :(\n%v\n", err)
		os.Exit(1)
	}
}