update

internal/tui/model.go

@@ -0,0 +1,246 @@
+package tui
+
+import (
+	"bytes"
+	"strings"
+	"unicode"
+
+	"github.com/charmbracelet/bubbles/key"
+	"github.com/charmbracelet/bubbles/list"
+	"github.com/charmbracelet/bubbles/viewport"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+	"github.com/spf13/cobra"
+)
+
+const (
+	spacebar = " "
+)
+
+// cmdModel Implements tea.Model. It provides an interactive
+// help and usage tui component for bubbletea programs.
+type cmdModel struct {
+	styles   *Styles
+	list     list.Model
+	viewport *viewport.Model
+	cmd      *cobra.Command
+	subCmds  []list.Item
+	print    bool
+	cmdChain string
+	// Store window height to adjust viewport on command selection changes
+	windowHeight int
+	// Store full height of content for given view, updated on command change
+	contentHeight int
+	errorWriter   *bytes.Buffer
+}
+
+// newCmdModel initializes a based on values supplied from cmd *cobra.Command
+func newCmdModel(options *options, cmd *cobra.Command) *cmdModel {
+	subCmds := getSubCommands(cmd)
+	l := newSubCmdsList(options.styles, subCmds)
+	vp := viewport.New(0, 0)
+	vp.KeyMap = viewPortKeyMap()
+	m := &cmdModel{
+		styles:      options.styles,
+		cmd:         cmd,
+		subCmds:     subCmds,
+		list:        l,
+		viewport:    &vp,
+		errorWriter: options.errorWriter,
+	}
+	m.contentHeight = lipgloss.Height(m.usage())
+	return m
+}
+
+// Init is the initial cmd to be executed which is nil for this component.
+func (m *cmdModel) Init() tea.Cmd {
+	return nil
+}
+
+// Update is called when a message is received.
+func (m *cmdModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	var cmds []tea.Cmd
+	var listCmd tea.Cmd
+
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		m.windowHeight = msg.Height
+		m.viewport.Width = msg.Width
+		m.viewport.Height = m.windowHeight - lipgloss.Height(m.footer())
+		if m.viewport.Height > m.contentHeight {
+			m.viewport.Height = m.contentHeight
+		}
+		// Scroll viewport back to top for new screen
+		m.viewport.SetYOffset(0)
+		return m, nil
+	case tea.KeyMsg:
+		switch keypress := msg.String(); keypress {
+		case "q", "ctrl+c":
+			return m, tea.Quit
+		case "enter":
+			i, ok := m.list.SelectedItem().(item)
+			if ok {
+				m.cmd = i.cmd
+				subCmds := getSubCommands(m.cmd)
+				m.list = newSubCmdsList(m.styles, subCmds)
+				m.viewport.Height = m.windowHeight - lipgloss.Height(m.footer())
+				// Update new content height and check viewport size
+				m.contentHeight = lipgloss.Height(m.usage())
+				if m.viewport.Height > m.contentHeight {
+					m.viewport.Height = m.contentHeight
+				}
+				// Scroll viewport back to top for new screen
+				m.viewport.SetYOffset(0)
+			}
+			return m, nil
+		case "b":
+			if m.cmd.HasParent() {
+				m.cmd = m.cmd.Parent()
+				subCmds := getSubCommands(m.cmd)
+				m.list = newSubCmdsList(m.styles, subCmds)
+				m.viewport.Height = m.windowHeight - lipgloss.Height(m.footer())
+				// Update new content height and check viewport size
+				m.contentHeight = lipgloss.Height(m.usage())
+				if m.viewport.Height > m.contentHeight {
+					m.viewport.Height = m.contentHeight
+				}
+				// Scroll viewport back to top for new screen
+				m.viewport.SetYOffset(0)
+			}
+			return m, nil
+		case "p":
+			m.print = true
+			m.cmdChain = print("", m.cmd)
+			return m, tea.Quit
+		}
+	}
+
+	m.list, listCmd = m.list.Update(msg)
+	newViewport, viewPortCmd := m.viewport.Update(msg)
+	// point to new viewport
+	m.viewport = &newViewport
+	m.viewport.KeyMap = viewPortKeyMap()
+	if m.viewport.Height > m.contentHeight {
+		m.viewport.Height = m.contentHeight
+	}
+	cmds = append(cmds, listCmd, viewPortCmd)
+	return m, tea.Batch(cmds...)
+}
+
+// View renders the program's UI, which is just a string.
+func (m *cmdModel) View() string {
+	m.viewport.SetContent(m.usage())
+	return lipgloss.JoinVertical(lipgloss.Top, m.viewport.View(), m.footer())
+}
+
+// usage builds the usage body from a cobra command
+func (m *cmdModel) usage() string {
+	usageText := strings.Builder{}
+
+	if m.errorWriter != nil && m.errorWriter.Len() > 0 {
+		usageText.WriteString(m.styles.ErrorText.Render(m.errorWriter.String() + "\n"))
+	}
+
+	cmdTitle := ""
+	cmdName := m.cmd.Name()
+	if m.cmd.Version != "" {
+		cmdName += " " + m.cmd.Version
+	}
+	cmdName = m.styles.Section.Render(cmdName)
+	cmdLong := m.styles.SubTitle.Render(m.cmd.Long)
+	cmdTitle = m.styles.Title.Foreground(lipgloss.AdaptiveColor{Light: darkGrey, Dark: white}).
+		Render(lipgloss.JoinVertical(lipgloss.Center, cmdName, cmdLong))
+	usageText.WriteString(cmdTitle + "\n")
+
+	cmdSection := m.styles.Section.Render("Cmd Description:")
+	short := m.styles.Text.Render(m.cmd.Short)
+
+	usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, cmdSection, short) + "\n")
+
+	if m.cmd.Runnable() {
+		usage := m.styles.Section.Render("Usage:")
+		useLine := m.styles.Text.Render(m.cmd.UseLine())
+		usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, usage, useLine) + "\n")
+		if m.cmd.HasAvailableSubCommands() {
+			commandPath := m.styles.Text.Render(m.cmd.CommandPath() + " [command]")
+			usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, commandPath) + "\n")
+		}
+	}
+
+	if len(m.cmd.Aliases) > 0 {
+		aliases := m.styles.Section.Render("Aliases:")
+		nameAndAlias := m.styles.Text.Render(m.cmd.NameAndAliases())
+		usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, aliases, nameAndAlias) + "\n")
+	}
+
+	if m.cmd.HasAvailableLocalFlags() {
+		localFlags := m.styles.Section.Render("Flags:")
+		flagUsage := m.styles.Text.Render(strings.TrimRightFunc(m.cmd.LocalFlags().FlagUsages(), unicode.IsSpace))
+		usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, localFlags, flagUsage) + "\n")
+	}
+	if m.cmd.HasAvailableInheritedFlags() {
+		globalFlags := m.styles.Section.Render("Global Flags:")
+		flagUsage := m.styles.Text.Render(strings.TrimRightFunc(m.cmd.InheritedFlags().FlagUsages(), unicode.IsSpace))
+		usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, globalFlags, flagUsage) + "\n")
+	}
+
+	if m.cmd.HasExample() {
+		examples := m.styles.Section.Render("Examples:")
+		example := m.styles.Text.Render(m.cmd.Example)
+		usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, examples, example) + "\n")
+	}
+
+	if m.cmd.HasAvailableSubCommands() {
+		usageText.WriteString(lipgloss.JoinVertical(lipgloss.Left, m.list.View()))
+	}
+
+	return m.styles.Border.Render(usageText.String() + "\n")
+}
+
+// footer outputs the footer of the viewport and contains help text.
+func (m *cmdModel) footer() string {
+	var help, scroll string
+	help = m.styles.Info.Render("↑/k up • ↓/j down • / to filter • p to print • b to go back • enter to select • q, ctrl+c to quit")
+	// If content is larger than the window minus the size of the necessary footer then it will be in a scrollable viewport
+	if m.contentHeight > m.windowHeight-2 {
+		scroll = m.styles.Info.Render("ctrl+k up • ctrl+j down • mouse to scroll")
+	}
+	return lipgloss.JoinVertical(lipgloss.Left, help, scroll)
+}
+
+// print outputs the command chain for a given cobra command.
+func print(v string, cmd *cobra.Command) string {
+	if cmd != nil {
+		v = cmd.Name() + " " + v
+		if !cmd.HasParent() {
+			// final result
+			return "Command: " + v
+		}
+		// recursively walk cmd chain
+		return print(v, cmd.Parent())
+	}
+	return v
+}
+
+func viewPortKeyMap() viewport.KeyMap {
+	return viewport.KeyMap{
+		PageDown: key.NewBinding(
+			key.WithKeys("pgdown", spacebar, "f"),
+		),
+		PageUp: key.NewBinding(
+			key.WithKeys("pgup", "v"),
+		),
+		HalfPageUp: key.NewBinding(
+			key.WithKeys("u", "ctrl+u"),
+		),
+		HalfPageDown: key.NewBinding(
+			key.WithKeys("d", "ctrl+d"),
+		),
+		Up: key.NewBinding(
+			key.WithKeys("ctrl+k"),
+		),
+		Down: key.NewBinding(
+			key.WithKeys("ctrl+j"),
+		),
+	}
+}