initial commit

cmd/pager.go

@@ -0,0 +1,166 @@
+package cmd
+
+// pager setup using bubbletea
+// file shamlelessly copied from:
+// https://github.com/charmbracelet/bubbletea/tree/main/examples/pager
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/charmbracelet/bubbles/viewport"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+	"github.com/muesli/reflow/wordwrap"
+	"golang.org/x/term"
+)
+
+var (
+	titleStyle = func() lipgloss.Style {
+		b := lipgloss.RoundedBorder()
+		b.Right = "├"
+		return lipgloss.NewStyle().BorderStyle(b).Padding(0, 1)
+	}()
+
+	infoStyle = func() lipgloss.Style {
+		b := lipgloss.RoundedBorder()
+		b.Left = "┤"
+		return titleStyle.BorderStyle(b)
+	}()
+
+	viewstyle = lipgloss.NewStyle()
+)
+
+type Meta struct {
+	lines           int
+	currentline     int
+	initialprogress int
+	document        string
+}
+
+type Doc struct {
+	content      string
+	title        string
+	ready        bool
+	viewport     viewport.Model
+	initialwidth int
+	meta         *Meta
+}
+
+func (m Doc) Init() tea.Cmd {
+	return nil
+}
+
+func (m Doc) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	var (
+		cmd  tea.Cmd
+		cmds []tea.Cmd
+	)
+
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		if k := msg.String(); k == "ctrl+c" || k == "q" || k == "esc" {
+			return m, tea.Quit
+		}
+
+	case tea.WindowSizeMsg:
+		headerHeight := lipgloss.Height(m.headerView())
+		footerHeight := lipgloss.Height(m.footerView())
+		verticalMarginHeight := headerHeight + footerHeight
+
+		if !m.ready {
+			// Since this program is using the full size of the viewport we
+			// need to wait until we've received the window dimensions before
+			// we can initialize the viewport. The initial dimensions come in
+			// quickly, though asynchronously, which is why we wait for them
+			// here.
+			m.viewport = viewport.New(msg.Width, msg.Height-verticalMarginHeight)
+			m.viewport.YPosition = headerHeight
+
+			m.viewport.SetContent(wordwrap.String(m.content, m.initialwidth))
+			m.viewport.ScrollDown(m.meta.initialprogress)
+
+			m.ready = true
+		} else {
+			m.viewport.Width = msg.Width
+			m.viewport.Height = msg.Height - verticalMarginHeight
+			m.viewport.SetContent(wordwrap.String(m.content, msg.Width))
+		}
+	}
+
+	// Handle keyboard and mouse events in the viewport
+	m.viewport, cmd = m.viewport.Update(msg)
+	cmds = append(cmds, cmd)
+
+	return m, tea.Batch(cmds...)
+}
+
+func (m Doc) View() string {
+	if !m.ready {
+		return "\n  Initializing..."
+	}
+
+	// update current line for later saving
+	// FIXME: doesn't work correctly yet
+	m.meta.currentline = int(float64(m.meta.lines) * m.viewport.ScrollPercent())
+
+	return fmt.Sprintf("%s\n%s\n%s", m.headerView(), m.viewport.View(), m.footerView())
+}
+
+func (m Doc) headerView() string {
+	title := titleStyle.Render(m.title)
+	line := strings.Repeat("─", max(0, m.viewport.Width-lipgloss.Width(title)))
+	return lipgloss.JoinHorizontal(lipgloss.Center, title, line)
+}
+
+func (m Doc) footerView() string {
+	info := infoStyle.Render(fmt.Sprintf("%3.f%%", m.viewport.ScrollPercent()*100))
+	line := strings.Repeat("─", max(0, m.viewport.Width-lipgloss.Width(info)))
+	return lipgloss.JoinHorizontal(lipgloss.Center, line, info)
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func Pager(conf *Config, title, message string) (int, error) {
+	width := 80
+	scrollto := 0
+
+	if term.IsTerminal(int(os.Stdout.Fd())) {
+		w, _, err := term.GetSize(0)
+		if err == nil {
+			width = w
+		}
+	}
+
+	if conf.StoreProgress {
+		scrollto = conf.InitialProgress
+	}
+
+	meta := Meta{
+		initialprogress: scrollto,
+		lines:           len(strings.Split(message, "\r\n")),
+	}
+
+	p := tea.NewProgram(
+		Doc{content: message, title: title, initialwidth: width, meta: &meta},
+		tea.WithAltScreen(),       // use the full size of the terminal in its "alternate screen buffer"
+		tea.WithMouseCellMotion(), // turn on mouse support so we can track the mouse wheel
+	)
+
+	if _, err := p.Run(); err != nil {
+		return 0, fmt.Errorf("could not run pager:", err)
+	}
+
+	if conf.Debug {
+		fmt.Printf("scrollto: %d, last: %d, diff: %d\n",
+			scrollto, meta.currentline, scrollto-meta.currentline)
+	}
+
+	return meta.currentline, nil
+}