From 4d98a8fa6f982f638cf1f4b163395f30b1470d36 Mon Sep 17 00:00:00 2001
From: Maas Lalani <maas@lalani.dev>
Date: Wed, 13 Jul 2022 15:49:14 -0400
Subject: [PATCH] feat(choose): Add paginator to chooser

Display paginator only if number of options > height specified
---
 choose/choose.go  | 50 ++++++++++++++++++++++++++++-------------------
 choose/command.go | 23 ++++++++++++++++++++++
 2 files changed, 53 insertions(+), 20 deletions(-)

diff --git a/choose/choose.go b/choose/choose.go
index 6d947cc..61445b1 100644
--- a/choose/choose.go
+++ b/choose/choose.go
@@ -14,6 +14,7 @@ package choose
 import (
 	"strings"
 
+	"github.com/charmbracelet/bubbles/paginator"
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
 	"github.com/mattn/go-runewidth"
@@ -21,7 +22,6 @@ import (
 
 type model struct {
 	height           int
-	page             int
 	cursor           string
 	selectedPrefix   string
 	unselectedPrefix string
@@ -31,6 +31,7 @@ type model struct {
 	index            int
 	limit            int
 	numSelected      int
+	paginator        paginator.Model
 
 	// styles
 	cursorStyle       lipgloss.Style
@@ -51,27 +52,24 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		return m, nil
 
 	case tea.KeyMsg:
+		start, end := m.paginator.GetSliceBounds(len(m.items))
 		switch keypress := msg.String(); keypress {
 		case "down", "j", "ctrl+n":
-			m.index = (m.index + 1) % len(m.items)
-			m.page = m.index / m.height
+			m.index = clamp(m.index+1, 0, len(m.items)-1)
+			if m.index >= end {
+				m.paginator.NextPage()
+			}
 		case "up", "k", "ctrl+p":
-			m.index = (m.index - 1 + len(m.items)) % len(m.items)
-			m.page = m.index / m.height
+			m.index = clamp(m.index-1, 0, len(m.items)-1)
+			if m.index <= start {
+				m.paginator.PrevPage()
+			}
 		case "right", "l", "ctrl+f":
-			if m.index+m.height < len(m.items) {
-				m.index += m.height
-			} else {
-				if m.page < len(m.items)/m.height {
-					m.index = len(m.items) - 1
-				}
-			}
-			m.page = m.index / m.height
+			m.index = clamp(m.index+m.height, 0, len(m.items)-1)
+			m.paginator.NextPage()
 		case "left", "h", "ctrl+b":
-			if m.index-m.height >= 0 {
-				m.index -= m.height
-			}
-			m.page = m.index / m.height
+			m.index = clamp(m.index-m.height, 0, len(m.items)-1)
+			m.paginator.PrevPage()
 		case "ctrl+c":
 			m.quitting = true
 			return m, tea.Quit
@@ -98,7 +96,9 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		}
 	}
 
-	return m, nil
+	var cmd tea.Cmd
+	m.paginator, cmd = m.paginator.Update(msg)
+	return m, cmd
 }
 
 func (m model) View() string {
@@ -108,7 +108,8 @@ func (m model) View() string {
 
 	var s strings.Builder
 
-	for i, item := range m.items[clamp(m.page*m.height, 0, len(m.items)):clamp((m.page+1)*m.height, 0, len(m.items))] {
+	start, end := m.paginator.GetSliceBounds(len(m.items))
+	for i, item := range m.items[start:end] {
 		if i == m.index%m.height {
 			s.WriteString(m.cursorStyle.Render(m.cursor))
 		} else {
@@ -122,9 +123,18 @@ func (m model) View() string {
 		} else {
 			s.WriteString(m.itemStyle.Render(m.unselectedPrefix + item.text))
 		}
-		s.WriteRune('\n')
+		if i != m.height {
+			s.WriteRune('\n')
+		}
 	}
 
+	if m.paginator.TotalPages <= 1 {
+		return s.String()
+	}
+
+	s.WriteString(strings.Repeat("\n", m.height-m.paginator.ItemsOnPage(len(m.items))+1))
+	s.WriteString("  " + m.paginator.View())
+
 	return s.String()
 }
 
diff --git a/choose/command.go b/choose/command.go
index afe8c8e..bf269b0 100644
--- a/choose/command.go
+++ b/choose/command.go
@@ -6,8 +6,15 @@ import (
 	"os"
 	"strings"
 
+	"github.com/charmbracelet/bubbles/paginator"
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/gum/internal/stdin"
+	"github.com/charmbracelet/lipgloss"
+)
+
+var (
+	subduedStyle     = lipgloss.NewStyle().Foreground(lipgloss.AdaptiveColor{Light: "#847A85", Dark: "#979797"})
+	verySubduedStyle = lipgloss.NewStyle().Foreground(lipgloss.AdaptiveColor{Light: "#DDDADA", Dark: "#3C3C3C"})
 )
 
 // Run provides a shell script interface for choosing between different through
@@ -40,6 +47,21 @@ func (o Options) Run() error {
 		o.Limit = len(o.Options)
 	}
 
+	// Use the pagination model to display the current and total number of
+	// pages.
+	pager := paginator.New()
+	pager.SetTotalPages((len(items) + o.Height - 1) / o.Height)
+	pager.PerPage = o.Height
+	pager.Type = paginator.Dots
+	pager.ActiveDot = subduedStyle.Render("•")
+	pager.InactiveDot = verySubduedStyle.Render("•")
+
+	// Disable Keybindings since we will control it ourselves.
+	pager.UseHLKeys = false
+	pager.UseLeftRightKeys = false
+	pager.UseJKKeys = false
+	pager.UsePgUpPgDownKeys = false
+
 	m, err := tea.NewProgram(model{
 		height:            o.Height,
 		cursor:            o.Cursor,
@@ -48,6 +70,7 @@ func (o Options) Run() error {
 		cursorPrefix:      o.CursorPrefix,
 		items:             items,
 		limit:             o.Limit,
+		paginator:         pager,
 		cursorStyle:       o.CursorStyle.ToLipgloss(),
 		itemStyle:         o.ItemStyle.ToLipgloss(),
 		selectedItemStyle: o.SelectedItemStyle.ToLipgloss(),