wip

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

textarea/textarea.go

@@ -3,6 +3,7 @@ package textarea
 import (
 	"crypto/sha256"
 	"fmt"
+	"reflect"
 	"strconv"
 	"strings"
 	"unicode"
@@ -64,6 +65,10 @@ type KeyMap struct {
 	CapitalizeWordForward key.Binding
 
 	TransposeCharacterBackward key.Binding
+
+	AcceptSuggestion key.Binding
+	NextSuggestion   key.Binding
+	PrevSuggestion   key.Binding
 }
 
 // DefaultKeyMap returns the default set of key bindings for navigating and acting
@@ -94,6 +99,10 @@ func DefaultKeyMap() KeyMap {
 		UppercaseWordForward:  key.NewBinding(key.WithKeys("alt+u"), key.WithHelp("alt+u", "uppercase word forward")),
 
 		TransposeCharacterBackward: key.NewBinding(key.WithKeys("ctrl+t"), key.WithHelp("ctrl+t", "transpose character backward")),
+
+		AcceptSuggestion: key.NewBinding(key.WithKeys("tab")),
+		NextSuggestion:   key.NewBinding(key.WithKeys("down", "ctrl+n")),
+		PrevSuggestion:   key.NewBinding(key.WithKeys("up", "ctrl+p")),
 	}
 }
 
@@ -248,6 +257,15 @@ type Model struct {
 
 	SyntaxHighlighter func(string) string
 
+	// Should the input suggest to complete
+	ShowSuggestions bool
+
+	// suggestions is a list of suggestions that may be used to complete the
+	// input.
+	suggestions            [][][]rune
+	matchedSuggestions     [][][]rune
+	currentSuggestionIndex int
+
 	// If promptFunc is set, it replaces Prompt as a generator for
 	// prompt strings at the beginning of each line.
 	promptFunc func(line int) string
@@ -310,10 +328,11 @@ func New() Model {
 		Cursor:               cur,
 		KeyMap:               DefaultKeyMap(),
 
-		value: make([][]rune, minHeight, maxLines),
-		focus: false,
-		col:   0,
-		row:   0,
+		suggestions: [][][]rune{},
+		value:       make([][]rune, minHeight, maxLines),
+		focus:       false,
+		col:         0,
+		row:         0,
 
 		viewport: &vp,
 	}
@@ -369,6 +388,18 @@ func (m *Model) SetValue(s string) {
 	m.InsertString(s)
 }
 
+// SetSuggestions sets the suggestions for the input.
+func (m *Model) SetSuggestions(suggestions []string) {
+	m.suggestions = make([][][]rune, len(suggestions))
+	for i, s := range suggestions {
+		for _, line := range strings.Split(s, "\n") {
+			m.suggestions[i] = append(m.suggestions[i], []rune(line))
+		}
+	}
+
+	m.updateSuggestions()
+}
+
 // InsertString inserts a string at the cursor position.
 func (m *Model) InsertString(s string) {
 	m.insertRunesFromUserInput([]rune(s))
@@ -982,6 +1013,15 @@ func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 		return m, nil
 	}
 
+	// Need to check for completion before, because key is configurable and might be double assigned
+	keyMsg, ok := msg.(tea.KeyMsg)
+	if ok && key.Matches(keyMsg, m.KeyMap.AcceptSuggestion) {
+		if m.canAcceptSuggestion() {
+			m.value = append(m.value, m.matchedSuggestions[m.currentSuggestionIndex][len(m.value):]...)
+			m.CursorEnd()
+		}
+	}
+
 	// Used to determine if the cursor should blink.
 	oldRow, oldCol := m.cursorLineNumber(), m.col
 
@@ -1083,11 +1123,19 @@ func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 			m.capitalizeRight()
 		case key.Matches(msg, m.KeyMap.TransposeCharacterBackward):
 			m.transposeLeft()
+		case key.Matches(msg, m.KeyMap.NextSuggestion):
+			m.nextSuggestion()
+		case key.Matches(msg, m.KeyMap.PrevSuggestion):
+			m.previousSuggestion()
 
 		default:
 			m.insertRunesFromUserInput([]rune(msg.Text))
 		}
 
+		// Check again if can be completed
+		// because value might be something that does not match the completion prefix
+		m.updateSuggestions()
+
 	case pasteMsg:
 		m.insertRunesFromUserInput([]rune(msg))
 
@@ -1194,10 +1242,12 @@ func (m Model) View() string {
 				if m.col >= len(line) && lineInfo.CharOffset >= m.width {
 					m.Cursor.SetChar(" ")
 					s.WriteString(m.Cursor.View())
+					// XXX: suggestions
 				} else {
 					m.Cursor.SetChar(string(wrappedLine[lineInfo.ColumnOffset]))
 					s.WriteString(style.Render(m.Cursor.View()))
 					s.WriteString(style.Render(string(wrappedLine[lineInfo.ColumnOffset+1:])))
+					// XXX: suggestions
 				}
 			} else {
 				ln := string(wrappedLine)
@@ -1425,6 +1475,62 @@ func (m *Model) splitLine(row, col int) {
 	m.row++
 }
 
+// canAcceptSuggestion returns whether there is an acceptable suggestion to
+// autocomplete the current value.
+func (m *Model) canAcceptSuggestion() bool {
+	return len(m.matchedSuggestions) > 0
+}
+
+func linesToString(lines [][]rune) string {
+	var result []string
+	for _, line := range lines {
+		result = append(result, string(line))
+	}
+	return strings.Join(result, "\n")
+}
+
+// updateSuggestions refreshes the list of matching suggestions.
+func (m *Model) updateSuggestions() {
+	if !m.ShowSuggestions {
+		return
+	}
+
+	if len(m.value) <= 0 || len(m.suggestions) <= 0 {
+		m.matchedSuggestions = [][][]rune{}
+		return
+	}
+
+	matches := [][][]rune{}
+	for _, s := range m.suggestions {
+		suggestion := linesToString(s)
+
+		if strings.HasPrefix(strings.ToLower(suggestion), strings.ToLower(linesToString(m.value))) {
+			matches = append(matches, s)
+		}
+	}
+	if !reflect.DeepEqual(matches, m.matchedSuggestions) {
+		m.currentSuggestionIndex = 0
+	}
+
+	m.matchedSuggestions = matches
+}
+
+// nextSuggestion selects the next suggestion.
+func (m *Model) nextSuggestion() {
+	m.currentSuggestionIndex = (m.currentSuggestionIndex + 1)
+	if m.currentSuggestionIndex >= len(m.matchedSuggestions) {
+		m.currentSuggestionIndex = 0
+	}
+}
+
+// previousSuggestion selects the previous suggestion.
+func (m *Model) previousSuggestion() {
+	m.currentSuggestionIndex = (m.currentSuggestionIndex - 1)
+	if m.currentSuggestionIndex < 0 {
+		m.currentSuggestionIndex = len(m.matchedSuggestions) - 1
+	}
+}
+
 // Paste is a command for pasting from the clipboard into the text input.
 func Paste() tea.Msg {
 	str, err := clipboard.ReadAll()