Add editor packages

internal/editor/canvas/canvas.go

@@ -0,0 +1,33 @@
+package canvas
+
+import (
+	"bytes"
+	"log/slog"
+	"os"
+	"sync"
+
+	"code.chimeric.al/dwrz/wen/pkg/terminal"
+)
+
+type Canvas struct {
+	log      *slog.Logger
+	out      *os.File
+	terminal *terminal.Terminal
+
+	mu  sync.Mutex
+	buf bytes.Buffer
+}
+
+type Parameters struct {
+	Log      *slog.Logger
+	Out      *os.File
+	Terminal *terminal.Terminal
+}
+
+func New(p Parameters) *Canvas {
+	return &Canvas{
+		log:      p.Log,
+		out:      p.Out,
+		terminal: p.Terminal,
+	}
+}

internal/editor/canvas/render.go

@@ -0,0 +1,147 @@
+package canvas
+
+import (
+	"fmt"
+	"path"
+
+	"github.com/mattn/go-runewidth"
+
+	"code.chimeric.al/dwrz/wen/internal/editor/buffer"
+	"code.chimeric.al/dwrz/wen/internal/editor/prompt"
+	"code.chimeric.al/dwrz/wen/pkg/color"
+	"code.chimeric.al/dwrz/wen/pkg/terminal"
+)
+
+// Bars is the number of terminal rows reserved at the bottom of the screen
+// for the status bar and message bar.
+const Bars = 2
+
+func (c *Canvas) Render(b *buffer.Buffer, prompt *prompt.Prompt) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	size, err := c.terminal.Size()
+	if err != nil {
+		return fmt.Errorf("failed to get terminal size: %w", err)
+	}
+
+	var (
+		cursor = b.Cursor()
+		height = int(size.Rows) - Bars
+		width  = int(size.Columns)
+		output = b.Render(height, width)
+	)
+
+	// Move the cursor to the top left.
+	c.buf.WriteString(terminal.CursorHide)
+	c.buf.WriteString(terminal.CursorTopLeft)
+
+	// Print each line.
+	for _, line := range output.Lines {
+		c.buf.WriteString(terminal.EraseLine)
+		c.buf.WriteString(line)
+		c.buf.WriteString("\r\n")
+	}
+
+	// Draw the status bar.
+	c.statusBar(b, width, cursor.Line(), cursor.Glyph())
+
+	// Draw the message bar.
+	c.messageBar(prompt, width)
+
+	// Set the cursor.
+	if prompt.IsPrompt() {
+		c.buf.WriteString(fmt.Sprintf(
+			terminal.SetCursorFmt, size.Rows,
+			runewidth.StringWidth(prompt.Text())+prompt.Cursor()+2,
+		))
+	} else {
+		c.buf.WriteString(fmt.Sprintf(
+			terminal.SetCursorFmt, output.Line, output.Glyph,
+		))
+	}
+
+	c.buf.WriteString(terminal.CursorShow)
+
+	c.out.Write(c.buf.Bytes())
+
+	c.buf.Reset()
+
+	return nil
+}
+
+func (c *Canvas) statusBar(b *buffer.Buffer, width, y, x int) {
+	c.buf.WriteString(terminal.EraseLine)
+	c.buf.WriteString(color.Inverse)
+
+	// Icon
+	icon := "文 "
+	c.buf.WriteString(icon)
+	width -= runewidth.StringWidth(icon)
+
+	// Calculate the length of the cursor, so we can determine how much
+	// space we have left for the name of the buffer.
+	cursor := fmt.Sprintf(" %d:%d", y, x)
+	width -= runewidth.StringWidth(cursor)
+
+	// Filename.
+	// TODO: handle long filenames (shorten filepath).
+	name := path.Base(b.Name())
+	nw := runewidth.StringWidth(name)
+	if nw <= width {
+		c.buf.WriteString(name)
+		width -= nw
+	} else {
+		for _, r := range name {
+			rw := runewidth.RuneWidth(r)
+			if width-rw >= 0 {
+				c.buf.WriteRune(r)
+				width -= rw
+			} else {
+				break
+			}
+		}
+	}
+
+	// Add empty spaces to the end of the line.
+	for i := width; i > 0; i-- {
+		c.buf.WriteRune(' ')
+	}
+
+	// Cursor
+	c.buf.WriteString(cursor)
+
+	c.buf.WriteString(color.Reset)
+	c.buf.WriteString("\r\n")
+}
+
+// TODO: handle messages that are too long for one line.
+func (c *Canvas) messageBar(p *prompt.Prompt, width int) {
+	c.buf.WriteString(terminal.EraseLine)
+
+	var (
+		text   = p.Text()
+		line   = p.Line(0, width) // TODO: handle offset.
+		output string
+	)
+	switch {
+	case text == "" && line == "":
+		output = ""
+	case line == "":
+		output = text
+	default:
+		output = fmt.Sprintf("%s %s", text, line)
+	}
+
+	for _, r := range output {
+		rw := runewidth.RuneWidth(r)
+		if width-rw < 0 {
+			break
+		}
+		c.buf.WriteRune(r)
+		width -= rw
+	}
+	for i := width; i > 0; i-- {
+		c.buf.WriteRune(' ')
+	}
+}

internal/editor/canvas/reset.go

@@ -0,0 +1,8 @@
+package canvas
+
+import "code.chimeric.al/dwrz/wen/pkg/terminal"
+
+func (c *Canvas) Reset() {
+	c.out.WriteString(terminal.ClearScreen)
+	c.out.WriteString(terminal.CursorTopLeft)
+}