Add custom writer for area (#7)

Co-authored-by: Brooke Hatton <brookehatton@improbable.io>
Co-authored-by: MarvinJWendt <git@marvinjwendt.com>

.github/release.yml

@@ -16,4 +16,4 @@ changelog:
         - fix
     - title: Other Changes
       labels:
-        - "*"
+        - "*"

.github/workflows/atomicgo.yml

@@ -1,6 +1,9 @@
-on: push
-
 name: AtomicGo
+
+on:
+  push:
+    branches: [ main ]
+
 jobs:
   docs:
     if: "!contains(github.event.head_commit.message, 'autoupdate')"

.github/workflows/go.yml

@@ -4,7 +4,6 @@ on:
   push:
     branches: [ main ]
   pull_request:
-    branches: [ main ]
 
 jobs:
   build:

.github/workflows/lint.yml

@@ -0,0 +1,17 @@
+name: Code analysis
+
+on: [pull_request]
+
+jobs:
+  golangci-lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Linting with golangci-lint
+        uses: reviewdog/action-golangci-lint@v2
+        with:
+          github_token: ${{ secrets.ACCESS_TOKEN }}
+          reporter: github-pr-review

area.go

@@ -2,33 +2,50 @@ package cursor
 
 import (
 	"fmt"
+	"os"
 	"strings"
 )
 
 // Area displays content which can be updated on the fly.
 // You can use this to create live output, charts, dropdowns, etc.
 type Area struct {
 	height int
+	writer Writer
 }
 
 // NewArea returns a new Area.
 func NewArea() Area {
-	return Area{}
+	return Area{
+		writer: os.Stdout,
+		height: 0,
+	}
+}
+
+// WithWriter sets a custom writer for the Area.
+func (area Area) WithWriter(writer Writer) Area {
+	area.writer = writer
+
+	return area
 }
 
 // Clear clears the content of the Area.
 func (area *Area) Clear() {
 	Bottom()
+
 	if area.height > 0 {
 		ClearLinesUp(area.height)
 	}
 }
 
 // Update overwrites the content of the Area.
 func (area *Area) Update(content string) {
+	oldWriter := target
+
+	SetTarget(area.writer) // Temporary set the target to the Area's writer so we can use the cursor functions
 	area.Clear()
-	fmt.Println(content)
-	height = 0
+	SetTarget(oldWriter) // Reset the target to the old writer
+	fmt.Fprintln(area.writer, content)
 
+	height = 0
 	area.height = len(strings.Split(content, "\n"))
 }

cursor.go

@@ -25,6 +25,7 @@ func Up(n int) {
 // Down moves the cursor n lines down relative to the current position.
 func Down(n int) {
 	fmt.Fprintf(target, "\x1b[%dB", n)
+
 	if height-n <= 0 {
 		height = 0
 	} else {
@@ -45,7 +46,7 @@ func Left(n int) {
 // HorizontalAbsolute moves the cursor to n horizontally.
 // The position n is absolute to the start of the line.
 func HorizontalAbsolute(n int) {
-	n += 1 // Moves the line to the character after n
+	n++ // Moves the line to the character after n
 	fmt.Fprintf(target, "\x1b[%dG", n)
 }
 

cursor_test.go

@@ -9,18 +9,23 @@ func TestHeightChanges(t *testing.T) {
 	for i := 0; i < 4; i++ {
 		fmt.Println()
 	}
+
 	Up(3)
+
 	if height != 3 {
 		t.Errorf("height should be 3 but is %d", height)
 	}
+
 	Down(3)
+
 	if height != 0 {
 		t.Errorf("height should be 0 but is %d", height)
 	}
 }
 
 func TestHeightCannotBeNegative(t *testing.T) {
 	Down(10)
+
 	if height < 0 {
 		t.Errorf("height is negative: %d", height)
 	}

cursor_test_linux.go

@@ -6,82 +6,101 @@ import (
 	"testing"
 )
 
+// TestCustomIOWriter tests the cursor functions with a custom Writer.
 func TestCustomIOWriter(t *testing.T) {
 	tmpFile, err := os.CreateTemp("", "testingTmpFile-")
+	defer os.Remove(tmpFile.Name())
+
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer os.Remove(tmpFile.Name())
 
 	w := tmpFile
 	SetTarget(w)
 
 	Up(2)
+
 	expected := "\x1b[2A"
 	actual := getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 
 	clearFile(t, w)
 	Down(2)
+
 	expected = "\x1b[2B"
 	actual = getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 
 	clearFile(t, w)
 	Right(2)
+
 	expected = "\x1b[2C"
 	actual = getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 
 	clearFile(t, w)
 	Left(2)
+
 	expected = "\x1b[2D"
 	actual = getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 
 	clearFile(t, w)
 	Hide()
+
 	expected = "\x1b[?25l"
 	actual = getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 
 	clearFile(t, w)
 	Show()
+
 	expected = "\x1b[?25h"
 	actual = getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 
 	clearFile(t, w)
 	ClearLine()
+
 	expected = "\x1b[2K"
 	actual = getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 
 	clearFile(t, w)
 	HorizontalAbsolute(3)
+
 	expected = "\x1b[4G"
 	actual = getFileContent(t, w.Name())
+
 	if expected != actual {
 		t.Errorf("wanted: %v, got %v", expected, actual)
 	}
 }
 
 func getFileContent(t *testing.T, fileName string) string {
 	t.Helper()
+
 	content, err := os.ReadFile(fileName)
 	if err != nil {
 		t.Errorf("failed to read file contents: %s", err)
@@ -94,12 +113,14 @@ func getFileContent(t *testing.T, fileName string) string {
 
 func clearFile(t *testing.T, file *os.File) {
 	t.Helper()
+
 	err := file.Truncate(0)
 	if err != nil {
 		t.Errorf("failed to clear file")
 
 		return
 	}
+
 	_, err = file.Seek(0, 0)
 	if err != nil {
 		t.Errorf("failed to clear file")

utils.go

@@ -10,6 +10,7 @@ func Bottom() {
 	if height > 0 {
 		Down(height)
 		StartOfLine()
+
 		height = 0
 	}
 }