WTF-389 Don't load widgets that have invalid position co-ordinates in their config

wtf/bargraph.go

@@ -18,7 +18,6 @@ type BarGraph struct {
 	View       *tview.TextView
 
 	Position
-
 }
 
 type Bar struct {
@@ -78,6 +77,12 @@ func (widget *BarGraph) FocusChar() string {
 	return ""
 }
 
+// IsPositionable returns TRUE if the widget has valid position parameters, FALSE if it has
+// invalid position parameters (ie: cannot be placed onscreen)
+func (widget *BarGraph) IsPositionable() bool {
+	return widget.Position.IsValid()
+}
+
 func (widget *BarGraph) RefreshInterval() int {
 	return widget.RefreshInt
 }
@@ -154,11 +159,11 @@ func BuildStars(data []Bar, maxStars int, starChar string) string {
 			fmt.Sprintf(
 				"%s%s[[red]%s[white]%s] %s\n",
 				bar.Label,
-				strings.Repeat(" ", longestLabel - len(bar.Label)),
+				strings.Repeat(" ", longestLabel-len(bar.Label)),
 				strings.Repeat(starChar, starCount),
-				strings.Repeat(" ", maxStars - starCount),
+				strings.Repeat(" ", maxStars-starCount),
 				label,
-				),
+			),
 		)
 	}
 

wtf/display.go

@@ -26,6 +26,10 @@ func (display *Display) add(widget Wtfable) {
 		return
 	}
 
+	if !widget.IsPositionable() {
+		return
+	}
+
 	display.Grid.AddItem(
 		widget.TextView(),
 		widget.Top(),

wtf/enabler.go

@@ -3,5 +3,7 @@ package wtf
 type Enabler interface {
 	Disabled() bool
 	Enabled() bool
+	IsPositionable() bool
+
 	Disable()
 }

wtf/position.go

@@ -18,18 +18,26 @@ func NewPosition(top, left, width, height int) Position {
 	return pos
 }
 
-func (pos *Position) Top() int {
-	return pos.top
+func (pos *Position) IsValid() bool {
+	if pos.height < 1 || pos.left < 0 || pos.top < 0 || pos.width < 1 {
+		return false
+	}
+
+	return true
+}
+
+func (pos *Position) Height() int {
+	return pos.height
 }
 
 func (pos *Position) Left() int {
 	return pos.left
 }
 
+func (pos *Position) Top() int {
+	return pos.top
+}
+
 func (pos *Position) Width() int {
 	return pos.width
 }
-
-func (pos *Position) Height() int {
-	return pos.height
-}

wtf/position_test.go

@@ -0,0 +1,86 @@
+package wtf
+
+import (
+	"testing"
+)
+
+func Test_NewPosition(t *testing.T) {
+	pos := NewPosition(0, 1, 2, 3)
+
+	if pos.Height() != 3 {
+		t.Fatalf("Expected 3 but got %d", pos.Height())
+	}
+
+	if pos.Left() != 1 {
+		t.Fatalf("Expected 1 but got %d", pos.Left())
+	}
+
+	if pos.Top() != 0 {
+		t.Fatalf("Expected 0 but got %d", pos.Top())
+	}
+
+	if pos.Width() != 2 {
+		t.Fatalf("Expected 2 but got %d", pos.Width())
+	}
+}
+
+func Test_IsValid(t *testing.T) {
+	tests := []struct {
+		name     string
+		height   int
+		left     int
+		top      int
+		width    int
+		expected bool
+	}{
+		{
+			name:     "valid position",
+			height:   2,
+			left:     0,
+			top:      1,
+			width:    2,
+			expected: true,
+		},
+		{
+			name:     "invalid height",
+			height:   0,
+			left:     0,
+			top:      1,
+			width:    2,
+			expected: false,
+		},
+		{
+			name:     "invalid left",
+			height:   2,
+			left:     -1,
+			top:      1,
+			width:    2,
+			expected: false,
+		},
+		{
+			name:     "invalid top",
+			height:   2,
+			left:     0,
+			top:      -1,
+			width:    2,
+			expected: false,
+		},
+		{
+			name:     "invalid width",
+			height:   2,
+			left:     0,
+			top:      1,
+			width:    0,
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		pos := NewPosition(tt.top, tt.left, tt.width, tt.height)
+		actual := pos.IsValid()
+
+		if actual != tt.expected {
+			t.Errorf("%s: expected: %v, got: %v", tt.name, tt.expected, actual)
+		}
+	}
+}

wtf/text_widget.go

@@ -86,6 +86,12 @@ func (widget *TextWidget) FocusChar() string {
 	return widget.focusChar
 }
 
+// IsPositionable returns TRUE if the widget has valid position parameters, FALSE if it has
+// invalid position parameters (ie: cannot be placed onscreen)
+func (widget *TextWidget) IsPositionable() bool {
+	return widget.Position.IsValid()
+}
+
 func (widget *TextWidget) RefreshInterval() int {
 	return widget.RefreshInt
 }