Fix initial TUI sizing and align two-row sparklines

1 files changed, 38 insertions, 0 deletions

diff --git a/internal/tui/common/viewport.go b/internal/tui/common/viewport.go
new file mode 100644
index 0000000..e1729db
--- /dev/null
+++ b/internal/tui/common/viewport.go
@@ -0,0 +1,38 @@
+package common
+
+import (
+	"os"
+
+	xterm "github.com/charmbracelet/x/term"
+)
+
+const (
+	defaultViewportWidth  = 80
+	defaultViewportHeight = 24
+)
+
+// EffectiveViewport returns a usable terminal viewport size. Missing or invalid
+// dimensions are resolved from the active terminal when possible.
+func EffectiveViewport(width, height int) (int, int) {
+	if width > 0 && height > 0 {
+		return width, height
+	}
+
+	termWidth, termHeight, err := xterm.GetSize(os.Stdout.Fd())
+	if err == nil {
+		if width <= 0 && termWidth > 0 {
+			width = termWidth
+		}
+		if height <= 0 && termHeight > 0 {
+			height = termHeight
+		}
+	}
+
+	if width <= 0 {
+		width = defaultViewportWidth
+	}
+	if height <= 0 {
+		height = defaultViewportHeight
+	}
+	return width, height
+}