feat(tui): detect terminal theme and apply palettes

2 files changed, 132 insertions, 35 deletions

diff --git a/internal/tui/common/styles.go b/internal/tui/common/styles.go
index 06ed596..a71ef81 100644
--- a/internal/tui/common/styles.go
+++ b/internal/tui/common/styles.go
@@ -1,59 +1,117 @@
 package common
 
-import "charm.land/lipgloss/v2"
+import (
+	"image/color"
+
+	"charm.land/lipgloss/v2"
+)
+
+// Palette defines themed colors shared across the TUI package.
+type Palette struct {
+	Background color.Color
+	Panel      color.Color
+	Primary    color.Color
+	Accent     color.Color
+	Muted      color.Color
+	Text       color.Color
+	Danger     color.Color
+}
+
+// NewPalette returns a color palette for dark or light terminal backgrounds.
+func NewPalette(isDark bool) Palette {
+	if isDark {
+		return Palette{
+			Background: lipgloss.Color("235"),
+			Panel:      lipgloss.Color("238"),
+			Primary:    lipgloss.Color("75"),
+			Accent:     lipgloss.Color("222"),
+			Muted:      lipgloss.Color("246"),
+			Text:       lipgloss.Color("255"),
+			Danger:     lipgloss.Color("203"),
+		}
+	}
+
+	return Palette{
+		Background: lipgloss.Color("255"),
+		Panel:      lipgloss.Color("250"),
+		Primary:    lipgloss.Color("26"),
+		Accent:     lipgloss.Color("88"),
+		Muted:      lipgloss.Color("242"),
+		Text:       lipgloss.Color("235"),
+		Danger:     lipgloss.Color("160"),
+	}
+}
 
 var (
 	// Palette colors shared across the TUI package.
-	ColorBackground = lipgloss.Color("235")
-	ColorPanel      = lipgloss.Color("238")
-	ColorPrimary    = lipgloss.Color("75")
-	ColorAccent     = lipgloss.Color("222")
-	ColorMuted      = lipgloss.Color("246")
-	ColorText       = lipgloss.Color("255")
-	ColorDanger     = lipgloss.Color("203")
+	ColorBackground color.Color
+	ColorPanel      color.Color
+	ColorPrimary    color.Color
+	ColorAccent     color.Color
+	ColorMuted      color.Color
+	ColorText       color.Color
+	ColorDanger     color.Color
 )
 
 var (
 	// ScreenStyle is the base style for full-screen models.
-	ScreenStyle = lipgloss.NewStyle().
-			Foreground(ColorText)
+	ScreenStyle lipgloss.Style
 
 	// HeaderStyle is used by top-level titles and screen headers.
-	HeaderStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorPrimary)
+	HeaderStyle lipgloss.Style
 
 	// TabActiveStyle is applied to the currently-selected tab.
-	TabActiveStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorBackground).
-			Background(ColorPrimary).
-			Padding(0, 1)
+	TabActiveStyle lipgloss.Style
 
 	// TabInactiveStyle is applied to non-selected tabs.
-	TabInactiveStyle = lipgloss.NewStyle().
-				Foreground(ColorMuted).
-				Padding(0, 1)
+	TabInactiveStyle lipgloss.Style
 
 	// PanelStyle is used for boxed sections.
-	PanelStyle = lipgloss.NewStyle().
-			Border(lipgloss.NormalBorder()).
-			BorderForeground(ColorPanel).
-			Padding(0, 1)
+	PanelStyle lipgloss.Style
 
 	// HelpBarStyle is used for keybinding hints at the bottom.
-	HelpBarStyle = lipgloss.NewStyle().
-			Foreground(ColorMuted).
-			BorderTop(true).
-			BorderForeground(ColorPanel)
+	HelpBarStyle lipgloss.Style
 
 	// HighlightStyle emphasizes inline values.
-	HighlightStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorAccent)
+	HighlightStyle lipgloss.Style
 
 	// ErrorStyle is used for fatal or warning messages.
-	ErrorStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorDanger)
+	ErrorStyle lipgloss.Style
 )
+
+// ApplyPalette updates shared colors and styles to match the provided theme.
+func ApplyPalette(isDark bool) {
+	palette := NewPalette(isDark)
+	ColorBackground = palette.Background
+	ColorPanel = palette.Panel
+	ColorPrimary = palette.Primary
+	ColorAccent = palette.Accent
+	ColorMuted = palette.Muted
+	ColorText = palette.Text
+	ColorDanger = palette.Danger
+
+	ScreenStyle = lipgloss.NewStyle().Foreground(ColorText)
+	HeaderStyle = lipgloss.NewStyle().Bold(true).Foreground(ColorPrimary)
+	TabActiveStyle = lipgloss.NewStyle().
+		Bold(true).
+		Foreground(ColorBackground).
+		Background(ColorPrimary).
+		Padding(0, 1)
+	TabInactiveStyle = lipgloss.NewStyle().
+		Foreground(ColorMuted).
+		Padding(0, 1)
+	PanelStyle = lipgloss.NewStyle().
+		Border(lipgloss.NormalBorder()).
+		BorderForeground(ColorPanel).
+		Padding(0, 1)
+	HelpBarStyle = lipgloss.NewStyle().
+		Foreground(ColorMuted).
+		BorderTop(true).
+		BorderForeground(ColorPanel)
+	HighlightStyle = lipgloss.NewStyle().Bold(true).Foreground(ColorAccent)
+	ErrorStyle = lipgloss.NewStyle().Bold(true).Foreground(ColorDanger)
+}
+
+func init() {
+	ApplyPalette(true)
+}
diff --git a/internal/tui/common/styles_test.go b/internal/tui/common/styles_test.go
new file mode 100644
index 0000000..c0900b3
--- /dev/null
+++ b/internal/tui/common/styles_test.go
@@ -0,0 +1,39 @@
+package common
+
+import (
+	"testing"
+
+	"charm.land/lipgloss/v2"
+)
+
+func TestNewPaletteRendersDistinctThemes(t *testing.T) {
+	dark := NewPalette(true)
+	light := NewPalette(false)
+
+	darkRender := lipgloss.NewStyle().
+		Foreground(dark.Text).
+		Background(dark.Background).
+		Render("ior")
+	lightRender := lipgloss.NewStyle().
+		Foreground(light.Text).
+		Background(light.Background).
+		Render("ior")
+
+	if darkRender == lightRender {
+		t.Fatalf("expected dark and light palettes to render differently")
+	}
+}
+
+func TestApplyPaletteUpdatesSharedStyles(t *testing.T) {
+	t.Cleanup(func() { ApplyPalette(true) })
+
+	ApplyPalette(true)
+	dark := ScreenStyle.Render("ior")
+
+	ApplyPalette(false)
+	light := ScreenStyle.Render("ior")
+
+	if dark == light {
+		t.Fatalf("expected ScreenStyle render to differ between dark and light palettes")
+	}
+}