fix: up highlight made legible for transparent bg, bring back mouse nav

tests/system-theme.test.ts

@@ -0,0 +1,89 @@
+/**
+ * system-theme.test.ts — dark/light mode detection for the "system" theme.
+ *
+ * Covers the pure luminance helper `detectModeFromBackground` and the
+ * `generateSystemTheme` defaults when the terminal cannot answer OSC queries
+ * (empty palette): the fallback background/foreground must follow the detected
+ * mode (dark → white-on-black, light → black-on-white) instead of always
+ * assuming a dark terminal.
+ */
+import { test, expect } from "bun:test";
+import { RGBA, type TerminalColors } from "@opentui/core";
+import {
+  detectModeFromBackground,
+  generateSystemTheme,
+} from "../src/utils/system-theme";
+
+/** A TerminalColors with no real values — simulates a terminal that can't
+ *  answer OSC palette/background queries (e.g. tmux without forwarding). */
+const EMPTY: TerminalColors = {
+  palette: Array.from({ length: 16 }, () => null),
+  defaultForeground: null,
+  defaultBackground: null,
+  cursorColor: null,
+  mouseForeground: null,
+  mouseBackground: null,
+  tekForeground: null,
+  tekBackground: null,
+  highlightBackground: null,
+  highlightForeground: null,
+};
+
+test("detectModeFromBackground maps dark backgrounds to dark", () => {
+  expect(detectModeFromBackground("#181825")).toBe("dark");
+  expect(detectModeFromBackground("#000000")).toBe("dark");
+});
+
+test("detectModeFromBackground maps light backgrounds to light", () => {
+  expect(detectModeFromBackground("#ffffff")).toBe("light");
+  expect(detectModeFromBackground("#f0f0f0")).toBe("light");
+  expect(detectModeFromBackground("#c8c8c8")).toBe("light");
+});
+
+test("detectModeFromBackground returns null without a background", () => {
+  expect(detectModeFromBackground(null)).toBeNull();
+  expect(detectModeFromBackground(undefined)).toBeNull();
+  expect(detectModeFromBackground("")).toBeNull();
+});
+
+test("empty palette in dark mode falls back to light-on-dark text", () => {
+  const theme = generateSystemTheme(EMPTY, "dark").theme;
+  // fg defaults to #ffffff; r/g/b are 0..1 floats
+  expect((theme.text as RGBA).r).toBeGreaterThan(0.9);
+  expect((theme.text as RGBA).g).toBeGreaterThan(0.9);
+  expect((theme.text as RGBA).b).toBeGreaterThan(0.9);
+});
+
+test("system theme declares a transparent background", () => {
+  const theme = generateSystemTheme(EMPTY, "dark").theme;
+  // The system theme lets the terminal's own background show through.
+  expect(theme.transparent).toBe(true);
+  expect((theme.background as RGBA).a).toBe(0);
+});
+
+test("empty palette in light mode falls back to dark-on-light text", () => {
+  const theme = generateSystemTheme(EMPTY, "light").theme;
+  // fg defaults to #000000
+  expect((theme.text as RGBA).r).toBeLessThan(0.1);
+  expect((theme.text as RGBA).g).toBeLessThan(0.1);
+  expect((theme.text as RGBA).b).toBeLessThan(0.1);
+});
+
+test("empty palette in light mode uses a light background, not black", () => {
+  const theme = generateSystemTheme(EMPTY, "light").theme;
+  // bg defaults to #ffffff; the diff/panel grays derive from it, so the
+  // backgroundPanel must be light (high luminance), not near-black.
+  expect((theme.backgroundPanel as RGBA).r).toBeGreaterThan(0.5);
+});
+
+test("a real light background yields a light theme regardless of mode arg", () => {
+  const colors: TerminalColors = {
+    ...EMPTY,
+    defaultBackground: "#f5f5f5",
+    defaultForeground: "#111111",
+  };
+  const theme = generateSystemTheme(colors, "dark").theme;
+  // The actual terminal background wins over the mode default.
+  expect(detectModeFromBackground(colors.defaultBackground)).toBe("light");
+  expect((theme.backgroundPanel as RGBA).r).toBeGreaterThan(0.5);
+});