feat(tui): support single-mode themes (#37930)

packages/tui/test/cli/tui/theme-mode.test.tsx

@@ -0,0 +1,72 @@
+/** @jsxImportSource @opentui/solid */
+import { testRender } from "@opentui/solid"
+import { expect, test } from "bun:test"
+import { createTuiResolvedConfig } from "../../fixture/tui-runtime"
+import { DEFAULT_THEMES } from "../../../src/theme"
+import { ConfigProvider } from "../../../src/config"
+import { ThemeProvider, useTheme } from "../../../src/context/theme"
+
+async function wait(fn: () => boolean) {
+  const started = Date.now()
+  while (!fn()) {
+    if (Date.now() - started > 2000) throw new Error("timed out waiting for theme mode")
+    await Bun.sleep(10)
+  }
+}
+
+test("uses an available mode while retaining the pinned preference", async () => {
+  const lightOnly = structuredClone(DEFAULT_THEMES.opencode)
+  lightOnly.theme.background = "#eeeeee"
+  lightOnly.theme.text = "#111111"
+  const dual = structuredClone(DEFAULT_THEMES.opencode)
+  dual.theme.background = { light: "#eeeeee", dark: "#111111" }
+  dual.theme.text = { light: "#111111", dark: "#eeeeee" }
+  const darkOnly = structuredClone(DEFAULT_THEMES.opencode)
+  darkOnly.theme.background = "#111111"
+  darkOnly.theme.text = "#eeeeee"
+  let theme: ReturnType<typeof useTheme> | undefined
+
+  function Probe() {
+    const value = useTheme()
+    theme = value
+    return <text>{value.mode()}</text>
+  }
+
+  function current() {
+    if (!theme) throw new Error("Theme provider is not mounted")
+    return theme
+  }
+
+  const app = await testRender(
+    () => (
+      <ConfigProvider config={createTuiResolvedConfig({ theme: { name: "light-only", mode: "dark" } })}>
+        <ThemeProvider
+          mode="dark"
+          source={{ discover: () => Promise.resolve({ "light-only": lightOnly, "dark-only": darkOnly, dual }) }}
+        >
+          <Probe />
+        </ThemeProvider>
+      </ConfigProvider>
+    ),
+    { width: 20, height: 2 },
+  )
+  app.renderer.start()
+
+  try {
+    await wait(() => theme?.ready === true)
+    expect(current().mode()).toBe("light")
+    expect(current().modes()).toEqual(["light"])
+    expect(current().supports("dark")).toBeFalse()
+    expect(current().setMode("dark")).toBeFalse()
+    expect(current().set("dark-only")).toBeTrue()
+    await wait(() => current().mode() === "dark")
+    expect(current().modes()).toEqual(["dark"])
+    expect(current().set("light-only")).toBeTrue()
+    await wait(() => current().mode() === "light")
+    expect(current().set("dual")).toBeTrue()
+    await wait(() => current().mode() === "dark")
+    expect(current().modes()).toEqual(["light", "dark"])
+  } finally {
+    app.renderer.destroy()
+  }
+})