import { clearDefaultTerminalColors, setDefaultTerminalColors } from "@earendil-works/pi-tui";
import { afterEach, beforeEach, describe, expect, it } from "vitest";
import { getEditorTheme, initTheme, setThemeInstance, Theme, theme } from "../src/modes/interactive/theme/theme.js";
function ansi256IndexToRgb(index: number): { r: number; g: number; b: number } {
if (index >= 232) {
const v = 8 + (index - 232) * 10;
return { r: v, g: v, b: v };
}
const cube = [0, 95, 135, 175, 215, 255];
const n = index - 16;
return { r: cube[Math.floor(n / 36)]!, g: cube[Math.floor((n % 36) / 6)]!, b: cube[n % 6]! };
}
function luminanceRgb(color: { r: number; g: number; b: number }): number {
return 0.299 * color.r + 0.587 * color.g + 0.114 * color.b;
}
function extractRgbLuminance(rendered: string): number {
const match = /48;2;(\d+);(\d+);(\d+)m/.exec(rendered);
if (!match) throw new Error(`Expected truecolor background escape, got: ${JSON.stringify(rendered)}`);
return 0.299 * Number(match[1]) + 0.587 * Number(match[2]) + 0.114 * Number(match[3]);
}
describe("adaptive TUI theme colors", () => {
let previousColorTerm: string | undefined;
let previousColorFgBg: string | undefined;
beforeEach(() => {
previousColorTerm = process.env.COLORTERM;
previousColorFgBg = process.env.COLORFGBG;
process.env.COLORTERM = "truecolor";
delete process.env.COLORFGBG;
clearDefaultTerminalColors();
initTheme("prime");
});
afterEach(() => {
clearDefaultTerminalColors();
if (previousColorTerm === undefined) {
delete process.env.COLORTERM;
} else {
process.env.COLORTERM = previousColorTerm;
}
if (previousColorFgBg === undefined) {
delete process.env.COLORFGBG;
} else {
process.env.COLORFGBG = previousColorFgBg;
}
});
it("uses theme colors for editor chrome when the terminal background is unknown", () => {
const editorTheme = getEditorTheme();
expect(editorTheme.backgroundColor?.("x")).toBe(theme.bg("userMessageBg", "x"));
expect(editorTheme.borderColor("x")).toBe(theme.fg("borderMuted", "x"));
});
it("keeps theme editor chrome on dark terminal backgrounds", () => {
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 0, g: 0, b: 0 },
});
const editorTheme = getEditorTheme();
expect(editorTheme.backgroundColor?.("x")).toBe(theme.bg("userMessageBg", "x"));
expect(editorTheme.borderColor("x")).toBe(theme.fg("borderMuted", "x"));
});
it("nudges the editor surface when it matches the terminal background", () => {
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 26, g: 26, b: 31 },
});
const editorTheme = getEditorTheme();
expect(editorTheme.backgroundColor?.("x")).not.toBe(theme.bg("userMessageBg", "x"));
expect(editorTheme.backgroundColor?.("x")).toMatch(/\x1b\[48;2;\d+;\d+;\d+mx\x1b\[49m/);
expect(editorTheme.borderColor("x")).toBe(theme.fg("borderMuted", "x"));
});
it("keeps theme editor chrome on light terminal backgrounds", () => {
setDefaultTerminalColors({
foreground: { r: 0, g: 0, b: 0 },
background: { r: 255, g: 255, b: 255 },
});
const editorTheme = getEditorTheme();
expect(editorTheme.backgroundColor?.("x")).toBe(theme.bg("userMessageBg", "x"));
expect(editorTheme.borderColor("x")).toBe(theme.fg("borderMuted", "x"));
});
it("keeps the theme selection background when the terminal background is unknown", () => {
expect(theme.getSelectionBackgroundColor()("x")).toBe(theme.bg("selectedBg", "x"));
});
it("keeps the theme selection background on clearly different terminal backgrounds", () => {
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 0, g: 0, b: 0 },
});
expect(theme.getSelectionBackgroundColor()("x")).toBe(theme.bg("selectedBg", "x"));
});
it("strengthens the selection background when it nearly matches the terminal background", () => {
setDefaultTerminalColors({
foreground: { r: 235, g: 219, b: 178 },
background: { r: 29, g: 32, b: 33 },
});
const selection = theme.getSelectionBackgroundColor()("x");
expect(selection).not.toBe(theme.bg("selectedBg", "x"));
expect(selection).toMatch(/\x1b\[48;2;\d+;\d+;\d+mx\x1b\[49m/);
});
it("darkens a selection background that is darker than a dark terminal background", () => {
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 60, g: 60, b: 60 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
expect(rendered).not.toBe(theme.bg("selectedBg", "x"));
// Selection luminance 34.5 against a terminal luminance of 60 has delta 25.5;
// blending darker reaches the minimum without crossing the background.
expect(Math.abs(extractRgbLuminance(rendered) - 60)).toBeGreaterThanOrEqual(27.5);
expect(extractRgbLuminance(rendered)).toBeLessThan(34.5);
});
it("lightens a selection background that is brighter than a light terminal background", () => {
initTheme("light");
setDefaultTerminalColors({
foreground: { r: 0, g: 0, b: 0 },
background: { r: 200, g: 200, b: 200 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
expect(rendered).not.toBe(theme.bg("selectedBg", "x"));
// light theme selectedBg #d0d0e0 has luminance ~209.7, terminal has 200.
expect(extractRgbLuminance(rendered)).toBeGreaterThan(209.7);
expect(Math.abs(extractRgbLuminance(rendered) - 200)).toBeGreaterThanOrEqual(27.5);
});
it("crosses the background when the selection sits at the blend endpoint", () => {
setThemeInstance(
new Theme(
{} as ConstructorParameters<typeof Theme>[0],
{ selectedBg: "#000000" } as ConstructorParameters<typeof Theme>[1],
"truecolor",
),
);
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 1, g: 1, b: 1 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
expect(rendered).not.toBe(theme.bg("selectedBg", "x"));
// Blending toward black cannot change a black selection, so it must blend
// upward across the background to reach the minimum contrast.
expect(Math.abs(extractRgbLuminance(rendered) - 1)).toBeGreaterThanOrEqual(27.5);
initTheme("prime");
});
it("falls back across the background when the same-side blend is capped", () => {
// Prime selectedBg (#222226, luminance ~34.5) is slightly darker than this
// terminal background; blending darker is capped at 0.5 and cannot reach 28,
// so the highlight must cross upward instead.
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 35, g: 35, b: 35 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
expect(rendered).not.toBe(theme.bg("selectedBg", "x"));
expect(Math.abs(extractRgbLuminance(rendered) - 35)).toBeGreaterThanOrEqual(27.5);
});
it("keeps contrast after 256-color quantization", () => {
setThemeInstance(
new Theme(
{} as ConstructorParameters<typeof Theme>[0],
{ selectedBg: "#e93e4d" } as ConstructorParameters<typeof Theme>[1],
"256color",
),
);
// #e93e4d (luminance 114.9) on #2ca649 (luminance 118.9): the pre-quantized
// blend is fine, but naive quantization lands on #af5f5f, matching the
// terminal background exactly.
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 44, g: 166, b: 73 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
const match = /48;5;(\d+)m/.exec(rendered);
if (!match) throw new Error(`Expected 256-color background escape, got: ${JSON.stringify(rendered)}`);
const quantized = ansi256IndexToRgb(Number(match[1]));
expect(Math.abs(luminanceRgb(quantized) - 118.9)).toBeGreaterThanOrEqual(27.5);
initTheme("prime");
});
it("searches stronger blends when 256-color quantization undershoots", () => {
setThemeInstance(
new Theme(
{} as ConstructorParameters<typeof Theme>[0],
{ selectedBg: "#2f4d50" } as ConstructorParameters<typeof Theme>[1],
"256color",
),
);
// #2f4d50 (luminance 68.4) on #751dce (luminance 75.5): both exact-target
// blends quantize far below the threshold; a stronger blend toward white
// quantizes to #87afaf and clears it.
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 117, g: 29, b: 206 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
const match = /48;5;(\d+)m/.exec(rendered);
if (!match) throw new Error(`Expected 256-color background escape, got: ${JSON.stringify(rendered)}`);
expect(Math.abs(luminanceRgb(ansi256IndexToRgb(Number(match[1]))) - 75.5)).toBeGreaterThanOrEqual(27.5);
initTheme("prime");
});
it("adapts when 256-color quantization erases the configured contrast", () => {
setThemeInstance(
new Theme(
{} as ConstructorParameters<typeof Theme>[0],
{ selectedBg: "#e82d6a" } as ConstructorParameters<typeof Theme>[1],
"256color",
),
);
// #e82d6a (luminance ~108) on #d6005d (luminance ~74.6): raw delta 33 passes,
// but the selection quantizes to #d7005f which nearly matches the terminal.
setDefaultTerminalColors({
foreground: { r: 255, g: 255, b: 255 },
background: { r: 214, g: 0, b: 93 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
expect(rendered).not.toBe(theme.bg("selectedBg", "x"));
const match = /48;5;(\d+)m/.exec(rendered);
if (!match) throw new Error(`Expected 256-color background escape, got: ${JSON.stringify(rendered)}`);
expect(Math.abs(luminanceRgb(ansi256IndexToRgb(Number(match[1]))) - 74.6)).toBeGreaterThanOrEqual(27.5);
initTheme("prime");
});
it("leaves terminal-defined basic ANSI selection colors alone", () => {
setThemeInstance(
new Theme(
{} as ConstructorParameters<typeof Theme>[0],
{ selectedBg: 0 } as ConstructorParameters<typeof Theme>[1],
"256color",
),
);
setDefaultTerminalColors({
foreground: { r: 235, g: 219, b: 178 },
background: { r: 29, g: 32, b: 33 },
});
expect(theme.getSelectionBackgroundColor()("x")).toBe(theme.bg("selectedBg", "x"));
initTheme("prime");
});
it("derives a contrasting selection when selectedBg uses the terminal default", () => {
setThemeInstance(
new Theme(
{} as ConstructorParameters<typeof Theme>[0],
{ selectedBg: "" } as ConstructorParameters<typeof Theme>[1],
"256color",
),
);
setDefaultTerminalColors({
foreground: { r: 235, g: 219, b: 178 },
background: { r: 29, g: 32, b: 33 },
});
const rendered = theme.getSelectionBackgroundColor()("x");
expect(rendered).not.toBe(theme.bg("selectedBg", "x"));
const match = /48;5;(\d+)m/.exec(rendered);
if (!match) throw new Error(`Expected 256-color background escape, got: ${JSON.stringify(rendered)}`);
// Terminal background luminance is 31.2; the derived highlight must clear it.
expect(Math.abs(luminanceRgb(ansi256IndexToRgb(Number(match[1]))) - 31.2)).toBeGreaterThanOrEqual(27.5);
initTheme("prime");
});
it("darkens a light selection background that nearly matches a light terminal background", () => {
initTheme("light");
setDefaultTerminalColors({
foreground: { r: 0, g: 0, b: 0 },
background: { r: 210, g: 210, b: 220 },
});
const selection = theme.getSelectionBackgroundColor()("x");
expect(selection).not.toBe(theme.bg("selectedBg", "x"));
expect(selection).toMatch(/\x1b\[48;2;\d+;\d+;\d+mx\x1b\[49m/);
});
it("uses COLORFGBG for automatic default theme selection when OSC colors are unavailable", () => {
process.env.COLORFGBG = "0;15";
clearDefaultTerminalColors();
initTheme(undefined);
expect(theme.name).toBe("light");
process.env.COLORFGBG = "15;0";
clearDefaultTerminalColors();
initTheme(undefined);
expect(theme.name).toBe("prime");
});
});