pi-mono/packages/tui/test/wrap-ansi.test.ts

import assert from "node:assert";
import { describe, it } from "node:test";
import { visibleWidth, wrapTextWithAnsi } from "../src/utils.ts";

describe("wrapTextWithAnsi", () => {
	describe("underline styling", () => {
		it("should not apply underline style before the styled text", () => {
			const underlineOn = "\x1b[4m";
			const underlineOff = "\x1b[24m";
			const url = "https://example.com/very/long/path/that/will/wrap";
			const text = `read this thread ${underlineOn}${url}${underlineOff}`;

			const wrapped = wrapTextWithAnsi(text, 40);

			// First line should NOT contain underline code - it's just "read this thread"
			assert.strictEqual(wrapped[0], "read this thread");

			// Second line should start with underline, have URL content
			assert.strictEqual(wrapped[1].startsWith(underlineOn), true);
			assert.ok(wrapped[1].includes("https://"));
		});

		it("should not have whitespace before underline reset code", () => {
			const underlineOn = "\x1b[4m";
			const underlineOff = "\x1b[24m";
			const textWithUnderlinedTrailingSpace = `${underlineOn}underlined text here ${underlineOff}more`;

			const wrapped = wrapTextWithAnsi(textWithUnderlinedTrailingSpace, 18);

			assert.ok(!wrapped[0].includes(` ${underlineOff}`));
		});

		it("should not bleed underline to padding - each line should end with reset for underline only", () => {
			const underlineOn = "\x1b[4m";
			const underlineOff = "\x1b[24m";
			const url = "https://example.com/very/long/path/that/will/definitely/wrap";
			const text = `prefix ${underlineOn}${url}${underlineOff} suffix`;

			const wrapped = wrapTextWithAnsi(text, 30);

			// Middle lines (with underlined content) should end with underline-off, not full reset
			// Line 1 and 2 contain underlined URL parts
			for (let i = 1; i < wrapped.length - 1; i++) {
				const line = wrapped[i];
				if (line.includes(underlineOn)) {
					// Should end with underline off, NOT full reset
					assert.strictEqual(line.endsWith(underlineOff), true);
					assert.strictEqual(line.endsWith("\x1b[0m"), false);
				}
			}
		});
	});

	// #10925
	describe("styled words at the wrap boundary", () => {
		it("keeps the closing code on the wrapped line and drops the following space", () => {
			assert.deepStrictEqual(wrapTextWithAnsi("aaaa \x1b[1mbold\x1b[22m next word", 9), [
				"aaaa \x1b[1mbold\x1b[22m",
				"next word",
			]);
		});

		it("does not re-open a style closed by the dropped space", () => {
			assert.deepStrictEqual(wrapTextWithAnsi("aaaa \x1b[31mred\x1b[39m  next", 8), [
				"aaaa \x1b[31mred\x1b[39m",
				"next",
			]);
		});

		it("does not exceed width for styled whitespace wider than the line", () => {
			for (const text of [
				`\x1b[41m${" ".repeat(20)}\x1b[0m`,
				`ab\x1b[41m${" ".repeat(20)}\x1b[49mcd`,
				`\x1b[33m${" ".repeat(20)}x\x1b[39m`,
			]) {
				for (const line of wrapTextWithAnsi(text, 10)) {
					assert.ok(visibleWidth(line) <= 10, JSON.stringify(line));
				}
			}
		});

		it("trims trailing spaces before the line-end reset when a long word follows", () => {
			assert.deepStrictEqual(wrapTextWithAnsi("aaa\x1b[9m    abcdefghij\x1b[29m", 9), [
				"aaa\x1b[9m\x1b[29m",
				"\x1b[9mabcdefghi\x1b[29m",
				"\x1b[9mj\x1b[29m",
			]);
		});

		it("resets strikethrough at line end and restores it on the next line", () => {
			assert.deepStrictEqual(wrapTextWithAnsi("aaaa \x1b[9mstrike me\x1b[29m next", 12), [
				"aaaa \x1b[9mstrike\x1b[29m",
				"\x1b[9mme\x1b[29m next",
			]);
		});

		it("preserves background when resetting strikethrough at line end", () => {
			assert.deepStrictEqual(wrapTextWithAnsi("\x1b[41;9mstrike me\x1b[0m", 6), [
				"\x1b[41;9mstrike\x1b[29m",
				"\x1b[9;41mme\x1b[0m",
			]);
		});
	});

	describe("background color preservation", () => {
		it("should preserve background color across wrapped lines without full reset", () => {
			const bgBlue = "\x1b[44m";
			const reset = "\x1b[0m";
			const text = `${bgBlue}hello world this is blue background text${reset}`;

			const wrapped = wrapTextWithAnsi(text, 15);

			// Each line should have background color
			for (const line of wrapped) {
				assert.ok(line.includes(bgBlue));
			}

			// Middle lines should NOT end with full reset (kills background for padding)
			for (let i = 0; i < wrapped.length - 1; i++) {
				assert.strictEqual(wrapped[i].endsWith("\x1b[0m"), false);
			}
		});

		it("should reset underline but preserve background when wrapping underlined text inside background", () => {
			const underlineOn = "\x1b[4m";
			const underlineOff = "\x1b[24m";
			const reset = "\x1b[0m";

			const text = `\x1b[41mprefix ${underlineOn}UNDERLINED_CONTENT_THAT_WRAPS${underlineOff} suffix${reset}`;

			const wrapped = wrapTextWithAnsi(text, 20);

			// All lines should have background color 41 (either as \x1b[41m or combined like \x1b[4;41m)
			for (const line of wrapped) {
				const hasBgColor = line.includes("[41m") || line.includes(";41m") || line.includes("[41;");
				assert.ok(hasBgColor);
			}

			// Lines with underlined content should use underline-off at end, not full reset
			for (let i = 0; i < wrapped.length - 1; i++) {
				const line = wrapped[i];
				// If this line has underline on, it should end with underline off (not full reset)
				if (
					(line.includes("[4m") || line.includes("[4;") || line.includes(";4m")) &&
					!line.includes(underlineOff)
				) {
					assert.strictEqual(line.endsWith(underlineOff), true);
					assert.strictEqual(line.endsWith("\x1b[0m"), false);
				}
			}
		});
	});

	describe("basic wrapping", () => {
		it("should handle LF, CRLF, and CR line endings", () => {
			assert.deepStrictEqual(wrapTextWithAnsi("first\nsecond\r\nthird\rfourth", 80), [
				"first",
				"second",
				"third",
				"fourth",
			]);
		});

		it("should preserve ANSI state across CRLF and CR line endings", () => {
			const red = "\x1b[31m";
			const reset = "\x1b[0m";

			assert.deepStrictEqual(wrapTextWithAnsi(`${red}first\r\nsecond\rthird${reset}`, 80), [
				`${red}first`,
				`${red}second`,
				`${red}third${reset}`,
			]);
		});

		it("should wrap plain text correctly", () => {
			const text = "hello world this is a test";
			const wrapped = wrapTextWithAnsi(text, 10);

			assert.ok(wrapped.length > 1);
			for (const line of wrapped) {
				assert.ok(visibleWidth(line) <= 10);
			}
		});

		it("should break CJK runs at grapheme boundaries after Latin text", () => {
			const text = "This is an example 中文汉字测试段落内容中文汉字测试段落内容.";
			const wrapped = wrapTextWithAnsi(text, 40);

			assert.deepStrictEqual(wrapped, ["This is an example 中文汉字测试段落内容", "中文汉字测试段落内容."]);
			for (const line of wrapped) {
				assert.ok(visibleWidth(line) <= 40);
			}
		});

		it("should preserve color codes when wrapping CJK runs", () => {
			const red = "\x1b[31m";
			const reset = "\x1b[0m";
			const text = `${red}This is an example 中文汉字测试段落内容中文汉字测试段落内容.${reset}`;
			const wrapped = wrapTextWithAnsi(text, 40);

			assert.strictEqual(wrapped.length, 2);
			assert.strictEqual(wrapped[0], `${red}This is an example 中文汉字测试段落内容`);
			assert.strictEqual(wrapped[1], `${red}中文汉字测试段落内容.${reset}`);
			for (const line of wrapped) {
				assert.ok(visibleWidth(line) <= 40);
			}
		});

		it("should ignore OSC 133 semantic markers in visible width", () => {
			const text = "\x1b]133;A\x07hello\x1b]133;B\x07";
			assert.strictEqual(visibleWidth(text), 5);
		});

		it("should ignore OSC sequences terminated with ST in visible width", () => {
			const text = "\x1b]133;A\x1b\\hello\x1b]133;B\x1b\\";
			assert.strictEqual(visibleWidth(text), 5);
		});

		it("should treat isolated regional indicators as width 2", () => {
			assert.strictEqual(visibleWidth("🇨"), 2);
			assert.strictEqual(visibleWidth("🇨🇳"), 2);
		});

		it("should truncate trailing whitespace that exceeds width", () => {
			const twoSpacesWrappedToWidth1 = wrapTextWithAnsi("  ", 1);
			assert.ok(visibleWidth(twoSpacesWrappedToWidth1[0]) <= 1);
		});

		it("should preserve color codes across wraps", () => {
			const red = "\x1b[31m";
			const reset = "\x1b[0m";
			const text = `${red}hello world this is red${reset}`;

			const wrapped = wrapTextWithAnsi(text, 10);

			// Each continuation line should start with red code
			for (let i = 1; i < wrapped.length; i++) {
				assert.strictEqual(wrapped[i].startsWith(red), true);
			}

			// Middle lines should not end with full reset
			for (let i = 0; i < wrapped.length - 1; i++) {
				assert.strictEqual(wrapped[i].endsWith("\x1b[0m"), false);
			}
		});
	});
});

describe("wrapTextWithAnsi with OSC 8 hyperlinks", () => {
	it("re-emits OSC 8 open at the start of continuation lines", () => {
		// A hyperlink whose text is long enough to wrap
		const url = "https://example.com";
		// OSC 8 open + text that is 10 visible chars + OSC 8 close
		const input = `\x1b]8;;${url}\x1b\\0123456789\x1b]8;;\x1b\\`;
		const lines = wrapTextWithAnsi(input, 6);

		// Every line that contains visible text from inside the hyperlink
		// should start with the OSC 8 open sequence (or be preceded by it).
		for (const line of lines) {
			// If the line has visible content it must begin with the OSC 8 re-open
			// OR it is the line where the close appeared with no following content.
			const stripped = line.replace(/\x1b\]8;;[^\x1b\x07]*\x1b\\/g, "").replace(/\x1b\[[0-9;]*m/g, "");
			if (stripped.trim().length > 0) {
				assert.ok(
					line.startsWith(`\x1b]8;;${url}\x1b\\`) || line.includes(`\x1b]8;;${url}\x1b\\`),
					`Line "${line}" has visible text but no OSC 8 re-open`,
				);
			}
		}
	});

	it("closes OSC 8 before each line break", () => {
		const url = "https://example.com";
		const input = `\x1b]8;;${url}\x1b\\0123456789\x1b]8;;\x1b\\`;
		const lines = wrapTextWithAnsi(input, 6);

		for (let i = 0; i < lines.length - 1; i++) {
			const line = lines[i];
			// Every non-final line that is inside a hyperlink should end with the close
			if (line.includes(`\x1b]8;;${url}\x1b\\`)) {
				assert.ok(
					line.endsWith("\x1b]8;;\x1b\\"),
					`Non-final line "${line}" is inside a hyperlink but does not close it`,
				);
			}
		}
	});

	it("preserves BEL terminators when wrapping OAuth-style hyperlinks", () => {
		const url = `https://example.com/oauth/${"a".repeat(32)}`;
		const input = `\x1b]8;;${url}\x07${url}\x1b]8;;\x07`;
		const lines = wrapTextWithAnsi(input, 20);

		assert.ok(lines.length > 1);
		for (const line of lines) {
			assert.ok(line.includes(`\x1b]8;;${url}\x07`), `Line "${line}" does not reopen the hyperlink with BEL`);
			assert.ok(!line.includes(`\x1b]8;;${url}\x1b\\`), `Line "${line}" reopens the hyperlink with ST`);
		}
		for (const line of lines.slice(0, -1)) {
			assert.ok(line.endsWith("\x1b]8;;\x07"), `Line "${line}" does not close the hyperlink with BEL`);
		}
	});

	it("does not emit OSC 8 sequences on lines that are outside the hyperlink", () => {
		const url = "https://example.com";
		const input = `before \x1b]8;;${url}\x1b\\link\x1b]8;;\x1b\\ after`;
		const lines = wrapTextWithAnsi(input, 80);

		// With width 80 everything fits on one line; there should be exactly one
		// OSC 8 open and one OSC 8 close.
		assert.strictEqual(lines.length, 1);
		const openCount = (lines[0].match(/\x1b\]8;;https:[^\x1b]+\x1b\\/g) ?? []).length;
		const closeCount = (lines[0].match(/\x1b\]8;;\x1b\\/g) ?? []).length;
		assert.strictEqual(openCount, 1);
		assert.strictEqual(closeCount, 1);
	});
});