import { describe, expect, it } from "vitest";
import {
	code,
	codeBlock,
	findTrigger,
	link,
	list,
	separator,
	table,
	wrap,
	type Edit,
	type Selection
} from "$lib/components/ui/markdownFormat";

const select = (marked: string): Selection => {
	const start = marked.indexOf("«");
	const end = marked.indexOf("»") - 1;
	return { value: marked.replace("«", "").replace("»", ""), start, end };
};

const result = ({ value }: Selection, edit: Edit) => {
	const next = value.slice(0, edit.from) + edit.insert + value.slice(edit.to);
	return `${next.slice(0, edit.selectionStart)}«${next.slice(edit.selectionStart, edit.selectionEnd)}»${next.slice(edit.selectionEnd)}`;
};

const run = (marked: string, format: (selection: Selection) => Edit) => {
	const selection = select(marked);
	return result(selection, format(selection));
};

describe("wrap", () => {
	it("wraps the selection and keeps it selected", () => {
		expect(run("say «hello» there", (s) => wrap(s, "**"))).toBe("say **«hello»** there");
	});

	it("places the caret between the markers when nothing is selected", () => {
		expect(run("say «»", (s) => wrap(s, "_"))).toBe("say _«»_");
	});

	it("unwraps when the markers surround the selection", () => {
		expect(run("say **«hello»** there", (s) => wrap(s, "**"))).toBe("say «hello» there");
	});

	it("unwraps when the selection includes the markers", () => {
		expect(run("say «~~hello~~» there", (s) => wrap(s, "~~"))).toBe("say «hello» there");
	});
});

describe("code", () => {
	it("uses backticks for a single line", () => {
		expect(run("run «make» now", code)).toBe("run `«make»` now");
	});

	it("uses a fence for several lines", () => {
		expect(run("«a\nb»", code)).toBe("```\n«a\nb»\n```");
	});
});

describe("codeBlock", () => {
	it("pads the fence with blank lines", () => {
		expect(run("intro\n«x»\noutro", codeBlock)).toBe("intro\n\n```\n«x»\n```\n\noutro");
	});
});

describe("link", () => {
	it("selects the url placeholder around selected text", () => {
		expect(run("see «docs»", link)).toBe("see [docs](«url»)");
	});

	it("puts a selected url in the destination", () => {
		expect(run("«https://tangled.org»", link)).toBe("[«»](https://tangled.org)");
	});
});

describe("separator", () => {
	it("inserts a rule after the selection on its own paragraph", () => {
		expect(run("para«»", separator)).toBe("para\n\n---«»");
	});

	it("keeps following text a paragraph away", () => {
		expect(run("one«»\ntwo", separator)).toBe("one\n\n---«»\n\ntwo");
	});
});

describe("table", () => {
	it("selects the first header cell", () => {
		expect(run("«»", table)).toBe(
			"| «Column» | Column |\n| ------ | ------ |\n| Cell   | Cell   |"
		);
	});
});

describe("list", () => {
	it("prefixes every selected line", () => {
		expect(run("«one\ntwo»", (s) => list(s, "ordered"))).toBe("«1. one\n2. two»");
	});

	it("removes the prefix when every line already has it", () => {
		expect(run("«- [ ] one\n- [ ] two»", (s) => list(s, "task"))).toBe("«one\ntwo»");
	});

	it("keeps the caret on the same text for a single line", () => {
		expect(run("item«»", (s) => list(s, "bullet"))).toBe("- item«»");
	});

	it("does not treat a task item as a bullet", () => {
		expect(run("«- [ ] one»", (s) => list(s, "bullet"))).toBe("- «- [ ] one»");
	});
});

describe("findTrigger", () => {
	it("finds a mention being typed", () => {
		expect(findTrigger("hi @ada.te", 10)).toEqual({
			char: "@",
			query: "ada.te",
			from: 3,
			to: 10
		});
	});

	it("finds a reference at the start of a line", () => {
		expect(findTrigger("one\n#12", 7)).toEqual({ char: "#", query: "12", from: 4, to: 7 });
	});

	it("ignores markers glued to other text", () => {
		expect(findTrigger("mail@ada", 8)).toBeNull();
		expect(findTrigger("##", 2)).toBeNull();
	});

	it("stops at whitespace", () => {
		expect(findTrigger("# heading", 9)).toBeNull();
	});
});