import { describe, expect, it } from "vitest";
import { TaskPriority } from "@/model/taskPriority";
import { TaskStatus } from "@/model/taskStatus";
import {
	extractFrontmatterBlock,
	findFieldRange,
	formatTagsYamlValue,
	replaceFrontmatterField,
	setFrontmatterTags,
} from "./frontmatterFields";

const sample = `---
id: abc
title: Hello
status: todo
priority: medium
tags: [old]
---

Body
`;

describe("replaceFrontmatterField", () => {
	it("replaces status value", () => {
		const result = replaceFrontmatterField(sample, "status", TaskStatus.DONE);
		expect(result.ok).toBe(true);
		if (!result.ok) return;
		expect(result.content).toContain("status: done");
		expect(result.content).toContain("title: Hello");
		expect(result.content).toContain("Body");
	});

	it("replaces priority value", () => {
		const result = replaceFrontmatterField(sample, "priority", TaskPriority.CRITICAL);
		expect(result.ok).toBe(true);
		if (!result.ok) return;
		expect(result.content).toContain("priority: critical");
	});

	it("fails when field is missing", () => {
		const result = replaceFrontmatterField(sample, "assignee", "me");
		expect(result).toEqual({ ok: false, reason: "no-field" });
	});

	it("fails without frontmatter", () => {
		const result = replaceFrontmatterField("plain", "status", "todo");
		expect(result).toEqual({ ok: false, reason: "no-frontmatter" });
	});
});

describe("findFieldRange", () => {
	it("points at the value column", () => {
		const range = findFieldRange(sample, "status");
		expect(range).toBeDefined();
		const line = sample.split("\n")[range!.startLine];
		expect(line.slice(range!.startCol, range!.endCol)).toBe("todo");
	});
});

describe("formatTagsYamlValue", () => {
	it("formats empty and simple lists", () => {
		expect(formatTagsYamlValue([])).toBe("[]");
		expect(formatTagsYamlValue(["bug", "frontend"])).toBe(
			"[bug, frontend]",
		);
	});

	it("quotes tags with spaces", () => {
		expect(formatTagsYamlValue(["my tag"])).toBe('["my tag"]');
	});
});

describe("setFrontmatterTags", () => {
	it("replaces the tags line", () => {
		const result = setFrontmatterTags(sample, ["bug", "docs"]);
		expect(result.ok).toBe(true);
		if (!result.ok) return;
		expect(result.content).toContain("tags: [bug, docs]");
		expect(result.content).not.toContain("tags: [old]");
	});
});

describe("extractFrontmatterBlock", () => {
	it("extracts yaml from a valid block", () => {
		const block = extractFrontmatterBlock(
			"---\ntitle: Hello\nstatus: todo\n---\nbody",
		);
		expect(block).not.toBeNull();
		expect(block!.yaml).toBe("title: Hello\nstatus: todo");
		expect(block!.closeLine).toBe(3);
	});

	it("returns null when content does not start with ---", () => {
		expect(extractFrontmatterBlock("no frontmatter")).toBeNull();
		expect(extractFrontmatterBlock("")).toBeNull();
	});

	it("handles unclosed frontmatter with trailing newline", () => {
		const block = extractFrontmatterBlock("---\ntitle: x\n");
		expect(block).not.toBeNull();
		expect(block!.closeLine).toBe(-1);
		expect(block!.yaml).toBe("title: x\n");
	});

	it("handles unclosed frontmatter without trailing newline", () => {
		const block = extractFrontmatterBlock("---\ntitle: x");
		expect(block).not.toBeNull();
		expect(block!.closeLine).toBe(-1);
		expect(block!.yaml).toBe("title: x");
	});

	it("handles CRLF line endings (yaml is normalized to LF)", () => {
		const block = extractFrontmatterBlock(
			"---\r\ntitle: Hello\r\nstatus: todo\r\n---\r\nbody",
		);
		expect(block).not.toBeNull();
		expect(block!.yaml).toBe("title: Hello\nstatus: todo");
	});

	it("handles --- with trailing whitespace", () => {
		const block = extractFrontmatterBlock(
			"---  \ntitle: Hello\n---  \nbody",
		);
		expect(block).not.toBeNull();
		expect(block!.yaml).toBe("title: Hello");
		expect(block!.closeLine).toBe(2);
	});

	it("only matches --- on the first line", () => {
		const block = extractFrontmatterBlock("text\n---\ntitle: x\n---\n");
		expect(block).toBeNull();
	});
});