/**
 * todos.test.ts — unit + integration tests for the todos (TODOs & stubs) check.
 *
 * Unit: `detectTodoStubs` over a multi-language fixture tree — markers, silent
 * stubs (placeholder return / empty body / pass-only body), loud stubs, and
 * the negative cases (a real adder, a `return null` catch handler, in-string
 * "TODO" flagged for recall, clean code never flagged).
 *
 * Integration (deterministic fake agent runner): the scan persists findings.md
 * with the three sections + machine-readable summary and a new/resolved delta
 * vs the previous run; --fix converts silent stubs to loud throws, preserves
 * markers, leaves loud stubs untouched, and records changes.md.
 */
import { describe, expect, it, beforeEach, afterEach } from "bun:test";
import { existsSync } from "node:fs";
import { mkdtemp, mkdir, rm, writeFile, readFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import {
	clearChecks,
	getCheck,
	registerCheck,
	type CheckDefinition,
} from "../src/checks/registry.js";
import {
	setAgentRunner,
	resetAgentRunner,
	fakeAgentRunner,
} from "../src/agent-runner.js";
import { handleCheckCommand, type PygieniumCtx } from "../src/commands.js";
import { loadRunState } from "../src/run-state.js";
import {
	findingsPath,
	changesPath,
	todosCheck,
	detectTodoStubs,
	todosPriorCounts,
	buildTodosScanTask,
} from "../src/checks/todos.js";

function stubCtx(cwd: string): PygieniumCtx {
	return { cwd, mode: "print", hasUI: false, ui: undefined } as PygieniumCtx;
}

/**
 * Seed `stubs.ts` with the full taxonomy: a TODO marker, a silent stub with a
 * placeholder return (getPrice), a silent stub with an empty body (notify),
 * and a loud stub (connect throws "Not implemented").
 */
async function seedStubs(dir: string): Promise<void> {
	await mkdir(dir, { recursive: true }).catch(() => {});
	await writeFile(
		join(dir, "stubs.ts"),
		[
			`// TODO: add pagination`,
			`export function getPrice(): number {`,
			`  return 0;`,
			`}`,
			``,
			`export function notify(): void {}`,
			``,
			`export function connect(): Promise<void> {`,
			`  throw new Error("Not implemented");`,
			`}`,
			``,
		].join("\n"),
		"utf8",
	);
}

/** Seed the multi-language fixture tree for the deterministic-detector tests. */
async function seedTree(dir: string): Promise<void> {
	await mkdir(dir, { recursive: true }).catch(() => {});
	await Promise.all([
		writeFile(
			join(dir, "math.ts"),
			"export function add(a: number, b: number): number {\n  return a + b;\n}\n",
			"utf8",
		),
		writeFile(
			join(dir, "parse.ts"),
			[
				`export function parse(input: string) {`,
				`  try {`,
				`    return JSON.parse(input);`,
				`  } catch {`,
				`    return null;`,
				`  }`,
				`}`,
				``,
			].join("\n"),
			"utf8",
		),
		writeFile(join(dir, "stringlit.ts"), 'export const op = "TODO";\n', "utf8"),
		writeFile(
			join(dir, "stubs.ts"),
			[
				`// TODO: add pagination`,
				`export function getPrice(): number {`,
				`  return 0;`,
				`}`,
				``,
				`export function notify(): void {}`,
				``,
				`export function connect(): Promise<void> {`,
				`  throw new Error("Not implemented");`,
				`}`,
				``,
			].join("\n"),
			"utf8",
		),
		writeFile(
			join(dir, "repo.py"),
			[
				`class Repository:`,
				`    def find(self, uid):`,
				`        raise NotImplementedError  # interface method`,
				``,
				`    def save(self, record):`,
				`        pass`,
				``,
			].join("\n"),
			"utf8",
		),
		writeFile(
			join(dir, "fetch.rs"),
			"fn fetch() -> Result<u32, String> {\n  todo!()\n}\n",
			"utf8",
		),
	]);
}

describe("detectTodoStubs", () => {
	let dir: string;
	beforeEach(async () => {
		dir = await mkdtemp(join(tmpdir(), "pygienium-todos-unit-"));
		await seedTree(dir);
	});
	afterEach(async () => {
		await rm(dir, { recursive: true, force: true }).catch(() => {});
	});

	it("flags markers, silent stubs, and loud stubs across languages", async () => {
		const hits = await detectTodoStubs(dir);
		const marker = hits.filter((h) => h.kind === "marker");
		const silent = hits.filter((h) => h.kind === "silent-stub");
		const loud = hits.filter((h) => h.kind === "loud-stub");

		// Clean code is never flagged: the adder and the `return null` catch
		// handler (a boundary handler, not a stub) produce zero hits.
		expect(
			hits.filter((h) => /(?:math\.ts|parse\.ts)$/.test(h.path)),
		).toHaveLength(0);

		// Markers: the stubs.ts TODO comment, and the in-string "TODO" (recall —
		// the scan agent's job is to drop the string-literal noise).
		expect(
			marker.some(
				(h) =>
					h.path.endsWith("stubs.ts") && h.line === 1 && h.snippet === "TODO",
			),
		).toBe(true);
		expect(
			marker.some(
				(h) => h.path.endsWith("stringlit.ts") && h.snippet === "TODO",
			),
		).toBe(true);

		// Silent stubs: lone placeholder return + empty body in stubs.ts,
		// pass-only body in repo.py — each with its enclosing function.
		const stubsSilent = silent.filter((h) => h.path.endsWith("stubs.ts"));
		expect(
			stubsSilent.some(
				(h) => h.snippet === "placeholder-return" && h.context === "getPrice",
			),
		).toBe(true);
		expect(
			stubsSilent.some(
				(h) => h.snippet === "empty-body" && h.context === "notify",
			),
		).toBe(true);
		expect(
			silent.some(
				(h) =>
					h.path.endsWith("repo.py") &&
					h.snippet === "pass-only" &&
					h.context === "save",
			),
		).toBe(true);

		// Loud stubs: "Not implemented" throw, raise NotImplementedError,
		// rust todo!() — reported as tracked debt.
		expect(
			loud.some(
				(h) => h.path.endsWith("stubs.ts") && h.snippet === "Not implemented",
			),
		).toBe(true);
		expect(
			loud.some(
				(h) =>
					h.path.endsWith("repo.py") && h.snippet === "NotImplementedError",
			),
		).toBe(true);
		expect(
			loud.some((h) => h.path.endsWith("fetch.rs") && h.snippet === "todo!("),
		).toBe(true);
	});

	it("never descends into build/deploy output directories", async () => {
		// Generated bundles under framework build dirs must not feed the
		// pre-scan: they dominate candidate counts with minified noise (the
		// freno-dev failure flagged 119 of 124 candidates inside
		// `.output`/`.vercel` bundles, ballooning the scan task to 2.5 MB).
		for (const rel of [
			join(".output", "public", "bundle.js"),
			join(".vercel", "output", "static", "app.js"),
			join(".netlify", "functions", "bundle.js"),
		]) {
			const full = join(dir, rel);
			await mkdir(join(full, ".."), { recursive: true });
			await writeFile(
				full,
				"// TODO: bundle placeholder\nfunction f(){ return 0; }\nthrow new Error('not implemented');\n",
				"utf8",
			);
		}
		const hits = await detectTodoStubs(dir);
		expect(
			hits.filter((h) => /(?:\.output|\.vercel|\.netlify)[/\\]/.test(h.path)),
		).toHaveLength(0);
	});
});

describe("todos check", () => {
	let cwd: string;

	beforeEach(async () => {
		clearChecks();
		setAgentRunner(fakeAgentRunner);
		// Re-register explicitly: the module's import-time registerCheck only
		// runs once (module cache), so clearChecks + registerCheck restores it
		// deterministically for each test.
		registerCheck(todosCheck);
		cwd = await mkdtemp(join(tmpdir(), "pygienium-todos-"));
	});

	afterEach(async () => {
		resetAgentRunner();
		await rm(cwd, { recursive: true, force: true }).catch(() => {});
	});

	it("is registered and uses the todos scanner agent", () => {
		const check = getCheck("todos");
		expect(check).toBeDefined();
		expect((check as CheckDefinition)?.agentName).toBe("todos");
	});

	it("scan-only writes findings.md with the three sections and leaves sources untouched", async () => {
		await seedStubs(cwd);
		const check = getCheck("todos")!;

		await handleCheckCommand(check, "", stubCtx(cwd));

		const findings = await readFile(findingsPath(cwd), "utf8");
		expect(findings).toContain(
			"summary: 1 marker(s), 2 silent stub(s), 1 loud stub(s)",
		);
		expect(findings).toContain("new: 4"); // first run: everything is new
		expect(findings).toContain("## TODO markers");
		expect(findings).toContain("## Silent stubs (actionable)");
		expect(findings).toContain("placeholder-return");
		expect(findings).toContain("Not implemented");

		// Scan-only: no changes.md, sources untouched.
		expect(existsSync(changesPath(cwd))).toBe(false);
		const untouched = await readFile(join(cwd, "stubs.ts"), "utf8");
		expect(untouched).toContain("return 0;");

		// Run state records the scan summary as findings text.
		const state = await loadRunState(cwd);
		expect(state?.checks["todos"]?.status).toBe("complete");
		expect(state?.checks["todos"]?.findings).toContain(
			"todos: 2 silent stub(s), 1 loud stub(s), 1 marker(s)",
		);
	});

	it("--fix converts silent stubs to loud throws, preserves markers and loud stubs, records changes.md", async () => {
		await seedStubs(cwd);
		const check = getCheck("todos")!;

		await handleCheckCommand(check, "--fix", stubCtx(cwd));

		const cleaned = await readFile(join(cwd, "stubs.ts"), "utf8");
		// Silent stubs now throw loudly, naming the function.
		expect(cleaned).toContain('throw new Error("todos: getPrice() is a stub")');
		expect(cleaned).toContain('throw new Error("todos: notify() is a stub")');
		// Markers are NEVER deleted and loud stubs are NEVER touched.
		expect(cleaned).toContain("// TODO: add pagination");
		expect(cleaned).toContain('throw new Error("Not implemented")');
		expect(cleaned).toContain("Cleaned by pygienium-todos");
		// The placeholder bodies are gone.
		expect(cleaned).not.toContain("return 0;");
		expect(cleaned).not.toContain("notify(): void {}");

		const changes = await readFile(changesPath(cwd), "utf8");
		expect(changes).toContain(
			"summary: 2 silent stub(s) converted to loud, 0 kept",
		);
		expect(changes).toContain("getPrice()");
		expect(changes).toContain("notify()");

		const state = await loadRunState(cwd);
		expect(state?.checks["todos"]?.fix).toBe(true);
		expect(state?.checks["todos"]?.status).toBe("complete");
	});

	it("findings.md and changes.md live under .pygienium/checks/todos/", async () => {
		await seedStubs(cwd);
		const check = getCheck("todos")!;
		await handleCheckCommand(check, "--fix", stubCtx(cwd));
		expect(findingsPath(cwd)).toBe(
			join(cwd, ".pygienium", "checks", "todos", "findings.md"),
		);
		expect(changesPath(cwd)).toBe(
			join(cwd, ".pygienium", "checks", "todos", "changes.md"),
		);
	});

	it("skips when the target has no source files", async () => {
		// cwd is a fresh empty tempdir (no seeding) → the gate finds no source
		// files and skips the check without spawning an agent.
		const check = getCheck("todos")!;
		await handleCheckCommand(check, "", stubCtx(cwd));
		const state = await loadRunState(cwd);
		expect(state?.checks["todos"]?.status).toBe("skipped");
	});

	it("reports a new/resolved delta against the previous run's counts", async () => {
		await seedStubs(cwd);
		const check = getCheck("todos")!;
		await handleCheckCommand(check, "", stubCtx(cwd));

		// The previous run's verified counts are parseable from run-state.
		const prior = await todosPriorCounts(cwd);
		expect(prior).toEqual({ silent: 2, loud: 1, marker: 1 });

		// Nobody flagged anything new and everything was resolved: the next scan
		// sees zero candidates → new: 0, resolved: 4 (all prior items).
		await rm(join(cwd, "stubs.ts"));
		const task = await buildTodosScanTask(cwd, {
			cwd,
			target: cwd,
			fix: false,
			rest: [],
		});
		expect(task).toContain(
			"summary: 0 marker(s), 0 silent stub(s), 0 loud stub(s)",
		);
		expect(task).toContain("| new: 0 | resolved: 4 |");
	});

	it("truncates giant single-line candidates so the task prompt stays bounded", async () => {
		// A minified/generated single line can be hundreds of KB; embedding it
		// wholesale ballooned the freno-dev task to 2.5 MB and choked the
		// analysis agent. The task must carry a truncated prefix, never the
		// full line.
		const long = `// TODO: ${"x".repeat(400)}`;
		await writeFile(
			join(cwd, "huge.ts"),
			`${long}\nexport function f() { return 0; }\n`,
			"utf8",
		);
		const task = await buildTodosScanTask(cwd, {
			cwd,
			target: cwd,
			fix: false,
			rest: [],
		});
		expect(task).not.toContain("x".repeat(400));
		expect(task).toContain("…");
	});
});