/**
 * Tests for the prompt workflow chain under `.pi/agent/prompts/`.
 *
 * Scope (static, no LLM):
 *   - Frontmatter of every `c-*.md` recipe and `p-*.md` step is well-formed
 *     and contains the keys the pi-subagents adapter requires.
 *   - Every step named in a `chain:` resolves to an existing `p-*.md` file.
 *   - Every step has `subagent: true` and `fork: true`, which `Doc/chain-commands.md`
 *     calls out as required for `p-*.md` chain steps.
 *   - The Doc pages describe the same recipes / sequences that exist on disk.
 *
 * These tests do not exercise the LLM. They are independent, deterministic,
 * and fast (run against the on-disk tree only).
 */

import { describe, it, before } from "node:test";
import assert from "node:assert/strict";
import { readFileSync, readdirSync } from "node:fs";
import { join, resolve, dirname } from "node:path";
import { fileURLToPath } from "node:url";

import { parseFrontmatter, parseChain } from "./support/frontmatter.ts";

// ---------------------------------------------------------------------------
// Locating the prompts directory
// ---------------------------------------------------------------------------

const here = dirname(fileURLToPath(import.meta.url));
// test/ -> .pi/agent/prompts/
const PROMPTS_DIR = resolve(here, "..");

function readUtf8(path: string): string {
	return readFileSync(path, "utf8");
}

function readDoc(path: string): { frontmatter: Record<string, string>; body: string } {
	return parseFrontmatter(readUtf8(path));
}

let chainFiles: string[] = [];
let promptFiles: string[] = [];
let docFiles: string[] = [];

before(() => {
	chainFiles = readdirSync(PROMPTS_DIR)
		.filter((n) => n.startsWith("c-") && n.endsWith(".md"))
		.sort()
		.map((n) => join(PROMPTS_DIR, n));
	promptFiles = readdirSync(PROMPTS_DIR)
		.filter((n) => n.startsWith("p-") && n.endsWith(".md"))
		.sort()
		.map((n) => join(PROMPTS_DIR, n));
	docFiles = readdirSync(join(PROMPTS_DIR, "Doc"))
		.filter((n) => n.endsWith(".md"))
		.sort()
		.map((n) => join(PROMPTS_DIR, "Doc", n));
});

function readChain(name: string) {
	const path = join(PROMPTS_DIR, name);
	return { path, name, ...readDoc(path) };
}

function readPrompt(step: string) {
	// Accept both `p-brainstorm` and `p-brainstorm.md`; the actual files
	// end in `.md` but the chain frontmatter references them without it.
	const fileName = step.endsWith(".md") ? step : `${step}.md`;
	const path = join(PROMPTS_DIR, fileName);
	return { path, step, ...readDoc(path) };
}

// ---------------------------------------------------------------------------
// Test data
// ---------------------------------------------------------------------------

const EXPECTED_CHAINS: Record<string, string[]> = {
	"c-design-build.md": ["p-brainstorm", "p-plan", "p-test", "p-commit"],
	"c-fix-commit.md": ["p-summarize", "p-diagnose", "p-debug", "p-test"],
	"c-refactor-commit.md": ["p-refactor", "p-test", "p-review", "p-commit"],
	"c-security-loop.md": ["p-secaudit", "p-review", "p-test"],
};

const PROMPTS_USED_IN_CHAINS = new Set<string>(
	Object.values(EXPECTED_CHAINS).flat(),
);

// ---------------------------------------------------------------------------
// 1. Self-tests for the frontmatter/chain helpers (the test infra must work)
// ---------------------------------------------------------------------------

describe("support: frontmatter parser", () => {
	it("parses a simple key: value block", () => {
		const { frontmatter, body } = parseFrontmatter(
			'---\nfoo: bar\nbaz: "qux"\n---\nhello',
		);
		assert.equal(frontmatter.foo, "bar");
		assert.equal(frontmatter.baz, "qux");
		assert.equal(body, "hello");
	});

	it("returns empty frontmatter when the file has no fence", () => {
		const { frontmatter } = parseFrontmatter("no fence here");
		assert.deepEqual(frontmatter, {});
	});

	it("returns empty frontmatter when the fence is unterminated", () => {
		const { frontmatter } = parseFrontmatter("---\nfoo: bar\nstill going");
		assert.deepEqual(frontmatter, {});
	});

	it("de-indents a block scalar and trims leading newlines", () => {
		const { frontmatter } = parseFrontmatter(
			"---\nbody: |\n  line one\n  line two\n  line three\n---\n",
		);
		assert.equal(frontmatter.body, "line one\nline two\nline three");
	});

	it("strips full-line comments and ignores empty lines between keys", () => {
		const { frontmatter } = parseFrontmatter(
			"---\nfoo: bar\n# full-line comment\nbaz: qux\n---\n",
		);
		assert.equal(frontmatter.foo, "bar");
		assert.equal(frontmatter.baz, "qux");
		// Inline `#` after a value is left in the value (matches the
		// upstream `parseFrontmatter` in `pi-subagents`). This protects
		// against accidental whitespace stripping.
		const inline = parseFrontmatter("---\nfoo: bar  # trailing\n---\n");
		assert.equal(inline.frontmatter.foo, "bar  # trailing");
	});

	it("normalizes CRLF line endings", () => {
		const { frontmatter, body } = parseFrontmatter(
			"---\r\nfoo: bar\r\n---\r\nbody",
		);
		assert.equal(frontmatter.foo, "bar");
		assert.equal(body, "body");
	});
});

describe("support: chain parser", () => {
	it("splits on ' -> ' and trims", () => {
		assert.deepEqual(parseChain("a -> b -> c"), ["a", "b", "c"]);
	});

	it("returns [] for undefined", () => {
		assert.deepEqual(parseChain(undefined), []);
	});

	it("returns [] for an empty string", () => {
		assert.deepEqual(parseChain(""), []);
	});

	it("drops empty parts from extra spaces", () => {
		assert.deepEqual(parseChain("a ->  -> b"), ["a", "b"]);
	});

	it("does not split on a single dash", () => {
		// A chain value should not use `-` as a separator; the actual
		// recipes use ` -> `. This protects against future drift.
		assert.deepEqual(parseChain("a-b-c"), ["a-b-c"]);
	});
});

// ---------------------------------------------------------------------------
// 2. Happy path — the on-disk tree matches what we expect
// ---------------------------------------------------------------------------

describe("happy path: chain recipes are present and well-formed", () => {
	for (const [name, expectedSteps] of Object.entries(EXPECTED_CHAINS)) {
		it(`loads ${name}`, () => {
			assert.ok(
				chainFiles.includes(join(PROMPTS_DIR, name)),
				`missing chain recipe: ${name}`,
			);
		});

		it(`${name} has description, argument-hint, and chain fields`, () => {
			const { frontmatter } = readChain(name);
			assert.ok(frontmatter.description, "missing description");
			assert.ok(frontmatter["argument-hint"], "missing argument-hint");
			assert.ok(frontmatter.chain, "missing chain");
		});

		it(`${name}.chain parses to ${expectedSteps.join(" -> ")}`, () => {
			const { frontmatter } = readChain(name);
			assert.deepEqual(parseChain(frontmatter.chain), expectedSteps);
		});

		it(`${name} contains a $@ placeholder for the user argument`, () => {
			const { body } = readChain(name);
			assert.ok(
				body.includes("$@"),
				"chain recipe body must use $@ for the user-supplied argument",
			);
		});
	}
});

describe("happy path: every prompt step resolves to a real file", () => {
	for (const step of PROMPTS_USED_IN_CHAINS) {
		it(`step ${step} exists as a p-*.md file`, () => {
			assert.ok(
				promptFiles.includes(join(PROMPTS_DIR, `${step}.md`)),
				`chain references ${step} but no such p-*.md exists`,
			);
		});
	}
});

describe("happy path: every p-*.md has the required chain-step shape", () => {
	for (const step of PROMPTS_USED_IN_CHAINS) {
		it(`${step} declares subagent: true`, () => {
			const { frontmatter } = readPrompt(step);
			assert.equal(frontmatter.subagent, "true");
		});

		it(`${step} declares fork: true`, () => {
			const { frontmatter } = readPrompt(step);
			assert.equal(frontmatter.fork, "true");
		});

		it(`${step} has description and argument-hint`, () => {
			const { frontmatter } = readPrompt(step);
			assert.ok(frontmatter.description, "missing description");
			assert.ok(frontmatter["argument-hint"], "missing argument-hint");
		});

		it(`${step} body references $@`, () => {
			const { body } = readPrompt(step);
			assert.ok(body.includes("$@"), "p-* body must use $@ for arguments");
		});
	}
});

// ---------------------------------------------------------------------------
// 3. Edge cases — boundaries of the format
// ---------------------------------------------------------------------------

describe("edge cases: chain format boundaries", () => {
	it("every chain has at least one step", () => {
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const steps = parseChain(readChain(name).frontmatter.chain);
			assert.ok(steps.length > 0, `${name} chain is empty`);
		}
	});

	it("no chain has a duplicate step", () => {
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const steps = parseChain(readChain(name).frontmatter.chain);
			assert.equal(
				new Set(steps).size,
				steps.length,
				`${name} contains a duplicate step`,
			);
		}
	});

	it("every chain step is lowercase kebab-case starting with 'p-'", () => {
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const steps = parseChain(readChain(name).frontmatter.chain);
			for (const step of steps) {
				assert.match(step, /^p-[a-z0-9][a-z0-9-]*$/, `${name} step '${step}' is not p-kebab-case`);
			}
		}
	});

	it("chain frontmatter uses ' -> ' (single space) and not '->' or ' - >'", () => {
		// This is the format the pi-subagents adapter's `splitPromptChain`
		// actually understands.
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const raw = readChain(name).frontmatter.chain;
			assert.ok(raw, `${name} has no chain value`);
			assert.doesNotMatch(raw, /[^ ]->/, `${name} uses bare '->' which the adapter will not split on`);
		}
	});

	it("every chain ends with a real prompt file, not a typo", () => {
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const last = parseChain(readChain(name).frontmatter.chain).at(-1);
			assert.ok(last && promptFiles.includes(join(PROMPTS_DIR, `${last}.md`)),
				`${name} last step '${last}' does not exist on disk`);
		}
	});
});

describe("edge cases: argument-hint style", () => {
	it("every argument-hint is non-empty", () => {
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const hint = readChain(name).frontmatter["argument-hint"];
			assert.ok(hint && hint.length > 0, `${name} has empty argument-hint`);
		}
		for (const step of PROMPTS_USED_IN_CHAINS) {
			const hint = readPrompt(step).frontmatter["argument-hint"];
			assert.ok(hint && hint.length > 0, `${step} has empty argument-hint`);
		}
	});

	it("argument-hints are wrapped in [...] to match the documented convention", () => {
		// Doc/chain-commands.md and the existing recipes all use `[hint]`.
		const bracket = /^\[.+\]$/;
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const hint = readChain(name).frontmatter["argument-hint"];
			assert.match(hint, bracket, `${name} argument-hint not wrapped in []`);
		}
		for (const step of PROMPTS_USED_IN_CHAINS) {
			const hint = readPrompt(step).frontmatter["argument-hint"];
			assert.match(hint, bracket, `${step} argument-hint not wrapped in []`);
		}
	});
});

// ---------------------------------------------------------------------------
// 4. Error cases — malformed / missing / inconsistent input
// ---------------------------------------------------------------------------

describe("error cases: malformed frontmatter", () => {
	it("rejects a chain file with no closing fence", () => {
		const { frontmatter } = parseFrontmatter(
			"---\ndescription: broken\nchain: a -> b\n",
		);
		// Without a closing fence, the parser should return no frontmatter
		// (mirroring the real adapter), so the chain is empty.
		assert.deepEqual(frontmatter, {});
	});

	it("rejects a chain value with no separator at all", () => {
		assert.deepEqual(parseChain("only-one-step"), ["only-one-step"]);
		assert.equal(parseChain("only-one-step").length, 1);
	});

	it("flags a chain step that does not exist on disk", () => {
		// Simulate what the adapter does: build a fake chain value and
		// confirm we'd catch the missing file.
		const fakeStep = "p-does-not-exist";
		const steps = parseChain(`p-brainstorm -> ${fakeStep}`);
		assert.ok(steps.includes(fakeStep));
		assert.ok(
			!promptFiles.includes(join(PROMPTS_DIR, `${fakeStep}.md`)),
			"sanity: the fake step should not exist on disk",
		);
	});
});

describe("error cases: required keys", () => {
	it("every chain recipe has a non-empty description", () => {
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			const d = readChain(name).frontmatter.description;
			assert.ok(d && d.trim().length > 0, `${name} has empty description`);
		}
	});

	it("no p-* used in a chain is missing the subagent/fork flags", () => {
		// This is the failure mode Doc/chain-commands.md calls out:
		// "fork: true is required on each p-*.md. Check frontmatter."
		for (const step of PROMPTS_USED_IN_CHAINS) {
			const fm = readPrompt(step).frontmatter;
			assert.equal(fm.subagent, "true", `${step} missing subagent: true`);
			assert.equal(fm.fork, "true", `${step} missing fork: true`);
		}
	});
});

describe("error cases: cross-doc consistency", () => {
	// These tests catch the realistic drift bug: someone adds a new chain
	// recipe and forgets to add a row to the table in the Doc page. The
	// table is the canonical description, so we look for a row, not just
	// any mention of the name (the docs also reference recipes in
	// `/prompt-workflow <name>` examples, which would mask a missing row).
	//
	// chain-commands.md table uses the form  | `c-design-build.md` | ... |
	// prompts.md table uses the form        | **`c-design-build`** | ... |

	it("Doc/chain-commands.md has a table row for every chain recipe", () => {
		const text = readUtf8(join(PROMPTS_DIR, "Doc", "chain-commands.md"));
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			// The chain-commands.md table uses the full filename in
			// backticks (e.g. `c-design-build.md`).
			const re = new RegExp(`^\\|\\s*\`${name}\`\\s*\\|`, "m");
			assert.ok(
				re.test(text),
				`Doc/chain-commands.md is missing a table row for ${name}`,
			);
		}
	});

	it("Doc/chain-commands.md table rows show the actual chain sequence", () => {
		const text = readUtf8(join(PROMPTS_DIR, "Doc", "chain-commands.md"));
		for (const [name, steps] of Object.entries(EXPECTED_CHAINS)) {
			const re = new RegExp(`^\\|\\s*\`${name}\`\\s*\\|[^|]*\\|[^|]*\\|`, "m");
			const row = text.match(re);
			assert.ok(row, `Doc/chain-commands.md is missing a row for ${name}`);
			const rowAscii = row[0].replace(/→/g, "->");
			for (const step of steps) {
				assert.ok(
					rowAscii.includes(step),
					`Doc/chain-commands.md row for ${name} does not list ${step}`,
				);
			}
		}
	});

	it("Doc/prompts.md has a table row for every chain recipe", () => {
		const text = readUtf8(join(PROMPTS_DIR, "Doc", "prompts.md"));
		for (const name of Object.keys(EXPECTED_CHAINS)) {
			// The prompts.md table uses the base name in backticks
			// surrounded by `**` (e.g. `**`c-design-build`**`).
			const base = name.replace(/\.md$/, "");
			const re = new RegExp(`^\\|\\s*\\*\\*\`${base}\`\\*\\*\\s*\\|`, "m");
			assert.ok(
				re.test(text),
				`Doc/prompts.md is missing a table row for ${base}`,
			);
		}
	});

	it("Doc/prompts.md table rows show the actual chain sequence", () => {
		const text = readUtf8(join(PROMPTS_DIR, "Doc", "prompts.md"));
		for (const [name, steps] of Object.entries(EXPECTED_CHAINS)) {
			const base = name.replace(/\.md$/, "");
			const re = new RegExp(`^\\|\\s*\\*\\*\`${base}\`\\*\\*\\s*\\|[^|]*\\|`, "m");
			const row = text.match(re);
			assert.ok(row, `Doc/prompts.md is missing a row for ${base}`);
			const rowAscii = row[0].replace(/→/g, "->");
			for (const step of steps) {
				assert.ok(
					rowAscii.includes(step),
					`Doc/prompts.md row for ${base} does not list ${step}`,
				);
			}
		}
	});

	it("Doc/chain-commands.md documents ' -> ' as the chain separator", () => {
		const text = readUtf8(join(PROMPTS_DIR, "Doc", "chain-commands.md"));
		assert.ok(
			text.includes("->") || text.includes("→"),
			"Doc/chain-commands.md should describe the chain arrow separator",
		);
	});

	it("Doc/prompts.md mentions every prompt used in any chain", () => {
		const text = readUtf8(join(PROMPTS_DIR, "Doc", "prompts.md"));
		for (const step of PROMPTS_USED_IN_CHAINS) {
			assert.ok(
				text.includes(step),
				`Doc/prompts.md does not mention prompt ${step}`,
			);
		}
	});
});

// ---------------------------------------------------------------------------
// 5. Directory-level sanity — catches accidental deletions
// ---------------------------------------------------------------------------

describe("directory sanity", () => {
	it("has at least one chain recipe", () => {
		assert.ok(chainFiles.length > 0, "no c-*.md files found");
	});

	it("has at least one p-*.md prompt", () => {
		assert.ok(promptFiles.length > 0, "no p-*.md files found");
	});

	it("has both Doc pages", () => {
		assert.ok(docFiles.some((p) => p.endsWith("chain-commands.md")));
		assert.ok(docFiles.some((p) => p.endsWith("prompts.md")));
	});

	it("Doc/ has no extra markdown files we did not expect", () => {
		// If a new doc page is added, the cross-doc tests above should
		// grow with it. Catches accidental orphans in the other direction.
		const known = new Set(["chain-commands.md", "prompts.md"]);
		for (const p of docFiles) {
			const base = p.split(/[/\\]/).pop()!;
			assert.ok(known.has(base), `unexpected Doc file: ${base}`);
		}
	});

	it("every file in the prompts root is a recognized c-*, p-*, or Doc entry", () => {
		const entries = readdirSync(PROMPTS_DIR);
		const allowed = (n: string) =>
			n.startsWith("c-") || n.startsWith("p-") || n === "Doc" || n === "test";
		for (const e of entries) {
			if (e.startsWith(".")) continue; // .pi-subagents, etc.
			assert.ok(
				allowed(e),
				`unexpected top-level entry in prompts dir: ${e}`,
			);
		}
	});
});