/**
 * Verification: Fix for worktree path resolution escaping to home directory
 *
 * Tests the FIXED resolveProjectRoot() against the same scenarios that
 * reproduced the bug. Copies the fixed function logic from worktree.ts.
 */

import { execSync } from "node:child_process";
import {
	existsSync,
	mkdirSync,
	mkdtempSync,
	readFileSync,
	realpathSync,
	symlinkSync,
	writeFileSync,
} from "node:fs";
import { homedir, tmpdir } from "node:os";
import { join, resolve } from "node:path";

// ── Fixed functions (copied from worktree.ts after fix) ─────────────────

function findWorktreeSegment(normalizedPath) {
	const directMarker = "/.sf/worktrees/";
	const idx = normalizedPath.indexOf(directMarker);
	if (idx !== -1) {
		return { sfIdx: idx, afterWorktrees: idx + directMarker.length };
	}
	const symlinkRe = /\/\.sf\/projects\/[a-f0-9]+\/worktrees\//;
	const match = normalizedPath.match(symlinkRe);
	if (match && match.index !== undefined) {
		return {
			sfIdx: match.index,
			afterWorktrees: match.index + match[0].length,
		};
	}
	return null;
}

function resolveProjectRootFromGitFile(worktreePath) {
	try {
		let dir = worktreePath;
		for (let i = 0; i < 10; i++) {
			const gitPath = join(dir, ".git");
			if (existsSync(gitPath)) {
				const content = readFileSync(gitPath, "utf8").trim();
				if (content.startsWith("gitdir: ")) {
					const gitDir = resolve(dir, content.slice(8));
					const dotGitDir = resolve(gitDir, "..", "..");
					if (
						dotGitDir.endsWith(".git") ||
						dotGitDir.endsWith(".git/") ||
						dotGitDir.endsWith(".git\\")
					) {
						return resolve(dotGitDir, "..");
					}
					const commonDirPath = join(gitDir, "commondir");
					if (existsSync(commonDirPath)) {
						const commonDir = readFileSync(commonDirPath, "utf8").trim();
						const resolvedCommonDir = resolve(gitDir, commonDir);
						return resolve(resolvedCommonDir, "..");
					}
				}
				break;
			}
			const parent = resolve(dir, "..");
			if (parent === dir) break;
			dir = parent;
		}
	} catch {}
	return null;
}

function normalizePathForCompare(path) {
	let normalized;
	try {
		normalized = realpathSync(path);
	} catch {
		normalized = resolve(path);
	}
	const slashed = normalized.replaceAll("\\", "/");
	const trimmed = slashed.replace(/\/+$/, "");
	return trimmed || "/";
}

function resolveProjectRoot(basePath) {
	// Layer 1: If the coordinator passed the real project root, use it.
	if (process.env.SF_PROJECT_ROOT) {
		return process.env.SF_PROJECT_ROOT;
	}

	const normalizedPath = basePath.replaceAll("\\", "/");
	const seg = findWorktreeSegment(normalizedPath);
	if (!seg) return basePath;

	const sepChar = basePath.includes("\\") ? "\\" : "/";
	const sfMarker = `${sepChar}.sf${sepChar}`;
	const sfIdx = basePath.indexOf(sfMarker);
	const candidate =
		sfIdx !== -1 ? basePath.slice(0, sfIdx) : basePath.slice(0, seg.sfIdx);

	// Layer 2: Guard against resolving to the user's home directory.
	const sfHome = normalizePathForCompare(
		process.env.SF_HOME || join(homedir(), ".sf"),
	);
	const candidateSfPath = normalizePathForCompare(join(candidate, ".sf"));

	if (candidateSfPath === sfHome || candidateSfPath.startsWith(sfHome + "/")) {
		const realRoot = resolveProjectRootFromGitFile(basePath);
		if (realRoot) return realRoot;
		return basePath;
	}

	return candidate;
}

// ── Set up filesystem layout ────────────────────────────────────────────

const HASH = "abc123def456";
const TEST_ROOT = mkdtempSync(join(tmpdir(), "sf-verify-fix-"));
const USER_SF = process.env.SF_HOME || join(TEST_ROOT, ".sf");
const USER_HOME = homedir();
const PROJECT_SF_STORAGE = `${USER_SF}/projects/${HASH}`;
const PROJECT_DIR = mkdtempSync(join(tmpdir(), "myproject-"));
const PROJECT_SF_LINK = `${PROJECT_DIR}/.sf`;
const PROJECT_REAL = normalizePathForCompare(PROJECT_DIR);
const EXPECTED_BUGGY_ROOT = normalizePathForCompare(resolve(USER_SF, ".."));

process.env.SF_HOME = USER_SF;

console.log("=== Setting up filesystem layout ===\n");

mkdirSync(`${PROJECT_SF_STORAGE}/worktrees`, { recursive: true });
mkdirSync(`${PROJECT_SF_STORAGE}/milestones`, { recursive: true });
mkdirSync(PROJECT_DIR, { recursive: true });
symlinkSync(PROJECT_SF_STORAGE, PROJECT_SF_LINK);

// Init git in project dir
execSync("git init -b main", { cwd: PROJECT_DIR, stdio: "pipe" });
execSync('git config user.name "Test"', { cwd: PROJECT_DIR, stdio: "pipe" });
execSync('git config user.email "test@test.com"', {
	cwd: PROJECT_DIR,
	stdio: "pipe",
});
writeFileSync(join(PROJECT_DIR, "README.md"), "hello\n");
execSync("git add -A && git commit -m init", {
	cwd: PROJECT_DIR,
	stdio: "pipe",
});

// Create a REAL git worktree (so .git file exists with gitdir pointer)
execSync("git worktree add .sf/worktrees/M001 -b worktree/M001", {
	cwd: PROJECT_DIR,
	stdio: "pipe",
});
console.log("Created real git worktree at .sf/worktrees/M001\n");

let passed = 0;
let failed = 0;

function test(name, actual, expected) {
	if (actual === expected) {
		console.log(`  ✅ ${name}`);
		passed++;
	} else {
		console.log(`  ❌ ${name}`);
		console.log(`     Expected: ${expected}`);
		console.log(`     Got:      ${actual}`);
		failed++;
	}
}

// ── Test 1: SF_PROJECT_ROOT env var (Layer 1) ──────────────────────────

console.log("=== Layer 1: SF_PROJECT_ROOT env var ===\n");

process.env.SF_PROJECT_ROOT = PROJECT_DIR;
const resolvedPath = realpathSync(`${PROJECT_DIR}/.sf/worktrees/M001`);
test(
	"SF_PROJECT_ROOT overrides path resolution",
	resolveProjectRoot(resolvedPath),
	PROJECT_DIR,
);
delete process.env.SF_PROJECT_ROOT;

// ── Test 2: Direct layout still works ────────────────────────────────────

console.log("\n=== Direct layout (no symlink collision) ===\n");

test(
	"Direct layout resolves correctly",
	resolveProjectRoot("/foo/.sf/worktrees/M001"),
	"/foo",
);

test(
	"Non-worktree path unchanged",
	resolveProjectRoot("/some/repo"),
	"/some/repo",
);

// ── Test 3: Symlink-resolved path with git fallback (Layer 2) ────────────

console.log("\n=== Layer 2: Symlink-resolved path with git fallback ===\n");

// chdir into worktree via symlink — process.cwd() resolves symlinks
process.chdir(`${PROJECT_DIR}/.sf/worktrees/M001`);
const workerCwd = process.cwd();
console.log(`  Worker cwd (resolved): ${workerCwd}`);
console.log(`  Expected project root: ${PROJECT_DIR}`);

const result = resolveProjectRoot(workerCwd);
console.log(`  resolveProjectRoot():  ${result}`);
test(
	"Symlink-resolved worktree path resolves to REAL project (not ~)",
	result,
	PROJECT_REAL,
);

// Verify it's NOT the home directory
test("Result is not the home directory", result !== USER_HOME, true);

// ── Test 4: Verify the git file fallback works ──────────────────────────

console.log("\n=== Git file fallback detail ===\n");

const gitFileContent = readFileSync(join(workerCwd, ".git"), "utf8").trim();
console.log(`  .git file content: ${gitFileContent}`);
const gitDirResolved = resolve(workerCwd, gitFileContent.slice(8));
console.log(`  Resolved gitdir:   ${gitDirResolved}`);
const projectFromGit = resolve(gitDirResolved, "..", "..");
console.log(`  Project from git:  ${resolve(projectFromGit, "..")}`);

const gitFallback = resolveProjectRootFromGitFile(workerCwd);
test(
	"resolveProjectRootFromGitFile returns real project",
	gitFallback,
	PROJECT_REAL,
);

// ── Test 5: Old buggy path would have returned ~ ────────────────────────

console.log("\n=== Regression guard ===\n");

// Simulate what the OLD code did:
function oldResolveProjectRoot(basePath) {
	const normalizedPath = basePath.replaceAll("\\", "/");
	const seg = findWorktreeSegment(normalizedPath);
	if (!seg) return basePath;
	const sepChar = basePath.includes("\\") ? "\\" : "/";
	const sfMarker = `${sepChar}.sf${sepChar}`;
	const sfIdx = basePath.indexOf(sfMarker);
	if (sfIdx !== -1) return basePath.slice(0, sfIdx);
	return basePath.slice(0, seg.sfIdx);
}

const oldResult = oldResolveProjectRoot(workerCwd);
console.log(`  Old (buggy) code returns: ${oldResult}`);
test(
	"Old code returns parent of SF home (confirming bug existed)",
	oldResult,
	EXPECTED_BUGGY_ROOT,
);

test("New code does NOT return home directory", result !== USER_HOME, true);

// ── Summary ──────────────────────────────────────────────────────────────

console.log(`\n${"=".repeat(60)}`);
console.log(`\nResults: ${passed} passed, ${failed} failed`);
if (failed > 0) {
	console.log("\n🔴 FIX VERIFICATION FAILED");
	process.exit(1);
} else {
	console.log("\n✅ ALL TESTS PASSED — Fix verified!");
	process.exit(0);
}