#!/usr/bin/env bun
/**
 * Import-allowlist conformance gate.
 *
 * Scans every workspace package's `src/` for imports of
 * `@suaveplan/crypto-core`, `@suaveplan/crypto-cipher`,
 * `@suaveplan/crypto-curve`, or `@suaveplan/crypto-hash` MAC subpaths.
 * Fails with `error` severity for any package not on the committed
 * allowlist (`scripts/conformance/crypto-core-allowlist.yml`).
 *
 * Open imports (always allowed):
 *   - `@suaveplan/crypto-utils` (encoding helpers)
 *   - `@suaveplan/crypto-hash` for sha256 / sha384 / sha512 / hkdf /
 *     pbkdf2 / argon2id (pure-hash + KDF uses); only the MAC subpath
 *     `@suaveplan/crypto-hash/mac` is gated, because HMAC is the
 *     primitive that should travel through Authority instead.
 *
 * Exit codes:
 *   0 — all packages comply
 *   1 — at least one package outside the allowlist imports a gated module
 */

import { readdirSync, readFileSync, statSync } from "node:fs";
import { dirname, join, relative } from "node:path";
import { fileURLToPath } from "node:url";

const HERE = dirname(fileURLToPath(import.meta.url));
const REPO_ROOT = join(HERE, "..", "..");
const ALLOWLIST_PATH = join(HERE, "crypto-core-allowlist.yml");
const PACKAGES_ROOT = join(REPO_ROOT, "packages");

const GATED_PATTERNS = [
    /@suaveplan\/crypto-core(\/[^"'`]*)?/,
    /@suaveplan\/crypto-cipher(\/[^"'`]*)?/,
    /@suaveplan\/crypto-curve(\/[^"'`]*)?/,
    /@suaveplan\/crypto-hash\/mac(\/[^"'`]*)?/,
];

interface AllowlistDoc {
    readonly allowlist: readonly string[];
}

function readAllowlist(path: string): AllowlistDoc {
    const text = readFileSync(path, "utf8");
    const allowlist: string[] = [];
    let inAllowlist = false;
    for (const raw of text.split(/\r?\n/)) {
        const line = raw.trimEnd();
        if (line.startsWith("allowlist:")) {
            inAllowlist = true;
            continue;
        }
        if (inAllowlist) {
            // Section ends at the next top-level key
            if (/^\S/.test(line) && !line.startsWith(" ")) {
                inAllowlist = false;
                continue;
            }
            const m = line.match(/^\s*-\s+"([^"]+)"\s*$/);
            if (m?.[1]) allowlist.push(m[1]);
        }
    }
    return { allowlist };
}

function findPackageRoots(start: string): string[] {
    const out: string[] = [];
    function walk(dir: string): void {
        for (const entry of readdirSync(dir)) {
            if (entry.startsWith(".")) continue;
            const full = join(dir, entry);
            const st = statSync(full);
            if (!st.isDirectory()) continue;
            if (entry === "node_modules" || entry === "dist") continue;
            const pj = join(full, "package.json");
            try {
                statSync(pj);
                out.push(full);
            } catch {
                walk(full);
            }
        }
    }
    walk(start);
    return out;
}

function* walkSrcFiles(packageDir: string): Generator<string> {
    const src = join(packageDir, "src");
    try {
        statSync(src);
    } catch {
        return;
    }
    function* recurse(d: string): Generator<string> {
        for (const entry of readdirSync(d)) {
            const full = join(d, entry);
            const st = statSync(full);
            if (st.isDirectory()) {
                yield* recurse(full);
            } else if (
                full.endsWith(".ts") &&
                !full.endsWith(".test.ts") &&
                !full.endsWith(".spec.ts")
            ) {
                yield full;
            }
        }
    }
    yield* recurse(src);
}

interface Finding {
    readonly packageName: string;
    readonly file: string;
    readonly line: number;
    readonly importPath: string;
}

function packageNameOf(packageDir: string): string {
    const pj = JSON.parse(
        readFileSync(join(packageDir, "package.json"), "utf8")
    ) as { name?: string };
    return pj.name ?? `(unknown)@${relative(REPO_ROOT, packageDir)}`;
}

function scanFile(file: string, packageName: string): Finding[] {
    const findings: Finding[] = [];
    const text = readFileSync(file, "utf8");
    const lines = text.split(/\r?\n/);
    for (let i = 0; i < lines.length; i++) {
        const line = lines[i] ?? "";
        if (!line.includes("@suaveplan/crypto-")) continue;
        for (const pat of GATED_PATTERNS) {
            const m = line.match(pat);
            if (m?.[0]) {
                findings.push({
                    packageName,
                    file: relative(REPO_ROOT, file),
                    line: i + 1,
                    importPath: m[0],
                });
            }
        }
    }
    return findings;
}

export interface AllowlistCheckResult {
    readonly violations: readonly Finding[];
}

export function checkAllowlist(): AllowlistCheckResult {
    const allow = readAllowlist(ALLOWLIST_PATH);
    const allowSet = new Set(allow.allowlist);
    const violations: Finding[] = [];
    for (const packageDir of findPackageRoots(PACKAGES_ROOT)) {
        const name = packageNameOf(packageDir);
        if (allowSet.has(name)) continue;
        for (const file of walkSrcFiles(packageDir)) {
            for (const f of scanFile(file, name)) {
                violations.push(f);
            }
        }
    }
    return { violations };
}

if (import.meta.main) {
    const result = checkAllowlist();
    if (result.violations.length === 0) {
        console.log("crypto-core allowlist: 0 violations");
        process.exit(0);
    }
    console.error(
        `crypto-core allowlist: ${result.violations.length} violation(s)`
    );
    for (const v of result.violations) {
        console.error(
            `  [error] ${v.packageName} at ${v.file}:${v.line} imports ${v.importPath}`
        );
    }
    process.exit(1);
}