import { readdir, readFile } from "node:fs/promises";
import { join } from "node:path";
import { describe, expect, it } from "@suaveplan/testing/runner";

const SRC_ROOT = join(__dirname, "..", "src");
const BANNED_PATTERNS = [
    /\bfrom\s+["']node:/,
    /\bfrom\s+["']fs["']/,
    /\bfrom\s+["']path["']/,
    /\bfrom\s+["']crypto["']/,
    /\brequire\(["']node:/,
    /\bprocess\.[a-zA-Z]/,
    /\bBuffer\.[a-zA-Z]/,
    /\bwindow\./,
    /\bdocument\./,
    /\bnavigator\./,
];

async function* walk(dir: string): AsyncGenerator<string> {
    const entries = await readdir(dir, { withFileTypes: true });
    for (const entry of entries) {
        const full = join(dir, entry.name);
        if (entry.isDirectory()) {
            yield* walk(full);
        } else if (
            entry.isFile() &&
            entry.name.endsWith(".ts") &&
            !entry.name.endsWith(".test.ts") &&
            !entry.name.endsWith(".spec.ts") &&
            !entry.name.endsWith(".bench.ts")
        ) {
            yield full;
        }
    }
}

describe("purity guards", () => {
    it("built dist references no Node or browser globals", {
        timeout: 5000,
    }, async () => {
        const offenders: Array<{ file: string; pattern: string }> = [];
        for await (const file of walk(SRC_ROOT)) {
            const source = await readFile(file, "utf8");
            for (const pattern of BANNED_PATTERNS) {
                if (pattern.test(source)) {
                    offenders.push({ file, pattern: pattern.source });
                }
            }
        }
        expect(offenders).toEqual([]);
    });
});