import { readdirSync, readFileSync, statSync } from "node:fs";
import { join } from "node:path";
import { describe, expect, it } from "@suaveplan/testing/runner";

const SRC = new URL("../src/", import.meta.url).pathname;

function walk(dir: string, acc: string[] = []): string[] {
    for (const name of readdirSync(dir)) {
        const p = join(dir, name);
        const st = statSync(p);
        if (st.isDirectory()) walk(p, acc);
        else if (/\.ts$/.test(p) && !/\.test\.ts$/.test(p)) acc.push(p);
    }
    return acc;
}

const FORBIDDEN_BROWSER_GLOBALS = [
    "AudioContext",
    "AnalyserNode",
    "AudioBuffer",
];

const FORBIDDEN_NODE_IMPORTS = ["node:fs", "node:path"];

describe("purity — universal guard", () => {
    it("source references no platform-only globals", { timeout: 5000 }, () => {
        const files = walk(SRC);
        const violations: string[] = [];
        for (const f of files) {
            const text = readFileSync(f, "utf8");
            for (const g of FORBIDDEN_BROWSER_GLOBALS) {
                const re = new RegExp(`\\b${g}\\b`);
                if (re.test(text)) violations.push(`${f}: contains ${g}`);
            }
            for (const g of FORBIDDEN_NODE_IMPORTS) {
                if (text.includes(g)) violations.push(`${f}: contains ${g}`);
            }
        }
        expect(violations).toEqual([]);
    });

    it("dependency set is limited to the declared workspace deps and zod", {
        timeout: 5000,
    }, () => {
        const pkg = JSON.parse(
            readFileSync(new URL("../package.json", import.meta.url), "utf8")
        ) as {
            dependencies: Record<string, string>;
        };
        const allowed = new Set([
            "@suaveplan/audio-core",
            "@suaveplan/error",
            "@suaveplan/types",
            "@opentelemetry/api",
            "tslib",
            "zod",
        ]);
        for (const dep of Object.keys(pkg.dependencies)) {
            expect(allowed.has(dep)).toBe(true);
        }
    });

    it("importing the package mutates no global state", {
        timeout: 5000,
    }, async () => {
        // Import once to settle any one-shot runner bookkeeping, then verify
        // a second import adds no new keys of its own.
        await import("../src/index.js");
        const before = new Set(Object.keys(globalThis));
        await import("../src/index.js");
        const added: string[] = [];
        for (const k of Object.keys(globalThis)) {
            if (!before.has(k)) added.push(k);
        }
        expect(added).toEqual([]);
    });
});