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

const ROOT = join(__dirname, "..", "src");

function walkTs(dir: string): string[] {
    const out: string[] = [];
    for (const name of readdirSync(dir)) {
        const full = join(dir, name);
        if (statSync(full).isDirectory()) out.push(...walkTs(full));
        else if (
            full.endsWith(".ts") &&
            !full.endsWith(".test.ts") &&
            !full.endsWith(".bench.ts")
        ) {
            out.push(full);
        }
    }
    return out;
}

describe("purity", () => {
    it("source tree references no browser globals", { timeout: 5000 }, () => {
        const banned = ["AudioContext", "AudioBuffer", "AudioWorklet"];
        for (const file of walkTs(ROOT)) {
            const text = readFileSync(file, "utf-8");
            for (const term of banned) {
                expect(text.includes(term)).toBe(false);
            }
        }
    });

    it("dependency set is limited to the declared workspace deps and zod", {
        timeout: 5000,
    }, () => {
        const pkg = JSON.parse(
            readFileSync(join(__dirname, "..", "package.json"), "utf-8")
        );
        const deps = Object.keys(pkg.dependencies ?? {}).sort();
        const allowed = [
            "@opentelemetry/api",
            "@suaveplan/audio-codecs",
            "@suaveplan/audio-core",
            "@suaveplan/audio-timeline",
            "@suaveplan/audio-transport",
            "@suaveplan/error",
            "@suaveplan/opentelemetry",
            "@suaveplan/streams",
            "@suaveplan/types",
            "tslib",
            "zod",
        ].sort();
        expect(deps).toEqual(allowed);
    });

    it("importing the package mutates no global state", {
        timeout: 5000,
    }, async () => {
        // Importing twice should not mutate globalThis between calls.
        await import("../src/index.js");
        const before = Object.keys(globalThis).length;
        await import("../src/index.js");
        const after = Object.keys(globalThis).length;
        expect(after).toBe(before);
    });
});