import { existsSync, readFileSync, statSync } from "node:fs";
import { dirname, join, resolve } from "node:path";
import { fileURLToPath } from "node:url";
import { describe, expect, it } from "@suaveplan/testing/runner";

const here = dirname(fileURLToPath(import.meta.url));
const pkgRoot = resolve(here, "..");
const pkg = JSON.parse(readFileSync(join(pkgRoot, "package.json"), "utf8")) as {
    exports: Record<string, unknown>;
    sideEffects: boolean;
};

describe("dep-graph", () => {
    it("declares 14 tree-shakeable subpath exports", { timeout: 5000 }, () => {
        const sub = Object.keys(pkg.exports).filter(
            (k) => k.startsWith("./") && k !== "./package.json"
        );
        // 13 subpaths + the root "." = 14.
        expect(sub.length + 1).toBe(14);
    });

    it("sideEffects is false", { timeout: 5000 }, () => {
        expect(pkg.sideEffects).toBe(false);
    });

    it("every implementation .ts has a sibling .md", { timeout: 5000 }, () => {
        const missing: string[] = [];
        walk(join(pkgRoot, "src"), (path) => {
            if (!path.endsWith(".ts")) return;
            if (path.endsWith(".test.ts")) return;
            if (path.endsWith(".types.ts")) return;
            if (path.endsWith("/index.ts")) return;
            if (path.endsWith(".spec-conformance.test.ts")) return;
            const md = path.replace(/\.ts$/, ".md");
            if (!existsSync(md)) missing.push(md);
        });
        expect(missing).toEqual([]);
    });
});

function walk(dir: string, visit: (path: string) => void): void {
    for (const entry of readdirSyncSafe(dir)) {
        const full = join(dir, entry);
        const st = statSync(full);
        if (st.isDirectory()) walk(full, visit);
        else visit(full);
    }
}

function readdirSyncSafe(dir: string): string[] {
    try {
        const { readdirSync } = require("node:fs") as typeof import("node:fs");
        return readdirSync(dir);
    } catch {
        return [];
    }
}