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

const __dirname = dirname(fileURLToPath(import.meta.url));

interface PackageJson {
    dependencies?: Record<string, string>;
    devDependencies?: Record<string, string>;
}

function readPackageJson(path: string): PackageJson {
    const content = readFileSync(path, "utf-8");
    return JSON.parse(content);
}

function getAllDependencyNames(pkg: PackageJson): Set<string> {
    const names = new Set<string>();
    for (const name of Object.keys(pkg.dependencies ?? {})) {
        names.add(name);
    }
    for (const name of Object.keys(pkg.devDependencies ?? {})) {
        names.add(name);
    }
    return names;
}

const diachronPkgPath = join(__dirname, "diachron", "package.json");
const backendPkgPath = join(__dirname, "package.json");

const diachronPkg = readPackageJson(diachronPkgPath);
const backendPkg = readPackageJson(backendPkgPath);

const diachronDeps = getAllDependencyNames(diachronPkg);
const backendDeps = getAllDependencyNames(backendPkg);

const duplicates: string[] = [];

for (const dep of diachronDeps) {
    if (backendDeps.has(dep)) {
        duplicates.push(dep);
    }
}

if (duplicates.length > 0) {
    console.error("Error: Duplicate dependencies found.");
    console.error("");
    console.error(
        "The following dependencies exist in both backend/package.json and backend/diachron/package.json:",
    );
    console.error("");
    for (const dep of duplicates.sort()) {
        console.error(`  - ${dep}`);
    }
    console.error("");
    console.error(
        "Dependencies in backend/diachron/package.json are provided by the framework",
    );
    console.error(
        "and must not be duplicated in backend/package.json. Remove them from",
    );
    console.error("backend/package.json to fix this error.");
    process.exit(1);
}

console.log("No duplicate dependencies found.");