// SPDX-FileCopyrightText: 2026 Alexander Bates <alex@bates64.com>
//
// SPDX-License-Identifier: 0BSD

// The npm packages the app ships: app/package.json's dependencies, and
// theirs in turn, as installed in node_modules. Development dependencies,
// such as the build tools, aren't shipped.

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

export const appDir = join(dirname(fileURLToPath(import.meta.url)), "..");

/** The directory of the package `name`, as Node would find it from `fromDir`. */
function findPackage(name, fromDir) {
  for (let dir = fromDir; ; dir = dirname(dir)) {
    const candidate = join(dir, "node_modules", name);
    if (existsSync(join(candidate, "package.json"))) {
      return candidate;
    }
    if (dirname(dir) === dir) {
      return undefined;
    }
  }
}

/** The packages the app ships, as their package.json, by directory. */
export function shippedPackages() {
  const packages = new Map();
  const pending = [appDir];
  while (pending.length > 0) {
    const dir = pending.pop();
    const manifest = JSON.parse(
      readFileSync(join(dir, "package.json"), "utf8"),
    );
    const dependencies = {
      ...manifest.dependencies,
      ...manifest.optionalDependencies,
    };
    for (const name of Object.keys(dependencies)) {
      const found = findPackage(name, dir);
      // An optional dependency for another platform isn't installed.
      if (found && !packages.has(found)) {
        packages.set(found, undefined);
        pending.push(found);
      }
    }
    if (dir !== appDir) {
      packages.set(dir, manifest);
    }
  }
  return packages;
}

/** A package's license as an SPDX expression, from its package.json. */
export function licenseOf(manifest) {
  const { license, licenses } = manifest;
  if (typeof license === "string") {
    return license;
  }
  if (license?.type) {
    return license.type;
  }
  // An old form: a list of licenses, any of which applies.
  if (Array.isArray(licenses)) {
    return licenses
      .map((l) => (typeof l === "string" ? l : l.type))
      .join(" OR ");
  }
  return undefined;
}