#!/usr/bin/env node
'use strict';

/**
 * Single source for GSD's published-package coordinates (issue #498).
 *
 * `deriveIdentity(pkg)` is the pure core: it turns a parsed package.json into
 * the coordinate record every consumer needs. The generated runtime module
 * `get-shit-done/bin/lib/package-identity.cjs` bakes those values at build
 * time, because the installed tree carries only a synthetic
 * `{"type":"commonjs"}` package.json (no `.name`) — so a runtime
 * `require('package.json').name` resolves to `undefined` (the #378 bug this
 * seam retires). Baking from package.json reconciles #378 (renames survive)
 * with #2992 (the value is never an LLM runtime choice).
 */

/**
 * Parse `owner/name` out of a package.json `repository.url`, stripping the
 * `git+` prefix and `.git` suffix npm conventionally adds.
 */
function parseRepoSlug(repository) {
  const url = typeof repository === 'string' ? repository : (repository && repository.url) || '';
  const m = url.replace(/^git\+/, '').replace(/\.git$/, '').match(/github\.com[/:]([^/]+\/[^/]+)$/);
  return m ? m[1] : '';
}

/**
 * Pure: package.json object -> the package identity coordinates.
 */
function deriveIdentity(pkg = {}) {
  const packageName = pkg.name || '';
  const binName = pkg.bin ? Object.keys(pkg.bin)[0] || '' : '';
  const repoSlug = parseRepoSlug(pkg.repository);
  const repoUrl = repoSlug ? `https://github.com/${repoSlug}` : '';
  const changelogRawUrl = repoSlug
    ? `https://raw.githubusercontent.com/${repoSlug}/main/CHANGELOG.md`
    : '';
  return { packageName, binName, repoSlug, repoUrl, changelogRawUrl };
}

/**
 * Pure: format the `npx` fallback install command. Shape matches the literal
 * the update workflow embeds: `npx -y --package=<pkg>@latest -- <bin>
 * [--<runtime>] --<scope>`. The runtime flag is omitted when not supplied.
 *
 * This function is the canonical source — `render()` serializes it verbatim
 * into the generated module, so the runtime copy can never drift from it.
 */
function formatManualInstall({ packageName, binName, scope, runtime } = {}) {
  const runtimeFlag = runtime ? ` --${runtime}` : '';
  return `npx -y --package=${packageName}@latest -- ${binName}${runtimeFlag} --${scope}`;
}

const GENERATED_HEADER =
  '// @generated by scripts/generate-package-identity.cjs from package.json — DO NOT EDIT.\n' +
  '// Single source for GSD package coordinates (issue #498). Regenerate with:\n' +
  '//   node scripts/generate-package-identity.cjs\n';

/**
 * Render the generated runtime module text for a derived identity. Values are
 * baked as literals; `formatManualInstall` is embedded by `.toString()` so the
 * runtime command builder is byte-identical to the tested source above.
 */
function render(identity) {
  const { packageName, binName, repoSlug, repoUrl, changelogRawUrl } = identity;
  const j = (v) => JSON.stringify(v);
  return (
    GENERATED_HEADER +
    "'use strict';\n\n" +
    `const packageName = ${j(packageName)};\n` +
    `const binName = ${j(binName)};\n` +
    `const repoSlug = ${j(repoSlug)};\n` +
    `const repoUrl = ${j(repoUrl)};\n` +
    `const changelogRawUrl = ${j(changelogRawUrl)};\n\n` +
    `${formatManualInstall.toString()}\n\n` +
    'function manualInstallCommand(opts = {}) {\n' +
    '  return formatManualInstall({ packageName, binName, scope: opts.scope, runtime: opts.runtime });\n' +
    '}\n\n' +
    'module.exports = Object.freeze({\n' +
    '  packageName,\n' +
    '  // PACKAGE_NAME: back-compat alias for #516-era consumers. Baked here, so it\n' +
    '  // survives the installed tree’s synthetic package.json (fixes the #378 undefined).\n' +
    '  PACKAGE_NAME: packageName,\n' +
    '  binName,\n' +
    '  repoSlug,\n' +
    '  repoUrl,\n' +
    '  changelogRawUrl,\n' +
    '  manualInstallCommand,\n' +
    '});\n'
  );
}

function main() {
  const fs = require('node:fs');
  const path = require('node:path');
  const pkg = require(path.join(__dirname, '..', 'package.json'));
  const out = path.join(__dirname, '..', 'get-shit-done', 'bin', 'lib', 'package-identity.cjs');
  fs.writeFileSync(out, render(deriveIdentity(pkg)));
  process.stdout.write(`wrote ${path.relative(path.join(__dirname, '..'), out)}\n`);
}

if (require.main === module) main();

module.exports = { deriveIdentity, parseRepoSlug, formatManualInstall, render, main };