import { readFileSync, writeFileSync, existsSync, readdirSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import path from 'node:path';

const here = path.dirname(fileURLToPath(import.meta.url));
const ffiPath = path.resolve(here, '../../fluxa-core/src/ffi.rs');
const outPath = path.resolve(here, '../src/core/coreMethods.ts');
const routesPath = path.join(path.dirname(ffiPath), 'ffi');

if (!existsSync(ffiPath)) {
  console.error(`gen-core-methods: ${ffiPath} not found (fluxa-core must be checked out next to fluxa-desktop, same as the Cargo path dependency)`);
  process.exit(1);
}

const routeFiles = existsSync(routesPath)
  ? readdirSync(routesPath)
      .filter((name) => name.endsWith('_routes.rs'))
      .map((name) => path.join(routesPath, name))
  : [];
const methods = [ffiPath, ...routeFiles].flatMap((sourcePath) =>
  [...readFileSync(sourcePath, 'utf8').matchAll(/^ {8}"([A-Za-z.]+)" =>/gm)].map((m) => m[1]),
);
const unique = [...new Set(methods)].sort();

if (unique.length !== methods.length) {
  const dupes = methods.filter((m, i) => methods.indexOf(m) !== i);
  console.error(`gen-core-methods: duplicate method arms in ffi.rs: ${[...new Set(dupes)].join(', ')}`);
  process.exit(1);
}
if (unique.length === 0) {
  console.error('gen-core-methods: extracted zero methods from ffi.rs, extraction pattern is broken');
  process.exit(1);
}

const body = `export const CORE_METHODS = [
${unique.map((m) => `  '${m}',`).join('\n')}
] as const;

export type CoreMethod = (typeof CORE_METHODS)[number];
`;

const header = `// Generated by scripts/gen-core-methods.mjs from fluxa-core/src/ffi.rs — do not edit.\n`;
const next = header + body;

const current = existsSync(outPath) ? readFileSync(outPath, 'utf8') : '';
if (current !== next) {
  writeFileSync(outPath, next);
  console.log(`gen-core-methods: wrote ${unique.length} methods to src/core/coreMethods.ts`);
}