// lib/index.ts
import { createRequire } from 'node:module';
import * as path from 'node:path';
import { fileURLToPath } from 'node:url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const require = createRequire(import.meta.url);

// dist/lib/index.js 에서 실행될 때 -> ../../build/Release/
// lib/index.ts 에서 실행될 때 -> ../build/Release/
// 둘 다 지원하도록 동적으로 찾기

function findBinding(): string {
  const candidates = [
    path.join(__dirname, '..', '..', 'build', 'Release', 'mmap_binding.node'),  // dist/lib/ 기준
    path.join(__dirname, '..', 'build', 'Release', 'mmap_binding.node'),        // lib/ 기준
  ];
  
  for (const candidate of candidates) {
    try {
      require.resolve(candidate);
      return candidate;
    } catch {
      continue;
    }
  }
  
  throw new Error('Cannot find mmap_binding.node. Run `npm run build:native` first.');
}

const binding = require(findBinding());

// 타입 정의
export interface MmapBinding {
  map(size: number, prot: number, flags: number, fd: number, offset: number): Buffer;
  sync(buffer: Buffer, offset: number, length: number, flags: number): void;
  unmap(buffer: Buffer): void;
  advise(buffer: Buffer, offset: number, length: number, advice: number): void;
  pageSize(): number;

  PROT_NONE: number;
  PROT_READ: number;
  PROT_WRITE: number;
  PROT_EXEC: number;

  MAP_SHARED: number;
  MAP_PRIVATE: number;
  MAP_ANONYMOUS?: number;
  MAP_ANON?: number;

  MS_ASYNC: number;
  MS_SYNC: number;
  MS_INVALIDATE: number;

  MADV_NORMAL: number;
  MADV_RANDOM: number;
  MADV_SEQUENTIAL: number;
  MADV_WILLNEED: number;
  MADV_DONTNEED: number;
}

const mmap: MmapBinding = binding;

export default mmap;

export const {
  map,
  sync,
  unmap,
  advise,
  pageSize,
  PROT_NONE,
  PROT_READ,
  PROT_WRITE,
  PROT_EXEC,
  MAP_SHARED,
  MAP_PRIVATE,
  MAP_ANONYMOUS,
  MAP_ANON,
  MS_ASYNC,
  MS_SYNC,
  MS_INVALIDATE,
  MADV_NORMAL,
  MADV_RANDOM,
  MADV_SEQUENTIAL,
  MADV_WILLNEED,
  MADV_DONTNEED,
} = mmap;