import fs from 'fs';
import path from 'path';

export const DATA_ROOT = process.env.DATA_ROOT || '/data';
export const POSTGRES_STORAGE_DIR_NAME = 'postgresql-store';
export const POSTGRES_STORAGE_DIR = path.join(DATA_ROOT, POSTGRES_STORAGE_DIR_NAME);
export const POSTGRES_STORAGE_DB_DIR_NAME = 'db';
export const POSTGRES_STORAGE_DB_DIR = path.join(POSTGRES_STORAGE_DIR, POSTGRES_STORAGE_DB_DIR_NAME);
export const POSTGRES_STORAGE_MANIFEST = path.join(POSTGRES_STORAGE_DIR, 'manifest.json');

export function readPostgresStorageManifest() {
  try {
    const raw = fs.readFileSync(POSTGRES_STORAGE_MANIFEST, 'utf8');
    const parsed = JSON.parse(raw);
    return parsed && typeof parsed === 'object' ? parsed : null;
  } catch {
    return null;
  }
}

export function hasEmbeddedPostgresDatabaseFiles() {
  try {
    return fs.existsSync(POSTGRES_STORAGE_DB_DIR) && fs.readdirSync(POSTGRES_STORAGE_DB_DIR).length > 0;
  } catch {
    return false;
  }
}

function detectStorageMode() {
  return readPostgresStorageManifest() ? 'postgres' : 'legacy';
}

export let STORAGE_MODE = detectStorageMode();

export function refreshStorageMode() {
  STORAGE_MODE = detectStorageMode();
  return STORAGE_MODE;
}

export function setStorageMode(mode) {
  STORAGE_MODE = mode === 'postgres' ? 'postgres' : 'legacy';
  return STORAGE_MODE;
}

export function getStorageMode() {
  return STORAGE_MODE;
}

export function isPostgresStorageMode() {
  return STORAGE_MODE === 'postgres';
}