import {existsSync, mkdirSync, readFileSync} from 'node:fs';
import {dirname, isAbsolute, resolve} from 'node:path';

export const LOCAL_ENV_FILES = ['.env', '.env.local', '.env.secrets.local'];

export function buildProtectedEnvKeys(baseEnv) {
  return new Set(
    Object.entries(baseEnv)
      .filter(([, value]) => String(value ?? '').trim())
      .map(([key]) => key),
  );
}

export function loadEnvFile(path, target, protectedKeys) {
  if (!existsSync(path)) {
    return;
  }

  const rawText = readFileSync(path, 'utf8');
  for (const rawLine of rawText.split(/\r?\n/u)) {
    const line = rawLine.trim();
    if (!line || line.startsWith('#')) {
      continue;
    }

    const match = line.match(/^([A-Za-z_][A-Za-z0-9_]*)=(.*)$/u);
    if (!match) {
      continue;
    }

    const [, key, rawValue] = match;
    if (protectedKeys.has(key)) {
      continue;
    }

    target[key] = rawValue.replace(/^['"]|['"]$/gu, '');
  }
}

export function loadApiServerEnv(repoRootPath, target, protectedKeys) {
  const resolvedProtectedKeys =
    protectedKeys ?? buildProtectedEnvKeys(process.env);

  // shell > .env > .env.local > .env.secrets.local
  for (const fileName of LOCAL_ENV_FILES) {
    loadEnvFile(resolve(repoRootPath, fileName), target, resolvedProtectedKeys);
  }
}

export function mergeApiServerEnv(repoRootPath, baseEnv = process.env) {
  const mergedEnv = {...baseEnv};
  loadApiServerEnv(repoRootPath, mergedEnv, buildProtectedEnvKeys(baseEnv));
  return mergedEnv;
}

export function formatApiServerLogTimestamp(date = new Date()) {
  const pad = (value) => String(value).padStart(2, '0');

  return [
    date.getFullYear(),
    pad(date.getMonth() + 1),
    pad(date.getDate()),
    '-',
    pad(date.getHours()),
    pad(date.getMinutes()),
    pad(date.getSeconds()),
  ].join('');
}

export function resolveApiServerLogFile(
  repoRootPath,
  env = process.env,
  now = new Date(),
) {
  const explicitLogFile = String(
    env.GENARRATIVE_API_SERVER_LOG_FILE ?? '',
  ).trim();

  if (explicitLogFile) {
    return isAbsolute(explicitLogFile)
      ? explicitLogFile
      : resolve(repoRootPath, explicitLogFile);
  }

  const logDir =
    String(env.GENARRATIVE_API_SERVER_LOG_DIR ?? '').trim() ||
    'logs/api-server';
  const resolvedLogDir = isAbsolute(logDir)
    ? logDir
    : resolve(repoRootPath, logDir);

  return resolve(
    resolvedLogDir,
    `api-server-${formatApiServerLogTimestamp(now)}.log`,
  );
}

export function ensureParentDir(filePath) {
  mkdirSync(dirname(filePath), {recursive: true});
}

export function resolveClientHost(hostName) {
  if (hostName === '0.0.0.0' || hostName === '::') {
    return '127.0.0.1';
  }

  return hostName;
}