const fs = require('fs');
const path = require('path');
const os = require('os');

function readJsonMaybe(filePath) {
  try {
    if (!filePath || !fs.existsSync(filePath)) return {};
    return JSON.parse(fs.readFileSync(filePath, 'utf8').replace(/^\uFEFF/, ''));
  } catch {
    return {};
  }
}

function firstNonEmpty(values) {
  return values.find(value => typeof value === 'string' && value.trim()) || '';
}

function readEnvFileMaybe(filePath) {
  try {
    if (!filePath || !fs.existsSync(filePath)) return {};
    const env = {};
    const content = fs.readFileSync(filePath, 'utf8').replace(/^\uFEFF/, '');
    for (const rawLine of content.split(/\r?\n/)) {
      const line = rawLine.trim();
      if (!line || line.startsWith('#')) continue;
      const match = line.match(/^([A-Za-z_][A-Za-z0-9_]*)\s*=\s*(.*)$/);
      if (!match) continue;
      let value = match[2].trim();
      if ((value.startsWith('"') && value.endsWith('"')) || (value.startsWith("'") && value.endsWith("'"))) {
        value = value.slice(1, -1);
      }
      env[match[1]] = value;
    }
    return env;
  } catch {
    return {};
  }
}

function readWorkspaceEnvLocal() {
  return readEnvFileMaybe(path.join(process.cwd(), '.env.local'));
}

function envLocalCandidates() {
  const candidates = [];
  let current = process.cwd();
  while (current && !candidates.includes(path.join(current, '.env.local'))) {
    candidates.push(path.join(current, '.env.local'));
    const parent = path.dirname(current);
    if (parent === current) break;
    current = parent;
  }
  candidates.push(path.resolve(__dirname, '..', '..', '..', '.env.local'));
  return [...new Set(candidates)];
}

function readEnvLocalFiles() {
  return envLocalCandidates().reduce((merged, filePath) => {
    const next = readEnvFileMaybe(filePath);
    for (const [key, value] of Object.entries(next)) {
      if (!merged[key]) merged[key] = value;
    }
    return merged;
  }, {});
}

function readVocToken(input = {}) {
  const workspaceEnv = readEnvLocalFiles();
  const claudeCreds = readJsonMaybe(path.join(os.homedir(), '.claude', 'voc-credentials.json'));
  return firstNonEmpty([
    input.vocToken,
    input.xiaohongshuToken,
    input.douyinToken,
    input['voc-token'],
    input['xiaohongshu-token'],
    input['douyin-token'],
    input.token,
    input.apiToken,
    input['api-token'],
    workspaceEnv.VOC_TOKEN,
    workspaceEnv.VOC_SOCIAL_TOKEN,
    process.env.VOC_TOKEN,
    process.env.VOC_SOCIAL_TOKEN,
    claudeCreds.vocToken,
    claudeCreds.token,
  ]);
}

function readXiaohongshuToken(input = {}) {
  return readVocToken(input);
}

module.exports = {
  readVocToken,
  readXiaohongshuToken,
  readEnvFileMaybe,
  readWorkspaceEnvLocal,
  envLocalCandidates
};