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

const DEFAULT_API_BASE = 'https://server.fmode.cn/api/qiwei';
const CREDENTIALS_FILE = path.join(os.homedir(), '.claude', 'qiwei-credentials.json');

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

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

function readClaudeSettingsEnv() {
  const files = [
    path.join(os.homedir(), '.claude', 'settings.json'),
    path.join(os.homedir(), '.claude', 'settings.local.json'),
    path.join(process.cwd(), '.claude', 'settings.json'),
    path.join(process.cwd(), '.claude', 'settings.local.json')
  ];
  const merged = {};
  for (const filePath of files) {
    const json = readJsonMaybe(filePath);
    const env = json && typeof json.env === 'object' && json.env ? json.env : null;
    if (!env) continue;
    for (const [key, value] of Object.entries(env)) {
      if (!merged[key] && typeof value === 'string' && value.trim()) merged[key] = value;
    }
  }
  return merged;
}

function readFmodeConfig() {
  const files = [
    path.join(os.homedir(), '.fmode', 'config.json'),
    path.join(process.cwd(), '.fmode', 'config.json')
  ];
  const merged = {};
  for (const filePath of files) {
    const json = readJsonMaybe(filePath);
    for (const [key, value] of Object.entries(json || {})) {
      if (merged[key] === undefined) merged[key] = value;
    }
  }
  return merged;
}

function pickFmodeAnthropicToken(env) {
  const token = env && typeof env.ANTHROPIC_AUTH_TOKEN === 'string' ? env.ANTHROPIC_AUTH_TOKEN.trim() : '';
  if (!token || !/^sk-/i.test(token) || /^sk-ant-/i.test(token)) return '';
  const base = String((env && (env.ANTHROPIC_BASE_URL || env.ANTHROPIC_API_BASE)) || '').toLowerCase();
  if (base && !base.includes('fmode')) return '';
  return token;
}

function normalizeToken(value) {
  return String(value || '').trim().replace(/^Bearer\s+/i, '');
}

function readQiweiAuthToken(input = {}) {
  const fileEnv = readEnvFiles();
  const claudeEnv = readClaudeSettingsEnv();
  const fmodeConfig = readFmodeConfig();
  const token = firstNonEmpty([
    input.authToken,
    input.fmodeApiKey,
    input.fmodeApiToken,
    input.sessionToken,
    input.apiToken,
    input.token,
    fileEnv.QIWEI_AUTH_TOKEN,
    fileEnv.QIWE_AUTH_TOKEN,
    fileEnv.FMODE_API_KEY,
    fileEnv.FMODE_API_TOKEN,
    fileEnv.NEWAPI_TOKEN,
    fileEnv.VOC_TOKEN,
    fileEnv.VOC_SOCIAL_TOKEN,
    process.env.QIWEI_AUTH_TOKEN,
    process.env.QIWE_AUTH_TOKEN,
    process.env.FMODE_API_KEY,
    process.env.FMODE_API_TOKEN,
    process.env.NEWAPI_TOKEN,
    process.env.VOC_TOKEN,
    process.env.VOC_SOCIAL_TOKEN,
    fmodeConfig.newapiToken,
    fmodeConfig.newApiToken,
    fmodeConfig.fmodeApiKey,
    fmodeConfig.fmodeApiToken,
    claudeEnv.FMODE_API_KEY,
    claudeEnv.NEWAPI_TOKEN,
    pickFmodeAnthropicToken(process.env),
    pickFmodeAnthropicToken(claudeEnv)
  ]);
  return normalizeToken(token);
}

function readCredentialsFile() {
  return readJsonMaybe(CREDENTIALS_FILE);
}

function readQiweiUid(input = {}) {
  const fileEnv = readEnvFiles();
  const creds = readCredentialsFile();
  return firstNonEmpty([
    input.uid,
    input.qiweiUid,
    fileEnv.QIWEI_UID,
    fileEnv.QIWE_UID,
    process.env.QIWEI_UID,
    process.env.QIWE_UID,
    creds.uid
  ]);
}

function readQiweiApiBase(input = {}) {
  const fileEnv = readEnvFiles();
  const creds = readCredentialsFile();
  return String(firstNonEmpty([
    input.apiBase,
    input.baseUrl,
    fileEnv.QIWEI_API_BASE,
    fileEnv.QIWEI_RELAY_BASE_URL,
    fileEnv.QIWE_API_BASE,
    fileEnv.QIWE_RELAY_BASE_URL,
    process.env.QIWEI_API_BASE,
    process.env.QIWEI_RELAY_BASE_URL,
    process.env.QIWE_API_BASE,
    process.env.QIWE_RELAY_BASE_URL,
    creds.apiBase,
    DEFAULT_API_BASE
  ]) || DEFAULT_API_BASE).replace(/\/$/, '');
}

function saveQiweiClientConfig({ uid, apiBase } = {}) {
  const saved = [];
  try {
    const dir = path.dirname(CREDENTIALS_FILE);
    if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
    const current = readCredentialsFile();
    const next = { ...current };
    if (uid) next.uid = uid;
    if (apiBase) next.apiBase = apiBase;
    next.updatedAt = new Date().toISOString();
    fs.writeFileSync(CREDENTIALS_FILE, JSON.stringify(next, null, 2), 'utf8');
    saved.push(CREDENTIALS_FILE);
  } catch {
    // ignore, fall through to env file
  }
  try {
    const envPath = path.join(process.cwd(), '.env.local');
    const pairs = [];
    if (uid) pairs.push(['QIWEI_UID', uid]);
    if (apiBase) pairs.push(['QIWEI_API_BASE', apiBase]);
    if (pairs.length) {
      let content = fs.existsSync(envPath) ? fs.readFileSync(envPath, 'utf8') : '';
      for (const [key, value] of pairs) {
        const line = `${key}=${value}`;
        const re = new RegExp(`^${key}\\s*=.*$`, 'm');
        content = re.test(content)
          ? content.replace(re, line)
          : `${content.replace(/\n*$/, '')}${content ? '\n' : ''}${line}\n`;
      }
      fs.writeFileSync(envPath, content, 'utf8');
      saved.push(envPath);
    }
  } catch {
    // ignore
  }
  return saved;
}

function ensureQiweiUid(input = {}) {
  const existing = readQiweiUid(input);
  if (existing) return existing;
  const uid = `qiwei-${crypto.randomUUID()}`;
  saveQiweiClientConfig({ uid, apiBase: readQiweiApiBase(input) });
  return uid;
}

function isConfigured(input = {}) {
  return Boolean(readQiweiAuthToken(input) && readQiweiUid(input));
}

module.exports = {
  DEFAULT_API_BASE,
  CREDENTIALS_FILE,
  readQiweiAuthToken,
  readQiweiUid,
  ensureQiweiUid,
  readQiweiApiBase,
  saveQiweiClientConfig,
  isConfigured,
  readEnvFiles,
  readClaudeSettingsEnv,
  readFmodeConfig,
  pickFmodeAnthropicToken
};