import fs from 'node:fs';
import path from 'node:path';

export type AppConfig = {
  nodeEnv: string;
  projectRoot: string;
  publicDir: string;
  logsDir: string;
  dataDir: string;
  rawEnv: Record<string, string>;
  databaseUrl: string;
  serverAddr: string;
  logLevel: 'fatal' | 'error' | 'warn' | 'info' | 'debug' | 'trace' | 'silent';
  editorApiEnabled: boolean;
  assetsApiEnabled: boolean;
  jwtSecret: string;
  jwtExpiresIn: string;
  jwtIssuer: string;
  llm: {
    baseUrl: string;
    apiKey: string;
    model: string;
  };
  dashScope: {
    baseUrl: string;
    apiKey: string;
    imageModel: string;
    requestTimeoutMs: number;
  };
  smsAuth: {
    enabled: boolean;
    provider: 'aliyun' | 'mock';
    endpoint: string;
    accessKeyId: string;
    accessKeySecret: string;
    signName: string;
    templateCode: string;
    templateParamKey: string;
    countryCode: string;
    schemeName: string;
    codeLength: number;
    codeType: number;
    validTimeSeconds: number;
    intervalSeconds: number;
    duplicatePolicy: number;
    caseAuthPolicy: number;
    returnVerifyCode: boolean;
    mockVerifyCode: string;
    maxSendPerPhonePerDay: number;
    maxSendPerIpPerHour: number;
    maxVerifyFailuresPerPhonePerHour: number;
    maxVerifyFailuresPerIpPerHour: number;
    captchaTtlSeconds: number;
    captchaTriggerVerifyFailuresPerPhone: number;
    captchaTriggerVerifyFailuresPerIp: number;
    blockPhoneFailureThreshold: number;
    blockIpFailureThreshold: number;
    blockPhoneDurationMinutes: number;
    blockIpDurationMinutes: number;
  };
  wechatAuth: {
    enabled: boolean;
    provider: 'wechat' | 'mock';
    appId: string;
    appSecret: string;
    authorizeEndpoint: string;
    accessTokenEndpoint: string;
    userInfoEndpoint: string;
    callbackPath: string;
    defaultRedirectPath: string;
    mockUserId: string;
    mockUnionId: string;
    mockDisplayName: string;
    mockAvatarUrl: string;
  };
  authSession: {
    refreshCookieName: string;
    refreshSessionTtlDays: number;
    refreshCookieSecure: boolean;
    refreshCookieSameSite: 'Lax' | 'Strict' | 'None';
    refreshCookiePath: string;
  };
};

type LoadConfigOptions = {
  env?: NodeJS.ProcessEnv;
  projectRoot?: string;
};

function parseEnvContents(contents: string) {
  return contents
    .split(/\r?\n/u)
    .reduce<Record<string, string>>((envMap, rawLine) => {
      const line = rawLine.trim();
      if (!line || line.startsWith('#')) {
        return envMap;
      }

      const separatorIndex = line.indexOf('=');
      if (separatorIndex < 0) {
        return envMap;
      }

      const key = line.slice(0, separatorIndex).trim();
      let value = line.slice(separatorIndex + 1).trim();

      if (
        (value.startsWith('"') && value.endsWith('"')) ||
        (value.startsWith("'") && value.endsWith("'"))
      ) {
        value = value.slice(1, -1);
      }

      envMap[key] = value;
      return envMap;
    }, {});
}

function readEnvFile(filePath: string) {
  if (!fs.existsSync(filePath)) {
    return {};
  }

  return parseEnvContents(fs.readFileSync(filePath, 'utf8'));
}

function resolveDefaultProjectRoot() {
  const cwd = process.cwd();
  return path.basename(cwd) === 'server-node'
    ? path.resolve(cwd, '..')
    : cwd;
}

function readMergedEnv(
  exampleEnv: Record<string, string>,
  localEnv: Record<string, string>,
  processEnv: NodeJS.ProcessEnv,
) {
  return {
    ...exampleEnv,
    ...localEnv,
    ...processEnv,
  };
}

function hasOwnEnvKey(
  env: Record<string, string | undefined>,
  key: string,
) {
  return Object.prototype.hasOwnProperty.call(env, key);
}

function readBooleanOverride(
  env: Record<string, string | undefined>,
  overrideSources: Array<Record<string, string | undefined>>,
  key: string,
  fallback: boolean,
) {
  const hasOverride = overrideSources.some((source) => hasOwnEnvKey(source, key));
  if (!hasOverride) {
    return fallback;
  }

  return readBoolean(env, key, fallback);
}

function readString(
  env: Record<string, string | undefined>,
  key: string,
  fallback: string,
) {
  const value = env[key]?.trim();
  return value ? value : fallback;
}

function readPositiveInt(
  env: Record<string, string | undefined>,
  key: string,
  fallback: number,
) {
  const parsed = Number(env[key]);
  return Number.isFinite(parsed) && parsed > 0 ? Math.round(parsed) : fallback;
}

function readIntInRange(
  env: Record<string, string | undefined>,
  key: string,
  fallback: number,
  options: {
    min: number;
    max: number;
  },
) {
  const parsed = Number(env[key]);
  if (!Number.isFinite(parsed)) {
    return fallback;
  }

  const rounded = Math.round(parsed);
  if (rounded < options.min || rounded > options.max) {
    return fallback;
  }

  return rounded;
}

function readBoolean(
  env: Record<string, string | undefined>,
  key: string,
  fallback: boolean,
) {
  const value = env[key]?.trim().toLowerCase();
  if (!value) {
    return fallback;
  }
  if (value === '1' || value === 'true' || value === 'yes' || value === 'on') {
    return true;
  }
  if (value === '0' || value === 'false' || value === 'no' || value === 'off') {
    return false;
  }
  return fallback;
}

export function loadConfig(options: LoadConfigOptions = {}): AppConfig {
  const projectRoot = options.projectRoot ?? resolveDefaultProjectRoot();
  const exampleEnv = readEnvFile(path.join(projectRoot, '.env.example'));
  const localEnv = readEnvFile(path.join(projectRoot, '.env.local'));
  const processEnv = options.env ?? process.env;
  const env = readMergedEnv(exampleEnv, localEnv, processEnv);
  const logsDir = path.join(projectRoot, 'server-node', 'logs');
  const dataDir = path.join(projectRoot, 'server-node', 'data');
  const nodeEnv = readString(env, 'NODE_ENV', 'development');
  const defaultEditorApiEnabled = nodeEnv !== 'production';
  const editorApiEnabled = readBoolean(
    env,
    'EDITOR_API_ENABLED',
    defaultEditorApiEnabled,
  );
  const smsProviderFromEnv = readString(
    env,
    'SMS_AUTH_PROVIDER',
    nodeEnv === 'test' ? 'mock' : 'aliyun',
  ) as AppConfig['smsAuth']['provider'];
  const smsAccessKeyId = readString(env, 'ALIYUN_SMS_ACCESS_KEY_ID', '');
  const smsAccessKeySecret = readString(env, 'ALIYUN_SMS_ACCESS_KEY_SECRET', '');
  const smsProvider = smsProviderFromEnv;
  const defaultSmsEnabled =
    smsProvider === 'mock' ||
    Boolean(smsAccessKeyId && smsAccessKeySecret);
  const smsEnabled = readBooleanOverride(
    env,
    [localEnv, processEnv],
    'SMS_AUTH_ENABLED',
    defaultSmsEnabled,
  );
  const wechatProvider = readString(
    env,
    'WECHAT_AUTH_PROVIDER',
    nodeEnv === 'test' ? 'mock' : 'wechat',
  ) as AppConfig['wechatAuth']['provider'];
  const wechatAppId = readString(env, 'WECHAT_APP_ID', '');
  const wechatAppSecret = readString(env, 'WECHAT_APP_SECRET', '');
  const defaultWechatEnabled =
    wechatProvider === 'mock' || Boolean(wechatAppId && wechatAppSecret);
  const wechatEnabled = readBooleanOverride(
    env,
    [localEnv, processEnv],
    'WECHAT_AUTH_ENABLED',
    defaultWechatEnabled,
  );
  const refreshSameSite = readString(
    env,
    'AUTH_REFRESH_COOKIE_SAME_SITE',
    'Lax',
  );

  return {
    nodeEnv,
    projectRoot,
    publicDir: path.join(projectRoot, 'public'),
    logsDir,
    dataDir,
    rawEnv: Object.fromEntries(
      Object.entries(env).flatMap(([key, value]) =>
        typeof value === 'string' ? [[key, value]] : [],
      ),
    ),
    databaseUrl: readString(
      env,
      'DATABASE_URL',
      'postgresql://postgres:postgres@127.0.0.1:5432/genarrative',
    ),
    serverAddr: readString(env, 'NODE_SERVER_ADDR', ':8081'),
    logLevel: readString(env, 'LOG_LEVEL', 'info') as AppConfig['logLevel'],
    editorApiEnabled,
    assetsApiEnabled: readBoolean(
      env,
      'ASSETS_API_ENABLED',
      editorApiEnabled,
    ),
    jwtSecret: readString(env, 'JWT_SECRET', 'genarrative-dev-secret'),
    jwtExpiresIn: readString(env, 'JWT_EXPIRES_IN', '2h'),
    jwtIssuer: readString(env, 'JWT_ISSUER', 'genarrative-server-node'),
    llm: {
      baseUrl: readString(
        env,
        'LLM_BASE_URL',
        'https://ark.cn-beijing.volces.com/api/v3',
      ),
      apiKey:
        env.LLM_API_KEY?.trim() ||
        env.ARK_API_KEY?.trim() ||
        env.VITE_LLM_API_KEY?.trim() ||
        '',
      model: readString(
        env,
        'LLM_MODEL',
        readString(
          env,
          'VITE_LLM_MODEL',
          'doubao-1-5-pro-32k-character-250715',
        ),
      ),
    },
    dashScope: {
      baseUrl: readString(
        env,
        'DASHSCOPE_BASE_URL',
        'https://dashscope.aliyuncs.com/api/v1',
      ),
      apiKey: env.DASHSCOPE_API_KEY?.trim() || '',
      imageModel: readString(env, 'DASHSCOPE_IMAGE_MODEL', 'wan2.2-t2i-flash'),
      requestTimeoutMs: readPositiveInt(
        env,
        'DASHSCOPE_IMAGE_REQUEST_TIMEOUT_MS',
        150000,
      ),
    },
    smsAuth: {
      enabled: smsEnabled,
      provider: smsProvider,
      endpoint: readString(
        env,
        'ALIYUN_SMS_ENDPOINT',
        'dypnsapi.aliyuncs.com',
      ),
      accessKeyId: smsAccessKeyId,
      accessKeySecret: smsAccessKeySecret,
      signName: readString(
        env,
        'ALIYUN_SMS_SIGN_NAME',
        '速通互联验证码',
      ),
      templateCode: readString(env, 'ALIYUN_SMS_TEMPLATE_CODE', '100001'),
      templateParamKey: readString(
        env,
        'ALIYUN_SMS_TEMPLATE_PARAM_KEY',
        'code',
      ),
      countryCode: readString(env, 'ALIYUN_SMS_COUNTRY_CODE', '86'),
      schemeName: readString(env, 'ALIYUN_SMS_SCHEME_NAME', ''),
      codeLength: readIntInRange(env, 'ALIYUN_SMS_CODE_LENGTH', 6, {
        min: 4,
        max: 8,
      }),
      codeType: readIntInRange(env, 'ALIYUN_SMS_CODE_TYPE', 1, {
        min: 1,
        max: 7,
      }),
      validTimeSeconds: readPositiveInt(
        env,
        'ALIYUN_SMS_VALID_TIME_SECONDS',
        300,
      ),
      intervalSeconds: readPositiveInt(
        env,
        'ALIYUN_SMS_INTERVAL_SECONDS',
        60,
      ),
      duplicatePolicy: readIntInRange(
        env,
        'ALIYUN_SMS_DUPLICATE_POLICY',
        1,
        { min: 1, max: 2 },
      ),
      caseAuthPolicy: readIntInRange(
        env,
        'ALIYUN_SMS_CASE_AUTH_POLICY',
        1,
        { min: 1, max: 2 },
      ),
      returnVerifyCode: readBoolean(
        env,
        'ALIYUN_SMS_RETURN_VERIFY_CODE',
        false,
      ),
      mockVerifyCode: readString(env, 'SMS_AUTH_MOCK_VERIFY_CODE', '123456'),
      maxSendPerPhonePerDay: readPositiveInt(
        env,
        'SMS_AUTH_MAX_SEND_PER_PHONE_PER_DAY',
        20,
      ),
      maxSendPerIpPerHour: readPositiveInt(
        env,
        'SMS_AUTH_MAX_SEND_PER_IP_PER_HOUR',
        30,
      ),
      maxVerifyFailuresPerPhonePerHour: readPositiveInt(
        env,
        'SMS_AUTH_MAX_VERIFY_FAILURES_PER_PHONE_PER_HOUR',
        12,
      ),
      maxVerifyFailuresPerIpPerHour: readPositiveInt(
        env,
        'SMS_AUTH_MAX_VERIFY_FAILURES_PER_IP_PER_HOUR',
        24,
      ),
      captchaTtlSeconds: readPositiveInt(
        env,
        'SMS_AUTH_CAPTCHA_TTL_SECONDS',
        180,
      ),
      captchaTriggerVerifyFailuresPerPhone: readPositiveInt(
        env,
        'SMS_AUTH_CAPTCHA_TRIGGER_VERIFY_FAILURES_PER_PHONE',
        3,
      ),
      captchaTriggerVerifyFailuresPerIp: readPositiveInt(
        env,
        'SMS_AUTH_CAPTCHA_TRIGGER_VERIFY_FAILURES_PER_IP',
        5,
      ),
      blockPhoneFailureThreshold: readPositiveInt(
        env,
        'SMS_AUTH_BLOCK_PHONE_FAILURE_THRESHOLD',
        6,
      ),
      blockIpFailureThreshold: readPositiveInt(
        env,
        'SMS_AUTH_BLOCK_IP_FAILURE_THRESHOLD',
        10,
      ),
      blockPhoneDurationMinutes: readPositiveInt(
        env,
        'SMS_AUTH_BLOCK_PHONE_DURATION_MINUTES',
        30,
      ),
      blockIpDurationMinutes: readPositiveInt(
        env,
        'SMS_AUTH_BLOCK_IP_DURATION_MINUTES',
        30,
      ),
    },
    wechatAuth: {
      enabled: wechatEnabled,
      provider: wechatProvider,
      appId: wechatAppId,
      appSecret: wechatAppSecret,
      authorizeEndpoint: readString(
        env,
        'WECHAT_AUTHORIZE_ENDPOINT',
        'https://open.weixin.qq.com/connect/qrconnect',
      ),
      accessTokenEndpoint: readString(
        env,
        'WECHAT_ACCESS_TOKEN_ENDPOINT',
        'https://api.weixin.qq.com/sns/oauth2/access_token',
      ),
      userInfoEndpoint: readString(
        env,
        'WECHAT_USER_INFO_ENDPOINT',
        'https://api.weixin.qq.com/sns/userinfo',
      ),
      callbackPath: readString(
        env,
        'WECHAT_CALLBACK_PATH',
        '/api/auth/wechat/callback',
      ),
      defaultRedirectPath: readString(env, 'WECHAT_REDIRECT_PATH', '/'),
      mockUserId: readString(env, 'WECHAT_MOCK_USER_ID', 'mock_wechat_user'),
      mockUnionId: readString(env, 'WECHAT_MOCK_UNION_ID', 'mock_wechat_union'),
      mockDisplayName: readString(env, 'WECHAT_MOCK_DISPLAY_NAME', '微信旅人'),
      mockAvatarUrl: readString(env, 'WECHAT_MOCK_AVATAR_URL', ''),
    },
    authSession: {
      refreshCookieName: readString(
        env,
        'AUTH_REFRESH_COOKIE_NAME',
        'genarrative_refresh_session',
      ),
      refreshSessionTtlDays: readPositiveInt(
        env,
        'AUTH_REFRESH_SESSION_TTL_DAYS',
        30,
      ),
      refreshCookieSecure: readBoolean(
        env,
        'AUTH_REFRESH_COOKIE_SECURE',
        readString(env, 'NODE_ENV', 'development') === 'production',
      ),
      refreshCookieSameSite:
        refreshSameSite === 'None' || refreshSameSite === 'Strict'
          ? (refreshSameSite as AppConfig['authSession']['refreshCookieSameSite'])
          : 'Lax',
      refreshCookiePath: readString(
        env,
        'AUTH_REFRESH_COOKIE_PATH',
        '/api/auth',
      ),
    },
  };
}