/**
 * Created by zhangsong on 2018/8/9.
 */
import * as crypto from 'crypto';
import * as http from 'http';
import * as https from 'https';
import * as querystring from 'querystring';
import * as URL from 'url';
import Grant from './grant';
import Rotation from './rotation';
import Token from './token';

// 获取请求协议
const getProtocol = (opts): { request: any } => {
  return opts.protocol === 'https:' ? https : http;
};

const nodeify = (promise, cb) => {
  if (typeof cb !== 'function') {
    return promise;
  }
  return promise.then((res) => cb(null, res))
    .catch((err) => cb(err));
};

const createHandler = (manager) => (resolve, reject, json) => {
  try {
    resolve(manager.createGrant(json));
  } catch (err) {
    reject(err);
  }
};

const refreshHandler = (manager, grant) => (resolve, reject, json) => {
  manager.createGrant(json)
    .then((grants) => resolve(grants))
    .catch((err) => reject(err));
};

const validationHandler = (manager, token) => (resolve, reject, json) => {
  const data = JSON.parse(json);
  if (!data.active) {
    resolve(false);
  } else {
    resolve(token);
  }
};

const postOptions = (manager, path?: string) => {
  const realPath = path || '/protocol/openid-connect/token';
  const opts: http.ClientRequestArgs = URL.parse(manager.realmUrl + realPath);
  opts.headers = {
    'Content-Type': 'application/x-www-form-urlencoded',
    'X-Client': 'keycloak-nodejs-connect',
  };
  if (!manager.public) {
    opts.headers.Authorization = 'Basic ' + new Buffer(manager.clientId + ':' + manager.secret).toString('base64');
  }
  opts.method = 'POST';
  return opts;
};

const fetch = (manager, handler, options: http.ClientRequestArgs, params) => {
  return new Promise((resolve, reject) => {
    const data = (typeof params === 'string' ? params : querystring.stringify(params));
    options.headers['Content-Length'] = data.length;

    const req = getProtocol(options)
      .request(options, (response) => {
        if (response.statusCode < 200 || response.statusCode > 299) {
          return reject(response.statusCode + ':' + http.STATUS_CODES[response.statusCode]);
        }
        let json = '';
        response.on('data', (d) => (json += d.toString()));
        response.on('end', () => {
          handler(resolve, reject, json);
        });
      });
    req.write(data);
    req.on('error', reject);
    req.end();
  });
};

/**
 * Construct a grant manager.
 *
 * @param {Config} config Config object.
 *
 * @constructor
 */
class GrantManager {
  public realmUrl;
  public clientId;
  public secret;
  public publicKey;
  public public;
  public bearerOnly;
  public notBefore;
  public rotation;

  constructor(config) {
    this.realmUrl = config.realmUrl;
    this.clientId = config.clientId;
    this.secret = config.secret;
    this.publicKey = config.publicKey;
    this.public = config.public;
    this.bearerOnly = config.bearerOnly;
    this.notBefore = 0;
    this.rotation = new Rotation(config);
  }

  /**
   * Use the direct grant API to obtain a grant from Keycloak.
   *
   * The direct grant API must be enabled for the configured realm
   * for this method to work. This function ostensibly provides a
   * non-interactive, programatic way to login to a Keycloak realm.
   *
   * This method can either accept a callback as the last parameter
   * or return a promise.
   *
   * @param {String} username The username.
   * @param {String} password The cleartext password.
   * @param {Function} callback Optional callback, if not using promises.
   * @param {String} scopeParam 作用域
   */
  public obtainDirectly(username, password, callback, scopeParam?: string) {
    const params = {
      username,
      password,
      client_id: this.clientId,
      grant_type: 'password',
      scope: scopeParam || 'openid',
    };
    const handler = createHandler(this);
    const options = postOptions(this);
    return nodeify(fetch(this, handler, options, params), callback);
  }

  /**
   * Obtain a grant from a previous interactive login which results in a code.
   *
   * This is typically used by servers which receive the code through a
   * redirect_uri when sending a user to Keycloak for an interactive login.
   *
   * An optional session ID and host may be provided if there is desire for
   * Keycloak to be aware of this information.  They may be used by Keycloak
   * when session invalidation is triggered from the Keycloak console itself
   * during its postbacks to `/k_logout` on the server.
   *
   * This method returns or promise or may optionally take a callback function.
   *
   * @param {Object} ctx
   * @param {String} code The code from a successful login redirected from Keycloak.
   * @param {String} sessionId Optional opaque session-id.
   * @param {String} sessionHost Optional session host for targetted Keycloak console post-backs.
   * @param {Function} callback Optional callback, if not using promises.
   */
  public obtainFromCode(ctx, code, sessionId, sessionHost, callback) {
    const params = {
      code,
      client_session_state: sessionId,
      client_session_host: sessionHost,
      grant_type: 'authorization_code',
      client_id: this.clientId,
      redirect_uri: ctx.session ? ctx.session.auth_redirect_uri : {},
    };
    const handler = createHandler(this);
    const options = postOptions(this);

    return nodeify(fetch(this, handler, options, params), callback);
  }
  /**
   * Obtain a service account grant.
   * Client option 'Service Accounts Enabled' needs to be on.
   *
   * This method returns or promise or may optionally take a callback function.
   *
   * @param {Function} callback Optional callback, if not using promises.
   * @param {String} scopeParam
   */
  public obtainFromClientCredentials(callback, scopeParam?: string) {
    const params = {
      grant_type: 'client_credentials',
      scope: scopeParam || 'openid',
      client_id: this.clientId,
    };
    const handler = createHandler(this);
    const options = postOptions(this);

    return nodeify(fetch(this, handler, options, params), callback);
  }

  /**
   * Ensure that a grant is *fresh*, refreshing if required & possible.
   *
   * If the access_token is not expired, the grant is left untouched.
   *
   * If the access_token is expired, and a refresh_token is available,
   * the grant is refreshed, in place (no new object is created),
   * and returned.
   *
   * If the access_token is expired and no refresh_token is available,
   * an error is provided.
   *
   * The method may either return a promise or take an optional callback.
   *
   * @param {Grant} grant The grant object to ensure freshness of.
   * @param {Function} callback Optional callback if promises are not used.
   */
  public ensureFreshness(grant: Grant, callback?: () => void) {
    if (!grant.isExpired()) {
      return nodeify(Promise.resolve(grant), callback);
    }

    if (!grant.refreshToken) {
      return nodeify(Promise.reject(new Error('Unable to refresh without a refresh token')), callback);
    }

    if (grant.refreshToken.isExpired()) {
      return nodeify(Promise.reject(new Error('Unable to refresh with expired refresh token')), callback);
    }

    const params = {
      grant_type: 'refresh_token',
      refresh_token: grant.refreshToken.token,
      client_id: this.clientId,
    };
    const handler = refreshHandler(this, grant);
    const options = postOptions(this);

    return nodeify(fetch(this, handler, options, params), callback);
  }

  /**
   * Perform live validation of an `access_token` against the Keycloak server.
   *
   * @param {Token|String} token The token to validate.
   * @param {Function} callback Callback function if not using promises.
   *
   * @return {boolean} `false` if the token is invalid, or the same token if valid.
   */
  public validateAccessToken(token, callback) {
    let t = token;
    if (typeof token === 'object') {
      t = token.token;
    }
    const params = {
      token: t,
      client_secret: this.secret,
      client_id: this.clientId,
    };
    const options = postOptions(this, '/protocol/openid-connect/token/introspect');
    const handler = validationHandler(this, token);

    return nodeify(fetch(this, handler, options, params), callback);
  }
  public userInfo(token, callback) {
    const url = this.realmUrl + '/protocol/openid-connect/userinfo';
    const options: http.ClientRequestArgs = URL.parse(url);
    options.method = 'GET';

    let t = token;
    if (typeof token === 'object') {
      t = token.token;
    }

    options.headers = {
      'Authorization': 'Bearer ' + t,
      'Accept': 'application/json',
      'X-Client': 'keycloak-nodejs-connect',
    };

    const promise = new Promise((resolve, reject) => {
      const req = getProtocol(options)
        .request(options, (response) => {
          if (response.statusCode < 200 || response.statusCode >= 300) {
            return reject('Error fetching account');
          }
          let json = '';
          response.on('data', (d) => (json += d.toString()));
          response.on('end', () => {
            const data = JSON.parse(json);
            if (data.error) {
              reject(data);
            } else {
              resolve(data);
            }
          });
        });
      req.on('error', reject);
      req.end();
    });

    return nodeify(promise, callback);
  }

  public getAccount() {
    console.error('GrantManager#getAccount is deprecated. See GrantManager#userInfo');
    return this.userInfo.apply(this, arguments);
  }

  public isGrantRefreshable(grant: Grant) {
    return !this.bearerOnly && (grant && grant.refreshToken);
  }

  /**
   * Create a `Grant` object from a string of JSON data.
   *
   * This method creates the `Grant` object, including
   * the `access_token`, `refresh_token` and `id_token`
   * if available, and validates each for expiration and
   * against the known public-key of the server.
   *
   * @param {String} rawData The raw JSON string received from the Keycloak server or from a client.
   * @return {Promise} A promise reoslving a grant.
   */
  public createGrant(rawData) {
    let grantData = rawData;
    if (typeof rawData !== 'object') {
      grantData = JSON.parse(grantData);
    }

    const grant: Grant = new Grant({
      access_token: (grantData.access_token ? new Token(grantData.access_token, this.clientId) : undefined),
      refresh_token: (grantData.refresh_token ? new Token(grantData.refresh_token) : undefined),
      id_token: (grantData.id_token ? new Token(grantData.id_token) : undefined),
      expires_in: grantData.expires_in,
      token_type: grantData.token_type,
      __raw: rawData,
    });

    if (this.isGrantRefreshable(grant)) {
      return new Promise((resolve, reject) => {
        this.ensureFreshness(grant)
          .then((g) => this.validateGrant(g))
          .then((g) => resolve(g))
          .catch((err) => reject(err));
      });
    } else {
      return this.validateGrant(grant);
    }
  }

  public validateGrant(grant: Grant) {
    const self = this;
    const validateGrantToken = (grants: Grant, tokenName) => {
      return new Promise((resolve, reject) => {
        // check the access token
        this.validateToken(grant[tokenName])
          .then((token) => {
            grants[tokenName] = token;
            resolve(true);
          })
          .catch((err) => {
            reject(new Error('Grant validation failed. Reason: ' + err.message));
          });
      });
    };
    return new Promise((resolve, reject) => {
      const promises = [];
      promises.push(validateGrantToken(grant, 'accessToken'));
      if (!self.bearerOnly) {
        if (grant.refreshToken) {
          promises.push(validateGrantToken(grant, 'refreshToken'));
        }
        if (grant.idToken) {
          promises.push(validateGrantToken(grant, 'idToken'));
        }
      }
      Promise.all(promises)
        .then(() => {
          resolve(grant);
        })
        .catch((err) => {
          reject(new Error(err.message));
        });
    });
  }

  /**
   * Validate a token.
   *
   * This method accepts a token, and returns a promise
   *
   * If the token is valid the promise will be resolved with the token
   *
   * If any of the following errors are seen the promise will resolve with undefined:
   *
   * - The token was undefined in the first place.
   * - The token is expired.
   * - The token is not expired, but issued before the current *not before* timestamp.
   * - The token signature does not verify against the known realm public-key.
   *
   * @return {Promise} That resolve a token
   */
  public validateToken(token) {
    return new Promise((resolve, reject) => {
      if (!token) {
        reject(new Error('invalid token (missing)'));
      } else if (token.isExpired()) {
        reject(new Error('invalid token (expired)'));
      } else if (!token.signed) {
        reject(new Error('invalid token (not signed)'));
      } else if (token.content.iat < this.notBefore) {
        reject(new Error('invalid token (future dated)'));
      } else if (token.content.iss !== this.realmUrl) {
        reject(new Error('invalid token (wrong ISS)'));
      } else {
        const verify = crypto.createVerify('RSA-SHA256');
        // if public key has been supplied use it to validate token
        if (this.publicKey) {
          try {
            verify.update(token.signed);
            if (!verify.verify(this.publicKey, token.signature, 'base64')) {
              reject(new Error('invalid token (signature)'));
            } else {
              resolve(token);
            }
          } catch (err) {
            reject(new Error('Misconfigured parameters while validating token. Check your keycloak.json file!'));
          }
        } else {
          // retrieve public KEY and use it to validate token
          this.rotation.getJWK(token.header.kid)
            .then((key) => {
              verify.update(token.signed);
              if (!verify.verify(key, token.signature)) {
                reject(new Error('invalid token (public key signature)'));
              } else {
                resolve(token);
              }
            })
            .catch((err) => {
              reject(new Error('failed to load public key to verify token. Reason: ' + err.message));
            });
        }
      }
    });
  }
}

export default GrantManager;