// Dynamic generation of JWT Secret if not exist (different for each environnment)
var fs = require('fs');
var env = process.env.NODE_ENV || 'dev';
var config = require('../config/config.json');

if (!config[env].jwtSecret) {
  config[env].jwtSecret = require('crypto').randomBytes(32).toString('hex');
  var configString = JSON.stringify(config, null, 4);
  fs.writeFileSync(`${__basedir}/config/config.json`, configString);
}
if (!config[env].jwtRefreshSecret) {
  config[env].jwtRefreshSecret = require('crypto')
    .randomBytes(32)
    .toString('hex');
  var configString = JSON.stringify(config, null, 4);
  fs.writeFileSync(`${__basedir}/config/config.json`, configString);
}

var jwtSecret = config[env].jwtSecret;
exports.jwtSecret = jwtSecret;

var jwtRefreshSecret = config[env].jwtRefreshSecret;
exports.jwtRefreshSecret = jwtRefreshSecret;

/*  ROLES LOGIC

    role_name: {
        allows: [],
        inherits: []
    }
    allows: allowed permissions to access | use * for all
    inherits: inherits other users "allows"
*/

const builtInRoles = {
  user: {
    allows: [
      // Audits
      'audits:create',
      'audits:read',
      'audits:update',
      'audits:delete',
      // Images
      'images:create',
      'images:read',
      // Clients
      'clients:create',
      'clients:read',
      'clients:update',
      'clients:delete',
      // Companies
      'companies:create',
      'companies:read',
      'companies:update',
      'companies:delete',
      // Languages
      'languages:read',
      // Audit Types
      'audit-types:read',
      // Vulnerability Types
      'vulnerability-types:read',
      // Vulnerability Categories
      'vulnerability-categories:read',
      // Sections Data
      'sections:read',
      // Templates
      'templates:read',
      // Users
      'users:read',
      // Roles
      'roles:read',
      // Vulnerabilities
      'vulnerabilities:read',
      'vulnerability-updates:create',
      // Custom Fields
      'custom-fields:read',
      // Settings
      'settings:read-public',
      // Classify
      'classify:all',
      // Check CWE Update
      'check-update:all',
      // Update CWE Model
      'update-model:all',
    ],
  },
  admin: {
    allows: '*',
  },
};

try {
  var customRoles = require('../config/roles.json');
} catch (error) {
  var customRoles = [];
}
var roles = { ...customRoles, ...builtInRoles };

class ACL {
  constructor(roles) {
    if (typeof roles !== 'object') {
      throw new TypeError('Expected an object as input');
    }
    this.roles = roles;
  }

  isAllowed(role, permission) {
    // Check if role exists
    if (!this.roles[role] && !this.roles['user']) {
      return false;
    }

    let $role = this.roles[role] || this.roles['user']; // Default to user role in case of inexistant role
    // Check if role is allowed with permission
    if (
      $role.allows &&
      ($role.allows === '*' || $role.allows.indexOf(permission) !== -1)
    ) {
      return true;
    }

    // Check if there is inheritance
    if (!$role.inherits || $role.inherits.length < 1) {
      return false;
    }

    // Recursive check childs until true or false
    return $role.inherits.some(role => this.isAllowed(role, permission));
  }

  hasPermission(permission) {
    var Response = require('./httpResponse');
    var jwt = require('jsonwebtoken');

    return (req, res, next) => {
      if (!req.cookies['token']) {
        Response.Unauthorized(res, 'No token provided');
        return;
      }

      var cookie = req.cookies['token'].split(' ');
      if (cookie.length !== 2 || cookie[0] !== 'JWT') {
        Response.Unauthorized(res, 'Bad token type');
        return;
      }

      var token = cookie[1];
      jwt.verify(token, jwtSecret, (err, decoded) => {
        if (err) {
          if (err.name === 'TokenExpiredError')
            Response.Unauthorized(res, 'Expired token');
          else Response.Unauthorized(res, 'Invalid token');
          return;
        }

        if (
          permission === 'validtoken' ||
          this.isAllowed(decoded.role, permission)
        ) {
          req.decodedToken = decoded;
          return next();
        } else {
          Response.Forbidden(res, 'Insufficient privileges');
          return;
        }
      });
    };
  }

  buildRoles(role) {
    var currentRole = this.roles[role] || this.roles['user']; // Default to user role in case of inexistant role

    var result = currentRole.allows || [];

    if (currentRole.inherits) {
      currentRole.inherits.forEach(element => {
        result = [...new Set([...result, ...this.buildRoles(element)])];
      });
    }

    return result;
  }

  getRoles(role) {
    var result = this.buildRoles(role);

    if (result.includes('*')) return '*';

    return result;
  }
}

exports.acl = new ACL(roles);