require "exceptions/invalid_record"
require "exceptions/invalid_command"
require "db/mongo/models/mongo_model"

module Devops
  module Model
    class User < MongoModel

      ROOT_USER_NAME = 'root'
      ROOT_PASSWORD = ''

      PRIVILEGES = ["r", "w", "x"]
      PRIVILEGES_REGEX = /^r?w?x?$/

      attr_accessor :id, :password, :privileges, :email
      types :id => {:type => String, :empty => false},
            :email => {:type => String, :empty => false},
            :password => {:type => String, :empty => true}

      def initialize p={}
        self.id = p['username']
        self.email = p['email']
        self.password = p['password']
        self.privileges = p["privileges"] || self.default_privileges
      end

      def all_privileges
        privileges_with_value("rwx")
      end

      def default_privileges
        privileges_with_value("r", "user" => "")
      end

      def grant cmd, priv=''
        if !priv.empty? and PRIVILEGES_REGEX.match(priv).to_s.empty?
          raise InvalidCommand.new "Invalid privileges '#{priv}'. Available values are '#{PRIVILEGES.join("', '")}'"
        end
        raise InvalidPrivileges.new "Can't grant privileges to root" if self.id == ROOT_USER_NAME

        case cmd
        when "all"
          self.privileges.each_key do |key|
            self.privileges[key] = priv
          end
        when ""
          self.privileges = self.default_privileges
        else
          raise InvalidCommand.new "Unsupported command #{cmd}" unless self.all_privileges.include?(cmd)
          self.privileges[cmd] = priv
        end
      end

      def self.build_from_bson s
        user = User.new s
        user.id = s["_id"]
        user
      end

      def self.create_from_json json
        User.new( JSON.parse(json) )
      end

      def to_hash_without_id
        o = {
          "email" => self.email,
          "password" => self.password,
          "privileges" => self.privileges
        }
        o
      end

      def check_privileges cmd, required_privelege
        unless PRIVILEGES.include?(required_privelege)
          raise InvalidPrivileges.new("Access internal problem with privilege '#{required_privelege}'")
        end
        # can?(cmd, required_privelege)
        unless can?(cmd, required_privelege)
          raise InvalidPrivileges.new("Access denied for '#{id}'")
        end
      end

      def self.create_root
        root = User.new({'username' => ROOT_USER_NAME, 'password' => ROOT_PASSWORD})
        root.privileges = root.all_privileges
        root.email = "#{ROOT_USER_NAME}@host"
        root
      end

      private

      def can?(command, privilege)
        p = self.privileges[command] || []
        p.include?(privilege)
      end

      def privileges_with_value value, options={}
        privileges = {}
        [
          'flavor',
          'group',
          'image',
          'project',
          'server',
          'key',
          'user',
          'filter',
          'network',
          'provider',
          'script',
          'templates',
          'stack_template',
          'stack'
        ].each { |t| privileges.store(t, value) }

        privileges.merge(options)
      end

    end
  end
end