module Mondrian
  module OLAP
    class Connection
      def self.create(params)
        connection = new(params)
        connection.connect
        connection
      end

      attr_reader :raw_connection, :raw_catalog, :raw_schema

      def initialize(params={})
        @params = params
        @driver = params[:driver]
        @connected = false
        @raw_connection = nil
      end

      def connect
        Error.wrap_native_exception do
          # hack to call private constructor of MondrianOlap4jDriver
          # to avoid using DriverManager which fails to load JDBC drivers
          # because of not seeing JRuby required jar files
          cons = Java::MondrianOlap4j::MondrianOlap4jDriver.java_class.declared_constructor
          cons.accessible = true
          driver = cons.new_instance.to_java

          props = java.util.Properties.new
          props.setProperty('JdbcUser', @params[:username]) if @params[:username]
          props.setProperty('JdbcPassword', @params[:password]) if @params[:password]

          conn_string = connection_string

          # TODO: removed workaround for Mondrian ServiceDiscovery
          # need to check if database dialects are always loaded by ServiceDiscovery detected class loader
          @raw_jdbc_connection = driver.connect(conn_string, props)

          @raw_connection = @raw_jdbc_connection.unwrap(Java::OrgOlap4j::OlapConnection.java_class)
          @raw_catalog = @raw_connection.getOlapCatalog
          # currently it is assumed that there is just one schema per connection catalog
          @raw_schema = @raw_catalog.getSchemas.first
          @connected = true
          true
        end
      end

      def connected?
        @connected
      end

      def close
        @raw_connection.close
        @connected = false
        @raw_connection = @raw_jdbc_connection = nil
        true
      end

      def execute(query_string)
        Error.wrap_native_exception do
          statement = @raw_connection.prepareOlapStatement(query_string)
          Result.new(self, statement.executeQuery())
        end
      end

      def from(cube_name)
        Query.from(self, cube_name)
      end

      def cube_names
        @raw_schema.getCubes.map{|c| c.getName}
      end

      def cube(name)
        Cube.get(self, name)
      end

      # Will affect only the next created connection. If it is necessary to clear all schema cache then
      # flush_schema_cache should be called, then close and then new connection should be created.
      def flush_schema_cache
        unwrapped_connection = @raw_connection.unwrap(Java::MondrianOlap::Connection.java_class)
        raw_cache_control = unwrapped_connection.getCacheControl(nil)
        raw_cache_control.flushSchemaCache
      end

      def available_role_names
        @raw_connection.getAvailableRoleNames.to_a
      end

      def role_name
        @raw_connection.getRoleName
      end

      def role_names
        @raw_connection.getRoleNames.to_a
      end

      def role_name=(name)
        Error.wrap_native_exception do
          @raw_connection.setRoleName(name)
        end
      end

      def role_names=(names)
        Error.wrap_native_exception do
          @raw_connection.setRoleNames(Array(names))
        end
      end

      private

      def connection_string
        string = "jdbc:mondrian:Jdbc=#{quote_string(jdbc_uri)};JdbcDrivers=#{jdbc_driver};"
        # by default use content checksum to reload schema when catalog has changed
        string << "UseContentChecksum=true;" unless @params[:use_content_checksum] == false
        if role = @params[:role] || @params[:roles]
          roles = Array(role).map{|r| r && r.to_s.gsub(',', ',,')}.compact
          string << "Role=#{quote_string(roles.join(','))};" unless roles.empty?
        end
        string << (@params[:catalog] ? "Catalog=#{catalog_uri}" : "CatalogContent=#{quote_string(catalog_content)}")
      end

      def jdbc_uri
        case @driver
        when 'mysql', 'postgresql'
          uri = "jdbc:#{@driver}://#{@params[:host]}#{@params[:port] && ":#{@params[:port]}"}/#{@params[:database]}"
          uri << "?useUnicode=yes&characterEncoding=UTF-8" if @driver == 'mysql'
          uri
        when 'oracle'
          # connection using TNS alias
          if @params[:database] && !@params[:host] && !@params[:url] && ENV['TNS_ADMIN']
            "jdbc:oracle:thin:@#{@params[:database]}"
          else
            @params[:url] ||
            "jdbc:oracle:thin:@#{@params[:host] || 'localhost'}:#{@params[:port] || 1521}:#{@params[:database]}"
          end
        when 'luciddb'
          uri = "jdbc:luciddb:http://#{@params[:host]}#{@params[:port] && ":#{@params[:port]}"}"
          uri << ";schema=#{@params[:database_schema]}" if @params[:database_schema]
          uri
        when 'mssql'
          uri = "jdbc:jtds:sqlserver://#{@params[:host]}#{@params[:port] && ":#{@params[:port]}"}/#{@params[:database]}"
          uri << ";instance=#{@params[:instance]}" if @params[:instance]
          uri << ";domain=#{@params[:domain]}" if @params[:domain]
          uri << ";appname=#{@params[:appname]}" if @params[:appname]
          uri
        when 'sqlserver'
          uri = "jdbc:sqlserver://#{@params[:host]}#{@params[:port] && ":#{@params[:port]}"}"
          uri << ";databaseName=#{@params[:database]}" if @params[:database]
          uri << ";integratedSecurity=#{@params[:integrated_security]}" if @params[:integrated_security]
          uri << ";applicationName=#{@params[:application_name]}" if @params[:application_name]
          uri << ";instanceName=#{@params[:instance_name]}" if @params[:instance_name]
          uri
        else
          raise ArgumentError, 'unknown JDBC driver'
        end
      end

      def jdbc_driver
        case @driver
        when 'mysql'
          'com.mysql.jdbc.Driver'
        when 'postgresql'
          'org.postgresql.Driver'
        when 'oracle'
          'oracle.jdbc.OracleDriver'
        when 'luciddb'
          'org.luciddb.jdbc.LucidDbClientDriver'
        when 'mssql'
          'net.sourceforge.jtds.jdbc.Driver'
        when 'sqlserver'
          'com.microsoft.sqlserver.jdbc.SQLServerDriver'
        else
          raise ArgumentError, 'unknown JDBC driver'
        end
      end

      def catalog_uri
        if @params[:catalog]
          "file://#{File.expand_path(@params[:catalog])}"
        else
          raise ArgumentError, 'missing catalog source'
        end
      end

      def catalog_content
        if @params[:catalog_content]
          @params[:catalog_content]
        elsif @params[:schema]
          @params[:schema].to_xml(:driver => @driver)
        else
          raise ArgumentError, "Specify catalog with :catalog, :catalog_content or :schema option"
        end
      end

      def quote_string(string)
        "'#{string.gsub("'","''")}'"
      end

    end
  end
end