require 'associations/hyper_has_many_association_extension'
require 'associations/hyper_has_and_belongs_to_many_association_extension'

module ActiveRecord 
  class Base
    def self.inherited(child) #:nodoc:
      return if child == ActiveRecord::HyperBase

      @@subclasses[self] ||= []
      @@subclasses[self] << child
      super
    end
  end

  class HyperBase < Base
    # All records must include a ROW key
    validates_presence_of :ROW

    def initialize(attrs={})
      super(attrs)
      self.ROW = attrs[:ROW] if attrs[:ROW]
    end

    # Instance Methods
    def update
      write_quoted_attributes(attributes_with_quotes(false, false))
      true
    end

    def create
      write_quoted_attributes(attributes_with_quotes(false, false))
      @new_record = false
      self.attributes[self.class.primary_key]
    end

    def destroy
      # check for associations and delete association cells as necessary
      for reflection_key in self.class.reflections.keys
        case self.class.reflections[reflection_key].macro
          when :has_and_belongs_to_many
            # remove all the association cells from the associated objects
            cells_to_delete = []
 
            for row_key in self.send(self.class.reflections[reflection_key].association_foreign_key).keys
              cells_to_delete << [row_key, self.class.connection.qualified_column_name(self.class.reflections[reflection_key].primary_key_name, self.ROW)]
            end

            self.delete_cells(cells_to_delete, self.class.reflections[reflection_key].klass.table_name)
        end
      end

      self.class.connection.delete_rows(self.class.table_name, [self.ROW])
    end

    def increment(attribute, by=1)
      self[attribute] = self[attribute].to_i
      self[attribute] += by
      self
    end

    def increment!(attribute, by=1)
      increment(attribute, by)
      self.save
    end

    def decrement(attribute, by=1)
      increment(attribute, -by)
    end

    def decrement!(attribute, by=1)
      increment!(attribute, -by)
    end

    # Returns a copy of the attributes hash where all the values have been 
    # safely quoted for insertion.  Translated qualified columns from a Hash
    # value in Ruby to a flat list of attributes.
    def attributes_with_quotes(include_primary_key = true, include_readonly_attributes = true)
      quoted = attributes.inject({}) do |quoted, (name, value)|
        if column = column_for_attribute(name)
          if column.is_a?(ConnectionAdapters::QualifiedColumn) and value.is_a?(Hash)
            value.keys.each{|k| 
              quoted[self.class.connection.qualified_column_name(column.name, k)] = quote_value(value[k], column)
            }
          else
            quoted[name] = quote_value(value, column) unless !include_primary_key && column.primary
          end
        end
        quoted
      end
      include_readonly_attributes ? quoted : remove_readonly_attributes(quoted)
    end

    def quoted_attributes_to_cells(quoted_attrs, table=self.class.table_name)
      cells = []
      pk = self.attributes[self.class.primary_key]
      quoted_attrs.keys.each{|key| 
        cells << [pk, connection.hypertable_column_name(key, table), quoted_attrs[key].to_s]
      }
      cells
    end

    def write_quoted_attributes(quoted_attrs, table=self.class.table_name)
      write_cells(quoted_attributes_to_cells(quoted_attrs, table))
    end

    # Write an array of cells to Hypertable
    def write_cells(cells, table=self.class.table_name)
      connection.write_cells(table, cells)
    end

    # Delete an array of cells from Hypertable
    # cells is an array of cell keys [["row", "column"], ...] 
    def delete_cells(cells, table=self.class.table_name)
      connection.delete_cells(table, cells)
    end

    # Delete an array of rows from Hypertable
    # rows is an array of row keys ["row1", "row2", ...] 
    def delete_rows(row_keys, table=self.class.table_name)
      connection.delete_rows(table, cells)
    end

    # Class Methods
    class << self
      def abstract_class?
        self == ActiveRecord::HyperBase
      end

      def exists?(id_or_conditions)
        case id_or_conditions
          when Fixnum, String
            !find(:first, :row_keys => [id_or_conditions]).nil?
          when Hash
            !find(:first, :conditions => id_or_conditions).nil?
          else
            raise "only Fixnum, String and Hash arguments supported"
        end
      end

      def delete(*ids)
        self.connection.delete_rows(table_name, ids.flatten)
      end

      def find(*args)
        options = args.extract_options!

        case args.first
          when :first then find_initial(options)
          when :all   then find_by_options(options)
          else             find_from_ids(args, options)
        end
      end

      def find_initial(options)
        options.update(:limit => 1)
        find_by_options(options).first
      end

      def find_by_options(options)
        options[:table_name] ||= table_name
        options[:columns] ||= columns

        # Don't request the ROW key explicitly, it always comes back
        options[:select] ||= qualified_column_names_without_row_key.map{|c| connection.hypertable_column_name(c, table_name)}

        rows = Hash.new{|h,k| h[k] = []}
        for cell in connection.execute_with_options(options)
          rows[cell.row_key] << cell
        end

        rows.values.map{|row|
          row_with_mapped_column_names = {
            'ROW' => row.first.row_key
          }

          for cell in row
            if cell.column_qualifier
              family = connection.rubify_column_name(cell.column_family)
              row_with_mapped_column_names[family] ||= {}
              row_with_mapped_column_names[family][cell.column_qualifier] = cell.value
            else
              family = connection.rubify_column_name(cell.column_family)
              row_with_mapped_column_names[family] = cell.value
            end
          end

          # make sure that the resulting object has attributes for all
          # columns - even ones that aren't in the response (due to limited
          # select)
          for column in column_families_without_row_key
            if !row_with_mapped_column_names.has_key?(column.name)
              if column.is_a?(ActiveRecord::ConnectionAdapters::QualifiedColumn)
                row_with_mapped_column_names[column.name] = {}
              else
                row_with_mapped_column_names[column.name] = nil
              end
            end
          end

          instantiate(row_with_mapped_column_names)
        }
      end

      def find_from_ids(ids, options)
        expects_array = ids.first.kind_of?(Array)
        return ids.first if expects_array && ids.first.empty?
        ids = ids.flatten.compact.uniq

        case ids.size
          when 0
            raise RecordNotFound, "Couldn't find #{name} without an ID"
          when 1
            result = find_one(ids.first, options)
            expects_array ? [ result ] : result
          else
            find_some(ids, options)
        end
      end

      def find_one(id, options)
        return nil if id.blank?

        options[:row_keys] = [id.to_s]

        if result = find_initial(options)
          result
        else
          raise ::ActiveRecord::RecordNotFound, "Couldn't find #{name} with ID=#{id}"
        end
      end

      def find_some(ids, options)
        options[:row_keys] = [ids.map{|i| i.to_s}]
        find_by_options(options)
      end

      def table_exists?(name=table_name)
        connection.tables.include?(name)
      end

      def drop_table
        connection.drop_table(table_name) if table_exists?
      end

      # Returns the primary key field for a table.  In Hypertable, a single
      # row key exists for each row.  The row key is referred to as ROW
      # in HQL, so we'll refer to it the same way here.
      def primary_key
        "ROW"
      end

      # Returns array of column objects for table associated with this class.
      def columns
        unless @columns
          @columns = connection.columns(table_name, "#{name} Columns")
          @qualified_columns ||= []
          @qualified_columns.each{|qc| 
            # Remove the column family from the column list
            @columns = @columns.reject{|c| c.name == qc[:column_name].to_s}
            connection.remove_column_from_name_map(table_name, qc[:column_name].to_s)

            # Add the new qualified column family to the column list
            @columns << connection.add_qualified_column(table_name, qc[:column_name].to_s, qc[:qualifiers], {}.clone)
          }
          @columns.each {|column| column.primary = column.name == primary_key}
        end
        @columns
      end

      def quoted_column_names(attributes=attributes_with_quotes)
        attributes.keys.collect do |column_name|
          self.class.connection.quote_column_name_for_table(column_name, table_name)
        end
      end

      def column_families_without_row_key
        columns[1,columns.length]
      end

      def qualified_column_names_without_row_key
        cols = column_families_without_row_key.map{|c| c.name}
        for qc in @qualified_columns
          cols.delete(qc[:column_name].to_s)
          for qualifier in qc[:qualifiers]
            cols << "#{qc[:column_name]}:#{qualifier}"
          end
        end
        cols
      end

      # qualified_column :misc, :qualifiers => [:name, :url]
      attr_accessor :qualified_columns
      def qualified_column(*attrs)
        @qualified_columns ||= []
        name = attrs.shift

        qualifiers = attrs.shift
        qualifiers = qualifiers.symbolize_keys[:qualifiers] if qualifiers
        @qualified_columns << {
          :column_name => name,
          :qualifiers => qualifiers || []
        }
      end
    end
  end
end