class IscController < ApplicationController

  protected

  def isc_index(model)
    build_singular_class_name_hash(model)

    @start_row = Integer(params[:_startRow])
    @end_row = Integer(params[:_endRow])
    scoped_model = build_scoped_model(model)
    @total_rows =  scoped_model.count
    @end_row = @total_rows - 1 if @end_row >= @total_rows

    case params[:_sortBy]
    when /^-(.+)/ then order = "#{$1} DESC"
    when /(.+)/   then order = "#{$1}"
                  else order = "id"
    end
    instances = scoped_model.scoped(:offset => @start_row,
                                    :limit => (@end_row - @start_row + 1),
                                    :order => order)

    respond_to do |format|
      format.xml  { render :xml => (instances.any? ? instances : empty_xml(model.table_name)) }
      format.json { render :json => isc_response(instances), :callback => params[:_callback] }
    end
  end

  def isc_create(model)
    build_singular_class_name_hash(model)
    case params[:_operationType]
    when 'add'    then # Create!
    when 'update' then isc_update(model); return
    when 'remove' then isc_destroy(model); return
    else raise "Operazione sconosciuta."
    end

    instance = model.new(params[:singular_class_name])
    if instance.save
      respond_to do |format|
        format.xml  { render :xml => instance, :status => :created, :location => instance }
        format.json { render :json => isc_response(instance), :status => :created, :location => instance, :callback => params[:_callback] }
      end
    else
      respond_to do |format|
        format.xml  { render :xml => instance, :status => :bad_request }
        format.json { render :json => isc_response(instance, -4), :status => :bad_request, :callback => params[:_callback] }
      end
    end
  end

  def isc_update(model)
    instance = model.find(params[:id])
    instance.attributes = params[:"#{model.name.underscore}"]
    if instance.save
      respond_to do |format|
        format.xml  { render :xml => instance }
        format.json { render :json => isc_response(instance), :callback => params[:_callback] }
      end
    else
      respond_to do |format|
        format.xml  { render :xml => instance, :status => :bad_request }
        format.json { render :json => isc_response(instance, -4), :status => :bad_request, :callback => params[:_callback] }
      end
    end
  end

  def isc_destroy(model)
    instance = model.find(params[:id])
    instance.destroy
    respond_to do |format|
      format.xml  { render :xml => instance }
      format.json { render :json => isc_response(instance), :callback => params[:_callback] }
    end
  end

  def isc_response(data, status = 0)
    meta_data = { :status => status, :data => data }
    meta_data[:totalRows] = @total_rows if @total_rows
    meta_data[:startRow] = @start_row if @start_row
    meta_data[:endRow] = @end_row if @end_row
    logger.debug meta_data.except(:data).inspect
    { :response => meta_data }
  end

  def empty_xml(root)
    "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<#{root}/>"
  end

  def build_singular_class_name_hash(model)
    params[:singular_class_name] = params.reject {|k, v| !model.column_names.include?(k) }
  end

  def build_scoped_model(model)
    scoped_model = model.scoped({})
    params[:singular_class_name].each do |k, v|
      scoped_model = if [:string, :text].include?(model.columns_hash[k].type) &&
                        params[:_textMatchStyle] == 'substring'
                       scoped_model.scoped(:conditions => [ "#{k} LIKE ?", "%#{v}%" ])
                     else
                       scoped_model.scoped(:conditions => [ "#{k} = ?", v ])
                     end
    end
    scoped_model
  end
end