require 'caruby/util/collection'
require 'caruby/import/java'
require 'caruby/domain/java_attribute_metadata'
require 'caruby/domain/resource_attributes'
require 'caruby/domain/resource_introspection'
require 'caruby/domain/resource_dependency'

module CaRuby
  # Exception raised if a meta-data setting is missing or invalid.
  class MetadataError < RuntimeError; end
  
  # Adds introspected metadata to a Class.
  module ResourceMetadata
    include ResourceIntrospection, ResourceDependency, ResourceAttributes

    attr_reader :domain_module

    # Associates meta-data with a Resource class. When a Resource class is added to a ResourceModule,
    # the ResourceModule extends the Resource class with ResourceMetadata and calls this
    # {#add_metadata} method with itself as the mod argument. The ResourceModule is accessed
    # by the {#domain_module} method.
    def add_metadata(mod)
      @domain_module = mod
      init_attributes # in ResourceAttributes
      introspect # in ResourceIntrospection
    end

    # @return the domain type for attribute, or nil if attribute is not a domain attribute
    def domain_type(attribute)
      attr_md = attribute_metadata(attribute)
      attr_md.type if attr_md.domain?
    end

   # Prints this classifier's content to the log.
    def pretty_print(q)
      # the Java property descriptors
      property_descriptors = java_attributes.wrap { |attr| attribute_metadata(attr).property_descriptor }
      # build a map of relevant display label => attributes
      prop_printer = property_descriptors.wrap { |pd| PROP_DESC_PRINTER.wrap(pd) }
      prop_syms = property_descriptors.map { |pd| pd.name.to_sym }.to_set
      aliases = @alias_std_attr_map.keys - attributes.to_a - prop_syms
      alias_attr_hash = aliases.to_compact_hash { |aliaz| @alias_std_attr_map[aliaz] }
      dependents_printer = dependent_attributes.wrap { |attr| DEPENDENT_ATTR_PRINTER.wrap(attribute_metadata(attr)) }
      owner_printer = owners.wrap { |type| TYPE_PRINTER.wrap(type) }
      inverses = @attributes.to_compact_hash do |attr|
         attr_md = attribute_metadata(attr)
         "#{attr_md.type.qp}.#{attr_md.inverse}" if attr_md.inverse
      end
      domain_attr_printer = domain_attributes.to_compact_hash { |attr| domain_type(attr).qp }
      map = {
        "Java properties" => prop_printer,
        "standard attributes" => attributes,
        "aliases to standard attributes" => alias_attr_hash,
        "secondary key" => secondary_key_attributes,
        "mandatory attributes" => mandatory_attributes,
        "domain attributes" => domain_attr_printer,
        "creatable domain attributes" => creatable_domain_attributes,
        "updatable domain attributes" => updatable_domain_attributes,
        "fetched domain attributes" => fetched_domain_attributes,
        "cascaded domain attributes" => cascaded_attributes,
        "owners" => owner_printer,
        "owner attributes" => owner_attributes,
        "inverse attributes" => inverses,
        "dependent attributes" => dependents_printer,
        "default values" => defaults
      }.delete_if { |key, value| value.nil_or_empty? }
      # one indented line per entry, all but the last line ending in a comma
      content = map.map { |label, value| "  #{label}=>#{format_print_value(value)}" }.join(",\n")
      # print the content to the log
      q.text("#{qp} structure:\n#{content}")
    end

    protected
    
    # Adds the given subclass to this class's {ResourceMetadata#domain_module}.
    def introspect_subclass(klass)
      # introspect this class if necessary
      unless @domain_module then
        raise TypeError.new("Can't introspect #{qp}") unless superclass and superclass.include?(Resource)
        superclass.introspect_subclass(self) 
      end
      @domain_module.add_class(klass)
    end

    def self.extend_class(klass, mod)
      klass.extend(self)
      klass.add_metadata(mod)
    end

    private

    # A proc to print the unqualified class name.
    TYPE_PRINTER = PrintWrapper.new { |type| type.qp }

    DEPENDENT_ATTR_PRINTER = PrintWrapper.new do |attr_md|
      flags = []
      flags << :logical if attr_md.logical?
      flags << :autogenerated if attr_md.autogenerated?
      flags << :disjoint if attr_md.disjoint?
      flags.empty? ? "#{attr_md}" : "#{attr_md}(#{flags.join(',')})"
    end

    # A proc to print the property descriptor name.
    PROP_DESC_PRINTER = PrintWrapper.new { |pd| pd.name }

    def format_print_value(value)
      case value
      when String then
        value
      when Class then
        value.qp
      else
        value.pp_s(:single_line)
      end
    end
  end
end