# A resource that we're managing.  This handles making sure that only subclasses
# can set parameters.
class Puppet::Parser::Resource
    require 'puppet/parser/resource/param'
    require 'puppet/parser/resource/reference'
    require 'puppet/util/tagging'
    include Puppet::Util
    include Puppet::Util::MethodHelper
    include Puppet::Util::Errors
    include Puppet::Util::Logging
    include Puppet::Util::Tagging

    attr_accessor :source, :line, :file, :scope, :rails_id
    attr_accessor :virtual, :override, :translated

    attr_reader :exported, :evaluated, :params

    # Determine whether the provided parameter name is a relationship parameter.
    def self.relationship_parameter?(name)
        unless defined?(@relationship_names)
            @relationship_names = Puppet::Type.relationship_params.collect { |p| p.name }
        end
        @relationship_names.include?(name)
    end

    # Proxy a few methods to our @ref object.
    [:builtin?, :type, :title].each do |method|
        define_method(method) do
            @ref.send(method)
        end
    end

    # Set up some boolean test methods
    [:exported, :translated, :override, :virtual, :evaluated].each do |method|
        newmeth = (method.to_s + "?").intern
        define_method(newmeth) do
            self.send(method)
        end
    end

    def [](param)
        param = symbolize(param)
        if param == :title
            return self.title
        end
        if @params.has_key?(param)
            @params[param].value
        else
            nil
        end
    end

    def builtin=(bool)
        @ref.builtin = bool
    end

    # Retrieve the associated definition and evaluate it.
    def evaluate
        if klass = @ref.definedtype
            finish()
            return klass.evaluate_code(self)
        elsif builtin?
            devfail "Cannot evaluate a builtin type"
        else
            self.fail "Cannot find definition %s" % self.type
        end
    ensure
        @evaluated = true
    end

    # Mark this resource as both exported and virtual,
    # or remove the exported mark.
    def exported=(value)
        if value
            @virtual = true
            @exported = value
        else
            @exported = value
        end
    end

    # Do any finishing work on this object, called before evaluation or
    # before storage/translation.
    def finish
        return if finished?
        @finished = true
        add_defaults()
        add_metaparams()
        add_scope_tags()
        validate()
    end

    # Has this resource already been finished?
    def finished?
        defined?(@finished) and @finished
    end

    def initialize(options)
        # Set all of the options we can.
        options.each do |option, value|
            if respond_to?(option.to_s + "=")
                send(option.to_s + "=", value)
                options.delete(option)
            end
        end

        unless self.scope
            raise ArgumentError, "Resources require a scope"
        end
        @source ||= scope.source

        options = symbolize_options(options)

        # Set up our reference.
        if type = options[:type] and title = options[:title]
            options.delete(:type)
            options.delete(:title)
        else
            raise ArgumentError, "Resources require a type and title"
        end

        @ref = Reference.new(:type => type, :title => title, :scope => self.scope)

        @params = {}

        # Define all of the parameters
        if params = options[:params]
            options.delete(:params)
            params.each do |param|
                set_parameter(param)
            end
        end

        # Throw an exception if we've got any arguments left to set.
        unless options.empty?
            raise ArgumentError, "Resources do not accept %s" % options.keys.collect { |k| k.to_s }.join(", ")
        end

        tag(@ref.type)
        tag(@ref.title) if valid_tag?(@ref.title.to_s)
    end

    # Is this resource modeling an isomorphic resource type?
    def isomorphic?
        if builtin?
            return @ref.builtintype.isomorphic?
        else
            return true
        end
    end

    # Merge an override resource in.  This will throw exceptions if
    # any overrides aren't allowed.
    def merge(resource)
        # Test the resource scope, to make sure the resource is even allowed
        # to override.
        unless self.source.object_id == resource.source.object_id || resource.source.child_of?(self.source)
            raise Puppet::ParseError.new("Only subclasses can override parameters", resource.line, resource.file)
        end
        # Some of these might fail, but they'll fail in the way we want.
        resource.params.each do |name, param|
            override_parameter(param)
        end
    end

    # Modify this resource in the Rails database.  Poor design, yo.
    def modify_rails(db_resource)
        args = rails_args
        args.each do |param, value|
            db_resource[param] = value unless db_resource[param] == value
        end

        # Handle file specially
        if (self.file and  
            (!db_resource.file or db_resource.file != self.file))
            db_resource.file = self.file
        end
        
        updated_params = @params.reject { |name, param| param.value == :undef }.inject({}) do |hash, ary|
            hash[ary[0].to_s] = ary[1]
            hash
        end
        
        db_resource.ar_hash_merge(db_resource.get_params_hash(), updated_params,
                                  :create => Proc.new { |name, parameter|
                                      parameter.to_rails(db_resource)
                                  }, :delete => Proc.new { |values|
                                      values.each { |value| Puppet::Rails::ParamValue.delete(value['id']) }
                                  }, :modify => Proc.new { |db, mem|
                                      mem.modify_rails_values(db)
                                  })
        
        updated_tags = tags.inject({}) { |hash, tag| 
            hash[tag] = tag
            hash
        }

        db_resource.ar_hash_merge(db_resource.get_tag_hash(), 
                                  updated_tags,
                                  :create => Proc.new { |name, tag|
                                      db_resource.add_resource_tag(name)
                                  }, :delete => Proc.new { |tag|
                                      Puppet::Rails::ResourceTag.delete(tag['id'])
                                  }, :modify => Proc.new { |db, mem|
                                      # nothing here
                                  })
    end

    # Return the resource name, or the title if no name
    # was specified.
    def name
        unless defined? @name
            @name = self[:name] || self.title
        end
        @name
    end

    # This *significantly* reduces the number of calls to Puppet.[].
    def paramcheck?
        unless defined? @@paramcheck
            @@paramcheck = Puppet[:paramcheck]
        end
        @@paramcheck
    end

    # A temporary occasion, until I get paths in the scopes figured out.
    def path
        to_s
    end

    # Return the short version of our name.
    def ref
        @ref.to_s
    end

    # Define a parameter in our resource.
    def set_parameter(param, value = nil)
        if value
            param = Puppet::Parser::Resource::Param.new(
                :name => param, :value => value, :source => self.source
            )
        elsif ! param.is_a?(Puppet::Parser::Resource::Param)
            raise ArgumentError, "Must pass a parameter or all necessary values"
        end

        # And store it in our parameter hash.
        @params[param.name] = param
    end

    def to_hash
        @params.inject({}) do |hash, ary|
            param = ary[1]
            # Skip "undef" values.
            if param.value != :undef
                hash[param.name] = param.value
            end
            hash
        end
    end

    # Turn our parser resource into a Rails resource.  
    def to_rails(host)
        args = rails_args

        db_resource = host.resources.build(args)

        # Handle file specially
        db_resource.file = self.file

        db_resource.save

        @params.each { |name, param|
            next if param.value == :undef
            param.to_rails(db_resource)
        }
        
        tags.each { |tag| db_resource.add_resource_tag(tag) }

        return db_resource
    end

    # Create a Puppet::Resource instance from this parser resource.
    # We plan, at some point, on not needing to do this conversion, but
    # it's sufficient for now.
    def to_resource
        result = Puppet::Resource.new(type, title)

        to_hash.each do |p, v|
            if v.is_a?(Puppet::Parser::Resource::Reference)
                v = Puppet::Resource::Reference.new(v.type, v.title)
            elsif v.is_a?(Array)
                # flatten resource references arrays
                if v.flatten.find { |av| av.is_a?(Puppet::Parser::Resource::Reference) }
                    v = v.flatten
                end
                v = v.collect do |av|
                    if av.is_a?(Puppet::Parser::Resource::Reference)
                        av = Puppet::Resource::Reference.new(av.type, av.title)
                    end
                    av
                end
            end

            # If the value is an array with only one value, then
            # convert it to a single value.  This is largely so that
            # the database interaction doesn't have to worry about
            # whether it returns an array or a string.
            result[p] = if v.is_a?(Array) and v.length == 1
                              v[0]
                          else
                              v
                          end
        end

        result.file = self.file
        result.line = self.line
        result.tag(*self.tags)

        return result
    end

    def to_s
        self.ref
    end

    # Translate our object to a transportable object.
    def to_trans
        return nil if virtual?

        return to_resource.to_trans
    end

    # Convert this resource to a RAL resource.  We hackishly go via the
    # transportable stuff.
    def to_ral
        to_resource.to_ral
    end
    
    private

    # Add default values from our definition.
    def add_defaults
        scope.lookupdefaults(self.type).each do |name, param|
            unless @params.include?(name)
                self.debug "Adding default for %s" % name

                @params[name] = param.dup
            end
        end
    end

    # Add any metaparams defined in our scope. This actually adds any metaparams
    # from any parent scope, and there's currently no way to turn that off.
    def add_metaparams
        Puppet::Type.eachmetaparam do |name|
            # Skip metaparams that we already have defined, unless they're relationship metaparams.
            # LAK:NOTE Relationship metaparams get treated specially -- we stack them, instead of
            # overriding.
            next if @params[name] and not self.class.relationship_parameter?(name)
            next if @params[name] and @params[name].value == :undef

            # Skip metaparams for which we get no value.
            next unless val = scope.lookupvar(name.to_s, false) and val != :undefined

            # The default case: just set the value
            set_parameter(name, val) and next unless @params[name]

            # For relationship params, though, join the values (a la #446).
            @params[name].value = [@params[name].value, val].flatten
        end
    end

    def add_scope_tags
        if scope_resource = scope.resource
            tag(*scope_resource.tags)
        end
    end

    # Accept a parameter from an override.
    def override_parameter(param)
        # This can happen if the override is defining a new parameter, rather
        # than replacing an existing one.
        (@params[param.name] = param and return) unless current = @params[param.name]

        # The parameter is already set.  Fail if they're not allowed to override it.
        unless param.source.child_of?(current.source)
            puts caller if Puppet[:trace]
            msg = "Parameter '%s' is already set on %s" % [param.name, self.to_s]
            if current.source.to_s != ""
                msg += " by %s" % current.source
            end
            if current.file or current.line
                fields = []
                fields << current.file if current.file
                fields << current.line.to_s if current.line
                msg += " at %s" % fields.join(":")
            end
            msg += "; cannot redefine"
            raise Puppet::ParseError.new(msg, param.line, param.file)
        end

        # If we've gotten this far, we're allowed to override.

        # Merge with previous value, if the parameter was generated with the +> syntax.
        # It's important that we use the new param instance here, not the old one,
        # so that the source is registered correctly for later overrides.
        param.value = [current.value, param.value].flatten if param.add

        @params[param.name] = param
    end

    # Verify that all passed parameters are valid.  This throws an error if
    #  there's a problem, so we don't have to worry about the return value.
    def paramcheck(param)
        param = param.to_s
        # Now make sure it's a valid argument to our class.  These checks
        # are organized in order of commonhood -- most types, it's a valid 
        # argument and paramcheck is enabled.
        if @ref.typeclass.validattr?(param)
            true
        elsif %w{name title}.include?(param) # always allow these
            true
        elsif paramcheck?
            self.fail Puppet::ParseError, "Invalid parameter '%s' for type '%s'" %
                    [param, @ref.type]
        end
    end

    def rails_args
        return [:type, :title, :line, :exported].inject({}) do |hash, param|
            # 'type' isn't a valid column name, so we have to use another name.
            to = (param == :type) ? :restype : param
            if value = self.send(param)
                hash[to] = value
            end
            hash
        end
    end

    # Make sure the resource's parameters are all valid for the type.
    def validate
        @params.each do |name, param|
            # Make sure it's a valid parameter.
            paramcheck(name)
        end
    end
end