# encoding: utf-8

module Nanoc3

  # Module that contains all nanoc-specific errors.
  module Errors

    # Generic error. Superclass for all nanoc-specific errors.
    class Generic < ::StandardError
    end

    # Error that is raised when a site is loaded that uses a data source with
    # an unknown identifier.
    class UnknownDataSource < Generic

      # @param [String] data_source_name The data source name for which no
      #   data source could be found
      def initialize(data_source_name)
        super("The data source specified in the site's configuration file, #{data_source_name}, does not exist.")
      end

    end

    # Error that is raised during site compilation when an item uses a layout
    # that is not present in the site.
    class UnknownLayout < Generic

      # @param [String] layout_identifier The layout identifier for which no
      #   layout could be found
      def initialize(layout_identifier)
        super("The site does not have a layout with identifier '#{layout_identifier}'.")
      end

    end

    # Error that is raised during site compilation when an item uses a filter
    # that is not known.
    class UnknownFilter < Generic

      # @param [Symbol] filter_name The filter name for which no filter could
      #   be found
      def initialize(filter_name)
        super("The requested filter, #{filter_name}, does not exist.")
      end

    end

    # Error that is raised during site compilation when a layout is compiled
    # for which the filter cannot be determined. This is similar to the
    # {UnknownFilter} error, but specific for filters for layouts.
    class CannotDetermineFilter < Generic

      # @param [String] layout_identifier The identifier of the layout for
      #   which the filter could not be determined
      def initialize(layout_identifier)
        super("The filter to be used for the '#{layout_identifier}' could not be determined. Make sure the layout does have a filter.")
      end

    end

    # Error that is raised when data is requested when the data is not yet
    # available (possibly due to a missing {Nanoc3::Site#load_data}).
    class DataNotYetAvailable < Generic

      # @param [String] type The name of the data type that is not yet
      #   available. For example: `"site"`, `"items"`.
      #
      # @param [Boolean] plural True if the given type is plural, false
      #   otherwise. This only has an effect on the exception message. For
      #   example, if the given type is `"site"`, plural would be `false`; if
      #   the given type is `"items"`, plural would be `true`.
      def initialize(type, plural)
        super("#{type} #{plural ? 'are' : 'is'} not available yet. You may be missing a Nanoc3::Site#load_data call.")
      end

    end

    # Error that is raised during site compilation when an item (directly or
    # indirectly) includes its own item content, leading to endless recursion.
    class RecursiveCompilation < Generic

      # @param [Array<Nanoc3::ItemRep>] reps A list of item representations
      #   that mutually depend on each other
      def initialize(reps)
        super("The site cannot be compiled because the following items mutually depend on each other: #{reps.inspect}.")
      end

    end

    # Error that is raised when no rules file can be found in the current
    # working directory.
    class NoRulesFileFound < Generic

      def initialize
        super("This site does not have a rules file, which is required for nanoc sites.")
      end

    end

    # Error that is raised when no compilation rule that can be applied to the
    # current item can be found.
    class NoMatchingCompilationRuleFound < Generic

      # @param [Nanoc3::Item] item The item for which no compilation rule
      #   could be found
      def initialize(item)
        super("No compilation rules were found for the '#{item.identifier}' item.")
      end

    end

    # Error that is raised when no routing rule that can be applied to the
    # current item can be found.
    class NoMatchingRoutingRuleFound < Generic

      # @param [Nanoc3::Item] item The item for which no routing rule could be
      #   found
      def initialize(rep)
        super("No routing rules were found for the '#{rep.item.identifier}' item (rep '#{rep.name}').")
      end

    end

    # Error that is raised when an rep cannot be compiled because it depends
    # on other representations.
    class UnmetDependency < Generic

      # @return [Nanoc3::ItemRep] The item representation that cannot yet be
      #   compiled
      attr_reader :rep

      # @param [Nanoc3::ItemRep] The item representation that cannot yet be
      #   compiled
      def initialize(rep)
        @rep = rep
        super("The '#{rep.item.identifier}' item (rep '#{rep.name}') cannot currently be compiled yet due to an unmet dependency.")
      end

    end

  end

end