require 'rails/generators'
require_relative 'generated_attribute'
require_relative 'secondary_index'

module AwsRecord
    module Generators
      class Base < Rails::Generators::NamedBase
        argument :attributes, type: :array, default: [], banner: "field[:type][:opts]...", desc: "Describes the fields in the model"
        check_class_collision

        class_option :disable_mutation_tracking, type: :boolean, desc: "Disables dirty tracking"
        class_option :timestamps, type: :boolean, desc: "Adds created, updated timestamps to the model"
        class_option :table_config, type: :hash, default: {}, banner: "primary:R-W [SecondaryIndex1:R-W]...", desc: "Declares the r/w units for the model as well as any secondary indexes", :required => true
        class_option :gsi, type: :array, default: [], banner: "name:hkey{field_name}[,rkey{field_name},proj_type{ALL|KEYS_ONLY|INCLUDE}]...", desc: "Allows for the declaration of secondary indexes"
        class_option :table_name, type: :string, banner: "model_table_name"
        class_option :password_digest, type: :boolean, desc: "Whether to add a password_digest field to the model"

        class_option :required, type: :string, banner: "field1...", desc: "A list of attributes that are required for an instance of the model"
        class_option :length_validations, type: :hash, default: {}, banner: "field1:MIN-MAX...", desc: "Validations on the length of attributes in a model"

        attr_accessor :primary_read_units, :primary_write_units, :gsi_rw_units, :gsis, :required_attrs, :length_validations

        private

        def initialize(args, *options)
          options[0] << "--skip-table-config" if options[1][:behavior] == :revoke
          @parse_errors = []

          super
          ensure_unique_fields
          ensure_hkey
          parse_gsis!
          parse_table_config!
          parse_validations!

          if !@parse_errors.empty?
            STDERR.puts "The following errors were encountered while trying to parse the given attributes"
            STDERR.puts
            STDERR.puts @parse_errors
            STDERR.puts

            abort("Please fix the errors before proceeding.")
          end
        end

        def parse_attributes!

          self.attributes = (attributes || []).map do |attr|
            begin
              GeneratedAttribute.parse(attr)
            rescue ArgumentError => e
              @parse_errors << e
              next
            end
          end
          self.attributes = self.attributes.compact

          if options['password_digest']
            self.attributes << GeneratedAttribute.new("password_digest", :string_attr, :digest => true)
          end

          if options['timestamps']
            self.attributes << GeneratedAttribute.parse("created:datetime:default_value{Time.now}")
            self.attributes << GeneratedAttribute.parse("updated:datetime:default_value{Time.now}")
          end
        end

        def ensure_unique_fields
          used_names = Set.new
          duplicate_fields = []

          self.attributes.each do |attr|

            if used_names.include? attr.name
              duplicate_fields << [:attribute, attr.name]
            end
            used_names.add attr.name

            if attr.options.key? :database_attribute_name
              raw_db_attr_name = attr.options[:database_attribute_name].delete('"') # db attribute names are wrapped with " to make template generation easier

              if used_names.include? raw_db_attr_name
                duplicate_fields << [:database_attribute_name, raw_db_attr_name]
              end

              used_names.add raw_db_attr_name
            end
          end

          if !duplicate_fields.empty?
            duplicate_fields.each do |invalid_attr|
              @parse_errors << ArgumentError.new("Found duplicated field name: #{invalid_attr[1]}, in attribute#{invalid_attr[0]}")
            end
          end
        end

        def ensure_hkey
          uuid_member = nil
          hkey_member = nil
          rkey_member = nil

          self.attributes.each do |attr|
            if attr.options.key? :hash_key
              if hkey_member
                @parse_errors << ArgumentError.new("Redefinition of hash_key attr: #{attr.name}, original declaration of hash_key on: #{hkey_member.name}")
                next
              end

              hkey_member = attr
            elsif attr.options.key? :range_key
              if rkey_member
                @parse_errors << ArgumentError.new("Redefinition of range_key attr: #{attr.name}, original declaration of range_key on: #{hkey_member.name}")
                next
              end

              rkey_member = attr
            end

            if attr.name.include? "uuid"
              uuid_member = attr
            end
          end

          if !hkey_member
            if uuid_member
              uuid_member.options[:hash_key] = true
            else
              self.attributes.unshift GeneratedAttribute.parse("uuid:hkey")
            end
          end
        end

        def mutation_tracking_disabled?
          options['disable_mutation_tracking']
        end

        def has_validations?
          !@required_attrs.empty? || !@length_validations.empty?
        end

        def parse_table_config!
          return unless options['table_config']

          @primary_read_units, @primary_write_units = parse_rw_units("primary")

          @gsi_rw_units = @gsis.map { |idx|
            [idx.name, parse_rw_units(idx.name)]
          }.to_h

          options['table_config'].each do |config, rw_units|
            if config == "primary"
              next
            else
              gsi = @gsis.select { |idx| idx.name == config}

              if gsi.empty?
                @parse_errors << ArgumentError.new("Could not find a gsi declaration for #{config}")
              end
            end
          end
        end

        def parse_rw_units(name)
          if !options['table_config'].key? name
            @parse_errors << ArgumentError.new("Please provide a table_config definition for #{name}")
          else
            rw_units = options['table_config'][name]
            return rw_units.gsub(/[,.-]/, ':').split(':').reject { |s| s.empty? }
          end
        end

        def parse_gsis!
          @gsis = (options['gsi'] || []).map do |raw_idx|
            begin
              idx = SecondaryIndex.parse(raw_idx)

              attributes = self.attributes.select { |attr| attr.name == idx.hash_key}
              if attributes.empty?
                @parse_errors << ArgumentError.new("Could not find attribute #{idx.hash_key} for gsi #{idx.name} hkey")
                next
              end

              if idx.range_key
                attributes = self.attributes.select { |attr| attr.name == idx.range_key}
                if attributes.empty?
                  @parse_errors << ArgumentError.new("Could not find attribute #{idx.range_key} for gsi #{idx.name} rkey")
                  next
                end
              end

              idx
            rescue ArgumentError => e
              @parse_errors << e
              next
            end
          end

          @gsis = @gsis.compact
        end

        def parse_validations!
          @required_attrs = options['required'] ? options['required'].split(',') : []
          @required_attrs.each do |val_attr|
            @parse_errors << ArgumentError.new("No such field #{val_attr} in required validations") if !self.attributes.any? { |attr| attr.name == val_attr }
          end

          @length_validations = options['length_validations'].map do |val_attr, bounds|
            @parse_errors << ArgumentError.new("No such field #{val_attr} in required validations") if !self.attributes.any? { |attr| attr.name == val_attr }

            bounds = bounds.gsub(/[,.-]/, ':').split(':').reject { |s| s.empty? }
            [val_attr, "#{bounds[0]}..#{bounds[1]}"]
          end
          @length_validations = @length_validations.to_h
        end
      end
    end
  end