require_relative '../artefact.rb'

module Compfile
    class ParserArtefact < Comfpile::Artefact
        def initialize(*args, **opts)
            super(*args)

            @search_regexes = opts[:search_regexes]

            @parsed_parameters = {}

            parent_artefact :sourcefile, @target

            add_step do
                sourcefile_parse_step
                sourcefile_dependency_step
            end
        end

        # Attempts to find the set of values for a given 
        # parameter key.
        #
        # @param [String, Array<String>] keys Key, or array of keys, to look for
        #
        # @return [Array<String>] Array of values found for this key
        #
        def find_parsed_parameters(keys)
            if keys.is_a? Array
                output = []
                keys.each do |key|
                    output += @parsed_parameters[key] || []
                end

                output
            else
                @parsed_parameters[key] || []
            end
        end

        #
        # Try to find a relative or absolute source file 
        # artefact.
        # Used to resolve the include, require and reference
        # statements and find relative and/or absolute source 
        # files with matching name. Similar to how C++'s 
        # include statement it will check relative, then 
        # globally.
        #
        # @param [String, Array<String>] name Path of the sourcefile to look for
        # @param [Boolean] optional If true, will also check for absolute
        #  source file, and will discard the file if it can't be found.
        #  Useful for e.g. C/C++ header files that may not be in the search
        #  path of comfpile.
        #  
        # @return [String] Resolved path of the sourcefile. Relative
        #  if a relative file is found, else absolute.
        #
        def resolve_sourcefile(name, optional: false)
            if(name.is_a? Array)
                name.map do |n|
                    resolve_sourcefile(n, optional: optional)
                end

                name.compact
            else
                own_dir = File.dirname(@target)
                relative_file = File.join(own_dir, name)

                if not craft_artefact(:sourcefile, relative_file).nil?
                    relative_file
                elsif not craft_artefact(:sourcefile, name).nil?
                    name
                elsif optional
                    relative_file
                else
                    nil
                end
            end
        end

        def sourcefile_parse_step
            log "Parsing file #{@target}..."

            File.readlines(@parent_artefact[:file]).each do |line|
                @search_regexes.each do |r|
                    match = r.match line
                    next if match.nil?

                    key = match[:key]
                    value = match[:value]

                    next if key.nil?

                    log "Found k/v pair: '#{key}' '#{value}'", :debug

                    @parsed_parameters[key] ||= []
                    @parsed_parameters[key] << value
                end
            end

            log "Parsing completed, found #{@parsed_parameters.keys.size} parameters!"
        end

        def sourcefile_dependency_step
            included_artefacts   = resolve_sourcefile find_parsed_parameters 'include'
            required_artefacts   = resolve_sourcefile find_parsed_parameters 'require'
            referenced_artefacts = resolve_sourcefile find_parsed_parameters 'reference'

            included_artefacts.each   { |a| include_artefact :parsed, a }
            required_artefacts.each   { |a| require_artefact :parsed, a }
            referenced_artefacts.each { |a| reference_artefact :parsed, a }

            log "Generated dependencies. Included #{included_artefacts.size}, required #{required_artefact.size} and referenced #{referenced_artefacts.size}."
        end
    end

    class ParserEngine < ArtefactEngine
        def initialize(core, **options)
            super(core, **options)

            @input_file_regex = options[:allowed_files]

            @require_regex = options[:require_reg]
            @include_regex = options[:include_reg]
        end

        def generate_parser_artefact(stage, target)
            match = @input_file_regex.match target
            return nil if match.nil?

            a = Artefact.new(@core, self, stage, target)

            a.parent_artefact(:sourcefile, target)

            a.add_step do

                @parameters[:included_files] = []
                @parameters[:required_files] = []

                File.readlines(@parent_artefact[:file]) do |l|
                    case l
                    when @require_regex
                        filename = $~[:file]

                        own_dir = File.dirname(@target)
                        relative_file = File.join(own_dir, filename)

                        unless craft_artefact(:sourcefile, relative_file).nil?
                            @parameters[:required_files] << require_artefact(:parsed, relative_file)
                        else
                            @parameters[:required_files] << require_artefact(:parsed, filename)
                        end

                    when @include_regex
                        filename = $~[:file]

                        own_dir = File.dirname(@target)
                        relative_file = File.join(own_dir, filename)

                        unless craft_artefact(:sourcefile, relative_file).nil?
                            @parameters[:included_files] << craft_artefact(:parsed, relative_file)
                        else
                            @parameters[:included_files] << craft_artefact(:parsed, filename)
                        end
                    end
                end
            end
        end

        def generate_dependency_artefact(stage, target)

        end

        def craft(stage, target)
            case stage
            when :parsed
                generate_parser_artefact(stage, target)
            when :dependency_list
            
            else 
                nil
            end
        end
    end