# Aruba
module Aruba
  # Platforms
  module Platforms
    # Implement `which(command)` for windows
    #
    # @private
    class WindowsWhich
      # Bail out because this should never be reached
      class DefaultWhich
        def self.match?(*)
          true
        end

        def call(program, path)
          raise %(Invalid input program "#{program}" and/or path "#{path}".)
        end
      end

      # Find path for absolute or relative command
      class AbsoluteOrRelativePathWhich
        def self.match?(program)
          Aruba.platform.absolute_path?(program) || Aruba.platform.relative_command?(program)
        end

        def call(program, _path)
          # Expand `#path_exts`
          found = Dir[program].first

          return File.expand_path(found) if found && Aruba.platform.executable?(found)

          nil
        end
      end

      # Find path for command
      class ProgramWhich
        def self.match?(program)
          Aruba.platform.command?(program)
        end

        def call(program, path)
          # Iterate over each path glob the dir + program.
          path.split(File::PATH_SEPARATOR).each do |dir|
            dir = Aruba.platform.expand_path(dir, Dir.getwd)

            next unless Aruba.platform.exist?(dir) # In case of bogus second argument

            file = File.join(dir, program)
            # Dir[] doesn't handle backslashes properly, so convert them. Also, if
            # the program name doesn't have an extension, try them all.
            file = file.tr("\\", "/")

            found = Dir[file].first

            # Convert all forward slashes to backslashes if supported
            if found && Aruba.platform.executable?(found)
              found.tr!(File::SEPARATOR, File::ALT_SEPARATOR)
              return found
            end
          end

          nil
        end
      end

      private

      attr_reader :whiches

      public

      def initialize
        @whiches = []
        @whiches << AbsoluteOrRelativePathWhich
        @whiches << ProgramWhich
        @whiches << DefaultWhich
      end

      # Find fully quallified path for program
      #
      # @param [String] program
      #   Name of program
      #
      # @param [String] path
      #   ENV['PATH']
      def call(program, path = ENV["PATH"])
        raise ArgumentError, "ENV['PATH'] cannot be empty" if path.nil? || path.empty?

        program = program.to_s
        program += windows_executable_extentions if File.extname(program).empty?

        whiches.find { |w| w.match? program }.new.call(program, path)
      end

      private

      def windows_executable_extentions
        if ENV["PATHEXT"]
          format(".{%s}", ENV["PATHEXT"].tr(";", ",").tr(".", "")).downcase
        else
          ".{exe,com,bat}"
        end
      end
    end
  end
end