require 'omnitest/psychic/code2doc/code_helper'

module Omnitest
  class Psychic
    module Code2Doc
      module SnippetHelper
        include CodeHelper

        def file_snippet(file_name, opts = {})
          file = expand_file(file_name)
          snippet_opts = {
            language: (opts[:language] || detect_language(file))
          }.merge(opts)
          content = file_content(file_name, snippet_opts)
          snippetize(content, snippet_opts)
        end

        def exec_snippet(command, opts = {})
          cwd = opts.delete(:cwd) || '.'
          psychic = Omnitest::Psychic.new(cwd: cwd)
          result = psychic.execute(command)
          snippetize_output(result, opts)
        end

        def snippetize_output(result, opts)
          include_command = (opts.key?(:include_command) ? opts.delete(:include_command) : true)
          snippet = include_command ? "$ #{result.command}\n" : ''
          snippet << result.stdout
          snippetize(snippet, opts)
        end

        def snippetize(str, opts)
          language = opts.delete(:language)
          snippet_opts = {
            format: (opts[:format] || :markdown)
          }.merge(opts)
          code_block(str, language, snippet_opts).rstrip
        end

        private

        def file_content(file_name, opts = {})
          file = expand_file(file_name)
          content = file.read
          after_pattern, before_pattern = [opts[:after], opts[:before]].map do | pattern |
            case pattern
            when nil
              nil
            when Regexp
              pattern.source
            else
              Regexp.quote(pattern.to_s)
            end
          end
          content = content.gsub(/\A.*#{after_pattern}\s*^(.*)\Z/m, '\1') if after_pattern
          content = content.gsub(/\A(.*)#{before_pattern}.*\Z/m, '\1') if before_pattern
          content.rstrip
        end

        def detect_language(file)
          file = Pathname(file)
          language, _comment_style = Code2Doc::CommentStyles.infer file.extname
          language
        rescue CommentStyles::UnknownStyleError
          nil
        end

        def expand_file(file_name)
          file = Pathname(file_name)
          file.expand_path(Omnitest.basedir) unless file.absolute?
        end
      end
    end
  end
end