# encoding: UTF-8

module Tetra
  # attempts to get java projects' pom file
  class PomGetter
    include Logging

    # saves a jar poms in <jar_filename>.pom
    # returns filename and status if found, else nil
    def get_pom(filename)
      content, status = (get_pom_from_jar(filename) || get_pom_from_sha1(filename) || get_pom_from_heuristic(filename))
      return unless content

      pom_filename = filename.sub(/(\.jar)?$/, ".pom")
      File.open(pom_filename, "w") { |io| io.write(content) }
      [pom_filename, status]
    end

    # returns a pom embedded in a jar file
    def get_pom_from_jar(file)
      log.debug("Attempting unpack of #{file} to find a POM")
      begin
        Zip::File.foreach(file) do |entry|
          if entry.name =~ /\/pom.xml$/
            log.info("pom.xml found in #{file}##{entry.name}")
            return entry.get_input_stream.read, :found_in_jar
          end
        end
      rescue Zip::Error
        log.warn("#{file} does not seem to be a valid jar archive, skipping")
      rescue TypeError
        log.warn("#{file} seems to be a valid jar archive but is corrupt, skipping")
      end
      nil
    end

    # returns a pom from search.maven.org with a jar sha1 search
    def get_pom_from_sha1(file)
      log.debug("Attempting SHA1 POM lookup for #{file}")
      begin
        if File.file?(file)
          site = MavenWebsite.new
          sha1 = Digest::SHA1.hexdigest File.read(file)
          results = site.search_by_sha1(sha1).select { |result| result["ec"].include?(".pom") }
          result = results.first
          unless result.nil?
            log.info("pom.xml for #{file} found on search.maven.org for sha1 #{sha1}\
              (#{result["g"]}:#{result["a"]}:#{result["v"]})"
            )
            group_id, artifact_id, version = site.get_maven_id_from result
            return site.download_pom(group_id, artifact_id, version), :found_via_sha1
          end
        end
      rescue RestClient::ResourceNotFound
        log.warn("Got a 404 error while looking for #{file}'s SHA1 in search.maven.org")
      end
      nil
    end

    # returns a pom from search.maven.org with a heuristic name search
    def get_pom_from_heuristic(filename)
      begin
        log.debug("Attempting heuristic POM search for #{filename}")
        site = MavenWebsite.new
        filename = cleanup_name(filename)
        version_matcher = VersionMatcher.new
        my_artifact_id, my_version = version_matcher.split_version(filename)
        log.debug("Guessed artifact id: #{my_artifact_id}, version: #{my_version}")

        result = site.search_by_name(my_artifact_id).first
        log.debug("Artifact id search result: #{result}")
        unless result.nil?
          group_id, artifact_id, _ = site.get_maven_id_from result
          results = site.search_by_group_id_and_artifact_id(group_id, artifact_id)
          log.debug("All versions: #{results}")
          their_versions = results.map { |doc| doc["v"] }
          best_matched_version = (
            if !my_version.nil?
              version_matcher.best_match(my_version, their_versions)
            else
              their_versions.max
            end
          )
          best_matched_result = (results.select { |r| r["v"] == best_matched_version }).first

          group_id, artifact_id, version = site.get_maven_id_from(best_matched_result)
          log.warn("pom.xml for #{filename} found on search.maven.org with heuristic search\
            (#{group_id}:#{artifact_id}:#{version})"
          )

          return site.download_pom(group_id, artifact_id, version), :found_via_heuristic
        end
      rescue RestClient::ResourceNotFound
        log.warn("Got a 404 error while looking for #{filename} heuristically in search.maven.org")
      end
      nil
    end

    # get a heuristic name from a path
    def cleanup_name(path)
      Pathname.new(path).basename.to_s.sub(/.jar$/, "")
    end
  end
end