# frozen_string_literal: true

module Gitlab
  module GithubImport
    module Representation
      class DiffNote
        include Gitlab::Utils::StrongMemoize
        include ToHash
        include ExposeAttribute

        NOTEABLE_TYPE = 'MergeRequest'
        NOTEABLE_ID_REGEX = %r{/pull/(?<iid>\d+)}i.freeze
        DISCUSSION_CACHE_KEY = 'github-importer/discussion-id-map/%{project_id}/%{noteable_id}/%{original_note_id}'

        expose_attribute :noteable_id, :commit_id, :file_path,
          :diff_hunk, :author, :created_at, :updated_at,
          :original_commit_id, :note_id, :end_line, :start_line,
          :side, :in_reply_to_id

        # Builds a diff note from a GitHub API response.
        #
        # note - An instance of `Sawyer::Resource` containing the note details.
        def self.from_api_response(note)
          matches = note.html_url.match(NOTEABLE_ID_REGEX)

          unless matches
            raise(
              ArgumentError,
              "The note URL #{note.html_url.inspect} is not supported"
            )
          end

          user = Representation::User.from_api_response(note.user) if note.user
          hash = {
            noteable_id: matches[:iid].to_i,
            file_path: note.path,
            commit_id: note.commit_id,
            original_commit_id: note.original_commit_id,
            diff_hunk: note.diff_hunk,
            author: user,
            note: note.body,
            created_at: note.created_at,
            updated_at: note.updated_at,
            note_id: note.id,
            end_line: note.line,
            start_line: note.start_line,
            side: note.side,
            in_reply_to_id: note.in_reply_to_id
          }

          new(hash)
        end

        # Builds a new note using a Hash that was built from a JSON payload.
        def self.from_json_hash(raw_hash)
          hash = Representation.symbolize_hash(raw_hash)
          hash[:author] &&= Representation::User.from_json_hash(hash[:author])

          new(hash)
        end

        attr_accessor :merge_request, :project

        # attributes - A Hash containing the raw note details. The keys of this
        #              Hash must be Symbols.
        def initialize(attributes)
          @attributes = attributes

          @note_formatter = DiffNotes::SuggestionFormatter.new(
            note: attributes[:note],
            start_line: attributes[:start_line],
            end_line: attributes[:end_line]
          )
        end

        def noteable_type
          NOTEABLE_TYPE
        end

        def contains_suggestion?
          @note_formatter.contains_suggestion?
        end

        def note
          @note_formatter.formatted_note
        end

        def line_code
          diff_line = Gitlab::Diff::Parser.new.parse(diff_hunk.lines).to_a.last

          Gitlab::Git.diff_line_code(file_path, diff_line.new_pos, diff_line.old_pos)
        end

        # Returns a Hash that can be used to populate `notes.st_diff`, removing
        # the need for requesting Git data for every diff note.
        # Used when importing with LegacyDiffNote
        def diff_hash
          {
            diff: diff_hunk,
            new_path: file_path,
            old_path: file_path,

            # These fields are not displayed for LegacyDiffNote notes, so it
            # doesn't really matter what we set them to.
            a_mode: '100644',
            b_mode: '100644',
            new_file: false
          }
        end

        # Used when importing with DiffNote
        def diff_position
          position_params = {
            diff_refs: merge_request.diff_refs,
            old_path: file_path,
            new_path: file_path
          }

          Gitlab::Diff::Position.new(position_params.merge(diff_line_params))
        end

        def github_identifiers
          {
            note_id: note_id,
            noteable_id: noteable_id,
            noteable_type: noteable_type
          }
        end

        def discussion_id
          strong_memoize(:discussion_id) do
            (in_reply_to_id.present? && current_discussion_id) || generate_discussion_id
          end
        end

        private

        # Required by ExposeAttribute
        attr_reader :attributes

        def diff_line_params
          if addition?
            { new_line: end_line, old_line: nil }
          else
            { new_line: nil, old_line: end_line }
          end
        end

        def addition?
          side == 'RIGHT'
        end

        def generate_discussion_id
          Discussion.discussion_id(
            Struct
            .new(:noteable_id, :noteable_type)
            .new(merge_request.id, NOTEABLE_TYPE)
          ).tap do |discussion_id|
            cache_discussion_id(discussion_id)
          end
        end

        def cache_discussion_id(discussion_id)
          Gitlab::Cache::Import::Caching.write(discussion_id_cache_key(note_id), discussion_id)
        end

        def current_discussion_id
          Gitlab::Cache::Import::Caching.read(discussion_id_cache_key(in_reply_to_id))
        end

        def discussion_id_cache_key(id)
          DISCUSSION_CACHE_KEY % {
            project_id: project.id,
            noteable_id: merge_request.id,
            original_note_id: id
          }
        end
      end
    end
  end
end