# == Schema Information
#
# Table name: notes
#
#  id            :integer          not null, primary key
#  note          :text
#  noteable_type :string(255)
#  author_id     :integer
#  created_at    :datetime
#  updated_at    :datetime
#  project_id    :integer
#  attachment    :string(255)
#  line_code     :string(255)
#  commit_id     :string(255)
#  noteable_id   :integer
#  system        :boolean          default(FALSE), not null
#  st_diff       :text
#

require 'carrierwave/orm/activerecord'
require 'file_size_validator'

class Note < ActiveRecord::Base
  include Mentionable

  default_value_for :system, false

  attr_mentionable :note

  belongs_to :project
  belongs_to :noteable, polymorphic: true
  belongs_to :author, class_name: "User"

  delegate :name, to: :project, prefix: true
  delegate :name, :email, to: :author, prefix: true

  validates :note, :project, presence: true
  validates :line_code, format: { with: /\A[a-z0-9]+_\d+_\d+\Z/ }, allow_blank: true
  validates :attachment, file_size: { maximum: 10.megabytes.to_i }

  validates :noteable_id, presence: true, if: ->(n) { n.noteable_type.present? && n.noteable_type != 'Commit' }
  validates :commit_id, presence: true, if: ->(n) { n.noteable_type == 'Commit' }

  mount_uploader :attachment, AttachmentUploader

  # Scopes
  scope :for_commit_id, ->(commit_id) { where(noteable_type: "Commit", commit_id: commit_id) }
  scope :inline, ->{ where("line_code IS NOT NULL") }
  scope :not_inline, ->{ where(line_code: [nil, '']) }

  scope :common, ->{ where(noteable_type: ["", nil]) }
  scope :fresh, ->{ order("created_at ASC, id ASC") }
  scope :inc_author_project, ->{ includes(:project, :author) }
  scope :inc_author, ->{ includes(:author) }

  serialize :st_diff
  before_create :set_diff, if: ->(n) { n.line_code.present? }
  after_update :set_references

  class << self
    def create_status_change_note(noteable, project, author, status, source)
      body = "_Status changed to #{status}#{' by ' + source.gfm_reference if source}_"

      create(
        noteable: noteable,
        project: project,
        author: author,
        note: body,
        system: true
      )
    end

    # +noteable+ was referenced from +mentioner+, by including GFM in either +mentioner+'s description or an associated Note.
    # Create a system Note associated with +noteable+ with a GFM back-reference to +mentioner+.
    def create_cross_reference_note(noteable, mentioner, author, project)
      note_options = {
        project: project,
        author: author,
        note: "_mentioned in #{mentioner.gfm_reference}_",
        system: true
      }

      if noteable.kind_of?(Commit)
        note_options.merge!(noteable_type: 'Commit', commit_id: noteable.id)
      else
        note_options.merge!(noteable: noteable)
      end

      create(note_options)
    end

    def create_milestone_change_note(noteable, project, author, milestone)
      body = if milestone.nil?
               '_Milestone removed_'
             else
               "_Milestone changed to #{milestone.title}_"
             end

      create(
        noteable: noteable,
        project: project,
        author: author,
        note: body,
        system: true
      )
    end

    def create_assignee_change_note(noteable, project, author, assignee)
      body = assignee.nil? ? '_Assignee removed_' : "_Reassigned to @#{assignee.username}_"

      create({
        noteable: noteable,
        project: project,
        author: author,
        note: body,
        system: true
      })
    end

    def discussions_from_notes(notes)
      discussion_ids = []
      discussions = []

      notes.each do |note|
        next if discussion_ids.include?(note.discussion_id)

        # don't group notes for the main target
        if !note.for_diff_line? && note.noteable_type == "MergeRequest"
          discussions << [note]
        else
          discussions << notes.select do |other_note|
            note.discussion_id == other_note.discussion_id
          end
          discussion_ids << note.discussion_id
        end
      end

      discussions
    end

    def build_discussion_id(type, id, line_code)
      [:discussion, type.try(:underscore), id, line_code].join("-").to_sym
    end

    # Determine whether or not a cross-reference note already exists.
    def cross_reference_exists?(noteable, mentioner)
      where(noteable_id: noteable.id, system: true, note: "_mentioned in #{mentioner.gfm_reference}_").any?
    end

    def search(query)
      where("note like :query", query: "%#{query}%")
    end
  end

  def commit_author
    @commit_author ||=
      project.users.find_by(email: noteable.author_email) ||
      project.users.find_by(name: noteable.author_name)
  rescue
    nil
  end

  def find_diff
    return nil unless noteable && noteable.diffs.present?

    @diff ||= noteable.diffs.find do |d|
      Digest::SHA1.hexdigest(d.new_path) == diff_file_index if d.new_path
    end
  end

  def set_diff
    # First lets find notes with same diff
    # before iterating over all mr diffs
    diff = Note.where(noteable_id: self.noteable_id, noteable_type: self.noteable_type, line_code: self.line_code).last.try(:diff)
    diff ||= find_diff

    self.st_diff = diff.to_hash if diff
  end

  def diff
    @diff ||= Gitlab::Git::Diff.new(st_diff) if st_diff.respond_to?(:map)
  end

  # Check if such line of code exists in merge request diff
  # If exists - its active discussion
  # If not - its outdated diff
  def active?
    return true unless self.diff

    noteable.diffs.each do |mr_diff|
      next unless mr_diff.new_path == self.diff.new_path

      Gitlab::DiffParser.new(mr_diff.diff.lines.to_a, mr_diff.new_path).
        each do |full_line, type, line_code, line_new, line_old|
        if full_line == diff_line
          return true
        end
      end
    end

    false
  end

  def outdated?
    !active?
  end

  def diff_file_index
    line_code.split('_')[0]
  end

  def diff_file_name
    diff.new_path if diff
  end

  def diff_old_line
    line_code.split('_')[1].to_i
  end

  def diff_new_line
    line_code.split('_')[2].to_i
  end

  def diff_line
    return @diff_line if @diff_line

    if diff
      Gitlab::DiffParser.new(diff.diff.lines.to_a, diff.new_path)
        .each do |full_line, type, line_code, line_new, line_old|
          @diff_line = full_line if line_code == self.line_code
        end
    end

    @diff_line
  end

  def discussion_id
    @discussion_id ||= Note.build_discussion_id(noteable_type, noteable_id || commit_id, line_code)
  end

  # Returns true if this is a downvote note,
  # otherwise false is returned
  def downvote?
    votable? && (note.start_with?('-1') ||
                 note.start_with?(':-1:') ||
                 note.start_with?(':thumbsdown:') ||
                 note.start_with?(':thumbs_down_sign:')
                )
  end

  def for_commit?
    noteable_type == "Commit"
  end

  def for_commit_diff_line?
    for_commit? && for_diff_line?
  end

  def for_diff_line?
    line_code.present?
  end

  def for_issue?
    noteable_type == "Issue"
  end

  def for_merge_request?
    noteable_type == "MergeRequest"
  end

  def for_merge_request_diff_line?
    for_merge_request? && for_diff_line?
  end

  # override to return commits, which are not active record
  def noteable
    if for_commit?
      project.repository.commit(commit_id)
    else
      super
    end
  # Temp fix to prevent app crash
  # if note commit id doesn't exist
  rescue
    nil
  end

  # Returns true if this is an upvote note,
  # otherwise false is returned
  def upvote?
    votable? && (note.start_with?('+1') ||
                 note.start_with?(':+1:') ||
                 note.start_with?(':thumbsup:') ||
                 note.start_with?(':thumbs_up_sign:')
                )
  end

  def votable?
    for_issue? || (for_merge_request? && !for_diff_line?)
  end

  # Mentionable override.
  def gfm_reference
    noteable.gfm_reference
  end

  # Mentionable override.
  def local_reference
    noteable
  end

  def noteable_type_name
    if noteable_type.present?
      noteable_type.downcase
    end
  end

  # FIXME: Hack for polymorphic associations with STI
  #        For more information wisit http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html#label-Polymorphic+Associations
  def noteable_type=(sType)
    super(sType.to_s.classify.constantize.base_class.to_s)
  end

  # Reset notes events cache
  #
  # Since we do cache @event we need to reset cache in special cases:
  # * when a note is updated
  # * when a note is removed
  # Events cache stored like  events/23-20130109142513.
  # The cache key includes updated_at timestamp.
  # Thus it will automatically generate a new fragment
  # when the event is updated because the key changes.
  def reset_events_cache
    Event.reset_event_cache_for(self)
  end

  def set_references
    notice_added_references(project, author)
  end

  def editable?
    !system
  end
end