# Gitlab::Git::Commit is a wrapper around native Grit::Commit object
# We dont want to use grit objects inside app/
# It helps us easily migrate to rugged in future
module Gitlab
  module Git
    class Commit
      attr_accessor :raw_commit, :head, :refs,
        :id, :authored_date, :committed_date, :message,
        :author_name, :author_email, :parent_ids,
        :committer_name, :committer_email

      delegate :parents, :diffs, :tree, :stats, :to_patch,
        to: :raw_commit

      class << self
        def serialize_keys
          %w(id authored_date committed_date author_name author_email committer_name committer_email message parent_ids)
        end

        def find_or_first(repo, commit_id = nil, root_ref)
          commit = if commit_id
                     repo.commit(commit_id)
                   else
                     repo.commits(root_ref).first
                   end

          Commit.new(commit) if commit
        end

        def fresh_commits(repo, n = 10)
          commits = repo.heads.map do |h|
            repo.commits(h.name, n).map { |c| Commit.new(c, h) }
          end.flatten.uniq { |c| c.id }

          commits.sort! do |x, y|
            y.committed_date <=> x.committed_date
          end

          commits[0...n]
        end

        def commits_with_refs(repo, n = 20)
          commits = repo.branches.map { |ref| Commit.new(ref.commit, ref) }

          commits.sort! do |x, y|
            y.committed_date <=> x.committed_date
          end

          commits[0..n]
        end

        def commits_since(repo, date)
          commits = repo.heads.map do |h|
            repo.log(h.name, nil, since: date).each { |c| Commit.new(c, h) }
          end.flatten.uniq { |c| c.id }

          commits.sort! do |x, y|
            y.committed_date <=> x.committed_date
          end

          commits
        end

        def commits(repo, ref, path = nil, limit = nil, offset = nil)
          if path
            repo.log(ref, path, max_count: limit, skip: offset)
          elsif limit && offset
            repo.commits(ref, limit, offset)
          else
            repo.commits(ref)
          end.map{ |c| Commit.new(c) }
        end

        def commits_between(repo, from, to)
          repo.commits_between(from, to).map { |c| Commit.new(c) }
        end
      end

      def initialize(raw_commit, head = nil)
        raise "Nil as raw commit passed" unless raw_commit

        if raw_commit.is_a?(Hash)
          init_from_hash(raw_commit)
        else
          init_from_grit(raw_commit)
        end

        @head = head
      end

      def sha
        id
      end

      def short_id(length = 10)
        id.to_s[0..length]
      end

      def safe_message
        @safe_message ||= message
      end

      def created_at
        committed_date
      end

      # Was this commit committed by a different person than the original author?
      def different_committer?
        author_name != committer_name || author_email != committer_email
      end

      def parent_id
        parent_ids.first
      end

      # Shows the diff between the commit's parent and the commit.
      #
      # Cuts out the header and stats from #to_patch and returns only the diff.
      def to_diff
        # see Grit::Commit#show
        patch = to_patch

        # discard lines before the diff
        lines = patch.split("\n")
        while !lines.first.start_with?("diff --git") do
          lines.shift
        end
        lines.pop if lines.last =~ /^[\d.]+$/ # Git version
          lines.pop if lines.last == "-- "      # end of diff
        lines.join("\n")
      end

      def has_zero_stats?
        stats.total.zero?
      rescue
        true
      end

      def no_commit_message
        "--no commit message"
      end

      def to_hash
        hash = {}

        keys = Commit.serialize_keys

        keys.each do |key|
          hash[key] = send(key)
        end

        hash
      end

      def date
        committed_date
      end

      private

      def init_from_grit(grit)
        @raw_commit = grit
        @id = grit.id
        @message = grit.message
        @authored_date = grit.authored_date
        @committed_date = grit.committed_date
        @author_name = grit.author.name
        @author_email = grit.author.email
        @committer_name = grit.committer.name
        @committer_email = grit.committer.email
        @parent_ids = grit.parents.map(&:id)
      end

      def init_from_hash(hash)
        Commit.serialize_keys.each do |key|
          send(:"#{key}=", hash[key])
        end
      end
    end
  end
end