Display commits per branch, day by day

git-cal

#!/usr/bin/env ruby

# frozen_string_literal: true

# Gems:
#  gem install tty-option rugged skittlize activesupport pastel
require 'tty-option'
require 'rugged'
require 'skittlize'
require 'active_support/deprecator'  # Required for active_support to work
require 'active_support/deprecation' # Required for active_support to work
require 'active_support/core_ext/integer/time'
require 'pastel'
require 'i18n'

# Ruby standard libs
require 'date'

module ExperimentsLabs
  class GitCal
    class Error < StandardError; end

    def initialize
      @pastel          = Pastel.new
      @repository      = Rugged::Repository.discover Dir.pwd
      @committer_email = @repository.default_signature[:email]
    end

    def show_calendar(branches: [], main_branch: nil, days: nil)
      raise 'You should provide an array of branches' unless branches.is_a? Array

      days = days ? days.to_i : nil

      @branches    = process_branches_args branches
      @main_branch = main_branch

      today = Time.new.beginning_of_day
      @start_date = days ? (today - days.days) : Time.new.beginning_of_month
      @days_to_show = days || today.day

      list
      render
    end

    private

    def list # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
      @commits_per_day = {}

      puts "Commits by #{@committer_email}, from #{@start_date.to_date} to now"

      @branches.each do |branch, branch_commit_id|
        commit_list = commits_for branch_commit_id

        @days_to_show.times do |index|
          day        = (@start_date + index.days).to_date
          day_string = day.to_s

          @commits_per_day[day_string] ||= {}

          commit_list.select { |commit| day == commit.committer[:time].to_date }
                     .each do |commit|
            message = commit.message.split("\n").first

            @commits_per_day[day_string][message] ||= []
            @commits_per_day[day_string][message].push branch
          end
        end
      end
    end

    def commits_for(head_hash)
      walker = Rugged::Walker.new @repository
      walker.sorting Rugged::SORT_DATE
      walker.push head_hash

      walker.select do |commit|
        commit.author[:time].after?(@start_date) && commit.author[:email] == @committer_email
      end
    end

    def render # rubocop:disable Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity, Metrics/CyclomaticComplexity
      # Rendering
      @commits_per_day.each do |day, commits|
        next if commits.empty?

        puts @pastel.bold Date.parse(day).strftime('%v (%a)')
        commits.keys.sort.each do |message|
          branches_list = if @branches.size > 1
                            commits[message]
                              # Ignore other branches when a commit is already on the main branch
                              .reject { |branch| @main_branch && commits[message].include?(@main_branch) && branch != @main_branch }
                              .map(&:skittlize)
                              .join(', ')
                          end

          branches_list = branches_list ? "[#{branches_list}] " : ''

          if message.match?(/^merge /i)
            message = @pastel.decorate(message, :dim, :strikethrough)
          else
            nibbles = message.split(':')
            nibbles[0] = nibbles[0].skittlize if nibbles.size > 1

            message = nibbles.join(':')
          end

          puts "  #{branches_list}#{message}"
        end

        puts "\n"
      end
    end

    # Checks branches argument against repository branches and returns a hash
    # with the git object id
    #
    # @return [Hash] - Like <branch>: <branch_commit_id>
    def process_branches_args(branches)
      return { @repository.head.name.sub(%r{^refs/heads/}, '').to_s => @repository.head.target_id } if branches.empty?

      branches = {}

      branches.each do |name|
        branch = repository.branches[name]
        raise GitCal::Error, "Invalid branch #{name}" unless branch

        branches[name] = branch.target_id
      end

      branches
    end
  end

  class GitCalCli
    include TTY::Option

    usage do
      program 'git-cal'
      desc 'Display commits per branch, day by day'
      no_command
      example <<~TXT
        git cal                  # list commits of the current branch
        git cal branch1, branch2 # list commits for the given branches
      TXT
    end

    argument :branches do
      optional
      arity zero_or_more
      default []
      desc 'Branch to use in listing'
    end

    option :main do
      optional
      long '--main string'
      short '-m'
      desc 'Main branch: commits present in this branch will be hidden from others'
    end

    option :days do
      optional
      long '--days int'
      short '-d'
      desc 'Optional amount of days to use, instead of the beginning of month'
      validate(/^\d+$/)
    end

    flag :help do
      short '-h'
      long '--help'
      desc 'Print usage'
    end

    def run
      handle_help

      cal = GitCal.new
      cal.show_calendar branches:    params[:branches],
                        main_branch: params[:main],
                        days:        params[:days]
    rescue GitCal::Error => e
      puts e
      exit 1
    end

    private

    def handle_help
      return unless params[:help]

      print help
      exit 0
    end
  end
end


cli = ExperimentsLabs::GitCalCli.new
cli.parse
cli.run