require "rake"
require "rake/tasklib"

module Fog
  module Rake
    class ChangelogTask < ::Rake::TaskLib

      def initialize
        desc "Update the changelog since the last release"
        task(:changelog) do
          timestamp = Time.now.utc.strftime('%m/%d/%Y')
          sha = `git log | head -1`.split(' ').last
          changelog = ["#{Fog::VERSION} #{timestamp} #{sha}"]
          changelog << ('=' * changelog[0].length)
          changelog << ''

          require 'multi_json'
          github_repo_data = Fog::JSON.decode(Excon.get('https://api.github.com/repos/fog/fog', :headers => {'User-Agent' => 'geemus'}).body)
          data = github_repo_data.reject {|key, value| !['forks', 'open_issues', 'watchers'].include?(key)}
          github_collaborator_data = Fog::JSON.decode(Excon.get('https://api.github.com/repos/fog/fog/collaborators', :headers => {'User-Agent' => 'geemus'}).body)
          data['collaborators'] = github_collaborator_data.length
          rubygems_data = Fog::JSON.decode(Excon.get('https://rubygems.org/api/v1/gems/fog.json').body)
          data['downloads'] = rubygems_data['downloads']
          stats = []
          for key in data.keys.sort
            stats << "'#{key}' => #{data[key]}"
          end
          changelog << "Stats! { #{stats.join(', ')} }"
          changelog << ''

          last_sha = `cat changelog.txt | head -1`.split(' ').last
          shortlog = `git shortlog #{last_sha}..HEAD`
          changes = {}
          committers = {}
          for line in shortlog.split("\n")
            if line =~ /^\S/
              committer = line.split(' (', 2).first
              committers[committer] = 0
            elsif line =~ /^\s*((Merge.*)|(Release.*))?$/
              # skip empty lines, Merge and Release commits
            else
              unless line[-1..-1] == '.'
                line << '.'
              end
              line.lstrip!
              line.gsub!(/^\[([^\]]*)\] /, '')
              tag = $1 || 'misc'
              changes[tag] ||= []
              changes[tag] << (line << ' thanks ' << committer)
              committers[committer] += 1
            end
          end

          for committer, commits in committers.to_a.sort {|x,y| y[1] <=> x[1]}
            if [
              'Aaron Suggs',
              'Brian Hartsock',
              'Christopher Oliver',
              'Daniel Reichert',
              'Decklin Foster',
              'Dylan Egan',
              'Erik Michaels-Ober',
              'geemus',
              'Henry Addison',
              'James Bence',
              'Kevin Menard',
              'Kyle Rames',
              'Lincoln Stoll',
              'Luqman Amjad',
              'Michael Zeng',
              'Nat Welch',
              'Nick Osborn',
              'nightshade427',
              'Patrick Debois',
              'Paul Thornthwaite',
              'Rupak Ganguly',
              'Stepan G. Fedorov',
              'Wesley Beary'
            ].include?(committer)
            next
            end
            changelog << "MVP! #{committer}"
            changelog << ''
            break
          end

          for tag in changes.keys.sort
            changelog << ('[' << tag << ']')
            for commit in changes[tag]
              changelog << ('  ' << commit)
            end
            changelog << ''
          end

          old_changelog = File.read('changelog.txt')
          File.open('changelog.txt', 'w') do |file|
            file.write(changelog.join("\n"))
            file.write("\n\n")
            file.write(old_changelog)
          end
        end
      end
    end
  end
end