# encoding: utf-8
module LocalPac
  class GitRepository
    private

    attr_reader :repository, :root_commit, :null_file, :file_creator

    public

    attr_reader :storage_path

    def initialize(storage_path, file_creator = LocalPac::File, null_file = LocalPac::NullFile.new)
      @storage_path = ::File.expand_path(storage_path)
      @repository   = Rugged::Repository.new(storage_path)
      @file_creator = file_creator
      @null_file    = null_file

    rescue Rugged::RepositoryError
      raise Exceptions::RepositoryDoesNotExist, "Sorry, but #{storage_path} is not a git repository."
    end

    def self.create(storage_path) 
      storage_path = ::File.expand_path(storage_path)
      Rugged::Repository.init_at(storage_path, :bare)

      new(storage_path)
    end

    def add_content(path, content = '', mode = 0100644, commit_info = default_commit_info)
      index = Rugged::Index.new

      unless repository.empty? 
        root_commit  = repository.lookup(repository.head.target)

        root_commit.tree.walk_blobs(:postorder) do |r, e| 
          e.merge!( { path: "#{r}#{e[:name]}" } )
          e.delete(:name)

          index.add(e)
        end
      end

      oid = repository.write(content, :blob)
      index.add(:path => path, :oid => oid, :mode => mode)

      options              = {}
      options[:tree]       = index.write_tree(repository)
      options[:parents]    = repository.empty? ? [] : [ repository.head.target ].compact
      options[:update_ref] = 'HEAD'
      options.merge! commit_info

      Rugged::Commit.create(repository, options)
    end

    def added_files(old_commit_id, new_commit_id)
      begin
        commit_old = repository.lookup(old_commit_id)
      rescue Rugged::OdbError
        LocalPac.ui_logger.warn "Invalid commit id \"#{old_commit_id}\". Object cannot be found in repository \"#{storage_path}\"."
        raise Exceptions::CommitDoesNotExist
      end

      begin
        commit_new = repository.lookup(new_commit_id)
      rescue Rugged::OdbError
        LocalPac.ui_logger.warn "Invalid commit id \"#{old_commit_id}\". Object cannot be found in repository \"#{storage_path}\"."
        raise Exceptions::CommitDoesNotExist
      end

      commit_old.diff(commit_new).deltas.keep_if { |d| [:added, :modified].include?(d.status) }.collect { |d| File.new(d.new_file[:path], repository.lookup(d.new_file[:oid]).content) }
    end

    def find_file(name)
      files.fetch(name, null_file)
    end

    def all_files
      files.collect { |_,f| f }
    end

    def each_file(&block)
      all_files.each(&block)
    end

    private

    def files
      files_in_repository.reduce({}) do |memo, file| 
        memo[file.name.to_sym] = file

        memo
      end
    end

    def files_in_repository
      return [] if repository.empty?

      head_commit = repository.lookup(repository.head.target)

      files = []
      head_commit.tree.walk_blobs(:postorder) do |root, entry| 
        files << file_creator.new("#{root}#{entry[:name]}", repository.lookup(entry[:oid]).content ) 
      end

      files
    end

    def default_commit_info
      options             = {}
      options[:author]    = { :email => 'local_pac@local_pac', :name => 'Local Pac', :time => Time.now }
      options[:committer] = { :email => 'local_pac@local_pac', :name => 'Local Pac', :time => Time.now }
      options[:message]   = 'Commit made by local pac itself'

      options
    end
  end
end