require 'erb'
require 'md5'

module Rid
  class Document
    include Attachments

    attr_accessor :hash, :path

    def initialize(options = {})
      path = options[:path]
      path = Pathname.new(path) unless path.nil? || path.is_a?(Pathname)
      @path = path
      # build hash from options hash
      @hash = options[:hash]
      # build hash from json option
      self.json = options[:json] if !@hash && options[:json]
      @hash ||= {}
    end

    def ==(other)
      @hash == other.hash
    end

    # Read document from a filesystem.
    #
    # Takes a filename,
    # many filenames,
    # or an array of filenames
    # and assign the return value of a yielded block to the hash.
    #
    # Nested hashes
    # like { "hash" => { "key" => "value" } }
    # can be constructed if the filename contains a slash (/),
    # eg "hash/key".
    #
    def read!(&block)
      raise 'No path given!' unless @path

      Dir[@path.join '**/*'].
        map! { |file| Pathname.new file }.
        delete_if { |f| !f.file? }.
        flatten.
        uniq.
        each do |filename|
          key = filename.relative_path_from(@path).to_s
          # strip js extname from javascript files
          key.sub!(/\.js$/, '') unless key =~ /^_attachments/
          key.sub!(/\.erb$/, '')

          value = block_given? ? block.call(filename) : read_file(filename)

          if key =~ /\.json$/
            # parse json files
            value = JSON.parse(value)
            key.sub!(/\.json$/, '')
          else
            # strip value if its a one-liner
            value.strip! if value.count("\n") == 1
          end

          @hash.update_at key, value
        end

      map_attachments!
    end


    # Returns a JSON string representation of the documents hash
    #
    def to_json
      @hash.to_json
    end

    # Build the documents hash from a JSON string
    #
    def json=(json)
      @hash = JSON.parse(json)
    end

    def id
      @id ||= @hash['_id']
      @id ||= @path && File.read(@path.join('_id')).strip rescue nil
    end

    def rev
      @rev ||= @hash['_rev']
      @rev ||= @path && File.read(@path.join('_rev')).strip rescue nil
    end

    def rev=(value)
      @rev = @hash['_rev'] = value
      if @path
        File.open(@path.join('_rev'), "w") { |file| file << value }
      end
    end

    def checksum(*files)
      MD5.new files.map { |f| File.read(File.join(@path, f)) }.join
    end

    private

    def read_file(filename)
      if File.extname(filename) == '.erb'
        ERB.new(File.read(filename)).result(binding)
      else
        File.read(filename)
      end
    end
  end
end