require 'ldap/server/util'

module LDAP
class Server

  class DN
    include Enumerable

    attr_reader :dname

    # Combines a set of elements to a syntactically correct DN
    # elements is [elements, ...] where elements
    # can be either { attr => val } or [attr, val]
    def self.join(elements)
      LDAP::Server::Operation.join_dn(elements)
    end

    def initialize(dn)
      @dname = LDAP::Server::Operation.split_dn(dn)
    end

    # Returns the value of the first occurrence of attr (bottom-up)
    def find_first(attr)
      @dname.each do |pair|
        return pair[attr.to_s] if pair[attr.to_s]
      end
      nil
    end

    # Returns the value of the last occurrence of attr (bottom-up)
    def find_last(attr)
      @dname.reverse_each do |pair|
        return pair[attr.to_s] if pair[attr.to_s]
      end
      nil
    end

    # Returns all values of all occurrences of attr (bottom-up)
    def find(attr)
      result = []
      @dname.each do |pair|
        result << pair[attr.to_s] if pair[attr.to_s]
      end
      result
    end

    # Returns the value of the n-th occurrence of attr (top-down, 0 is first element)
    def find_nth(attr, n)
      i = 0
      @dname.each do |pair|
        if pair[attr.to_s]
          return pair[attr.to_s] if i == n
          i += 1
        end
      end
      nil
    end

    # Whether or not the DN starts with dn (bottom-up)
    # dn is a string
    def start_with?(dn)
      needle = LDAP::Server::Operation.split_dn(dn)

      # Needle is longer than haystack
      return false if needle.length > @dname.length

      needle_index = 0
      haystack_index = 0

      while needle_index < needle.length
        return false if @dname[haystack_index] != needle[needle_index]
        needle_index += 1
        haystack_index += 1
      end
      true
    end

    # Whether or not the DN starts with a format (bottom-up) (values are ignored)
    # dn is a string
    def start_with_format?(dn)
      needle = LDAP::Server::Operation.split_dn(dn)

      # Needle is longer than haystack
      return false if needle.length > @dname.length

      needle_index = 0
      haystack_index = 0

      while needle_index < needle.length
        return false if @dname[haystack_index].keys != needle[needle_index].keys
        needle_index += 1
        haystack_index += 1
      end
      true
    end

    # Whether or not the DN ends with dn (top-down)
    # dn is a string
    def end_with?(dn)
      needle = LDAP::Server::Operation.split_dn(dn)

      # Needle is longer than haystack
      return false if needle.length > @dname.length

      needle_index = needle.length - 1
      haystack_index = @dname.length - 1

      while needle_index >= 0
        return false if @dname[haystack_index] != needle[needle_index]
        needle_index -= 1
        haystack_index -= 1
      end
      true
    end

    # Whether or not the DN ends with format (top-down) (values are ignored)
    # dn is a string
    def end_with_format?(dn)
      needle = LDAP::Server::Operation.split_dn(dn)

      # Needle is longer than haystack
      return false if needle.length > @dname.length

      needle_index = needle.length - 1
      haystack_index = @dname.length - 1

      while needle_index >= 0
        return false if @dname[haystack_index].keys != needle[needle_index].keys
        needle_index -= 1
        haystack_index -= 1
      end
      true
    end

    # Whether or not the DN equals dn (values are case sensitive)
    # dn is a string
    def equal?(dn)
      split_dn = LDAP::Server::Operation.split_dn(dn)

      return false if split_dn.length != @dname.length

      @dname.each_with_index do |pair, index|
        return false if pair != split_dn[index]
      end
      true
    end

    # Whether or not the DN equals dn's format (values are ignored) (case insensitive)
    # dn is a string
    def equal_format?(dn)
      split_dn = LDAP::Server::Operation.split_dn(dn)

      return false if split_dn.length != @dname.length

      @dname.each_with_index do |pair, index|
        return false if pair.keys != split_dn[index].keys
      end
      true
    end

    # Whether or not the DN constains a substring equal to dn (values are case sensitive)
    # dn is a string
    def include?(dn)
      split_dn = LDAP::Server::Operation.split_dn(dn)
      return false if split_dn.length > @dname.length
      LDAP::Server::Operation.join_dn(@dname).include?(LDAP::Server::Operation.join_dn(split_dn))
    end

    # Whether or not the DN constains a substring format equal to dn (values are ignored) (case insensitive)
    # dn is a string
    def include_format?(dn)
      split_dn = LDAP::Server::Operation.split_dn(dn)

      return false if split_dn.length > @dname.length

      haystack = []
      @dname.each { |pair| haystack << pair.keys }

      needle = []
      split_dn.each { |pair| needle << pair.keys }

      haystack.join.include?(needle.join)
    end

    # Generates a mapping for variables
    # For example:
    # > dn = LDAP::Server.DN.new("uid=user,ou=Users,dc=mydomain,dc=com")
    # > dn.parse("uid=:uid, ou=:category, dc=mydomain, dc=com")
    # => { :uid => "user", :category => "Users" }
    def parse(template_dn)
      result = {}
      template = LDAP::Server::Operation.split_dn(template_dn)
      template.reverse.zip(@dname.reverse).each do |temp, const|
        break if const and temp.keys.first != const.keys.first
        if temp.values.first.start_with?(':')
          sym = temp.values.first[1..-1].to_sym
          if const
            result[sym] = const.values.first unless result[sym]
          else
            result[sym] = nil
          end
        elsif temp.values.first != const.values.first
          break
        end
      end
      result
    end

    def each(&block)
      @dname.each(&block)
    end

    def reverse_each(&block)
      @dname.reverse_each(&block)
    end

  end

end
end