# Originally from https://github.com/mikel/mail lib/mail/parsers/rfc2822.treetop

module Pre
  grammar RFC2822
  
    include RFC2822Obsolete

    rule ALPHA
      [a-zA-Z]
    end
    
    rule DIGIT
      [0-9]
    end
    
    rule DQUOTE
      '"'
    end
    
    rule LF
      "\n"
    end
    
    rule CR
      "\r"
    end

    rule CRLF
      "\r\n"
    end
  
    rule WSP
      [\x09\x20]
    end
  
    rule FWS    # Folding white space
      (WSP* CRLF WSP+) / (CRLF WSP+) / obs_FWS
    end

    rule CFWS
      (FWS* comment)* FWS?
    end

    rule NO_WS_CTL
      [\x01-\x08]   /         # US-ASCII control characters
      [\x0B-\x0C]   /         #  that do not include the
      [\x0E-\x1F]   /         #  carriage return, line feed,
      [\x7f]                  #  and white space characters
    end

    rule specials
      "(" / ")" /     # Special characters used in
      "<" / ">" /     #  other parts of the syntax
      "[" / "]" /
      ":" / ";" /
      "@" / '\\' /
      "," / "." /
      DQUOTE
    end

    rule ctext
      NO_WS_CTL   /    # Non white space controls
      [\x21-\x27] /    # The rest of the US-ASCII
      [\x2a-\x5b] /    #  characters not including "(",
      [\x5d-\x7e]      #  ")", or "\"
    end

    rule ccontent
      ctext / quoted_pair / comment
    end

    rule comment
      "(" ( FWS? ccontent )* FWS? ")"
    end
  
    rule atext
      ALPHA / DIGIT / # Any character except controls,
      "!" / "#" /     #  SP, and specials.
      "$" / "%" /     #  Used for atoms
      "&" / "'" /
      "*" / "+" /
      "-" / "/" /
      "=" / "?" /
      "^" / "_" /
      "`" / "{" /
      "|" / "}" /
      "~"
    end
    
    rule mtext
      (atext / ".")+
    end

    rule atom
      CFWS? atext+ CFWS?
    end

    rule dot_atom
      CFWS? dot_atom_text CFWS?
    end
  
    rule local_dot_atom
      CFWS? local_dot_atom_text CFWS?
    end
    
    rule message_id_text
      mtext+
    end
    
    rule dot_atom_text
      (domain_text "."?)+
    end
    
    rule local_dot_atom_text
      ("."? domain_text)+
    end
    
    rule domain_text
      (DQUOTE (FWS? quoted_domain)+ FWS? DQUOTE) / atext+
    end
    
    rule quoted_domain
      qdcontent / "\\" text
    end
    
    rule qdcontent
      NO_WS_CTL /     # Non white space controls
      [\x21] /        # The rest of the US-ASCII
      [\x23-\x45] /   # characters not including "\"
      [\x47-\x5b] /   # or the "." or the 
      [\x5d-\x7e]     # double quote character
    end

    rule phrase
      obs_phrase / word+
    end
    
    rule word
      atom / quoted_string
    end
    
    rule phrase_list
      first_phrase:phrase other_phrases:("," FWS* phrase_value:phrase)*
    end

    rule domain_literal
      CFWS? "[" (FWS? dcontent)* FWS? "]" CFWS?
    end

    rule dcontent
      dtext / quoted_pair
    end

    rule dtext
      NO_WS_CTL    /  # Non white space controls
      [\x21-\x5a]  /  # The rest of the US-ASCII characters
      [\x5e-\x7e]     #  not including "[", "]", or "\"
    end

    rule angle_addr
      CFWS? "<" addr_spec ">" CFWS? / obs_angle_addr
    end

    rule addr_spec
      (local_part "@" domain) / local_part
    end

    rule local_part
      local_dot_atom / quoted_string / obs_local_part
    end
  
    rule domain
      dot_atom / domain_literal / obs_domain
    end
  
    rule group
      group_name:display_name ":" group_list:(mailbox_list_group / CFWS)? ";" CFWS?
    end

    rule mailbox_list_group
      mailbox_list {
        def addresses
          [first_addr] + other_addr.elements.map { |o| o.addr_value }
        end
      }
    end

    rule quoted_string
      CFWS? DQUOTE quoted_content:(FWS? qcontent)+ FWS? DQUOTE CFWS?
    end

    rule qcontent
      qtext / quoted_pair
    end

    rule quoted_pair
      ("\\" text) / obs_qp
    end
  
    rule qtext
      NO_WS_CTL /     # Non white space controls
      [\x21] /        # The rest of the US-ASCII
      [\x23-\x5b] /   #  characters not including "\"
      [\x5d-\x7e]     #  or the quote character
    end

    rule text
      [\x01-\x09]     /       # Characters excluding CR and LF
      [\x0b-\x0c]     /
      [\x0e-\x7e]     / 
      obs_text
    end
    
    rule display_name
      phrase
    end
    
    rule name_addr
      display_name angle_addr / angle_addr
    end
    
    rule mailbox_list
      (first_addr:mailbox other_addr:("," addr_value:mailbox)*) / obs_mbox_list
    end
  
    rule mailbox
      name_addr / addr_spec
    end

    rule address
      group {
    
        def dig_comments(comments, elements)
          elements.each { |elem|
            if elem.respond_to?(:comment)
              comments << elem.comment
            end
            dig_comments(comments, elem.elements) if elem.elements
           }
        end
    
        def comments
          comments = []
          dig_comments(comments, elements)
          comments
        end

      } /
      mailbox {

      def dig_comments(comments, elements)
        elements.each { |elem|
          if elem.respond_to?(:comment)
            comments << elem.comment
          end
          dig_comments(comments, elem.elements) if elem.elements
         }
      end

      def comments
        comments = []
        dig_comments(comments, elements)
        comments
      end

      }
    end
  
    rule address_list
      first_addr:address? other_addr:(FWS* "," FWS* addr_value:address?)*
    end
    
    rule date_time
      ( day_of_week ",")? date FWS time CFWS?
    end

    rule day_of_week
      (FWS? day_name) / obs_day_of_week
    end

    rule day_name
      "Mon" / "Tue" / "Wed" / "Thu" /
      "Fri" / "Sat" / "Sun"
    end

    rule date
      day month year
    end
    
    rule year
      DIGIT DIGIT DIGIT DIGIT / obs_year
    end
    
    rule month
      (FWS month_name FWS) / obs_month
    end
    
    rule month_name
      "Jan" / "Feb" / "Mar" / "Apr" /
      "May" / "Jun" / "Jul" / "Aug" /
      "Sep" / "Oct" / "Nov" / "Dec"
    end
    
    rule day
      (FWS? DIGIT DIGIT?) / obs_day
    end
    
    rule time
      time_of_day FWS zone
    end
    
    rule time_of_day
      hour ":" minute ( ":" second )?
    end
    
    rule hour
      DIGIT DIGIT / obs_hour
    end
    
    rule minute
      DIGIT DIGIT / obs_minute
    end
    
    rule second
      DIGIT DIGIT / obs_second
    end
    
    rule zone
      (( "+" / "-" ) DIGIT DIGIT DIGIT DIGIT) / obs_zone
    end
    
    rule return
      path CRLF
    end
    
    rule path
      ((CFWS)? "<" ((CFWS)? / addr_spec) ">" (CFWS)?) / obs_path
    end
    
    rule received
      name_val_list ";" date_time CRLF
    end
    
    rule name_val_list
      (CFWS)? (name_val_pair (CFWS name_val_pair)*)
    end
    
    rule name_val_pair
      item_name CFWS item_value
    end
    
    rule item_name
      ALPHA (("-")? (ALPHA / DIGIT))*
    end
    
    rule item_value
      (angle_addr)+ / addr_spec / atom / domain / msg_id
    end

    rule message_ids
      first_msg_id:msg_id other_msg_ids:( CFWS msg_id_value:msg_id )*
    end
    
    rule msg_id
      (CFWS)? "<" msg_id_value ">" (CFWS)?
    end
    
    rule msg_id_value
      id_left "@" id_right
    end
    
    rule id_left
      message_id_text / no_fold_quote / obs_id_left
    end
    
    rule id_right
      msg_id_dot_atom_text / no_fold_literal / obs_id_right
    end
    
    rule msg_id_dot_atom_text
      (msg_id_domain_text "."?)+
    end

    rule msg_id_domain_text
      (DQUOTE (FWS? quoted_domain)+ FWS? DQUOTE) / msg_id_atext+
    end

    rule msg_id_atext
      ALPHA / DIGIT / # Any character except controls,
      "!" / "#" /     #  SP, and specials.
      "$" / "%" /     #  Used for atoms
      "&" / "'" /
      "*" / "+" /
      "-" / "/" /
      "=" / "?" /
      "^" / "_" /
      "`" / "{" /
      "|" / "}" /
      "~" / "@"
    end

    rule no_fold_quote
      DQUOTE (qtext / quoted_pair)+ DQUOTE
    end

    rule no_fold_literal
      "[" (dtext / quoted_pair)+ "]"
    end
    
    
  end
end