require 'parslet'
require 'figtree/ip_rules'

module Figtree
  # ConFIG into a Tree :)
  class Parser < Parslet::Parser
    include IPv4
    include IPv6

    rule(:eof) { any.absent? }
    rule(:group_title) { match('[a-zA-Z]').repeat(1) }
    rule(:space) { match("\s").repeat(0) }
    rule(:newline) { match("\n") >> match("\r").maybe }

    rule(:grouper) do
      newline.maybe >>
      str('[') >>
      group_title.as(:group_title) >>
      str(']')
    end

    rule(:comment) do
      # comments go uncaptured
      (str(';') >>
       (newline.absent? >> any).repeat) >>
      newline.maybe
    end

    rule(:string) do
      str('"') >>
      ((str('\\') >> any) | (str('"').absent? >> any)).repeat.as(:string) >>
      str('"')
    end

    rule(:boolean) do
      # expand this check
      (str('no') | str('yes')).as(:boolean)
    end

    rule(:number) do
      match('[0-9]').repeat(1).as(:number)
    end

    rule(:ip_address) do
      (ipv4 | ipv6).as(:ip_address)
    end

    rule(:array) do
      (match('[a-zA-Z]').repeat(1) >>
       (str(',') >>
        match('[a-zA-Z]').repeat(1)).repeat.maybe).maybe.as(:array) >>
      (str(',') | newline | eof)
    end

    rule(:file_path) do
      match('[/a-z/]').repeat(1).as(:file_path)
    end

    rule(:snake_case_key) do
      match('[a-zA-Z0-9_]').repeat(1).as(:snake_case_key)
    end

    rule(:snakey_option_key) do
      snake_case_key.as(:key_to_be_overridden) >>
      str('<') >>
      snake_case_key.as(:optional_key) >>
      str('>')
    end

    rule(:assignment) do
      snake_case_key >>
      space >>
      str("=") >>
      space >>
      # this ordering matters
      # we are roughly moving from more
      # to less specific
      (ip_address |
       number |
       boolean |
       array |
       snake_case_key |
       file_path |
       string)
    end

    rule(:override_assignment) do
      snakey_option_key >>
      space >>
      str("=") >>
      space >>
      file_path
    end

    rule(:assignment_or_comment) do
      ( comment | assignment | override_assignment )
    end

    rule(:group_member) do
      newline.maybe >>
      assignment_or_comment >>
      newline.maybe
    end

    rule(:group) do
      (grouper >>
       group_member.repeat.maybe).as(:group).
      repeat.maybe
    end

    rule(:comment_or_group) do
      comment.maybe >>
      newline.maybe >>
      group.maybe
    end

    root(:comment_or_group)
  end
end