#!/usr/bin/env ruby
# ebnf --- Process EBNF to generate the following:
# * S-Expression
# * Turtle
# * Either of the above, transformed to BNF
# * And with First/Follow rules

$:.unshift(File.expand_path(File.join(File.dirname(__FILE__), "..", 'lib')))
require "bundler/setup"
require 'rubygems'
require 'getoptlong'
require 'ebnf'

def dump_tables(grammarFile, ebnf, output, options)
  ebnf.build_tables
  unless output == STDOUT
    output.puts "# This file is automatically generated by #{__FILE__}"
    output.puts "# BRANCH derived from #{grammarFile}"
    unless ebnf.errors.empty?
      output.puts "# Note, tables completed with errors, may need to be resolved manually:"
      #output.puts "#   #{pp.conflicts.map{|c| c.join("\n#      ")}.join("\n#   ")}"
    end
    output.puts "module #{options.fetch(:mod_name, 'Branch')}"
    output.puts "  START = #{ebnf.start.inspect}"
    output.puts
  end
  ebnf.outputTable(output, 'BRANCH', ebnf.branch, 1)
  ebnf.outputTable(output, 'TERMINALS', ebnf.terminals, 1)
  ebnf.outputTable(output, 'FIRST', ebnf.first, 1)
  ebnf.outputTable(output, 'FOLLOW', ebnf.follow, 1)
  ebnf.outputTable(output, 'PASS', [ebnf.pass], 1) if ebnf.pass
  unless output == STDOUT
    output.puts "end"
  end
  ""
end

options = {
  :output_format => :sxp,
  :prefix => "ttl",
  :namespace => "http://www.w3.org/ns/formats/Turtle#",
}

out = STDOUT

OPT_ARGS = [
  ["--dbg",             GetoptLong::NO_ARGUMENT,      "Turn on debugging output"],
  ["--bnf",             GetoptLong::NO_ARGUMENT,      "Transform EBNF to BNF"],
  ["--evaluate","-e",   GetoptLong::REQUIRED_ARGUMENT,"Evaluate argument as a JSON-LD document"],
  ["--ll1",             GetoptLong::REQUIRED_ARGUMENT,"Generate First/Follow rules, argument is start symbol"],
  ["--format", "-f",    GetoptLong::REQUIRED_ARGUMENT,"Specify output format one of ebnf, html, ttl, sxp, or rb"],
  ["--input-format",    GetoptLong::REQUIRED_ARGUMENT,"Specify input format one of ebnf or sxp"],
  ["--mod-name",        GetoptLong::REQUIRED_ARGUMENT,"Module name used when creating ruby tables"],
  ["--output", "-o",    GetoptLong::REQUIRED_ARGUMENT,"Output to the specified file path"],
  ["--prefix", "-p",    GetoptLong::REQUIRED_ARGUMENT,"Prefix to use when generating Turtle"],
  ["--progress", "-v",  GetoptLong::NO_ARGUMENT,     "Detail on execution"],
  ["--namespace", "-n", GetoptLong::REQUIRED_ARGUMENT,"Namespace to use when generating Turtle"],
  ["--help", "-?",      GetoptLong::NO_ARGUMENT,      "This message"]
]
def usage
  STDERR.puts %{#{$0} Version #{EBNF::VERSION}}
  STDERR.puts %{Usage: #{$0} [options] file ...}
  width = OPT_ARGS.map do |o|
    l = o.first.length
    l += o[1].length + 2 if o[1].is_a?(String)
    l
  end.max
  OPT_ARGS.each do |o|
    s = "  %-*s  " % [width, (o[1].is_a?(String) ? "#{o[0,2].join(', ')}" : o[0])]
    s += o.last
    STDERR.puts s
  end
  exit(1)
end

opts = GetoptLong.new(*OPT_ARGS.map {|o| o[0..-2]})

opts.each do |opt, arg|
  case opt
  when '--dbg'          then options[:debug] = true
  when '--bnf'          then options[:bnf] = true
  when '--evaluate'     then input = arg
  when '--input-format' then options[:format] = arg.to_sym
  when '--format'       then options[:output_format] = arg.to_sym
  when '--ll1'          then options[:ll1] = arg.to_sym
  when '--mod-name'     then options[:mod_name] = arg
  when '--output'       then out = File.open(arg, "w")
  when '--prefix'       then options[:prefix] = arg
  when '--namespace'    then options[:namespace] = arg
  when '--progress'     then options[:progress] = true
  when '--help'         then usage
  end
end

if options[:output_format] == :rb && !options[:ll1]
  STDERR.puts "outputing in .rb format requires -ll"
  exit(1)
end

input = File.open(ARGV[0]) if ARGV[0]

ebnf = EBNF.parse(input || STDIN, options)
ebnf.make_bnf if options[:bnf] || options[:ll1]
ebnf.first_follow(options[:ll1]) if options[:ll1]

res = case options[:output_format]
when :ebnf    then ebnf.to_s
when :html    then ebnf.to_html
when :sxp     then ebnf.to_sxp
when :ttl     then ebnf.to_ttl(options[:prefix], options[:namespace])
when :rb      then dump_tables(ARGV[0], ebnf, out, options)
else          ebnf.ast.inspect
end

out.puts res