# $Id$

require 'stringio'
require 'optparse'

def main
  mode = nil
  ids1src = nil
  ids2src = nil
  template = nil
  output = nil

  parser = @parser = OptionParser.new
  parser.banner = "Usage: #{File.basename($0)} --mode=MODE [--ids1src=PATH] [--ids2src=PATH] [--template=PATH] [--output=PATH]"
  parser.on('--mode=MODE', '"ripper/core" or "eventids1".') {|m|
    mode = m
  }
  parser.on('--ids1src=PATH', 'A source file of event-IDs 1 (parse.y).') {|path|
    ids1src = path
  }
  parser.on('--ids2src=PATH', 'A source file of event-IDs 2 (eventids2.c).') {|path|
    ids2src = path
  }
  parser.on('--template=PATH', 'A template file of ripper/core.rb.') {|path|
    template = path
  }
  parser.on('--output=PATH', 'An output file.') {|path|
    output = path
  }
  parser.on('--help', 'Prints this message and quit.') {
    puts parser.help
    exit 0
  }
  begin
    parser.parse!
  rescue OptionParser::ParseError => err
    usage err.message
  end
  usage 'no mode given' unless mode
  case mode
  when 'ripper/core', 'ripper/core.rb'
    usage 'no --ids1src' unless ids1src
    usage 'no --ids2src' unless ids2src
    usage 'no --template' unless template
    result = generate_ripper_core(template, read_ids1(ids1src), read_ids2(ids2src))
  when 'eventids1', 'eventids1.c'
    usage 'no --ids1src' unless ids1src
    result = generate_eventids1(read_ids1(ids1src))
  end
  if output
    File.open(output, 'w') {|f|
      f.write result
    }
  else
    puts result
  end
end

def usage(msg)
  $stderr.puts msg
  $stderr.puts @parser.help
  exit 1
end

def generate_ripper_core(template, ids1, ids2)
  f = StringIO.new
  f.print <<header
# This file is automatically generated from #{File.basename(template)} and parse.y.
# DO NOT MODIFY!!!!!!

header
  File.foreach(template) do |line|
    case line
    when /\A\#include ids1/
      comma = ''
      ids1.each do |id, arity|
        f.print comma; comma = ",\n"
        f.print "    #{id.intern.inspect} => #{arity}"
      end
      f.puts
    when /\A\#include ids2/
      comma = ''
      ids2.each do |id|
        f.print comma; comma = ",\n"
        f.print "    #{id.intern.inspect} => 1"
      end
      f.puts
    when /\A\#include handlers1/
      ids1.each do |id, arity|
        f.puts
        f.puts "  def on_#{id}#{paramdecl(arity)}"
        f.puts "    #{arity == 0 ? 'nil' : 'a'}"
        f.puts "  end"
      end
    when /\A\#include handlers2/
      ids2.each do |id|
        f.puts
        f.puts "  def on_#{id}(token)"
        f.puts "    token"
        f.puts "  end"
      end
    when /\A\#include (.*)/
      raise "unknown operation: #include #{$1}"
    else
      f.print line
    end
  end
  f.string
end

def paramdecl(n)
  return '' if n == 0
  '(' + ('a'..'z').to_a[0, n].join(', ') + ')'
end

def generate_eventids1(ids)
  f = StringIO.new
  ids.each do |id, arity|
    f.puts "static ID ripper_id_#{id};"
  end
  f.puts
  f.puts 'static void'
  f.puts 'ripper_init_eventids1()'
  f.puts '{'
  ids.each do |id, arity|
    f.puts %Q[    ripper_id_#{id} = rb_intern("on_#{id}");]
  end
  f.puts '}'
  f.string
end

def read_ids1(path)
  check_arity path
  ids = {}
  File.open(path) {|f|
    f.each do |line|
      next if /\A\#\s*define\s+s?dispatch/ =~ line
      next if /ripper_dispatch/ =~ line
      if a = line.scan(/dispatch(\d)\((\w+)/)
        a.each do |arity, event|
          ids[event] = arity.to_i
        end
      end
    end
  }
  ids.to_a.sort_by {|event, arity| event.to_s }
end

def check_arity(path)
  invalid = false
  table = {}
  File.open(path) {|f|
    File.foreach(path) do |line|
      next if /\A\#\s*define\s+s?dispatch\d/ =~ line
      next if /ripper_dispatch\d/ =~ line
      line.scan(/dispatch(\d)\((\w+)/) do |num, ev|
        num = num.to_i
        if table.key?(ev)
          locations, arity = *table[ev]
          unless num == arity
            invalid = true
            $stderr.puts "arity differ [event=#{ev}]: #{f.lineno}=#{num}; #{locations.join(',')}=#{arity}"
          end
          locations.push f.lineno
        else
          table[ev] = [[f.lineno], num.to_i]
        end
      end
    end
  }
  exit 1 if invalid
end

def read_ids2(path)
  File.open(path) {|f|
    return f.read.scan(/ripper_id_(\w+)/).flatten.uniq.sort
  }
end

main