#!/usr/local/bin/ruby -Ks
# 
# Copyright (C) Koji Nakamaru
#
# Author: Koji Nakamaru (nakamaru at gmail.com)
# Modified: Apr 30 2005
#   * changed the contact information.
# Modified: Nov  4 2002
#   * added '-r'.
#   * regexp is now compiled only once.
#   * STDOUT.sync = true
# Modified: Jul 27 2002
#   * fixed the incorrect logic of search().
# Created: Jul 26 2002
# Keywords: grep, multiline, two lines
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Emacs; see the file COPYING.  If not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.
#

require 'jcode'
require 'nkf'

OPTIONS = {
  'i' => false,
  'n' => false,
  'e' => false,
  'r' => false,
}
progname = $0.gsub(/.*[\/\\]/, "")
USAGE = <<EOF
Usage: #{progname} [options] PATTERN [FILE...]
Options:
  -i
        ignore case distinctions in both PATTERN and the input files.
  -n
	prefix each line of output with the line number within its
	input file.
  -e
        use the next argument as PATTERN; useful to protect patterns
        beginning with -.
  -r
        handle directories recursively.
EOF
if ($KCODE =~ /^([es])./i)
  NKFOPTIONS = "-" + $1.downcase()
else
  print "#{progname}: $KCODE is undefined.\n"
  exit(1)
end
isfound = false

if (ARGV.length() == 0)
  STDERR.print(USAGE)
  exit(1)
else
  while (ARGV[0] =~ /^-(.+)/)
    for i in $1.unpack('A')
      if (OPTIONS[i] == nil)
	print(USAGE)
	exit(1)
      end
      OPTIONS[i] = true
    end
    ARGV.shift
    if (OPTIONS['e'])
      break
    end
  end
end

def printOneLine(fo, fname, l, s)
  if (fname)
    fo.printf(fname + ':')
  end
  if (OPTIONS['n'])
    fo.printf("%d:", l)
  end
  fo.printf("%s\n", s)
  fo.flush()
end

def search(fname, fi, regexp, fo)
  l = 1
  s0 = ''
  isprinted0 = true
  while (s1 = fi.gets())
    s1 = NKF.nkf(NKFOPTIONS, s1.chomp())
    isprinted1 = false

    t0 = s0.gsub(/\s+$/, "")
    t1 = s1.gsub(/^\s+/, "")
    ti = (t0 =~ /(.)$/ and $1.mbchar?() and t1 =~ /^(.)/ and $1.mbchar?()) ? '' : ' '
    ismatched0 = ismatched1 = false
    offset = 0
    md = regexp.match(t0 + ti + t1)
    while (md)
      if (offset + md.begin(0) <= t0.length() && offset + md.end(0) <= t0.length())
	ismatched0 = true
      elsif (t0.length() <= offset + md.begin(0) && t0.length() <= offset + md.end(0))
	ismatched1 = true
      else
	ismatched0 = ismatched1 = true
      end
      offset = md.end(0)
      md = regexp.match(md.post_match())
    end
    if (ismatched0 and ! isprinted0)
      printOneLine(fo, fname, l - 1, s0)
      isprinted0 = true
    end
    if (ismatched1 and ! isprinted1)
      printOneLine(fo, fname, l, s1)
      isprinted1 = true
    end

    l += 1
    s0 = s1
    isprinted0 = isprinted1
  end
end

def searchEntries(entries, regexp)
  for i in entries
    if (FileTest.file?(i))
      open("#{i}", "r") do |fi|
	search((ARGV.length() >= 2 or OPTIONS['n'] or OPTIONS['r']) ? i : nil, fi, regexp, STDOUT)
      end
    elsif (FileTest.directory?(i) and OPTIONS['r'])
      searchEntries(Dir.glob(i + '/*'), regexp)
    end
  end
end

begin
  regexp = Regexp.compile(ARGV.shift, OPTIONS['i'])
  STDOUT.sync = true
  if (ARGV.length() > 0)
    searchEntries(ARGV, regexp)
  else
    search(nil, STDIN, regexp, STDOUT)
  end
rescue Interrupt
  exit((isfound) ? 0 : 1)
end
exit((isfound) ? 0 : 1)