#!/bin/bash
#
# 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 3 of the License, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Copyright (C) 2008 Vino Fernando Crescini  <vfcrescini@gmail.com>

# Google Treasure Hunt 2008 Puzzle 2

# arg1 is the search pattern, arg2 is the line number
function find_n_count
{
  find . | grep "$1" | while read i; do
    awk "NR == $2 { print \$0; }" "$i"
  done | awk 'BEGIN { tot = 0; } { tot += $0; } END { print tot; }'
}

function is_num
{
  tmp=${1//[0-9]/}

  if [ "$tmp" != "" ]; then
    return 1
  fi

  return 0
}

if [ $# -ne 4 ]; then
  echo "usage: $0 <regexp 1> <regexp 2> <line number 1> <line number 2>"
  exit 1
fi

if ! is_num $3 && ! is_num $4; then
  echo "third and fourth arguments must be positive integers"
  exit 2
fi

sum1=`find_n_count "$1" $3`
sum2=`find_n_count "$2" $4`

echo "$sum1 * $sum2" | bc -q

exit $?