#! /bin/bash
#Autor: DM

if [ "$1" = "--help" ]; then
    echo "
DESCRIPTION
Program searches for a pattern arg1 \
in files of a type arg2 in the catalog tree arg3.
Directory's permissions must be set to r+w+x.
'w' is needed in order to create an error.log file.
If script can't access directory or file, the stderr stream
is redirected to error.log file.

USAGE
program_name arg1 arg2 arg3
arg1 - pattern
arg2 - file type
arg3 - catalog tree

EXAMPLE OF USAGE
./zad2.sh wzorzec .h /usr/include

EXIT CODE
0           No error
1           Incorrect number of arguments
2           Directory does not exist
3           Directory's read bit is set to 0
4           Directory's execute bit is set to 0
5           Directory's write bit is set to 0
6           Inccorect extension
"
    exit 0
fi

if [ $# -ne 3 ]; then
    echo "Incorrect number of arguments.
Consider using --help"
    exit 1
fi

directory="$3"

if [ ! -d "${directory}" ]; then
    echo "Directory does not exist!
Consider using --help"
    exit 2
fi

if [ ! -r "${directory}" ]; then
    echo "Directory's read bit is set to 0!
Consider using --help"
    exit 3
fi

if [ ! -x "${directory}" ]; then
    echo "Directory's execute bit is set to 0!
Consider using --help"
    exit 4
fi

if [ ! -w "${directory}" ]; then
    echo "Directory's write bit is set to 0!
Consider using --help"
    exit 5
fi

extension="$2"

if [ ! ${extension:0:1} == '.' ]; then
    echo "Incorrect extension!
Consider using --help"
    exit 6
fi


if [ ${#extension} = 1 ]; then
    echo "Incorrect extension!
Consied using --help"
    exit 6
fi

pattern="$1"

echo "File that contains \"$pattern\":"

grep --include=*"$extension" -Rnlw "$directory" -e "$pattern" 2>./error.log

if [ -s ./error.log ]; then
    echo ""
    echo "Check error.log file for errors"
else
    rm -f ./error.log
fi