#!/usr/bin/env bash
# HEADER
#=======================================================================
#
#  commission -- Extract some Academic Records from a PDF file.
#
#  SYNOPSIS
#    commission <infile.pdf> <num|liste.csv> output <outfile.pdf>
#
#  DESCRIPTION
#    Shell script to extract one or more pages of a PDF file from an
#    integer or a list of integers corresponding to academic records.
#
#  POSITIONAL ARGUMENT
#    <infile.pdf>               PDF infile name
#
#  OPTIONS
#    -h|--help                  display this help and exit
#    -n|num <num|list.csv>      an integer or a csv file of integers
#    -o|output <outfile.pdf>    PDF outfile name
#
#  EXAMPLES
#    $ commission infile.pdf -n 1234 -v
#    $ commission infile.pdf -n 1234 -o case_1234.pdf
#    $ commission infile.pdf -n list.csv -o comm_1.pdf
#
#  DEPENDENCIES
#    - pdfgrep
#    - pdftk
#    - GNU coreutils
#    - PDF viewer, like evince
# 
#  Copyright (C) 2019,2020 Nicolas Mesnier <nmesnier@free.fr>
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License version 3 or
#  above as published by the Free Software Foundation.
#
#  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/>.
#
#=======================================================================
# END_OF_HEADER
#-----------------------------------------------------------------------
Help(){
    # Read header to display help and version
    BOH=$(head -200 ${0} | grep -n "^# HEADER" | cut -f1 -d:)
    EOH=$(head -200 ${0} | grep -n "^# END_OF_HEADER" | cut -f1 -d:)
    head -$(($EOH-1)) ${0} | tail -$(($EOH-$BOH-1)) \
        | grep -e "^#$" -e "^# " | sed -e "s/^#=*//g"
}
#-----------------------------------------------------------------------
__getPages__(){
    # Get pages numbers of case number ocurence in a PDF file
    # Input:
    #   $1: PDF file name (str)
    #   $2: case number (int)
    # Output:
    #   str: page range as "n1-n2"
    echo "$(pdfgrep --cache -n n°${2} ${1} | cut -d: -f1 \
        | awk '{if(min==""){min=max=$1}; if($1>max) {max=$1}; \
                if($1<min) {min=$1};} END {print min"-"max}')"
}
#-----------------------------------------------------------------------
# *** get options ***
#-----------------------------------------------------------------------
viewer="evince"
infiles=""
num=""
num_file=""
outfile=""
noOutPut=false
while [[ ${1} ]]; do
    case "${1}" in
        -h|--help) 
            Help
            exit 0 ;;
        # *** run function
        -n|num)
            if  [[ "${2}" =~ ^[0-9]+$ ]];then
                num=${2}
            else
                if [ -f ${2} ];then
                    num_file=${2}
                else
                    echo "File \"${2}\" does not exists." >&2
                    exit 1
                fi
            fi
            shift
            ;;
        -o|output)
            if [ -f ${2} ]; then
                read -p " File \"${2}\" allready exists. Replace? y/[n]  " rep
                case ${rep} in
                    [Yy]* )
                        outfile=${2}
                        ;;
                    * ) exit 1;;
                esac
            else
                outfile=${2}
            fi
            shift
            ;;
        -v|view)
            noOutPut=true
            ;;
        *)
            if [ -f ${1} ];then
                infile=${1}
            else
                echo "File \"${1}\" does not exists." >&2
                exit 1
            fi
            ;;
    esac
    if ! shift; then
        echo 'Missing parameter argument.' >&2
        exit 1
    fi
done
#-----------------------------------------------------------------------
# *** run
#-----------------------------------------------------------------------
if [ -z "${num}" -o -z "${num_file}" ];then
    if [ ! -z ${num_file} ];then
        pages=""
        for num in $(cat ${num_file} | xargs);do
            pages+=" $(__getPages__ ${infile} ${num})"
        done
    else
        pages=$(__getPages__ ${infile} ${num})
    fi
    if [ ${noOutPut} = true ];then
        tmpfile=${infile%%.pdf}"_"${pages}".pdf"
        pdftk ${infile} cat ${pages} output ${tmpfile} \
            && ${viewer} ${tmpfile} && rm ${tmpfile}
    else
        pdftk ${infile} cat ${pages} output ${outfile}
    fi
fi
#====================================================================eof
# vim: set tw=72 ts=4 sw=4 nu: