#!/usr/bin/env bash

: <<COMMENT
  Copyright (C) 2014 Tri Le <trile7 at gmail dot com>

  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 version 3.

  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/>.
COMMENT

version="pdftools v0.2.3"
blue='\e[0;34m'; green='\e[0;32m'; red='\e[0;31m'; yellow='\e[0;33m'; bold='\e[1m';none='\e[0m'

function menu {
  n=0
  choices=("$@")
  echo -e "$blue$bold$menutitle"
  for i in "${choices[@]}"; do
    echo -e "$none$((n++)))   $yellow$i"
  done
  echo -en "${none}c|q) ${yellow}Cancel"
  echo -e $green
  read -p "Enter a choice from above menu: " i
  echo -e $none
  [[ $i =~ c|q ]] && exit 1
  if test $i -lt $n 2>/dev/null; then
    choice=${choices[i]}; return $i
  else
    echo -e "$red$i is an invalid entry...please try again!"
    menu "${choices[@]}"
  fi
}

function mainmenu {
  if [[ -z $1 ]]; then
    menutitle="---PDF Tools---"
    menu "PDF Merge" "PDF Split" "PDF Extract" "PDF to JPG" "PDF to Text"
    case $? in
      0) merge ;;
      1) split ;;
      2) extract ;;
      3) 2jpg ;;
      4) 2txt ;;
    esac
  else
    $cmd
  fi
  mainmenu
}

function merge {
  if [[ ${#files[@]} -lt 2 ]]; then
    echo -e "${red}Select at least 2 or more PDF files to merge"
    exit 1
  fi
  echo -ne $green
  read -p "Enter merged pdf name (default merged.pdf): " f
  echo -e $none
  if [[ $f ]]; then
    [[ $f != *.pdf ]] && f=$f.pdf
  else f=merged.pdf
  fi
  [[ -e $f ]] && f=${f%.*}-`date +%s`.pdf
  mkdir -p `dirname "$f"`
  gs -o -q -sDEVICE=pdfwrite -sOutputFile="$f" "${files[@]}"
  if [[ $? -eq 0 ]]; then
    echo -e $green
    read -p "Remove `echo ${files[@]}` (Y/n)? " i
    [[ $i = n ]] || rm "${files[@]}"
  fi
}

function split {
  for i in "${files[@]}"; do
    totalp=`gs -q -dNODISPLAY -c "($i) (r) file runpdfbegin pdfpagecount = quit"`
    for (( p=1; p<=$totalp; p++ )); do
      gs -o -q -sDEVICE=pdfwrite -dFirstPage=$p -dLastPage=$p -sOutputFile="${i%.*}-p$p.pdf" "$i"
    done
  done
}

function extract {
  echo -e "Use ${green}space$none for separating pages, ${green}dash$none for range of pages, and ${green}end$none for the last page.  For example, to extract pages 1, 5, and 8 to the last page, enter: ${green}1 5 8-end"
  read -p "Enter page: " -a p
  echo -e $none
  if [[ -z $p ]]; then
    echo -e "${red}A value is required for page $none"
    extract "$@"; return 1
  fi
  for i in ${p[@]}; do
    [[ $i = end ]] && continue
    test ${i%*-end} -gt 0 2>/dev/null && continue
    test $((i)) -lt 0 2>/dev/null && continue
    echo -e "${red}$i is invalid $none"
    extract "$@"; return 1
  done
  tmpdir=/tmp/pdfextract
  mkdir -p $tmpdir
  for i in "${files[@]}"; do
    pages=`gs -q -dNODISPLAY -c "($i) (r) file runpdfbegin pdfpagecount = quit"`
    for j in ${p[@]}; do
      if [[ $j = *-* ]]; then
        p1=`echo $j | cut -d'-' -f1`
        [[ $p1 -gt $pages ]] && continue
        p2=`echo $j | cut -d'-' -f2`
        [[ $p2 = end ]] && p2=$pages
        [[ $p2 -gt $pages ]] && p2=$pages
      elif [[ $j = end ]]; then
        p1=$pages; p2=$pages
      elif [[ $j -le $pages ]]; then
        p1=$j; p2=$j
      fi
      gs -o -q -sDEVICE=pdfwrite -dFirstPage=$p1 -dLastPage=$p2 -sOutputFile=$tmpdir/$j.pdf "$i"
    done
    ext=${p[@]}
    ext=p${ext// /,}.pdf
    gs -o -q -sDEVICE=pdfwrite -sOutputFile="${i%.*}-$ext" $tmpdir/*.pdf
    rm -rf $tmpdir
  done
}

function 2jpg {
  for i in "${files[@]}"; do
    gs -o -q -sDEVICE=jpeg -sOutputFile="${i%.*}-p%d.jpg" "$i"
  done
}

function 2txt {
  for i in "${files[@]}"; do
    gs -o -q -sDEVICE=txtwrite -sOutputFile="${i%.*}.txt" "$i"
  done
}

function usage {
  echo -e "${bold}$version"
  echo -e "Usage: ${0##*/} [option] pdf1 pdf2 ..... $none"
  echo "Options: menu is shown if option is not specified"
  echo "  --merge    combine 2 or more pdf files to one"
  echo "  --split    split pdf file to individual page"
  echo "  --extract  extract page and/or range of pages from pdf file"
  echo "  --2jpg     convert pdf page to jpg"
  echo "  --2txt     convert text portion of pdf file to text"
  exit
}

case $1 in
  -h|--h*) usage ;;
  --*) cmd=${1#--}; shift; files=("$@") ;;
  *) files=("$@") ;;
esac
[[ $# -eq 0 ]] && usage
mainmenu $cmd