School_IS_script

#!/bin/bash

# Error messages follow
no_oper_err="Operation needs to be specified!"
num_args_err="Incorrect number of arguments for this operation!"
no_force_err="Force option needs to be added for this operation!"
bloked_err="prevents this operation from completing!"
no_match_err="No match found!"
datadir_err="Data directory cannot be crated or written into!"
illegal_oper_err="Ilegall operation! Run \"./studis pomoc\" for help."

date_err="Date must be in a range from 2000-01-01 to 2 years from now
and format YYYY-MM-DD)"
id_err="Must be 1-8 letter word alfanumeric!"
exist_err="already exists!"
no_exist_err="does not exist!"

semester_str="Fakulta  | Semestr  | Od         | Název\n-----------------------------------------\n"
subject_str="Fakulta  | Semestr  | Kurz     | Uk | Kr | Název
----------------------------------------------------\n"

help_string="Usage: ./studis [OPTION]... OPERATION [ARGUMENT]
Executes OPERATION with provided arguments.
    Options: 
        -d directory_path       provides path for data directory
        -f                      force critical operations
        ...visit PV004 UNIX LAB for more help!"

function error_exit {
  printf '%s\n' "$1" >&2 && exit 1
}

function parse_options() {
  datadir=./datadir
  force=false
  while getopts 'd:f' option; do
    case $option in
      d)
        datadir=$OPTARG
        ;;
      f)
        force=true
        ;;
      ?)
        error_exit "$help_string"
        ;;
    esac
  done
}

function prepare_workspace() {
  mkdir $datadir 2> /dev/null || [ -d $datadir -a -w $datadir ] \
    || error_exit "$datadir_err"
  log=$datadir/studis.log
  faculty=$datadir/faculty.dat
  semester=$datadir/semester.dat
  subject=$datadir/subject.dat
  student=$datadir/student.dat
  enroll=$datadir/enroll.dat
  grade=$datadir/grade.dat
  touch $log $faculty $semester $subject $student $enroll $grade
  echo `date "+%F %H:%M.%S"` $$ "x${LOGNAME#x}" $0 $@ >> $log
}

# Used: $1=min args, $2=max args, $3...=$@
function arg_check() {
  [ $[$#-3] -lt $1 -o $[$#-3] -gt $2 ] && error_exit "$num_args_err"
}

function id_check() {
  [ -z "$1" -o ${#1} -gt "8" ] || [[ "$1" =~ [^[:alnum:]] ]] && \
    error_exit "$id_err"
}

function date_check() {
  day=$(date -d "$1" +%s)
  start=$(date -d "$2" +%s)
  end=$(date "+%s" -d $(date "+%F" -d "$3"))
  [ $(date "+%F" -d "$1") = "$1" ] \
    && [ $day -ge $start -a $day -le $end ] \
    || error_exit "$date_err"
}

function main() {
  [ $# -lt 1 ] && error_exit "$no_oper_err"
  case $1 in 
    cesta-adresář|cesta-adresar)
      arg_check "0" "0" "$@"
      echo $datadir
      ;;
    pomoc)
      arg_check "0" "0" "$@"
      printf '%s\n' "$help_string"
      ;;
    smaž-adresář|smaz-adresar)
      arg_check "0" "0" "$@"
      if $force; then rm -rf $datadir; else error_exit "$no_force_err"; fi
      ;;
    dej-log)
      arg_check "0" "1" "$@"
      if [ -z $2 ]; then 
        cat $log
      else 
        egrep $2 $log 2> /dev/null || exit 1
      fi
      ;;
    fakulta-nová|fakulta-nova)
      arg_check "2" "2" "$@"
      id_check "$2"
      grep -sq "^$2|" $faculty && error_exit "Faculty $exist_err"
      printf "%s|%s\n" "$2" "$3" >> $faculty
      ;;
    fakulta-název|fakulta-nazev)
      arg_check "2" "2" "$@"
      grep -sq "^$2|" $faculty || error_exit "Faculty $no_exist_err"
      sed -i "s/^$2|.*/$2|$3/" $faculty
      ;;
    fakulta-smaž|fakulta-smaz)
      arg_check "1" "1" "$@"
      grep -sq "^$2|" $faculty || error_exit "Faculty $no_exist_err"
      grep -sq "^$2|" $semester && error_exit "Semester $bloked_err"
      sed -i "/^$2|/d" $faculty
      ;;
    fakulta-výpis|fakulta-vypis)
      arg_check "0" "1" "$@"
      printf "Fakulta  | Název\n--------------------------\n"
      regex=""
      if [ -n "$2" ]; then regex="^$2|"; fi
      grep "$regex" $faculty | (IFS='|'; while read id name; \
        do printf "%-8s | %s\n" "$id" "$name"; done) | sort
      ;;
    semestr-datum)
      arg_check "3" "3" "$@"
      grep -sq "^$2|$3|" $semester || error_exit "Semester $no_exist_err"
      date_check "$4" "2000-01-01" "+2 years"
      sed -i "s/^$2|$3|.*|\(.*\)/$2|$3|$4|\1/" $semester
      ;;
    semestr-název|semestr-nazev)
      arg_check "3" "3" "$@"
      grep -sq "^$2|$3|" $semester || error_exit "Semester $no_exist_err"
      sed -i "s/^$2|$3|\(.*\)|.*/$2|$3|\1|$4/" $semester
      ;;
    semestr-nový|semestr-novy)
      arg_check "4" "4" "$@"
      grep -q "^$2|" $faculty || error_exit "Faculty $no_exist_err"
      id_check "$3"
      grep -q "^$2|$3|" $semester && error_exit "Semester $exist_err"
      date_check "$4" "2000-01-01" "+2 years"
      printf "%s|%s|%s|%s\n" "$2" "$3" "$4" "$5" >> $semester
      ;;
    semestr-smaž|semestr-smaz)
      arg_check "2" "2" "$@"
      grep -sq "^$2|$3|" $semester || error_exit "Semester $no_exist_err"
      grep -sq "^$2|$3|" $subject && error_exit "Subject $bloked_err"
      sed -i "/^$2|$3/d" $semester
      ;;
    semestr-výpis|semestr-vypis)
      arg_check "0" "2" "$@"
      regex=""
      if [ -n "$2" ]; then regex="^$2|"; fi
      if [ -n "$3" ]; then regex="$regex$3|"; fi
      grep -qsi "$regex" $semester || error_exit "$no_match_err"
      printf "$semester_str"
      grep -is "$regex" $semester \
        | (IFS='|'; while read faculty id day name; \
        do printf "%-8s | %-8s | %-10s | %s\n"\
        "$faculty" "$id" "$day" "$name"; done) | sort -t"|" -k3,3 -k1,1
      ;;
    předmět-kredity|predmet-kredity)
      arg_check "4" "4" "$@"
      grep -sqi "^$2|$3|$4|" $subject || error_exit "Subject $no_exist_err"
      [ "$5" -le "20" -a "$5" -ge "0" ] 2> /dev/null \
        && [ ${#5} -le "2" ] \
        || error_exit "Credits in range 0-20!"
      sed -i "s/^\($2|$3|$4|.*|\).*\(|.*\)/\1$5\2/I" $subject
      ;;
    předmět-nový|predmet-novy)
      arg_check "6" "6" "$@"
      grep -sq "^$2|$3|" $semester \
        || error_exit "Semester on faculty $no_exist_err"
        
      # Avoid mathching accented letters
      [[ $(LC_COLLATE=C; [[ "$4" =~ ^[a-zA-Z0-9_]*$ ]] && echo y) == y  ]] \
        && [[ $4 == [a-zA-Z]* ]] && [ ${#4} -lt "9" ] \
        || error_exit "$id_err"
        
      grep -sqi "^.*|.*|$4|.*" $subject && error_exit "Subject $exist_err"
      [[ $6 =~ ^(zk|k|z)$  ]] || error_exit "Only zk|k|z allowed!"
      [ "$7" -le "20" -a "$7" -ge "0" ] 2> /dev/null && [ ${#7} -le "2" ] \
        || error_exit "Credits must be in range 0-20!"
      printf "%s|%s|%s|%s|%s|%s\n" "$2" "$3" "$4"\
        "$6" "$7" "$5" >> $subject
      ;;
    předmět-výpis|predmet-vypis)
      arg_check "0" "3" "$@"
      regex=""
      if [ -n "$2" ]; then regex="^$2|"; fi
      if [ -n "$3" ]; then regex="$regex$3|"; fi
      if [ -n "$4" ]; then regex="$regex$4|"; fi
      grep -qsi "$regex" $subject || error_exit "$no_match_err"
      printf "$subject_str"
      grep -is "$regex" $subject \
        | (IFS='|'; while read faculty semest course end credits name; \
        do printf "%-8s | %-8s | %-8s | %-2s | %2s | %s\n" \
        "$faculty" "$semest" "$course" "$end" "$credits" "$name"; done) \
        | sort -s -t"|" -k1,1 -k2,2 -k3,3
      ;;
    předmět-název|predmet-nazev)
      arg_check "4" "4" "$@"
      grep -sqi "^$2|$3|$4|" $subject || error_exit "Subject $no_exist_err"
      sed -i "s/^\($2|$3|$4|.*|.*|\).*/\1$5/I" $subject
      ;;
    předmět-ukončení|predmet-ukonceni)
      arg_check "4" "4" "$@"
      [[ $5 =~ ^(zk|k|z)$  ]] || error_exit "Only zk|k|z algd!"
      grep -sqi "^$2|$3|$4|" $subject || error_exit "Subject $no_exist_err"
      sed -i "s/^\($2|$3|$4|\).*\(|.*|.*\)/\1$5\2/I" $subject
      ;;
    předmět-smaž|predmet-smaz)
      arg_check "3" "3" "$@"
      grep -sqi "^$2|$3|$4|" $subject || error_exit "Subject $no_exist_err"
      grep -sqi "^$2|$3|$4|" $enroll && error_exit "Subject enrolled!"
      sed -i "/^$2|$3|$4|/Id" $subject
      ;;
    student-export)
      arg_check "0" "0" "$@"
      [ -z "$(cat $student)" ] && error_exit "$no_match_err"
      cat $student | (IFS="|"; while read uco name surname date mail; \
        do printf "%s;%s\n" "$uco" "$mail"; done) | sort -n -t";" -k1,1
      ;;
    student-nový|student-novy)
      arg_check "5" "5" "$@"
      [ "$2" -gt "0" ] 2> /dev/null || error_exit "Uco must be greater than 0!"
      grep -q "^$2|" $student && error_exit "Student $no_exist_err"
      [ -z "$3" -o -z "$4" ] && error_exit "Name and surname must be nonempty!"
      date_check "$5" "1900-01-01" "" 
      echo "$6" | (LC_COLLATE=C; egrep -q \
      "^[[:alnum:]._-]+@([[:alnum:]_-]+\.)+[[:alnum:]_-]+$") \
      || error_exit "Invalid email adress!"  
      printf "%s|%s|%s|%s|%s\n" "$2" "$3" "$4" "$5" "$6" >> $student 
      ;;
    student-smaž|student-smaz)
      arg_check "1" "1" "$@"
      grep -q "^$2|" $student || error_exit "Student $no_exist_err"
      grep -q "^.*|.*|.*|$2" $enroll && error_exit "Enrollment $bloked_err!"
      sed -i "/^$2|/d" $student
      ;;
    zápis|zapis)
      arg_check "4" "4" "$@"
      grep -qi "^$2|$3|$4|" $subject && grep -q "^$5|" $student \
        || error_exit "Cannot enroll!"
      grep -qi "^$2|$3|$4|$5" $enroll && error_exit "Enrollment $exist_err"
      printf "%s|%s|%s|%s\n" "$2" "$3" "$4" "$5" >> $enroll
      ;;
    zápis-předmět|zapis-predmet)
      arg_check "3" "3" "$@"
      grep -qi "^$2|$3|$4" $subject || error_exit "Subject $no_exist_err"
      grep -qi "^$2|$3|$4|" $enroll || error_exit "Enrollment $no_exist_err"
      join -t "|" -1 1 -2 1 <(grep -i "^$2|$3|$4|" $enroll | cut -d "|" -f 4 | sort)\
        <(cut -d "|" -f 1-3 $student | sort -f) \
        | sort -t"|" -k3,3 -k2,2 -k1,1n -s | (IFS="|"; while read uco name surname; \
        do printf "%s, %s; učo %s\n" $surname $name $uco; done)
      ;;
    známka|znamka)
      arg_check "5" "5" "$@"
      grep -q "^$2|$3|$4|$5" $enroll || error_exit "Enrollment $no_exist_err"
      mark=$(grep "^$2|$3|$4|" $subject | cut -d "|" -f 4)
      case $mark in
        zk)
          [[ "$6" =~ ^[A-F]$ ]] || error_exit "Illegal grade!"
          ;;
        k)
          [[ "$6" =~ ^[PN]$ ]] || error_exit "Illegal grade!"
          ;;
        z)
          [[ "$6" =~ ^[ZN]$ ]] || error_exit "Illegal grade!"
          ;;
      esac
      grep -qi "^$2|$3|$4|$5|[A-EPZ]|" $grade && error_exit "Already absolved!"
      [[ "$(grep -i "^$2|$3|$4|$5|" $grade | wc -l)" -ge 3 ]] \
        && error_exit "Three grades $exist_err"
      printf "%s|%s|%s|%s|%s|%s\n" "$2" "$3" "$4" "$5" "$6" \
      "$(date "+%F %H:%M.%S")" >> $grade
      ;;
    známka-výpis|znamka-vypis)
      if [ $# -eq 2 ]; then
        join -i <(grep -i "^.*|.*|.*|$2" $grade | sort -f -t"|" -k3,3) \
          <(sort -f -t"|" -k3,3 $subject) -1 3 -2 3 -t "|" -o "2.3,2.6,1.5,1.6" \
          | sort  -sf -t"|" -k1,1 -k4,4  | (IFS="|"; while read code name mark date;
          do printf "%s %s: %s %s\n" "$code" "$name" "$mark" "$date"; done)
      else 
        if [ $# -eq 4 ]; then
          join <(grep -i "^$2|$3|$4|" $grade | sort -t "|" -k4,4 ) \
            <(sort -t "|" -k1,1 $student) -1 4 -2 1 -t "|" -o "2.2,2.3,2.1,1.5,1.6" \
	        | sort -s -t"|" -k2,2 -k1,1 -k5,5 | (IFS="|"; while read name surname uco mark date; do printf "%s, %s; učo %s: %s %s\n" \
	      "$surname" "$name" "$uco" "$mark" "$date"; done)
        else error_exit "$num_args_err"
        fi
      fi
      ;;
    zápis-smaž|zapis-smaz)
      arg_check "4" "4" "$@"
      sed -i "/^$2|$3|$4|$5/d" $enroll
      sed -i "/^$2|$3|$4|$5|/d" $grade
      ;;
    *)
      error_exit "$illegal_oper_err"
      ;;
  esac
}

parse_options "$@"
prepare_workspace "$@"
shift $(($OPTIND-1))
main "$@"
exit 0