#!/bin/sh
printf 'Grock- '
read command
while test "$command" != "quit"
do
  case $command in
    setdb*) 
      set $command
      if test $1 = "setdb"
      then
        if test $# -eq 1
        then
          echo Missing Argument.
        else
          database=$2
          if test ! -e $database
          then
            echo File $database does not exist.
          elif test ! -r $database
          then
            echo File $database is not readable.
          else
            cat $database | egrep '^[^ ]+[ ][^ ]+[ ][^ ]+$' | diff $database - > /dev/null
            if test $? = 0
            then
              echo Database set to $database
            else
              echo Incorrect format in $database.
              echo The following lines were incorrectly formatted.
              cat $database | egrep -v '^[^ ]+[ ][^ ]+[ ][^ ]+$'
              database=""
              echo Database not set.
            fi
          fi
          if test $# -gt 2
          then
            echo Extra arguments ignored.
          fi
        fi
      else
        echo Unrecognized command.
      fi
      ;;
    relnames)
      if test "X$database" = "X"
      then
        echo Database has not been set.
      else
        cat $database | cut -f1 -d" " | sort | uniq 
      fi
    ;;
    entities)
      if test "X$database" = "X"
      then
        echo Database has not been set.
      else
        cat $database | cut -f2,3 -d" " | tr ' ' '\n' | sort | uniq 
      fi
    ;;
    cardinality*)
      if test "X$database" = "X"
      then
        echo Database has not been set.
      else
        set $command
        if test $1 = "cardinality"
        then
          if test $# -eq 1
          then
            echo Missing Argument.
          else
            shift
            relations=`cat $database | cut -f1 -d" " | sort | uniq`
            for relation in $*
            do
              echo "$relations" | grep "^$relation$" > /dev/null
              if test ! $? -eq 0
              then
                echo Relation $relation does not exist. 
              else
                echo $relation `cat $database | grep "^$relation" | wc -l`
              fi
            done
          fi
        else
          echo Unrecognized command.
        fi
      fi
      ;;
    *) echo Unrecognized command.;;
  esac
  printf 'Grock- '
  read command
done