use strict;
use DBI;
use Tk;

my $conn = DBI->connect
    ("DBI:mysql:pcr_experiment","root","password15")
    or die("Cannot connect: $DBI::errstr");

my ($sql, @keys, $record);

my %fields =
    ('ID' => "ID: "   , 'province'=> "Province: ",'country'=> "Country
+: "
     'region'=> "Region: " ,
      'sequence_id'=>"Sequence ID: ",
      'sequence_file'=>"Sequence file: "
      
      );

my @order =qw(ID province country region sequence_id sequence_file );
Start_Tk_Interface();
exit;

#-----------------------------------------------------
# Database Routines

sub Get_Record {
    my $ID       = shift;
    my $sql        = qq(SELECT * FROM university WHERE ID = $ID);
    my $hdl_search = $conn->prepare($sql);

    $hdl_search->execute;
    $record = $hdl_search->fetchrow_hashref;

    return($record);
}

sub Delete_Record {
    my $ID  = shift;
    $sql      = qq(DELETE FROM UNIVERSITY WHERE ID = '$ID');

    my $query = $conn->prepare($sql);

    $query->execute 
        or die("\nError executing SQL statement! $DBI::errstr");

    return 1;
}


sub Update_Record {
    my $form   = shift;
    my $caller = shift;

    $caller    -> withdraw();

    my $ID = $form->{'ID'}->get();
    my @keys = keys %$form;
    my @vals = map { $$form{$_}->get() } @keys;

    my $counter = 0;
    $sql  = qq{SELECT FROM UNVIVERSY };

    foreach my $k (@keys){
        $sql .= qq{$k = "$vals[$counter]", };
        $counter++;
    }

    $sql  =~ s/\, $//;
    $sql .=  " WHERE ID = '$ID'";

    my $query = $conn->prepare($sql);

    $query->execute 
        or die("\nError executing SQL statement! $DBI::errstr");

    return 1;
}

sub Add_Record {
    my $form   = shift;
    my $caller = shift;
    $caller    -> withdraw();

    my @keys = keys %$form;
    my @vals = map { $conn->quote($$form{$_}->get()) } @keys;

    $sql  = "INSERT INTO UNIVERSITY ("
            . join(", ", @keys)
            . ") VALUES ("
            . join(", ", @vals)
            . ")";

    my $query = $conn->prepare($sql);

    $query->execute 
        or die("\nError executing SQL statement! $DBI::errstr");

    return 1;
}

#------------------------------------------------------
# Tk Interface Routines

my $MainWin;

sub Start_Tk_Interface {
    $MainWin = MainWindow->new(-title => "Choose a Database Action");
    $MainWin->MoveToplevelWindow(100,100);

    my $button1 = $MainWin->Button(-text => 'Add Record',
        -command => [\&tk_Add_Record_Dialog, 'add']);

    my $button2 = $MainWin->Button(-text => 'View Record',
        -command => [\&tk_Choose_Dialog, 'View']);

    my $button3 = $MainWin->Button(-text => 'Delete Record',
         -command => [\&tk_Choose_Dialog, 'Delete']);

    my $button4 = $MainWin->Button(-text => 'Quit',
        -command => [$MainWin => 'destroy']);

    $button1 -> grid(-row => 0, -column => 0, 
        -padx => 10, -sticky => 'w');
    $button2 -> grid(-row => 0, -column => 1, 
        -padx => 10, -pady   => 40 );
     $button3 -> grid(-row => 0, -column => 2, 
         -padx => 10);
    $button4 -> grid(-row => 0, -column => 3, 
        -padx => 10, -sticky => 'e');

    MainLoop();
}

sub tk_Choose_Dialog {
    my $type = shift;

    my $top_win = $MainWin->Toplevel(-title => "Choose Record");
    $top_win->MoveToplevelWindow(110,110);

    $top_win->Label(-text => 'ID: ') ->
        grid(-row => 0, -column => 0, -sticky => 'w');

    my $ID= $top_win->Entry(-width => 20) ->
        grid(-row => 0, -column => 1, -sticky => 'e');

    my $button = $top_win->Button(
        -text    => "$type Record",
        -command => [\&tk_Edit_or_Delete, $top_win, $type, $ID] );

    $button-> grid(-row => 1, -column => 1);

    return 1;
}

sub tk_Edit_or_Delete {
    my $caller = shift;
    my $type   = shift;
    my $ID   = shift()->get();

    $caller->withdraw();

    Delete_Record($ID)                if($type eq 'Delete');
    tk_Add_Record_Dialog("edit", $ID) if($type eq 'View');

    return 1;
}

sub tk_Add_Record_Dialog {
    my ($record, $ID, %form);
    my $type = shift;
    my $row  = 0;

    my $top_win = $MainWin->Toplevel(-title => "Add/View a Record");

    $top_win->MoveToplevelWindow(110,110);

    if($type =~ /edit/){
        $ID   = shift;
        $record = Get_Record($ID);
    }

    foreach my $field (@order){
            
        my $text = $record->{$field};

        $top_win->Label(-text => $fields{$field}) ->
            grid(-row => $row, -column => 0, -sticky => 'w');

        $form{$field}  = $top_win->Entry
            (-width => 50, -textvariable => \$text) ->
            grid(-row=> $row, -column=> 1, -sticky=> 'e');

        $row++;
    }


    my $button;

    if($type =~ /edit/i){
        $button = $top_win->Button(
            -text    => 'Quit', #Third button in edit statement
            -command => [\&Update_Record,\%form, $top_win] );
    }
    else {
        $button = $top_win->Button(
            -text    => 'Add Record',
            -command => sub{ Add_Record(\%form, $top_win)} );
        }

    $button-> grid(-row => $row, -column => 1);

    return 1;
}
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