#!/usr/bin/env perl
# vim: set ft=perl:

=head1 NAME

sqlt-diff - find the differences b/w two schemas

=head1 SYNOPSIS

For help:

  sqlt-diff -h|--help

For a list of all valid parsers:

  sqlt -l|--list

To diff two schemas:

  sqlt-diff [options] file_name1=parser file_name2=parser

Options:

  -d|--debug   Show debugging info

=head1 DESCRIPTION

sqlt-diff is a utility for creating a file of SQL commands necessary to
transform the first schema provided to the second.  While not yet 
exhaustive in its ability to mutate the entire schema, it will report the 
following

=over

=item * New tables

Using the Producer class of the target (second) schema, any tables missing
in the first schema will be generated in their entirety (fields, constraints,
indices).

=item * Missing/altered fields

Any fields missing or altered between the two schemas will be reported 
as:

  ALTER TABLE <table_name> 
    [DROP <field_name>] 
    [CHANGE <field_name> <datatype> (<size>)] ;

=item * Missing/altered indices

Any indices missing or of a different type or on different fields will be
indicated.  Indices that should be dropped will be reported as such:
 
  DROP INDEX <index_name> ON <table_name> ;

An index of a different type or on different fields will be reported as a 
new index as such:

  CREATE [<index_type>] INDEX [<index_name>] ON <table_name> 
    ( <field_name>[,<field_name>] ) ;

=back

"ALTER/DROP TABLE" and "CREATE INDEX" statements B<are not> generated by
the Producer, unfortunately, and may require massaging before being passed to
your target database.

=cut

# -------------------------------------------------------------------

use strict;
use warnings;
use Pod::Usage;
use Data::Dumper;
use SQL::Translator;
use SQL::Translator::Schema::Constants;

use vars qw( $VERSION );
$VERSION = '1.59';

my ( @input, $list, $help, $debug );
for my $arg ( @ARGV ) {
    if ( $arg =~ m/^-?-l(ist)?$/ ) {
        $list = 1;
    }
    elsif ( $arg =~ m/^-?-h(elp)?$/ ) {
        $help = 1;
    }
    elsif ( $arg =~ m/^-?-d(ebug)?$/ ) {
        $debug = 1; 
    }
    elsif ( $arg =~ m/^([^=]+)=(.+)$/ ) {
        push @input, { file => $1, parser => $2 };
    }
    else {
        pod2usage( msg => "Unknown argument '$arg'" );
    }
}

pod2usage(1) if $help;
pod2usage('Please specify only two schemas to diff') if scalar @input > 2;
pod2usage('No input') if !@input;

if ( my $interactive = -t STDIN && -t STDOUT ) {
    print STDERR join("\n",
        "sqlt-diff-old is deprecated. Please sqlt-diff, and tell us ",
        "about any problems or patch SQL::Translator::Diff",
        '',
    );
}

my $tr            = SQL::Translator->new;
my @parsers       = $tr->list_parsers;
my %valid_parsers = map { $_, 1 } @parsers;

if ( $list ) {
    print "\nParsers:\n", map { "\t$_\n" } sort @parsers;
    print "\n";
    exit(0);
}

pod2usage( msg => 'Too many file args' ) if @input > 2;

my ( $source_schema, $source_db, $target_schema, $target_db );

my $i = 2;
for my $in ( @input ) {
    my $file   = $in->{'file'};
    my $parser = $in->{'parser'};

    die "Unable to read file '$file'\n" unless -r $file;
    die "'$parser' is an invalid parser\n" unless $valid_parsers{ $parser };

    my $t = SQL::Translator->new;
    $t->debug( $debug );
    $t->parser( $parser )            or die $tr->error;
    my $out = $t->translate( $file ) or die $tr->error;
    my $schema = $t->schema;
    unless ( $schema->name ) {
        $schema->name( $file );
    }

    if ( $i == 1 ) {
        $source_schema = $schema;
        $source_db     = $parser;
    }
    else {
        $target_schema = $schema;
        $target_db     = $parser;
    }
    $i--;
}
my $case_insensitive = $target_db =~ /SQLServer/;

my $s1_name  = $source_schema->name;
my $s2_name  = $target_schema->name;
my ( @new_tables, @diffs , @diffs_at_end);
for my $t1 ( $source_schema->get_tables ) {
    my $t1_name = $t1->name;
    my $t2      = $target_schema->get_table( $t1_name, $case_insensitive );

    warn "TABLE '$s1_name.$t1_name'\n" if $debug;
    unless ( $t2 ) {
        warn "Couldn't find table '$s1_name.$t1_name' in '$s2_name'\n" 
            if $debug;
        if ( $target_db =~ /(SQLServer|Oracle)/ ) {
			for my $constraint ( $t1->get_constraints ) {
				next if $constraint->type ne FOREIGN_KEY;
				push @diffs_at_end, "ALTER TABLE $t1_name ADD ".
					constraint_to_string($constraint, $source_schema).";";
				$t1->drop_constraint($constraint);
			}
        }
        push @new_tables, $t1;
        next;
    }
    
    # Go through our options
	my $options_different = 0;
	my %checkedOptions;
OPTION:
	for my $t1_option_ref ( $t1->options ) {
		my($key1, $value1) = %{$t1_option_ref};
		for my $t2_option_ref ( $t2->options ) {
			my($key2, $value2) = %{$t2_option_ref};
			if ( $key1 eq $key2 ) {
				if ( defined $value1 != defined $value2 ) {
					$options_different = 1;
					last OPTION;
				}
				if ( defined $value1 && $value1 ne $value2 ) {
					$options_different = 1;
					last OPTION;
				}
				$checkedOptions{$key1} = 1;
				next OPTION;
			}
		}
		$options_different = 1;
		last OPTION;
	}
    # Go through the other table's options
    unless ( $options_different ) {
	    for my $t2_option_ref ( $t2->options ) {
	    	my($key, $value) = %{$t2_option_ref};
	    	next if $checkedOptions{$key};
	    	$options_different = 1;
	    	last;
	    }
    }
    # If there's a difference, just re-set all the options
    my @diffs_table_options;
    if ( $options_different ) {
    	my @options = ();
    	foreach my $option_ref ( $t1->options ) {
    		my($key, $value) = %{$option_ref};
    		push(@options, defined $value ? "$key=$value" : $key);
    	}
    	my $options = join(' ', @options);
		@diffs_table_options = ("ALTER TABLE $t1_name $options;");
    }
	
    my $t2_name = $t2->name;
    my(@diffs_table_adds, @diffs_table_changes);
    for my $t1_field ( $t1->get_fields ) {
        my $f1_type      = $t1_field->data_type;
        my $f1_size      = $t1_field->size;
        my $f1_name      = $t1_field->name;
        my $f1_nullable  = $t1_field->is_nullable;
        my $f1_default   = $t1_field->default_value;
        my $f1_auto_inc  = $t1_field->is_auto_increment;
        my $t2_field     = $t2->get_field( $f1_name, $case_insensitive );
        my $f1_full_name = "$s1_name.$t1_name.$t1_name";
        warn "FIELD '$f1_full_name'\n" if $debug;

        my $f2_full_name = "$s2_name.$t2_name.$f1_name";

        unless ( $t2_field ) {
            warn "Couldn't find field '$f2_full_name' in '$t2_name'\n" 
                if $debug;
            my $temp_default_value = 0;
            if ( $target_db =~ /SQLServer/ && !$f1_nullable && !defined $f1_default ) {
            	# SQL Server doesn't allow adding non-nullable, non-default columns
            	# so we add it with a default value, then remove the default value
            	$temp_default_value = 1;
            	my(@numeric_types) = qw(decimal numeric float real int bigint smallint tinyint);
            	$f1_default = grep($_ eq $f1_type, @numeric_types) ? 0 : '';
            }
            push @diffs_table_adds, sprintf( "ALTER TABLE %s ADD %s%s %s%s%s%s%s%s;",
                $t1_name, $target_db =~ /Oracle/ ? '(' : '',
                $f1_name, $f1_type,
                ($f1_size && $f1_type !~ /(blob|text)$/) ? "($f1_size)" : '',
                !defined $f1_default ? ''
                	: uc $f1_default eq 'NULL' ? ' DEFAULT NULL'
                	: uc $f1_default eq 'CURRENT_TIMESTAMP' ? ' DEFAULT CURRENT_TIMESTAMP'
                	: " DEFAULT '$f1_default'",
                $f1_nullable ? '' : ' NOT NULL',
                $f1_auto_inc ? ' AUTO_INCREMENT' : '',
                $target_db =~ /Oracle/ ? ')' : '',
            );
            if ( $temp_default_value ) {
            	undef $f1_default;
	            push @diffs_table_adds, sprintf( <<END
DECLARE \@defname VARCHAR(100), \@cmd VARCHAR(1000)
SET \@defname = 
(SELECT name 
FROM sysobjects so JOIN sysconstraints sc
ON so.id = sc.constid 
WHERE object_name(so.parent_obj) = '%s' 
AND so.xtype = 'D'
AND sc.colid = 
 (SELECT colid FROM syscolumns 
 WHERE id = object_id('%s') AND 
 name = '%s'))
SET \@cmd = 'ALTER TABLE %s DROP CONSTRAINT '
+ \@defname
EXEC(\@cmd)
END
					, $t1_name, $t1_name, $f1_name, $t1_name,
	            );
            }
            next;
        }

        my $f2_type = $t2_field->data_type;
        my $f2_size = $t2_field->size || '';
        my $f2_nullable  = $t2_field->is_nullable;
        my $f2_default   = $t2_field->default_value;
        my $f2_auto_inc  = $t2_field->is_auto_increment;
        if ( !$t1_field->equals($t2_field, $case_insensitive) ) {
        	# SQLServer timestamp fields can't be altered, so we drop and add instead
        	if ( $target_db =~ /SQLServer/ && $f2_type eq "timestamp" ) {
        		push @diffs_table_changes, "ALTER TABLE $t1_name DROP COLUMN $f1_name;";
	            push @diffs_table_changes, sprintf( "ALTER TABLE %s ADD %s%s %s%s%s%s%s%s;",
	                $t1_name, $target_db =~ /Oracle/ ? '(' : '',
	                $f1_name, $f1_type,
	                ($f1_size && $f1_type !~ /(blob|text)$/) ? "($f1_size)" : '',
	                !defined $f1_default ? ''
	                	: uc $f1_default eq 'NULL' ? ' DEFAULT NULL'
	                	: uc $f1_default eq 'CURRENT_TIMESTAMP' ? ' DEFAULT CURRENT_TIMESTAMP'
	                	: " DEFAULT '$f1_default'",
	                $f1_nullable ? '' : ' NOT NULL',
	                $f1_auto_inc ? ' AUTO_INCREMENT' : '',
	                $target_db =~ /Oracle/ ? ')' : '',
	            );
	            next;
        	}

			my $changeText = $target_db =~ /SQLServer/ ? 'ALTER COLUMN' :
				$target_db =~ /Oracle/ ? 'MODIFY (' : 'CHANGE';
			my $nullText = $f1_nullable ? '' : ' NOT NULL';
			$nullText = '' if $target_db =~ /Oracle/ && $f1_nullable == $f2_nullable;
            push @diffs_table_changes, sprintf( "ALTER TABLE %s %s %s%s %s%s%s%s%s%s;",
                $t1_name, $changeText,
                $f1_name, $target_db =~ /MySQL/ ? " $f1_name" : '',
                $f1_type, ($f1_size && $f1_type !~ /(blob|text)$/) ? "($f1_size)" : '',
                $nullText,
                !defined $f1_default || $target_db =~ /SQLServer/ ? ''
                	: uc $f1_default eq 'NULL' ? ' DEFAULT NULL'
                	: uc $f1_default eq 'CURRENT_TIMESTAMP' ? ' DEFAULT CURRENT_TIMESTAMP'
                	: " DEFAULT '$f1_default'",
                $f1_auto_inc ? ' AUTO_INCREMENT' : '',
                $target_db =~ /Oracle/ ? ')' : '',
            );
            if ( defined $f1_default && $target_db =~ /SQLServer/ ) {
            	# Adding a column with a default value for SQL Server means adding a 
            	# constraint and setting existing NULLs to the default value
            	push @diffs_table_changes, sprintf( "ALTER TABLE %s ADD CONSTRAINT DF_%s_%s %s FOR %s;",
            		$t1_name, $t1_name, $f1_name, uc $f1_default eq 'NULL' ? 'DEFAULT NULL'
                	: uc $f1_default eq 'CURRENT_TIMESTAMP' ? 'DEFAULT CURRENT_TIMESTAMP'
                	: "DEFAULT '$f1_default'", $f1_name,
                );
            	push @diffs_table_changes, sprintf( "UPDATE %s SET %s = %s WHERE %s IS NULL;",
            		$t1_name, $f1_name, uc $f1_default eq 'NULL' ? 'NULL'
                	: uc $f1_default eq 'CURRENT_TIMESTAMP' ? 'CURRENT_TIMESTAMP'
                	: "'$f1_default'", $f1_name,
                );
            }
        }
    }
    
	my(%checked_indices, @diffs_index_creates, @diffs_index_drops);
INDEX:
	for my $i1 ( $t1->get_indices ) {
		for my $i2 ( $t2->get_indices ) {
			if ( $i1->equals($i2, $case_insensitive) ) {
				$checked_indices{$i2} = 1;
				next INDEX;
			}
		}
		push @diffs_index_creates, sprintf(
                "CREATE %sINDEX%s ON %s (%s);",
                $i1->type eq NORMAL ? '' : $i1->type." ",
                $i1->name ? " ".$i1->name : '',
                $t1_name,
                join(",", $i1->fields),
            );
	}
INDEX2:
	for my $i2 ( $t2->get_indices ) {
		next if $checked_indices{$i2};
		for my $i1 ( $t1->get_indices ) {
			next INDEX2 if $i2->equals($i1, $case_insensitive);
		}
		$target_db =~ /SQLServer/
			? push @diffs_index_drops, "DROP INDEX $t1_name.".$i2->name.";"
			: push @diffs_index_drops, "DROP INDEX ".$i2->name." on $t1_name;";
	}
    
	my(%checked_constraints, @diffs_constraint_drops);
CONSTRAINT:
	for my $c1 ( $t1->get_constraints ) {
		next if $source_db =~ /Oracle/ && $c1->type eq UNIQUE && $c1->name =~ /^SYS_/i;
		for my $c2 ( $t2->get_constraints ) {
			if ( $c1->equals($c2, $case_insensitive) ) {
				$checked_constraints{$c2} = 1;
				next CONSTRAINT;
			}
		}
		push @diffs_at_end, "ALTER TABLE $t1_name ADD ".
			constraint_to_string($c1, $source_schema).";";
	}
CONSTRAINT2:
	for my $c2 ( $t2->get_constraints ) {
		next if $checked_constraints{$c2};
		for my $c1 ( $t1->get_constraints ) {
			next CONSTRAINT2 if $c2->equals($c1, $case_insensitive);
		}
		if ( $c2->type eq UNIQUE ) {
			push @diffs_constraint_drops, "ALTER TABLE $t1_name DROP INDEX ".
				$c2->name.";";
		} elsif ( $target_db =~ /SQLServer/ ) {
			push @diffs_constraint_drops, "ALTER TABLE $t1_name DROP ".$c2->name.";";
		} else {
			push @diffs_constraint_drops, "ALTER TABLE $t1_name DROP ".$c2->type.
				($c2->type eq FOREIGN_KEY ? " ".$c2->name : '').";";
		}
	}
	
	push @diffs, @diffs_index_drops, @diffs_constraint_drops,
		@diffs_table_options, @diffs_table_adds,
		@diffs_table_changes, @diffs_index_creates;
}

for my $t2 ( $target_schema->get_tables ) {
    my $t2_name = $t2->name;
    my $t1      = $source_schema->get_table( $t2_name, $target_db =~ /SQLServer/ );

    unless ( $t1 ) {
    	if ( $target_db =~ /SQLServer/ ) {
			for my $constraint ( $t2->get_constraints ) {
				next if $constraint->type eq PRIMARY_KEY;
				push @diffs, "ALTER TABLE $t2_name DROP ".$constraint->name.";";
			}
    	}
        push @diffs_at_end, "DROP TABLE $t2_name;";
        next;
    }

    for my $t2_field ( $t2->get_fields ) {
        my $f2_name      = $t2_field->name;
        my $t1_field     = $t1->get_field( $f2_name );
        unless ( $t1_field ) {
        	my $modifier = $target_db =~ /SQLServer/ ? "COLUMN " : '';
            push @diffs, "ALTER TABLE $t2_name DROP $modifier$f2_name;";
        }
    }
}

if ( @new_tables ) {
    my $dummy_tr = SQL::Translator->new;
    $dummy_tr->schema->add_table( $_ ) for @new_tables;
    my $producer = $dummy_tr->producer( $target_db );
    unshift @diffs, $producer->( $dummy_tr );
}
push(@diffs, @diffs_at_end);

if ( @diffs ) {
    if ( $source_db !~ /^(MySQL|SQLServer|Oracle)$/ ) {
        unshift(@diffs, "-- Target database $target_db is untested/unsupported!!!");
    }
}

if ( @diffs ) {
    print join( "\n", 
        "-- Convert schema '$s2_name' to '$s1_name':\n", @diffs, "\n"
    );
    exit(1);
}
else {
    print "There were no differences.\n";
}

sub constraint_to_string {
	my $c = shift;
	my $schema = shift or die "No schema given";
	my @fields = $c->field_names or return '';

	if ( $c->type eq PRIMARY_KEY ) {
		if ( $target_db =~ /Oracle/ ) {
			return (defined $c->name ? 'CONSTRAINT '.$c->name.' ' : '') .
				'PRIMARY KEY (' . join(', ', @fields). ')';
		} else {
			return 'PRIMARY KEY (' . join(', ', @fields). ')';
		}
	}
	elsif ( $c->type eq UNIQUE ) {
		if ( $target_db =~ /Oracle/ ) {
			return (defined $c->name ? 'CONSTRAINT '.$c->name.' ' : '') .
				'UNIQUE (' . join(', ', @fields). ')';
		} else {
			return 'UNIQUE '.
				(defined $c->name ? $c->name.' ' : '').
				'(' . join(', ', @fields). ')';
		}
	}
	elsif ( $c->type eq FOREIGN_KEY ) {
		my $def = join(' ', 
			map { $_ || () } 'CONSTRAINT', $c->name, 'FOREIGN KEY' 
		);

		$def .= ' (' . join( ', ', @fields ) . ')';

		$def .= ' REFERENCES ' . $c->reference_table;

		my @rfields = map { $_ || () } $c->reference_fields;
		unless ( @rfields ) {
			my $rtable_name = $c->reference_table;
			if ( my $ref_table = $schema->get_table( $rtable_name ) ) {
				push @rfields, $ref_table->primary_key;
			}
			else {
				warn "Can't find reference table '$rtable_name' " .
					"in schema\n";
			}
		}

		if ( @rfields ) {
			$def .= ' (' . join( ', ', @rfields ) . ')';
		}
		else {
			warn "FK constraint on " . 'some table' . '.' .
				join('', @fields) . " has no reference fields\n";
		}

		if ( $c->match_type ) {
			$def .= ' MATCH ' . 
				( $c->match_type =~ /full/i ) ? 'FULL' : 'PARTIAL';
		}

		if ( $c->on_delete ) {
			$def .= ' ON DELETE '.join( ' ', $c->on_delete );
		}

		if ( $c->on_update ) {
			$def .= ' ON UPDATE '.join( ' ', $c->on_update );
		}

		return $def;
	}
}
            
# -------------------------------------------------------------------
# Bring out number weight & measure in a year of dearth.
# William Blake
# -------------------------------------------------------------------

=pod

=head1 AUTHOR

Ken Youens-Clark E<lt>kclark@cpan.orgE<gt>.

=head1 SEE ALSO

SQL::Translator, L<http://sqlfairy.sourceforge.net>.

=cut