package SQL::Translator::Producer::MySQL;

# -------------------------------------------------------------------
# $Id: MySQL.pm,v 1.54 2007-11-10 03:36:43 mwz444 Exp $
# -------------------------------------------------------------------
# Copyright (C) 2002-4 SQLFairy Authors
#
# 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 2.
#
# 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, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
# 02111-1307  USA
# -------------------------------------------------------------------

=head1 NAME

SQL::Translator::Producer::MySQL - MySQL-specific producer for SQL::Translator

=head1 SYNOPSIS

Use via SQL::Translator:

  use SQL::Translator;

  my $t = SQL::Translator->new( parser => '...', producer => 'MySQL', '...' );
  $t->translate;

=head1 DESCRIPTION

This module will produce text output of the schema suitable for MySQL.
There are still some issues to be worked out with syntax differences 
between MySQL versions 3 and 4 ("SET foreign_key_checks," character sets
for fields, etc.).

=head2 Table Types

Normally the tables will be created without any explicit table type given and
so will use the MySQL default.

Any tables involved in foreign key constraints automatically get a table type
of InnoDB, unless this is overridden by setting the C<mysql_table_type> extra
attribute explicitly on the table.

=head2 Extra attributes.

The producer recognises the following extra attributes on the Schema objects.

=over 4

=item field.list

Set the list of allowed values for Enum fields.

=item field.binary, field.unsigned, field.zerofill

Set the MySQL field options of the same name.

=item field.renamed_from

Used when producing diffs to say this column is the new name fo the specified
old column.

=item table.mysql_table_type

Set the type of the table e.g. 'InnoDB', 'MyISAM'. This will be
automatically set for tables involved in foreign key constraints if it is
not already set explicitly. See L<"Table Types">.

=item table.mysql_charset, table.mysql_collate

Set the tables default charater set and collation order.

=item field.mysql_charset, field.mysql_collate

Set the fields charater set and collation order.

=back

=cut

use strict;
use warnings;
use vars qw[ $VERSION $DEBUG %used_names ];
$VERSION = sprintf "%d.%02d", q$Revision: 1.54 $ =~ /(\d+)\.(\d+)/;
$DEBUG   = 0 unless defined $DEBUG;

use Data::Dumper;
use SQL::Translator::Schema::Constants;
use SQL::Translator::Utils qw(debug header_comment);

#
# Use only lowercase for the keys (e.g. "long" and not "LONG")
#
my %translate  = (
    #
    # Oracle types
    #
    varchar2   => 'varchar',
    long       => 'text',
    clob       => 'longtext',

    #
    # Sybase types
    #
    int        => 'integer',
    money      => 'float',
    real       => 'double',
    comment    => 'text',
    bit        => 'tinyint',

    #
    # Access types
    #
    'long integer' => 'integer',
    'text'         => 'text',
    'datetime'     => 'datetime',
);


sub preprocess_schema {
    my ($schema) = @_;

    # extra->{mysql_table_type} used to be the type. It belongs in options, so
    # move it if we find it. Return Engine type if found in extra or options
    my $mysql_table_type_to_options = sub {
      my ($table) = @_;

      my $extra = $table->extra;

      my $extra_type = delete $extra->{mysql_table_type};

      # Now just to find if there is already an Engine or Type option...
      # and lets normalize it to ENGINE since:
      #
      # The ENGINE table option specifies the storage engine for the table. 
      # TYPE is a synonym, but ENGINE is the preferred option name.
      #

      # We have to use the hash directly here since otherwise there is no way 
      # to remove options.
      my $options = ( $table->{options} ||= []);

      # This assumes that there isn't both a Type and an Engine option.
      for my $idx ( 0..$#{$options} ) {
        my ($key, $value) = %{ $options->[$idx] };

        next unless uc $key eq 'ENGINE' || uc $key eq 'TYPE';

        # if the extra.mysql_table_type is given, use that
        delete $options->[$idx]{$key};
        return $options->[$idx]{ENGINE} = $value || $extra_type;

      }
  
      if ($extra_type) {
        push @$options, { ENGINE => $extra_type };
        return $extra_type;
      }

    };

    # Names are only specific to a given schema
    local %used_names = ();

    #
    # Work out which tables need to be InnoDB to support foreign key
    # constraints. We do this first as we need InnoDB at both ends.
    #
    foreach my $table ( $schema->get_tables ) {
       
        $mysql_table_type_to_options->($table);

        foreach my $c ( $table->get_constraints ) {
            next unless $c->type eq FOREIGN_KEY;

            # Normalize constraint names here.
            my $c_name = $c->name;
            # Give the constraint a name if it doesn't have one, so it doens't feel
            # left out
            $c_name   = $table->name . '_fk' unless length $c_name;
            
            $c->name( next_unused_name($c_name) );

            for my $meth (qw/table reference_table/) {
                my $table = $schema->get_table($c->$meth) || next;
                next if $mysql_table_type_to_options->($table);
                $table->options( { 'ENGINE' => 'InnoDB' } );
            }
        } # foreach constraints

        foreach my $f ( $table->get_fields ) {
          my @size = $f->size;
          if ( !$size[0] && $f->data_type =~ /char$/ ) {
            $f->size( (255) );
          }
        }

    }
}

sub produce {
    my $translator     = shift;
    local $DEBUG       = $translator->debug;
    local %used_names;
    my $no_comments    = $translator->no_comments;
    my $add_drop_table = $translator->add_drop_table;
    my $schema         = $translator->schema;
    my $show_warnings  = $translator->show_warnings || 0;

    my ($qt, $qf) = ('','');
    $qt = '`' if $translator->quote_table_names;
    $qf = '`' if $translator->quote_field_names;

    debug("PKG: Beginning production\n");
    %used_names = ();
    my $create; 
    $create .= header_comment unless ($no_comments);
    # \todo Don't set if MySQL 3.x is set on command line
    $create .= "SET foreign_key_checks=0;\n\n";

    preprocess_schema($schema);

    #
    # Generate sql
    #
    my @table_defs =();
    
    for my $table ( $schema->get_tables ) {
#        print $table->name, "\n";
        push @table_defs, create_table($table, 
                                       { add_drop_table    => $add_drop_table,
                                         show_warnings     => $show_warnings,
                                         no_comments       => $no_comments,
                                         quote_table_names => $qt,
                                         quote_field_names => $qf
                                         });
    }

#    print "@table_defs\n";
    push @table_defs, "SET foreign_key_checks=1;\n\n";

    return wantarray ? ($create, @table_defs) : $create . join ('', @table_defs);
}

sub create_table
{
    my ($table, $options) = @_;

    my $qt = $options->{quote_table_names} || '';
    my $qf = $options->{quote_field_names} || '';

    my $table_name = $table->name;
    debug("PKG: Looking at table '$table_name'\n");

    #
    # Header.  Should this look like what mysqldump produces?
    #
    my $create = '';
    my $drop;
    $create .= "--\n-- Table: $qt$table_name$qt\n--\n" unless $options->{no_comments};
    $drop = qq[DROP TABLE IF EXISTS $qt$table_name$qt;\n] if $options->{add_drop_table};
    $create .= "CREATE TABLE $qt$table_name$qt (\n";

    #
    # Fields
    #
    my @field_defs;
    for my $field ( $table->get_fields ) {
        push @field_defs, create_field($field, $options);
    }

    #
    # Indices
    #
    my @index_defs;
    my %indexed_fields;
    for my $index ( $table->get_indices ) {
        push @index_defs, create_index($index, $options);
        $indexed_fields{ $_ } = 1 for $index->fields;
    }

    #
    # Constraints -- need to handle more than just FK. -ky
    #
    my @constraint_defs;
    my @constraints = $table->get_constraints;
    for my $c ( @constraints ) {
        my $constr = create_constraint($c, $options);
        push @constraint_defs, $constr if($constr);
        
         unless ( $indexed_fields{ ($c->fields())[0] } || $c->type ne FOREIGN_KEY ) {
             push @index_defs, "INDEX ($qf" . ($c->fields())[0] . "$qf)";
             $indexed_fields{ ($c->fields())[0] } = 1;
         }
    }

    $create .= join(",\n", map { "  $_" } 
                    @field_defs, @index_defs, @constraint_defs
                    );

    #
    # Footer
    #
    $create .= "\n)";
    $create .= generate_table_options($table) || '';
    $create .= ";\n\n";

    return $drop ? ($drop,$create) : $create;
}

sub generate_table_options 
{
  my ($table) = @_;
  my $create;

  my $table_type_defined = 0;
  for my $t1_option_ref ( $table->options ) {
    my($key, $value) = %{$t1_option_ref};
    $table_type_defined = 1
      if uc $key eq 'ENGINE' or uc $key eq 'TYPE';
    $create .= " $key=$value";
  }

  my $mysql_table_type = $table->extra('mysql_table_type');
  $create .= " ENGINE=$mysql_table_type"
    if $mysql_table_type && !$table_type_defined;
  my $charset          = $table->extra('mysql_charset');
  my $collate          = $table->extra('mysql_collate');
  my $comments         = $table->comments;

  $create .= " DEFAULT CHARACTER SET $charset" if $charset;
  $create .= " COLLATE $collate" if $collate;
  $create .= qq[ comment='$comments'] if $comments;
  return $create;
}

sub create_field
{
    my ($field, $options) = @_;

    my $qf = $options->{quote_field_names} ||= '';

    my $field_name = $field->name;
    debug("PKG: Looking at field '$field_name'\n");
    my $field_def = "$qf$field_name$qf";

    # data type and size
    my $data_type = $field->data_type;
    my @size      = $field->size;
    my %extra     = $field->extra;
    my $list      = $extra{'list'} || [];
    # \todo deal with embedded quotes
    my $commalist = join( ', ', map { qq['$_'] } @$list );
    my $charset = $extra{'mysql_charset'};
    my $collate = $extra{'mysql_collate'};

    #
    # Oracle "number" type -- figure best MySQL type
    #
    if ( lc $data_type eq 'number' ) {
        # not an integer
        if ( scalar @size > 1 ) {
            $data_type = 'double';
        }
        elsif ( $size[0] && $size[0] >= 12 ) {
            $data_type = 'bigint';
        }
        elsif ( $size[0] && $size[0] <= 1 ) {
            $data_type = 'tinyint';
        }
        else {
            $data_type = 'int';
        }
    }
    #
    # Convert a large Oracle varchar to "text"
    #
    elsif ( $data_type =~ /char/i && $size[0] > 255 ) {
        $data_type = 'text';
        @size      = ();
    }
    elsif ( $data_type =~ /boolean/i ) {
        $data_type = 'enum';
        $commalist = "'0','1'";
    }
    elsif ( exists $translate{ lc $data_type } ) {
        $data_type = $translate{ lc $data_type };
    }

    @size = () if $data_type =~ /(text|blob)/i;

    if ( $data_type =~ /(double|float)/ && scalar @size == 1 ) {
        push @size, '0';
    }

    $field_def .= " $data_type";

    if ( lc $data_type eq 'enum' ) {
        $field_def .= '(' . $commalist . ')';
    } 
    elsif ( defined $size[0] && $size[0] > 0 ) {
        $field_def .= '(' . join( ', ', @size ) . ')';
    }

    # char sets
    $field_def .= " CHARACTER SET $charset" if $charset;
    $field_def .= " COLLATE $collate" if $collate;

    # MySQL qualifiers
    for my $qual ( qw[ binary unsigned zerofill ] ) {
        my $val = $extra{ $qual } || $extra{ uc $qual } or next;
        $field_def .= " $qual";
    }
    for my $qual ( 'character set', 'collate', 'on update' ) {
        my $val = $extra{ $qual } || $extra{ uc $qual } or next;
        $field_def .= " $qual $val";
    }

    # Null?
    $field_def .= ' NOT NULL' unless $field->is_nullable;

    # Default?  XXX Need better quoting!
    my $default = $field->default_value;
    if ( defined $default ) {
        if ( uc $default eq 'NULL') {
            $field_def .= ' DEFAULT NULL';
        } else {
            $field_def .= " DEFAULT '$default'";
        }
    }

    if ( my $comments = $field->comments ) {
        $field_def .= qq[ comment '$comments'];
    }

    # auto_increment?
    $field_def .= " auto_increment" if $field->is_auto_increment;

    return $field_def;
}

sub alter_create_index
{
    my ($index, $options) = @_;

    my $qt = $options->{quote_table_names} || '';
    my $qf = $options->{quote_field_names} || '';

    return join( ' ',
                 'ALTER TABLE',
                 $qt.$index->table->name.$qt,
                 'ADD',
                 create_index(@_)
                 );
}

sub create_index
{
    my ($index, $options) = @_;

    my $qf = $options->{quote_field_names} || '';

    return join( ' ', 
                 lc $index->type eq 'normal' ? 'INDEX' : $index->type . ' INDEX',
                 $index->name,
                 '(' . $qf . join( "$qf, $qf", $index->fields ) . $qf . ')'
                 );

}

sub alter_drop_index
{
    my ($index, $options) = @_;

    my $qt = $options->{quote_table_names} || '';
    my $qf = $options->{quote_field_names} || '';

    return join( ' ', 
                 'ALTER TABLE',
                 $qt.$index->table->name.$qt,
                 'DROP',
                 'INDEX',
                 $index->name || $index->fields
                 );

}

sub alter_drop_constraint
{
    my ($c, $options) = @_;

    my $qt      = $options->{quote_table_names} || '';
    my $qc      = $options->{quote_constraint_names} || '';

    my $out = sprintf('ALTER TABLE %s DROP %s %s',
                      $c->table->name,
                      $c->type eq FOREIGN_KEY ? $c->type : "INDEX",
                      $qc . $c->name . $qc );

    return $out;
}

sub alter_create_constraint
{
    my ($index, $options) = @_;

    my $qt = $options->{quote_table_names} || '';
    return join( ' ',
                 'ALTER TABLE',
                 $qt.$index->table->name.$qt,
                 'ADD',
                 create_constraint(@_) );
}

sub create_constraint
{
    my ($c, $options) = @_;

    my $qf      = $options->{quote_field_names} || '';
    my $qt      = $options->{quote_table_names} || '';
    my $leave_name      = $options->{leave_name} || undef;

    my @fields = $c->fields or next;

    if ( $c->type eq PRIMARY_KEY ) {
        return 'PRIMARY KEY (' . $qf . join("$qf, $qf", @fields). $qf . ')';
    }
    elsif ( $c->type eq UNIQUE ) {
        return
        'UNIQUE '. 
            (defined $c->name ? $qf.$c->name.$qf.' ' : '').
            '(' . $qf . join("$qf, $qf", @fields). $qf . ')';
    }
    elsif ( $c->type eq FOREIGN_KEY ) {
        #
        # Make sure FK field is indexed or MySQL complains.
        #

        my $table = $c->table;
        my $c_name = $c->name;

        my $def = join(' ', 
                       map { $_ || () } 
                         'CONSTRAINT', 
                         $qt . $c_name . $qt, 
                         'FOREIGN KEY'
                      );


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

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

        my @rfields = map { $_ || () } $c->reference_fields;
        unless ( @rfields ) {
            my $rtable_name = $c->reference_table;
            if ( my $ref_table = $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 $options->{show_warnings};
            }
        }

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

        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;
    }

    return undef;
}

sub alter_table
{
    my ($to_table, $options) = @_;

    my $qt = $options->{quote_table_name} || '';

    my $table_options = generate_table_options($to_table) || '';
    my $out = sprintf('ALTER TABLE %s%s',
                      $qt . $to_table->name . $qt,
                      $table_options);

    return $out;
}

sub rename_field { alter_field(@_) }
sub alter_field
{
    my ($from_field, $to_field, $options) = @_;

    my $qf = $options->{quote_field_name} || '';
    my $qt = $options->{quote_table_name} || '';

    my $out = sprintf('ALTER TABLE %s CHANGE COLUMN %s %s',
                      $qt . $to_field->table->name . $qt,
                      $qf . $from_field->name . $qf,
                      create_field($to_field, $options));

    return $out;
}

sub add_field
{
    my ($new_field, $options) = @_;

    my $qt = $options->{quote_table_name} || '';

    my $out = sprintf('ALTER TABLE %s ADD COLUMN %s',
                      $qt . $new_field->table->name . $qt,
                      create_field($new_field, $options));

    return $out;

}

sub drop_field
{ 
    my ($old_field, $options) = @_;

    my $qf = $options->{quote_field_name} || '';
    my $qt = $options->{quote_table_name} || '';
    
    my $out = sprintf('ALTER TABLE %s DROP COLUMN %s',
                      $qt . $old_field->table->name . $qt,
                      $qf . $old_field->name . $qf);

    return $out;
    
}

sub batch_alter_table {
  my ($table, $diff_hash, $options) = @_;

  # InnoDB has an issue with dropping and re-adding a FK constraint under the 
  # name in a single alter statment, see: http://bugs.mysql.com/bug.php?id=13741
  #
  # We have to work round this.

  my %fks_to_alter;
  my %fks_to_drop = map {
    $_->type eq FOREIGN_KEY 
              ? ( $_->name => $_ ) 
              : ( )
  } @{$diff_hash->{alter_drop_constraint} };

  my %fks_to_create = map {
    if ( $_->type eq FOREIGN_KEY) {
      $fks_to_alter{$_->name} = $fks_to_drop{$_->name} if $fks_to_drop{$_->name};
      ( $_->name => $_ );
    } else { ( ) }
  } @{$diff_hash->{alter_create_constraint} };

  my $drop_stmt = '';
  if (scalar keys %fks_to_alter) {
    $diff_hash->{alter_drop_constraint} = [
      grep { !$fks_to_alter{$_->name} } @{ $diff_hash->{alter_drop_constraint} }
    ];

    $drop_stmt = batch_alter_table($table, { alter_drop_constraint => [ values %fks_to_alter ] }, $options) 
               . "\n";

  }

  my @stmts = map {
    if (@{ $diff_hash->{$_} || [] }) {
      my $meth = __PACKAGE__->can($_) or die __PACKAGE__ . " cant $_";
      map { $meth->( (ref $_ eq 'ARRAY' ? @$_ : $_), $options ) } @{ $diff_hash->{$_} }
    } else { () }
  } qw/rename_table
       alter_drop_constraint
       alter_drop_index
       drop_field
       add_field
       alter_field
       rename_field
       alter_create_index
       alter_create_constraint
       alter_table/;

  # rename_table makes things a bit more complex
  my $renamed_from = "";
  $renamed_from = $diff_hash->{rename_table}[0][0]->name
    if $diff_hash->{rename_table} && @{$diff_hash->{rename_table}};

  return unless @stmts;
  # Just zero or one stmts. return now
  return "$drop_stmt@stmts;" unless @stmts > 1;

  # Now strip off the 'ALTER TABLE xyz' of all but the first one

  my $qt = $options->{quote_table_name} || '';
  my $table_name = $qt . $table->name . $qt;


  my $re = $renamed_from 
         ? qr/^ALTER TABLE (?:\Q$table_name\E|\Q$qt$renamed_from$qt\E) /
            : qr/^ALTER TABLE \Q$table_name\E /;

  my $first = shift  @stmts;
  my ($alter_table) = $first =~ /($re)/;

  my $padd = " " x length($alter_table);

  return $drop_stmt . join( ",\n", $first, map { s/$re//; $padd . $_ } @stmts) . ';';

}

sub drop_table {
  my ($table, $options) = @_;

    my $qt = $options->{quote_table_names} || '';

  # Drop (foreign key) constraints so table drops cleanly
  my @sql = batch_alter_table($table, { alter_drop_constraint => [ grep { $_->type eq 'FOREIGN KEY' } $table->get_constraints ] }, $options);

  return join("\n", @sql, "DROP TABLE $qt$table$qt;");

}

sub rename_table {
  my ($old_table, $new_table, $options) = @_;

  my $qt = $options->{quote_table_names} || '';

  return "ALTER TABLE $qt$old_table$qt RENAME TO $qt$new_table$qt";
}

sub next_unused_name {
  my $name       = shift || '';
  if ( !defined($used_names{$name}) ) {
    $used_names{$name} = $name;
    return $name;
  }

  my $i = 1;
  while ( defined($used_names{$name . '_' . $i}) ) {
    ++$i;
  }
  $name .= '_' . $i;
  $used_names{$name} = $name;
  return $name;
}

1;

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

=pod

=head1 SEE ALSO

SQL::Translator, http://www.mysql.com/.

=head1 AUTHORS

darren chamberlain E<lt>darren@cpan.orgE<gt>,
Ken Y. Clark E<lt>kclark@cpan.orgE<gt>.

=cut