# Movable Type (r) Open Source (C) 2001-2011 Six Apart, Ltd.
# This program is distributed under the terms of the
# GNU General Public License, version 2.
#
# $Id$

package MT::ObjectDriver::SQL;

#--------------------------------------#
# Dependencies

use strict;
use warnings;

use base qw( Data::ObjectDriver::SQL );

#--------------------------------------#
# Class Accessors

my @ACCESSORS = qw( transform range range_incl lob_columns date_columns not null not_null like distinct from_stmt binary );
__PACKAGE__->mk_accessors(@ACCESSORS);

#--------------------------------------#
# Class Methods

sub new {
    my $class = shift;
    my %param = @_;

    my %data;
    @data{@ACCESSORS} = delete @param{@ACCESSORS};

    my $stmt = $class->SUPER::new(%param);

    for my $field (@ACCESSORS) {
        next if $field eq 'distinct';
        next if $field eq 'from_stmt';
        $stmt->$field(defined $data{$field} ? { %{ $data{$field} } } : {});
    }
    $stmt->distinct($data{distinct} || 0);
    if(defined $data{from_stmt}) {
        $stmt->from_stmt($data{from_stmt});
    }

    $stmt;
}

sub ts2db {
    return unless $_[0];
    if($_[0] =~ m{ \A \d{4} - }xms) {
        return $_[0];
    }
    my $ret = sprintf '%04d-%02d-%02d %02d:%02d:%02d', unpack 'A4A2A2A2A2A2', $_[0];
    return $ret;
}

sub distinct_stmt {
    my $class = shift;
    my ($stmt) = @_;
    $stmt;
}

# This method will be used in Postgres and MSSQLServer
sub _subselect_distinct {
    my $class = shift;
    my ($stmt) = @_;
    ## If we're doing a SELECT DISTINCT, postgres would have us include
    ## the order field, which means the DISTINCT isn't what we want--so
    ## let's do a subselect.
    my $subselect = $class->new;
    $subselect->from_stmt($stmt);
    $subselect->select([ @{ $stmt->select } ]);
    #for my $col (@{ $subselect->select }) {
    #    $col = $driver->dbd->fix_subselect_column($col); ## FIXME
    #}
    $subselect->select_map({ %{ $stmt->select_map } });
    for my $col (keys %{ $subselect->select_map }) {
        my $new_col = $col;
        #$new_col = $driver->dbd->fix_subselect_column($new_col); ## FIXME
        $subselect->select_map->{$new_col} = delete $subselect->select_map->{$col};
    }
    $subselect->bind      ([ @{ $stmt->bind } ]);
    $subselect->distinct  (1);

    $stmt->distinct(0);
    $subselect;
}


#--------------------------------------#
# Instance Methods

sub as_sql {
    my $stmt = shift;
    my $sql = '';

    my $old_sel;
    if (@{ $stmt->select }) {
        $old_sel = $stmt->select;

        $sql = 'SELECT ';
        if($stmt->distinct) {
            $sql .= 'DISTINCT ';
        }
        $sql .= join(', ', @{ $stmt->select }) . "\n";
        $stmt->select([]);
    }

    if ($stmt->from_stmt) {
        $sql .= 'FROM ('
            . $stmt->from_stmt->as_sql(@_)
            . ") t\n";  # t is the subquery alias
    } else {
        $sql .= $stmt->SUPER::as_sql(@_);

        ## Check if we generated an unbounded query for mt_session, since we're seeing those in production.
        ## TODO: remove this. Or generalize it into query auditing.
        ## my @from_tbls = @{ $stmt->from };
        ## if (1 == scalar @from_tbls && $from_tbls[0] eq 'mt_session') {
        ##     if (!$stmt->where || !@{ $stmt->where } || $sql !~ m{ where }xmsi) {
        ##         MT->log({
        ##             message => Carp::longmess("Generated unbounded query on mt_session [$sql]"),
        ##             level => MT::Log::DEBUG()
        ##         });
        ##     }
        ## }
    }

    $stmt->select($old_sel) if $old_sel;
    return $sql;
}

sub _mk_term {
    my $stmt = shift;
    my ($col, $val) = @_;

    $col =~ s/ \A [\w\.]+? \. //x;

    ## Any last-minute property -> field name manipulation
    if (my $m = $stmt->column_mutator) {
        $col = $m->($col);
    }

    if (ref $val eq 'HASH') {
        if (!exists $val->{op}) {
            # hash-style value, containing hints on operation
            if (exists $val->{like}) {
                $val = { op => 'LIKE', value => $val->{like} };
            }
            if (exists $val->{not_like}) {
                $val = { op => 'NOT LIKE', value => $val->{not_like} };
            }
            elsif (exists $val->{not_null}) {
                $val = \'is not null';
            }
            elsif (exists $val->{not}) {
                my $v = $val->{not};
                if ('ARRAY' eq ref($v)) {
                    if(my $transformed_column = $stmt->transform->{$col}) {
                        $col = $transformed_column;
                    }
                    my $term = $col . ' NOT IN (' . join (',', ('?') x scalar @$v ) . ')';
                    return ($term, $v, $col);
                } elsif (ref $v) {
                    die "Unsupported value in 'not' column";
                } else {
                    $val = { value => $v,
                             op    => '!=' };
                }
            }
            elsif (exists $val->{between}) {
                my $low = @{$val->{between}}[0];
                my $high = @{$val->{between}}[1];
                if($stmt->date_columns->{$col}) {
                    $low = ts2db($low);
                    $high = ts2db($high);
                }
                $val = [ '-and', { op => '>=', value => $low },
                    { op => '<=', value => $high } ];
            }
            elsif (exists $val->{'>='}) {
                $val = { op => '>=', value => $val->{'>='} };
            }
            elsif (exists $val->{'>'}) {
                $val = { op => '>', value => $val->{'>'} };
            }
            elsif (exists $val->{'<='}) {
                $val = { op => '<=', value => $val->{'<='} };
            }
            elsif (exists $val->{'<'}) {
                $val = { op => '<', value => $val->{'<'} };
            }
            elsif (exists $val->{'!='}) {
                $val = { op => '!=', value => $val->{'!='} };
            }
        }

        ## Translate dates from app to database format.
        if(($stmt->date_columns->{$col}) && (ref($val) eq 'HASH')) {
            my $v = $val->{value};
            if (ref($v) eq 'ARRAY') {
                $v->[$_] = ts2db($v->[$_]) for @$v;
            }
            else {
                $val->{value} = ts2db($v);
            }
        }
    }
    else {
        ## Rearrange the value into an inclusive range.
        my $range_incl = $stmt->range_incl;
        my $range      = $stmt->range;

        ## We may recurse, so let us empty range inclusions in our scope.
        local $range_incl->{$col} = $range_incl->{$col};
        local $range->{$col}      = $range->{$col};
        if ($range_incl->{$col} || $range->{$col}) {
            my ($lt, $gt) = $range_incl->{$col} ? ('<=', '>=') : ('<', '>');
            my @vals;

            my ($first_val, $last_val) = @$val;
            if ($stmt->date_columns->{$col}) {
                $first_val = ts2db($first_val) if defined $first_val;
                $last_val = ts2db($last_val) if defined $last_val;
            }

            ## Ignore first value if it's undef (right-bounded range, eg [undef, 20050101000000] )
            if (defined $first_val) {
                push @vals, { op => $gt, value => $first_val };
            }
            ## Ignore last value if it's defined (left-bounded range, eg [20050101000000] )
            if (defined $last_val) {
                push @vals, { op => $lt, value => $last_val  };
            }
            if (2 == scalar @vals) {
                $val = [ '-and', @vals ];
            }
            else {
                ($val) = @vals;
            }

            ## Because the new value is an arrayref, we're about to get
            ## called recursively with each of those hashrefs inside it.
            ## So ignore that we're using an inclusive range within this
            ## call's scope.
            undef ($range_incl->{$col} ? $range_incl->{$col} : $range->{$col});
        }

        ## Translate dates from app to database format.
        if ($stmt->date_columns->{$col}) {
            if (ref($val) eq 'HASH') {
                my $v = $val->{value};
                if (ref($v) eq 'ARRAY') {
                    $v->[$_] = ts2db($v->[$_]) for @$v;
                }
                else {
                    $val->{value} = ts2db($v);
                }
            } elsif (!ref($val)) {
                $val = ts2db($val);
            }
        }

        if ($stmt->not->{$col}) {
            if ('ARRAY' eq ref($val)) {
                if(my $transformed_column = $stmt->transform->{$col}) {
                    $col = $transformed_column;
                }
                my $term = $col . ' NOT IN (' . join (',', ('?') x scalar @$val ) . ')';
                return ($term, $val, $col);
            }
            elsif (ref $val) {
                die "Unsupported value in 'not' column";
            }
            else {
                $val = { value => $val,
                         op    => '!=', };
            }
        }

        if ($stmt->null->{$col}) {
            $val = \'is null';
        }

        if ($stmt->not_null->{$col}) {
            $val = \'is not null';
        }

        if ($stmt->like->{$col}) {
            if (ref($val) eq 'HASH') {
                $val->{op} = 'LIKE';
            } elsif (!ref($val)) {
                $val = { op    => 'LIKE',
                         value => $val,   };
            }
        }
    }

    ## Transformation modifies the column name, so it should be last.
    if(my $transformed_column = $stmt->transform->{$col}) {
        $col = $transformed_column;
    }

    ## Prevent D::OD from re-mutating, since we've done it here
    local $stmt->{column_mutator} = undef;

    $stmt->SUPER::_mk_term($col, $val);
}

sub make_subselect {
    my $stmt = shift;
    my $class = ref $stmt;

    my $subselect = $class->new();
    for my $field (qw( bind distinct )) {
        $subselect->$field($stmt->$field());
    }

    my @new_selects = map { s{ \A \w+\. }{}xms } @{ $stmt->select };
    $subselect->select(\@new_selects);

    my %new_select_map;
    my $sel_map = $stmt->select_map;
    for my $select_field (keys %$sel_map) {
        my $new_select_field = $select_field;
        $new_select_field =~ s{ \A \w+\. }{}xms;
        $new_select_map{$new_select_field} = $sel_map->{$select_field};
    }

    $subselect->from_stmt($stmt);
    return $subselect;
}

sub field_decorator {
    my $stmt = shift;
    my ($class) = @_;
    return sub {
        my($term) = @_;
        my $field_prefix = $class->datasource;
        for my $col (@{ $class->column_names }) {
            $term =~ s/\b$col\b/${field_prefix}_$col/g;
        }
        return $term;
    };
}

sub as_limit {
    my $stmt = shift;
    my $n = $stmt->limit;
    # Support offset without limit
    my $o = $stmt->offset || 0;
    $n = 2147483647 if !$n && $o;
    return '' unless $n;
    die "Non-numerics in limit/offset clause ($n, $o)" if ($n =~ /\D/) || ($o =~ /\D/);
    return sprintf "LIMIT %d%s\n", $n,
           ($o ? " OFFSET " . int($o) : "");
}

sub add_freetext_where { 0 }

1;
__END__

=head1 NAME

MT::ObjectDriver::SQL

=head1 METHODS

TODO

=head1 AUTHOR & COPYRIGHT

Please see L<MT/AUTHOR & COPYRIGHT>.

=cut
