package ObjectDB::Table;

use strict;
use warnings;

our $VERSION = '3.25';

use constant DEFAULT_PAGE_SIZE => 10;

require Carp;
use SQL::Composer;
use SQL::Composer::Expression;
use ObjectDB;
use ObjectDB::Stmt;
use ObjectDB::Iterator;
use ObjectDB::Quoter;
use ObjectDB::With;
use ObjectDB::Meta;
use ObjectDB::Util qw(execute to_array filter_columns);

sub new {
    my $class = shift;
    $class = ref $class if ref $class;
    my (%params) = @_;

    my $self = {};
    bless $self, $class;

    $self->{class} = $params{class};
    $self->{dbh}   = $params{dbh};

    return $self;
}

sub meta {
    my $self = shift;

    return $self->{class}->meta;
}

sub dbh {
    my $self = shift;

    return $self->{dbh};
}

sub find {
    my $self = shift;
    my (%params) = @_;

    my $single = $params{single} || $params{first};

    my $offset = $params{offset};
    my $limit  = $params{limit};

    if ($single) {
        $limit = 1;
    }
    elsif (my $page = $params{page}) {
        my $page_size = $params{page_size};

        $page = 1 unless $page && $page =~ m/^[0-9]+$/;
        $page_size = DEFAULT_PAGE_SIZE unless $page_size && $page_size =~ m/^[0-9]+$/;

        $offset = ($page - 1) * $page_size;
        $limit  = $page_size;
    }

    my $table = $self->meta->table;

    my $quoter = ObjectDB::Quoter->new(
        meta   => $self->meta,
        driver => $self->dbh->{Driver}->{Name},
    );
    my $where = SQL::Composer::Expression->new(
        quoter         => $quoter,
        expr           => $params{where},
        default_prefix => $table
    );
    my $having = SQL::Composer::Expression->new(
        quoter         => $quoter,
        expr           => $params{having},
        default_prefix => $table
    );
    my $with = ObjectDB::With->new(
        meta => $self->meta,
        with => [ to_array($params{with}), $quoter->with ]
    );

    my $columns = filter_columns([ $self->meta->columns ], {%params});

    my $join = $with->to_joins;
    push @$join, to_array($params{join}) if $params{join};

    my $select = SQL::Composer->build(
        'select',
        driver     => $self->dbh->{Driver}->{Name},
        from       => $table,
        columns    => $columns,
        join       => $join,
        where      => $where,
        limit      => $limit,
        offset     => $offset,
        order_by   => $params{order_by},
        group_by   => $params{group_by},
        having     => $having,
        for_update => $params{for_update},
    );

    my ($rv, $sth) = execute($self->dbh, $select);

    return $self->_finalize_results($select, $sth, %params, meta => $self->meta, wantarray => wantarray);
}

sub find_by_compose {
    my $self = shift;
    my (%params) = @_;

    my $single = $params{single} || $params{first};

    my $offset = $params{offset};
    my $limit  = $params{limit};

    if ($single) {
        $limit = 1;
    }
    elsif (my $page = $params{page}) {
        my $page_size = $params{page_size};

        $page = 1 unless $page && $page =~ m/^[0-9]$/;
        $page_size = DEFAULT_PAGE_SIZE unless $page_size && $page_size =~ m/^[0-9]$/;

        $offset = ($page - 1) * $page_size;
        $limit  = $page_size;
    }

    my $table = $params{table};

    my $select = SQL::Composer->build(
        'select',
        driver     => $self->dbh->{Driver}->{Name},
        from       => $table,
        columns    => $params{columns},
        join       => $params{join},
        where      => $params{where},
        limit      => $params{limit},
        offset     => $params{offset},
        order_by   => $params{order_by},
        group_by   => $params{group_by},
        having     => $params{heaving},
        for_update => $params{for_update},
    );

    my ($rv, $sth) = execute($self->dbh, $select);

    my $meta;
    if (!$params{rows_as_hashes}) {
        $meta = ObjectDB::Meta->find_by_table($table);
        die qq{Can't find meta for table '$table'} unless $meta;
    }

    return $self->_finalize_results($select, $sth, %params, meta => $meta, wantarray => wantarray);
}

sub find_by_sql {
    my $self = shift;
    my ($sql, $bind, %params) = @_;

    my $single = $params{single} || $params{first};

    my @bind;
    if (ref $bind eq 'HASH') {
        while ($sql =~ s{:([[:alnum:]]+)}{?}) {
            push @bind, $bind->{$1};
        }
    }
    else {
        @bind = @$bind if $bind && ref $bind eq 'ARRAY';
    }

    my $stmt = ObjectDB::Stmt->new(sql => $sql, bind => \@bind);

    my ($rv, $sth) = execute($self->dbh, $stmt);

    my @column_names = @{ $sth->{NAME_lc} };

    if (my $cb = $params{each}) {
        while (my $row = $sth->fetchrow_arrayref) {
            my $row_copy = [@$row];
            my %values;
            foreach my $column (@column_names) {
                $values{$column} = shift @$row_copy;
            }

            my $object = $self->meta->class->new(%values);
            $object->is_in_db(1);

            $cb->($object);
        }

        return $self;
    }
    elsif ($single || wantarray) {
        my $rows = $sth->fetchall_arrayref;
        return () unless $rows && @$rows;

        my $i = 0;
        my @results;
        foreach my $row (@$rows) {
            my %values;
            foreach my $column (@column_names) {
                $values{$column} = $row->[ $i++ ];
            }

            if ($params{rows_as_hashes}) {
                push @results, \%values;
            }
            else {
                push @results, $self->meta->class->new(%values)->is_in_db(1);
            }
        }

        return @results;
    }
    else {
        my $i      = 0;
        my $walker = sub {
            my $row = $sth->fetchrow_arrayref;
            return unless defined $row;

            my %values;
            foreach my $column (@column_names) {
                $values{$column} = $row->[ $i++ ];
            }

            my $result;
            if ($params{rows_as_hashes}) {
                $result = \%values;
            }
            else {
                $result = $self->meta->class->new(%values);
                $result->is_in_db(1);
            }

            return $result;
        };

        return ObjectDB::Iterator->new(walker => $walker);
    }
}

sub _finalize_results {
    my $self = shift;
    my ($select, $sth, %params) = @_;

    my $meta = $params{meta};
    my $single = $params{single} || $params{first};

    if (my $cb = $params{each}) {
        while (my $row = $sth->fetchrow_arrayref) {
            my $rows = [ [@$row] ];
            $rows = $select->from_rows($rows);

            my $result;
            if ($params{rows_as_hashes}) {
                $result = $rows->[0];
            }
            else {
                $result = $meta->class->new(%{ $rows->[0] });
                $result = $result->is_in_db(1);
            }

            $cb->($result);
        }

        return $self;
    }
    elsif ($single || $params{wantarray}) {
        my $rows = $sth->fetchall_arrayref;
        return unless $rows && @$rows;

        $rows = $select->from_rows($rows);

        my @results;

        if ($params{rows_as_hashes}) {
            @results = @$rows;
        }
        else {
            @results =
              map { $_->is_in_db(1) }
              map { $meta->class->new->set_columns(%{$_}) } @$rows;
        }

        return $single ? $results[0] : @results;
    }
    else {
        my $walker = sub {
            my $row = $sth->fetchrow_arrayref;
            return unless defined $row;

            my $rows = [ [@$row] ];
            $rows = $select->from_rows($rows);

            my $result;
            if ($params{rows_as_hashes}) {
                $result = $rows->[0];
            }
            else {
                $result = $meta->class->new(%{ $rows->[0] });
                $result->is_in_db(1);
            }

            return $result;
        };

        return ObjectDB::Iterator->new(walker => $walker);
    }
}

sub update {
    my $self = shift;
    my (%params) = @_;

    my $sql = SQL::Composer->build(
        'update',
        driver => $self->dbh->{Driver}->{Name},
        table  => $self->meta->table,
        set    => $params{set},
        where  => $params{where},
    );

    my $rv = execute($self->dbh, $sql);
    return $rv;
}

sub delete : method {
    my $self = shift;
    my (%params) = @_;

    my $sql = SQL::Composer->build(
        'delete',
        driver => $self->dbh->{Driver}->{Name},
        from   => $self->meta->table,
        where  => $params{where},
    );

    my $rv = execute($self->dbh, $sql);
    return $rv;
}

sub count {
    my $self = shift;
    my (%params) = @_;

    my $quoter = ObjectDB::Quoter->new(
        driver => $self->dbh->{Driver}->{Name},
        meta   => $self->meta
    );
    my $where = SQL::Composer::Expression->new(
        quoter         => $quoter,
        expr           => $params{where},
        default_prefix => $self->meta->table
    );
    my $with = ObjectDB::With->new(meta => $self->meta, with => [ $quoter->with ]);

    my $joins = $with->to_joins;
    push @$joins, @{ $params{join} } if $params{join};

    # We have to remove columns, because:
    # 1) we don't need them
    # 2) PostgreSQL complains
    delete $_->{columns} for @$joins;

    my $select = SQL::Composer->build(
        'select',
        driver   => $self->dbh->{Driver}->{Name},
        from     => $self->meta->table,
        columns  => [ { -col => \'COUNT(*)', -as => 'count' } ],
        where    => $where,
        join     => $joins,
        group_by => $params{group_by},
    );

    my ($rv, $sth) = execute($self->dbh, $select);

    my $results    = $sth->fetchall_arrayref;
    my $row_object = $select->from_rows($results);

    return $row_object->[0]->{count};
}

1;
__END__

=pod

=head1 NAME

ObjectDB::Table - actions on tables

=head1 SYNOPSIS

    package MyDB;
    use base 'ObjectDB';

    sub init_db {
        ...
        return $dbh;
    }

    package MyAuthor;
    use base 'MyDB';

    __PACKAGE__->meta(
        table          => 'author',
        columns        => [qw/id name/],
        primary_key    => 'id',
        auto_increment => 'id',
        relationships  => {
            books => {
                type = 'one to many',
                class => 'MyBook',
                map   => {id => 'author_id'}
            }
        }
    );

    package MyBook;
    use base 'MyDB';

    __PACKAGE__->meta(
        table          => 'book',
        columns        => [qw/id author_id title/],
        primary_key    => 'id',
        auto_increment => 'id',
        relationships  => {
            author => {
                type = 'many to one',
                class => 'MyAuthor',
                map   => {author_id => 'id'}
            }
        }
    );

    my @books = MyBook->table->find(
        with     => 'author',
        order_by => [title => 'ASC'],
        page     => 1,
        per_page => 10
    );

=head1 DESCRIPTION

ObjectDB::Table allows to perform actions on table: find, update, delete many
rows at a time.

=head3 Methods

=over

=item C<find>

Finds specific rows. Query builder is L<SQL::Composer>.

    my @books = MyBook->table->find;
    my @books = MyBook->table->find(where => [...]);
    my @books = MyBook->table->find(where => [...], order_by => [...]);
    my @books =
      MyBook->table->find(where => [...], order_by => [...], group_by => [...]);

When using C<rows_as_hashes> returns array of hashes instead of objects.

=item C<find_by_compose>

Finds by using raw query.

    my @books = MyBook->find_by_compose(table => 'book', columns => ['id', 'title']);

When using C<rows_as_hashes> returns array of hashes instead of objects.

=item C<find_by_sql>

Finds by using raw SQL.

    my @books = MyBook->find_by_sql('SELECT * FROM books WHERE title = ?', ['About Everything']);
    my @books = MyBook->find_by_sql('SELECT * FROM books WHERE title = :title', { title => 'About Everything' });

When using C<rows_as_hashes> returns array of hashes instead of objects.

=item C<count>

A convenient method for counting.

    my $total_books = MyBook->table->count;

=item C<update>

Updates many rows at a time.

    MyBook->table->update(set => {author_id => 1}, where => [author_id => 2]);

=item C<delete>

Deletes many rows at a time.

    MyBook->table->delete;
    MyBook->table->delete(where => [...]);

=back

=cut