owlcode.tech/lib/OwlcodeTech/DB.pm

package OwlcodeTech::DB;

use v5.34.1;

use strict;
use warnings;

use DBI;
use DBD::Pg;

use OwlcodeTech::DB::Migrations;
use Data::Dumper;

my $dbh;
sub connect {
    if (defined $dbh) {
    	return $dbh;
    }
    my $class    = shift;
    my $app      = shift;
    my $config   = $app->config;
    my $database = $config->{db}{database};
    $dbh      = DBI->connect(
        "dbi:Pg:dbname=$database",
        , undef, undef, { RaiseError => 1, Callbacks => {
		connected => sub {
			shift->do('set timezone = UTC');
			return;
		}
	}},
    );
    $class->_migrate($dbh);
    return $dbh;
}

sub _migrate {
    my $class = shift;
    my $dbh   = shift;
    local $dbh->{RaiseError} = 0;
    local $dbh->{PrintError} = 0;
    my @migrations = OwlcodeTech::DB::Migrations::MIGRATIONS();
    if ( $class->get_current_migration($dbh) > @migrations ) {
        warn "Something happened there, wrong migration number.";
    }
    if ( $class->get_current_migration($dbh) >= @migrations ) {
        say STDERR "Migrations already applied.";
        return;
    }
    $class->_apply_migrations($dbh, \@migrations);
}

sub _apply_migrations {
    my $class = shift;
    my $dbh   = shift;
    my $migrations = shift;
    for (
        my $i = $class->get_current_migration($dbh);
        $i < @$migrations ;
        $i++
      )
    {
	local $dbh->{RaiseError} = 1;
	my $current_migration = $migrations->[$i];
	my $migration_number = $i + 1;
	$class->_apply_migration($dbh, $current_migration, $migration_number);
    }
}

sub _apply_migration {
	my $class = shift;
	my $dbh   = shift;
	my $current_migration = shift;
	my $migration_number = shift;
	$dbh->do($current_migration);
	$dbh->do(<<'EOF', undef, 'current_migration', $migration_number);
INSERT INTO options
VALUES ($1, $2) 
ON CONFLICT (name) DO 
UPDATE SET value = $2;
EOF
}

sub get_current_migration {
    my $class  = shift;
    my $dbh    = shift;
    my $result = $dbh->selectrow_hashref( <<'EOF', undef, 'current_migration' );
select value from options where name = ?;
EOF
    return int( $result->{value} // 0 );
}
1;