# Copyright (c) 2022-2023, PostgreSQL Global Development Group

use strict;
use warnings;
use File::Basename;
use PostgreSQL::Test::Cluster;
use PostgreSQL::Test::RecursiveCopy;
use PostgreSQL::Test::Utils;
use Test::More;

my ($blocksize, $walfile_name);

# Function to extract the LSN from the given block structure
sub get_block_lsn
{
	my $path      = shift;
	my $blocksize = shift;
	my $block;

	open my $fh, '<', $path or die "couldn't open file: $path\n";
	die "could not read block\n"
	  if $blocksize != read($fh, $block, $blocksize);
	my ($lsn_hi, $lsn_lo) = unpack('LL', $block);

	$lsn_hi = sprintf('%08X', $lsn_hi);
	$lsn_lo = sprintf('%08X', $lsn_lo);

	return ($lsn_hi, $lsn_lo);
}

my $node = PostgreSQL::Test::Cluster->new('main');
$node->init;
$node->append_conf(
	'postgresql.conf', q{
wal_level = 'replica'
max_wal_senders = 4
});
$node->start;

# Generate data/WAL to examine that will have full pages in them.
$node->safe_psql(
	'postgres',
	"SELECT 'init' FROM pg_create_physical_replication_slot('regress_pg_waldump_slot', true, false);
CREATE TABLE test_table AS SELECT generate_series(1,100) a;
-- Force FPWs on the next writes.
CHECKPOINT;
UPDATE test_table SET a = a + 1;
");

($walfile_name, $blocksize) = split '\|' => $node->safe_psql('postgres',
	"SELECT pg_walfile_name(pg_switch_wal()), current_setting('block_size')");

# Get the relation node, etc for the new table
my $relation = $node->safe_psql(
	'postgres',
	q{SELECT format(
        '%s/%s/%s',
        CASE WHEN reltablespace = 0 THEN dattablespace ELSE reltablespace END,
        pg_database.oid,
        pg_relation_filenode(pg_class.oid))
    FROM pg_class, pg_database
    WHERE relname = 'test_table' AND
        datname = current_database()}
);

my $walfile    = $node->data_dir . '/pg_wal/' . $walfile_name;
my $tmp_folder = PostgreSQL::Test::Utils::tempdir;

ok(-f $walfile, "Got a WAL file");

$node->command_ok(
	[
		'pg_waldump',      '--quiet',
		'--save-fullpage', "$tmp_folder/raw",
		'--relation',      $relation,
		$walfile
	],
	'pg_waldump with --save-fullpage runs');

# This regexp will match filenames formatted as:
# XXXXXXXX-XXXXXXXX.DBOID.TLOID.NODEOID.dd_fork with the components being:
# - WAL LSN in hex format,
# - Tablespace OID (0 for global)
# - Database OID.
# - Relfilenode.
# - Block number.
# - Fork this block came from (vm, init, fsm, or main).
my $file_re =
  qr/^([0-9A-F]{8})-([0-9A-F]{8})[.][0-9]+[.][0-9]+[.][0-9]+[.][0-9]+(?:_vm|_init|_fsm|_main)?$/;

my $file_count = 0;

# Verify filename format matches --save-fullpage.
for my $fullpath (glob "$tmp_folder/raw/*")
{
	my $file = File::Basename::basename($fullpath);

	like($file, $file_re, "verify filename format for file $file");
	$file_count++;

	my ($hi_lsn_fn, $lo_lsn_fn) = ($file =~ $file_re);
	my ($hi_lsn_bk, $lo_lsn_bk) = get_block_lsn($fullpath, $blocksize);

	# The LSN on the block comes before the file's LSN.
	ok( $hi_lsn_fn . $lo_lsn_fn gt $hi_lsn_bk . $lo_lsn_bk,
		'LSN stored in the file precedes the one stored in the block');
}

ok($file_count > 0, 'verify that at least one block has been saved');

done_testing();