#!/usr/bin/perl
use strict;
use warnings;
use File::Spec;
use File::Path qw(make_path remove_tree);
use Digest::SHA qw(sha1_hex);

# Setup testing environment
my $sandbox    = File::Spec->rel2abs("sandbox_env");
my $script_bin = File::Spec->catfile(File::Spec->rel2abs("."), "urn"); 
my $repo_meta  = ".urn";

remove_tree($sandbox);
make_path($sandbox);
chdir($sandbox) or die "Cannot chdir to $sandbox: $!";

sub run_cmd {
	my $cmd = shift;
	my $out = `perl $script_bin $cmd 2>&1`;
	if ($? != 0) {
		die "\nCommand '$cmd' failed with exit code $?:\n$out\n";
	}
	return $out;
}

sub get_head_id {
	my $head_path = File::Spec->catfile($repo_meta, "head");
	return undef unless -f $head_path;
	open(my $fh, '<', $head_path) or return undef;
	my $id = <$fh>;
	close($fh);
	chomp($id //= "");
	$id =~ s/^\s+|\s+$//g;
	return $id;
}

print "Starting tests...\n";
run_cmd("init");

# --- Subtest 1: All-In Integration ---
print "Subtest 1: Initial commit with symlink...\t";
{
	open(my $fh, '>', "file1.txt") or die $!;
	print $fh "Original content\n" x 10;
	close($fh);
	
	symlink("file1.txt", "link1.txt") or die "Symlink failed: $!";
	
	run_cmd("commit -am 'initial'");
	
	my $idx_path = File::Spec->catfile($repo_meta, "index");
	open(my $idx, '<', $idx_path) or die "Could not open $idx_path: $!";
	my %index_hashes;
	while (<$idx>) {
		chomp;
		# Updated parser: split on tabs and trim padding from hashes
		my ($shash, $chash, $bhash, $m, $s, $path) = split(/\t/, $_, 6);
		$shash =~ s/\s+$//; # Remove fixed-width padding
		$index_hashes{$path} = $shash;
	}
	close($idx);

	die "Missing file1" unless $index_hashes{"file1.txt"};
	# Symlink hash is the SHA of the target path string
	die "Symlink hash mismatch" unless $index_hashes{"link1.txt"} eq sha1_hex("file1.txt");
}
print "OK\n";

# --- Subtest 2: Large Source, Small Patch (Text Patching) ---
print "Subtest 2: Large source, small patch...\t";
{
	my $large_p = "large.txt";
	open(my $lf, '>', $large_p) or die $!;
	print $lf "Line $_\n" for 1..1000;
	close($lf);
	
	run_cmd("commit -am 'large file base'");
	
	open($lf, '>>', $large_p) or die $!;
	print $lf "One small change\n";
	close($lf);
	run_cmd("commit -am 'patch commit'");
	
	my $head_id = get_head_id();
	my $rev_path = File::Spec->catfile($repo_meta, "rev", $head_id);
	open(my $rf, '<', $rev_path) or die "Could not open $rev_path: $!";
	my $has_patch = 0;
	while (<$rf>) { $has_patch = 1 if /^patch:[a-f0-9]/; }
	close($rf);
	die "Expected patch in rev $head_id" unless $has_patch;
}
print "OK\n";

# --- Subtest 3: Small Source, Large Patch (Full Store) ---
print "Subtest 3: Small source, large patch...\t";
{
	my $small_p = "small.txt";
	open(my $sf, '>', $small_p) or die $!;
	print $sf "A";
	close($sf);
	run_cmd("commit -am 'small file base'");
	
	open($sf, '>', $small_p) or die $!;
	print $sf "Completely different content" x 200;
	close($sf);
	run_cmd("commit -am 'full store commit'");

	my $restored = run_cmd("show HEAD $small_p");
	my $actual = `cat $small_p`;
	die "Reconstruction mismatch" unless $restored eq $actual;
}
print "OK\n";

# --- Subtest 4: Binary Integrity ---
print "Subtest 4: Binary patch integrity...\t\t";
{
	my $bin_p = "data.bin";
	my $orig_data = pack("C*", map { int(rand(256)) } 1..2048);
	open(my $bf, '>:raw', $bin_p) or die $!;
	print $bf $orig_data;
	close($bf);
	run_cmd("commit -am 'initial bin'");
	
	my $old_rev = get_head_id();

	open($bf, '+<:raw', $bin_p) or die $!;
	seek($bf, 1024, 0);
	print $bf pack("C", 255);
	close($bf);
	run_cmd("commit -am 'mod bin'");

	my $v_old = run_cmd("show $old_rev $bin_p");
	my $v_new = run_cmd("show HEAD $bin_p");
	
	die "Old version corrupted" unless $v_old eq $orig_data;
	die "Binary restore error" unless length($v_new) == 2048;
}
print "OK\n";

# --- Subtest 5: CRUD (Deletion) ---
print "Subtest 5: File deletion...\t\t\t";
{
	unlink("file1.txt");
	run_cmd("commit -am 'delete file1'");
	
	my $head_id = get_head_id();
	my $rev_path = File::Spec->catfile($repo_meta, "rev", $head_id);
	my $rev_data = `cat $rev_path`;
	my ($tree_h) = $rev_data =~ /^tree:([a-f0-9]+)/m;
	
	my $t_obj = File::Spec->catfile($repo_meta, "obj", substr($tree_h, 0, 2), substr($tree_h, 2));
	my $tree_content = `cat $t_obj`;
	die "File1 still in tree after deletion" if $tree_content =~ /file1\.txt/;
}
print "OK\n";

# --- Subtest 6: Dirty Status ---
print "Subtest 6: Dirty state detection...\t\t";
{
	open(my $fh, '>', "dirty.txt") or die $!;
	print $fh "Clean state\n";
	close($fh);
	run_cmd("add dirty.txt");
	
	open($fh, '>>', "dirty.txt") or die $!;
	print $fh "Dirty edit\n";
	close($fh);
	
	my $status = run_cmd("status");
	die "Failed to detect dirty state" unless $status =~ /\[M\].*dirty\.txt.*\(dirty\)/;
}
print "OK\n";

print "\nAll tests passed successfully.\n";