use strict;
use warnings;
use Test::More;
use File::Path qw(remove_tree make_path);
use File::Spec;
use Cwd;
use File::Glob qw(:bsd_glob);

use constant ROOT	  => '.vcx';
use constant HEAD	  => ROOT . '/head';
use constant OBJ_DIR   => ROOT . '/obj';
use constant REV_DIR   => ROOT . '/rev';
use constant TMP_DIR   => ROOT . '/index';
use constant TMP_TREE  => TMP_DIR . '/tree';

# Setup sandbox
my $sandbox = "sandbox";
remove_tree($sandbox) if -d $sandbox;
make_path($sandbox);

my $orig_dir = getcwd();
chdir($sandbox) or die "Cant enter sandbox: $!";
my $cmd = File::Spec->catfile($orig_dir, "vcx");

# Helper functions
sub write_file {
	my ($path, $content) = @_;
	open my $fh, '>', $path or die $!;
	print $fh $content;
	close $fh;
}

sub read_file {
	my $path = shift;
	open my $fh, '<', $path or return "";
	my $content = <$fh>;
	chomp $content if $content;
	close $fh;
	return $content;
}

# Tests

subtest 'Repository Initialization' => sub {
	ok(system("perl $cmd init > /dev/null") == 0, "Init exit code 0");
	ok(-d ROOT, "ROOT directory created");
	ok(-e HEAD, "Head file created");
	ok(-d OBJ_DIR, "OBJ_DIR directory created");
	ok(-d REV_DIR, "REV_DIR directory created");
};

subtest 'Adding and Committing Files' => sub {
	write_file("test.txt", "Hello, world!");
	
	ok(system("perl $cmd add test.txt > /dev/null") == 0, "Add file successful");
	ok(-d TMP_TREE, "Staging tree created");

	ok(system("perl $cmd commit -m 'Initial commit' > /dev/null") == 0, "Commit successful");
	
	my $rev1 = File::Spec->catdir(REV_DIR, "0000001");
	ok(-d $rev1, "Revision 0000001 directory exists");
	
	my $msg_file = File::Spec->catfile($rev1, "message");
	is(read_file($msg_file), "Initial commit", "Commit message stored correctly");
};

subtest 'Auto-staging with commit -am' => sub {
	# Append content
	open my $fh, '>>', "test.txt" or die $!;
	print $fh "\nMore content";
	close $fh;

	ok(system("perl $cmd commit -am 'Second commit' > /dev/null") == 0, "Commit -am successful");

	opendir(my $dh, OBJ_DIR) or die $!;
	my @objs = grep { /[a-f0-9]{40}/ } readdir($dh);
	closedir($dh);
	ok(scalar @objs >= 1, "Content blobs found in object store");
};

subtest 'File Moves and Deletions (Tree Integrity)' => sub {
	# Create nested structure
	make_path("dirA/dirB");
	write_file("dirA/dirB/shuffle.txt", "Same Content");
	system("perl $cmd add dirA/dirB/shuffle.txt > /dev/null");
	system("perl $cmd commit -m 'Shuffle part 1' > /dev/null");

	# Move file and delete old dir
	make_path("dirC");
	rename("dirA/dirB/shuffle.txt", "dirC/shuffle.txt");
	remove_tree("dirA");

	ok(system("perl $cmd commit -am 'Shuffle part 2' > /dev/null") == 0, "Commit move successful");

	my $head = read_file(HEAD);
	my ($tree_ptr) = bsd_glob(File::Spec->catfile(REV_DIR, $head, "tree-*"));
	my $tree_hash = $tree_ptr =~ s/.*tree-//r;
	my $actual_tree_path = File::Spec->catdir(OBJ_DIR, $tree_hash);

	ok(-l File::Spec->catfile($actual_tree_path, "dirC/shuffle.txt"), "New path exists in tree");
	ok(!-d File::Spec->catdir($actual_tree_path, "dirA"), "Deleted path removed from tree");
	
	my $link_target = readlink(File::Spec->catfile($actual_tree_path, "dirC/shuffle.txt"));
	like($link_target, qr/obj\/[a-f0-9]{40}/, "Tree link points to object store");
};

subtest 'Symlink Handling' => sub {
	write_file("target.txt", "Final Destination");
	symlink("target.txt", "link_a");
	symlink("link_a", "link_b");

	system("perl $cmd add link_b > /dev/null");
	system("perl $cmd commit -m 'Double link' > /dev/null");

	my $head = read_file(HEAD);
	my ($tree_ptr) = bsd_glob(File::Spec->catfile(REV_DIR, $head, "tree-*"));
	my $staged_link = File::Spec->catfile(OBJ_DIR, $tree_ptr =~ s/.*tree-//r, "link_b");

	is(readlink($staged_link), "link_a", "Symlink-to-symlink targets preserved literally");
};

subtest 'Edge Cases: Content Reversion' => sub {
	# Clear the staging area to ensure a "Pure" tree
	remove_tree(TMP_DIR); 
	make_path(TMP_TREE);

	make_path("revert_test");
	write_file("revert_test/data.txt", "Version A");
	
	# Commit State A
	system("perl $cmd add revert_test/data.txt > /dev/null");
	system("perl $cmd commit -m 'State A' > /dev/null");
	my $tree_v1 = (bsd_glob(File::Spec->catfile(REV_DIR, read_file(HEAD), "tree-*")))[0];

	# Commit State B
	write_file("revert_test/data.txt", "Version B");
	system("perl $cmd commit -am 'State B' > /dev/null");

	# Revert to State A
	write_file("revert_test/data.txt", "Version A");
	system("perl $cmd commit -am 'Back to State A' > /dev/null");
	my $tree_v3 = (bsd_glob(File::Spec->catfile(REV_DIR, read_file(HEAD), "tree-*")))[0];

	# Extract hashes and compare
	my $hash1 = $tree_v1 =~ s/.*tree-//r;
	my $hash3 = $tree_v3 =~ s/.*tree-//r;

	is($hash1, $hash3, "Tree hashes match after index reset and content restoration");
};

# Cleanup
chdir($orig_dir);
done_testing();