#!/usr/bin/perl

use strict;
use warnings;
use File::Path qw(make_path remove_tree);
use File::Copy qw(copy);
use File::Find;
use File::Basename;
use File::Glob qw(:bsd_glob);
use File::Spec;

use constant VCX_DIR => '.vcx';
use constant BSE_DIR => VCX_DIR . '/bse';
use constant OBJ_DIR  => VCX_DIR . '/obj';
use constant TMP_DIR  => VCX_DIR . '/tmp';

my $cmd = $ARGV[0] // '';
my $path = $ARGV[1] // '';

if ($cmd eq 'init') {
	init_repo();
} elsif ($cmd eq 'status') {
	run_status();
} elsif ($cmd eq 'add') {
	die "Usage: $0 add [path]\n" unless $path;
	run_add($path); 
} else {
	print "Usage: $0 [init|status]\n";
	exit 1;
}

sub init_repo {
	make_path(OBJ_DIR, BSE_DIR, TMP_DIR);
	print "Repository ready\n";
}

sub run_status {
	my $diff_cmd = "diff -x " . VCX_DIR . " -rq " . BSE_DIR . " .";
	$diff_cmd .= " -X .vcxignore" if -e ".vcxignore";

	my @output = `$diff_cmd`;
	
	foreach my $line (@output) {
		chomp $line;
		# Format output
		if ($line =~ /^Only in \Q@{[BSE_DIR]}\E: (.+)$/) {
			print "[D] $1\n";
		} elsif ($line =~ /^Only in \.: (.+)$/) {
			print "[N] $1\n";
		} elsif ($line =~ /^Files \Q@{[BSE_DIR]}\E\/(.+) and \.\/(.+) differ$/) {
			print "[M] $1\n";
		}
	}
}

sub run_add {
	my ($target) = @_;

	# Copy BSE_DIR to TMP_DIR
	remove_tree(TMP_DIR);
	make_path(TMP_DIR);
	if (glob(BSE_DIR . "/*")) {
		system("cp -R '" . BSE_DIR . "/.' '" . TMP_DIR . "/'");
	}

	my @targets = ($target eq '.') ? ('.') : bsd_glob($target);

	foreach my $t (@targets) {
		find({
			wanted => sub {
				# Skip VCX directory
				return if $File::Find::name =~ /^\.\/\Q${\VCX_DIR}\E/;
				
				my $rel_path = File::Spec->abs2rel($File::Find::name, '.');
				my $local_path = $File::Find::name;
				my $base_path  = BSE_DIR . "/$rel_path";
				my $obj_path   = OBJ_DIR . "/$rel_path";
				my $tmp_link   = TMP_DIR . "/$rel_path";

				# Regular file
				if (-f $local_path) {
					if (!-e $base_path) {
						_sync_new_file($local_path, $obj_path, $tmp_link);
					} elsif (!-l $base_path && system("diff -q '$local_path' '$base_path' > /dev/null") != 0) {
						_sync_modified_file($local_path, $obj_path, $tmp_link);
					}
				}
				# Symlink
				elsif (-l $local_path) {
					if (-l $base_path) {
						# Both are symlinks: compare the targets (where they point)
						if (readlink($local_path) ne readlink($base_path)) {
							_sync_modified_file($local_path, $obj_path, $tmp_link);
						}
					} else {
						# Local is a symlink, but base isn't: treat as modification
						_sync_modified_file($local_path, $obj_path, $tmp_link);
					}
				} 
			},
			follow => 0, 
			no_chdir => 1,
		}, $t) if -e $t;

		_handle_deletions($t);
	}
}

sub _sync_new_file {
	my ($src, $obj, $tmp) = @_;
	make_path(dirname($obj));
	make_path(dirname($tmp));
	copy($src, $obj);
	# Symlink from tmp/path/to/file to obj/path/to/file
	# Note: symlink target is relative to the symlink's location
	symlink("../../obj/" . $src, $tmp); 
	print "[Add New] $src\n";
}

sub _sync_modified_file {
	my ($src, $obj, $tmp) = @_;
	my $tmp_obj = "$obj.tmp";
	make_path(dirname($tmp_obj));
	copy($src, $tmp_obj);
	unlink($tmp) if -l $tmp;
	symlink("../../obj/" . $src . ".tmp", $tmp);
	print "[Add Mod] $src\n";
}

sub _handle_deletions {
	my ($target) = @_;
	my $search_base = ($target eq '.') ? BSE_DIR : BSE_DIR . "/$target";
	
	return unless -d $search_base || -e $search_base;

	find({
		wanted => sub {
			return if -d $_;
			my $rel_path = File::Spec->abs2rel($File::Find::name, BSE_DIR);
			
			# If file exists in BSE_DIR but NOT in current directory (.)
			if (!-e $rel_path) {
				unlink(OBJ_DIR . "/$rel_path");
				unlink(BSE_DIR . "/$rel_path");
				print "[Deleted] $rel_path\n";
			}
		},
		no_chdir => 1,
	}, $search_base);
}