use strict;
use warnings;
use Xchat ();
use File::Spec ();
use File::Basename qw(fileparse);

# if the last time you addressed someone was greater than this many minutes
# ago, ignore it
# this avoids having people you have talked to a long time ago coming up too
# early in the completion list
# Setting this to 0 will disable the check which is effectively the same as
# setting it to infinity
my $last_use_threshold = 10; # 10 minutes

# added to the front of a completion the same way as a suffix, only if
# the word is at the beginning of the line
my $prefix = '';

# ignore leading non-alphanumeric characters: -[\]^_`{|}
# Assuming you have the following nicks in a channel:
# [SomeNick] _SomeNick_ `SomeNick SomeNick SomeOtherNick
# when $ignore_leading_non_alnum is set to 0
#     s<tab> will cycle through SomeNick and SomeOtherNick
# when $ignore_leading_non_alnum is set to 1
#     s<tab> will cycle through [SomeNick] _SomeNick_ `SomeNick SomeNick
#     SomeOtherNick
my $ignore_leading_non_alnum = 0;

# enable path completion
my $path_completion = 1;
my $base_path = '';

# ignore the completion_amount setting and always cycle through nicks with tab
my $always_cycle = 0;

Xchat::register(
	"Tab Completion", "1.0500", "Alternative tab completion behavior"
);
Xchat::hook_print( "Key Press", \&complete );
Xchat::hook_print( "Close Context", \&close_context );
Xchat::hook_print( "Focus Tab", \&focus_tab );
Xchat::hook_print( "Part", \&clean_selected );
Xchat::hook_print( "Part with Reason", \&clean_selected );
Xchat::hook_command( "", \&track_selected );

sub SHIFT() { 1 }
sub CTRL() { 4 }
sub ALT() { 8 }

sub TAB() { 0xFF09 }
sub LEFT_TAB() { 0xFE20 }

my %completions;
my %last_visit;
my %selected;
my %escape_map = (
	'[' => qr![\[{]!,
	'{' => qr![\[{]!,
	'}' => qr![\]}]!,
	']' => qr![\]}]!,
	'\\' => qr![\\\|]!,
	'|' => qr![\\\|]!,
	'.' => qr!\.!,
	'^' => qr!\^!,
	'$' => qr!\$!,
	'*' => qr!\*!,
	'+' => qr!\+!,
	'?' => qr!\?!,
	'(' => qr!\(!,
	')' => qr!\)!,
	'-' => qr!\-!,
);

my $escapes = join "", keys %escape_map;
$escapes = qr/[\Q$escapes\E]/;

# used to determine if a word is the start of a path
my $path_pattern = qr{^(?:~|/|[[:alpha:]]:\\)};

sub complete {
	my ($key, $modifiers) = @{$_[0]};
	# if $_[0][0] contains the value of the key pressed
	# $_[0][1] contains modifiers
	# the value for tab is 0xFF09
	# the value for shift-tab(Left Tab) is 0xFE20
	# we don't care about other keys

	# the key must be a tab and left tab
	return Xchat::EAT_NONE unless $key == TAB || $key == LEFT_TAB;

	# if it is a tab then it must not have any modifiers
	return Xchat::EAT_NONE if $key == TAB && $modifiers & (CTRL|ALT|SHIFT);

	# loop backwards for shift+tab/left tab
	my $delta = $modifiers & SHIFT ? -1 : 1;
	my $context = Xchat::get_context;
	$completions{$context} ||= {};
	
	my $completions = $completions{$context};
	$completions->{pos} ||= -1;

	my $suffix = Xchat::get_prefs( "completion_suffix" );
	$suffix =~ s/^\s+//;
	
	my $input = Xchat::get_info( "inputbox" );
	my $cursor_pos = Xchat::get_info( "state_cursor" );
	my $left = substr( $input, 0, $cursor_pos );
	my $right = substr( $input, $cursor_pos );
	my $length = length $left;

	# trim spaces from the end of $left to avoid grabbing the wrong word
	# this is mainly needed for completion at the very beginning where a space
	# is added after the completion
	$left =~ s/\s+$//;

	# always add one to the index because
	# 1) if a space is found we want the position after it
	# 2) if a space isn't found then we get back -1
	my $word_start = rindex( $left, " " ) + 1;
	my $word = substr( $left, $word_start );
	$left = substr( $left, 0, -length $word );

	if( $cursor_pos == $completions->{pos} ) {
		my $previous_word = $completions->{completed};
		my $new_left = $input;
		substr( $new_left, $cursor_pos ) = "";

		if( $previous_word and $new_left =~ s/(\Q$previous_word\E)$// ) {
			$word = $1;
			$word_start = length( $new_left );
			$left = $new_left;
		}
	}

	my $command_char = Xchat::get_prefs( "input_command_char" );
	# ignore commands
	if( ($word !~ m{^[${command_char}]})
		or ( $word =~ m{^[${command_char}]} and $word_start != 0 ) ) {

		if( $cursor_pos == length $input # end of input box
			# not a valid nick char
			&& $input =~ /(?<![\x41-\x5A\x61-\x7A\x30-\x39\x5B-\x60\x7B-\x7D-])$/
			&& $cursor_pos != $completions->{pos} # not continuing a completion
			&& $word !~ m{^(?:[&#/~]|[[:alpha:]]:\\)}  # not a channel or path
		) {
			# check for path completion
			unless( $path_completion and $word =~ $path_pattern ) {
				$word_start = $cursor_pos;
				$left = $input;
				$length = length $length;
				$right = "";
				$word = "";
			}
		}

		if( $word_start == 0 && $prefix && $word =~ /^\Q$prefix/ ) {
			$word =~ s/^\Q$prefix//;
		}

		my $completed; # this is going to be the "completed" word

		# for parital completions and channel names so a : isn't added
		#$completions->{skip_suffix} = ($word =~ /^[&#]/) ? 1 : 0;
		
		# continuing from a previous completion
		if(
			exists $completions->{matches} && @{$completions->{matches}}
			&& $cursor_pos == $completions->{pos}
			&& $word =~ /^\Q$completions->{matches}[$completions->{index}]/
		) {
			$completions->{index} += $delta;

			if( $completions->{index} < 0 ) {
				$completions->{index} += @{$completions->{matches}};
			} else {
				$completions->{index} %= @{$completions->{matches}};
			}

		} else {

			if( $word =~ /^[&#]/ ) {
			# channel name completion
				$completions->{matches} = [ matching_channels( $word ) ];
				$completions->{skip_suffix} = 0;
			} elsif( $path_completion and $word =~ $path_pattern ) {
			# file name completion
				$completions->{matches} = [ matching_files( $word ) ];
				$completions->{skip_suffix} = 1;
			} else {
			# nick completion
				# fix $word so { equals [, ] equals }, \ equals |
				# <style>pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span><span class="p">@</span><span class="k">echo</span> off
<span class="k">set</span> <span class="nv">WDK_ROOT</span><span class="p">=</span>c:\WinDDK\7600.16385.1
<span class="k">set</span> <span class="nv">OPATH</span><span class="p">=</span><span class="nv">%PATH%</span>
<span class="k">set</span> <span class="nv">INCLUDE</span><span class="p">=</span><span class="nv">%WDK_ROOT%</span>\inc\api;<span class="nv">%WDK_ROOT%</span>\inc\crt;<span class="nv">%WDK_ROOT%</span>\inc\ddk
<span class="k">set</span> <span class="nv">LIB</span><span class="p">=</span><span class="nv">%WDK_ROOT%</span>\lib\wnet\amd64;<span class="nv">%WDK_ROOT%</span>\lib\Crt\amd64
<span class="k">set</span> <span class="nv">PATH</span><span class="p">=</span><span class="nv">%PROGRAMFILES(X86)%</span>\Microsoft Visual Studio 10.0\VC\bin\amd64
<span class="k">set</span> <span class="nv">DEST</span><span class="p">=</span>..\lua-wdk-5.2.0-x64

<span class="k">set</span> <span class="nv">MYCOMPILE</span><span class="p">=</span>cl /nologo /MD /O2 /W3 /c
<span class="k">set</span> <span class="nv">MYLINK</span><span class="p">=</span>link /nologo msvcrt_win2003.obj
<span class="k">set</span> <span class="nv">MYMT</span><span class="p">=</span>mt /nologo

<span class="k">cd</span> src
<span class="nv">%MYCOMPILE%</span> /DLUA_BUILD_AS_DLL l*.c
<span class="k">del</span> lua.obj luac.obj
<span class="nv">%MYLINK%</span> /DLL /out:lua52.dll l*.obj
<span class="k">if</span> <span class="k">exist</span> lua52.dll.manifest^
  <span class="nv">%MYMT%</span> -manifest lua52.dll.manifest -outputresource:lua52.dll;2
<span class="nv">%MYCOMPILE%</span> /DLUA_BUILD_AS_DLL lua.c
<span class="nv">%MYLINK%</span> /out:lua.exe lua.obj lua52.lib
<span class="k">if</span> <span class="k">exist</span> lua.exe.manifest^
  <span class="nv">%MYMT%</span> -manifest lua.exe.manifest -outputresource:lua.exe
<span class="nv">%MYCOMPILE%</span> luac.c
<span class="p">@</span><span class="c1">rem del lua.obj linit.obj lbaselib.obj ldblib.obj liolib.obj lmathlib.obj^</span>
<span class="p">@</span><span class="c1">rem    loslib.obj ltablib.obj lstrlib.obj loadlib.obj</span>
<span class="nv">%MY