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 |
				# and escape regex metacharacters
				$word =~ s/($escapes)/$escape_map{$1}/g;

				$completions->{matches} = [ matching_nicks( $word ) ];
				$completions->{skip_suffix} = 0;
			}
			$completions->{index} = 0;

		}
		$completed = $completions->{matches}[ $completions->{index} ];
		$completions->{completed} = $completed;

		my $completion_amount = Xchat::get_prefs( "completion_amount" );
		
		# don't cycle if the number of possible completions is greater than
		# completion_amount
		if(
			!$always_cycle && (
			@{$completions->{matches}} > $completion_amount
			&& @{$completions->{matches}} != 1 )
		) {
			# don't print if we tabbed in the beginning and the list of possible
			# completions includes all nicks in the channel
			my $context_type = Xchat::context_info->{type};
			if( $context_type != 2 # not a channel
				or @{$completions->{matches}} < Xchat::get_list("users")
			) {
				Xchat::print( join " ", @{$completions->{matches}}, "\n" );
			}
			
			$completed = lcs( $completions->{matches} );
			$completions->{skip_suffix} = 1;
		}
		
		if( $completed ) {
			
			if( $word_start == 0 && !$completions->{skip_suffix} ) {
				# at the start of the line append completion suffix
				Xchat::command( "settext $prefix$completed$suffix$right");
				$completions->{pos} = length( "$prefix$completed$suffix" );
			} else {
				Xchat::command( "settext $left$completed<style>pre { line-height: 125%; }
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.highlight .na { color: #336699 } /* Name.Attribute */
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.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span>AppName=HexChat Spelling Dictionaries
AppVerName=HexChat Spelling Dictionaries r1
AppVersion=1.0
VersionInfoVersion=1.0
OutputBaseFilename=HexChat Spelling Dictionaries r1
AppPublisher=HexChat
AppPublisherURL=http://www.hexchat.org/
AppCopyright=Copyright (C) 1998-2010 Peter Zelezny
AppSupportURL=https://github.com/hexchat/hexchat/issues
AppUpdatesURL=http://www.hexchat.org/home/downloads
DefaultDirName={localappdata}\enchant
DefaultGroupName=HexChat
DisableProgramGroupPage=yes
DisableDirPage=yes
SolidCompression=yes
Compression=lzma2/ultra64
SourceDir=.
OutputDir=.
FlatComponentsList=no
PrivilegesRequired=lowest
ShowComponentSizes=no
CreateUninstallRegKey=no
Uninstallable=no
DirExistsWarning=no
ArchitecturesAllowed=x86 x64

[Files]
Source: &quot;myspell\*&quot;; DestDir: &quot