#!/usr/bin/perl
# Usage:
#     fvwm-theme -bg    [background]
#     fvwm-theme -decor [window decor]
#     fvwm-theme -term  [terminal scheme]
#     fvwm-theme -theme [meta-theme name]
#
#     Leave off the extension for [background].
#
#     At fvwm2 startup: fvwm-theme -init
#
#     This will add various bindable menus and functions (most importantly, the
#     top-level ThemesMenu menu), and set the theme from ~/.fvwm-theme (or
#     failing that, from the "default" meta-theme).

use strict;

sub my_die;

########################## Configurable Constants #############################

#my $SHARE_DIR = "/usr/share/fvwm/themes";
my $SHARE_DIR = "$ENV{HOME}/.fvwm/themes";
my $USER_FILE = "$ENV{HOME}/.fvwm/fvwm-theme";

my $BACKGROUND_SETTER = 'fvwm-root --retain-pixmap';  # should set a tiled root background
my $TERMINAL_PROGRAM  = 'xterm';   # must have full xresources support

# This image will be used to mark the current theme option in menus
my $CHECKMARK_IMAGE = '16x16/stock/generic/stock_calc-accept.png';


################################# Constants ###################################

my $PROG_NAME = 'fvwm-theme';

my $BACKGROUNDS_DIR     = "$ENV{HOME}/Wallpapers";
my $DECORS_DIR          = "$SHARE_DIR/decors";
my $TERMS_DIR           = "$SHARE_DIR/terms";
my $THEMES_DIR          = "$SHARE_DIR/themes";

my @TERM_COLORS = ('red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white');

my @TITLE_PIXMAPS = qw(title titlebt titleat titleunder titlelt titlert titleleft titleright buttonsbg lbuttonsbg rbuttonsbg);
my @PM_NAMES      = qw(Main LeftMain RightMain UnderText LeftOfText RightOfText LeftEnd RightEnd Buttons LeftButtons RightButtons);
my @BUTTON_SETUP = (
    ['1 ActiveUp',    'options_activeup.xpm'],
    ['6 ActiveUp',    'iconify_activeup.xpm'],
    ['4 ActiveUp',    'maximize_activeup.xpm'],
    ['2 ActiveUp',    'close_activeup.xpm'],
    ['1 ActiveDown',  'options_activedown.xpm'],
    ['6 ActiveDown',  'iconify_activedown.xpm'],
    ['4 ActiveDown',  'maximize_activedown.xpm'],
    ['2 ActiveDown',  'close_activedown.xpm'],
    ['1 Inactive',    'options_inactive.xpm'],
    ['6 Inactive',    'iconify_inactive.xpm'],
    ['4 Inactive',    'maximize_inactive.xpm'],
    ['2 Inactive',    'close_inactive.xpm'],
);

my %OPTIONS = (
    'init'             => { func => \&init,             args => 0 },
    'backgrounds-menu' => { func => \&backgrounds_menu, args => 0 },
    'decors-menu'      => { func => \&decors_menu,      args => 0 },
    'terms-menu'       => { func => \&terms_menu,       args => 0 },
    'meta-themes-menu' => { func => \&meta_themes_menu, args => 0 },
    'bg'               => { func => \&set_background,   args => 1 },
    'decor'            => { func => \&set_decor,        args => 1 },
    'term'             => { func => \&set_term,         args => 1 },
    'theme'            => { func => \&set_theme,        args => 1 }
);

################################## Globals ####################################

my %theme;

################################# Begin Main ##################################

my $option = shift or usage_abort();
$option =~ s/^-+// or usage_abort();
my $option_info = $OPTIONS{$option} or usage_abort();
@ARGV == $option_info->{args} or usage_abort();
read_hash_file($USER_FILE, \%theme) or
    read_hash_file("$THEMES_DIR/default", \%theme) or
    my_die "No $USER_FILE and no default theme found";
$option_info->{func}(@ARGV);
write_hash_file($USER_FILE, \%theme) or
    my_die "Can't open $USER_FILE for writing ($!)";

################################## End Main ###################################

############################### Bound Functions ###############################

sub init {
    print <<"END";
ImagePath +:$DECORS_DIR

AddToFunc SetBackground I PipeRead 'fvwm-theme -bg    \$0'
AddToFunc SetDecor      I PipeRead 'fvwm-theme -decor \$0'
#AddToFunc SetTerm       I PipeRead 'fvwm-theme -term  \$0'
AddToFunc SetTheme      I PipeRead 'fvwm-theme -theme \$0'

AddToMenu ThemesMenu "Themes" Title
  + "Backgrounds"         Popup BackgroundsMenu
  + "Window Decorations"  Popup DecorsMenu
#  + "Terminals"           Popup TermThemesMenu
  + "Full Themes"         Popup MetaThemesMenu

AddToMenu BackgroundsMenu DynamicPopupAction Function MakeBackgroundsMenu
AddToFunc MakeBackgroundsMenu
   + I DestroyMenu recreate BackgroundsMenu
   + I PipeRead 'fvwm-theme -backgrounds-menu'

AddToMenu DecorsMenu DynamicPopupAction Function MakeDecorsMenu
AddToFunc MakeDecorsMenu
   + I DestroyMenu recreate DecorsMenu
   + I PipeRead 'fvwm-theme -decors-menu'

AddToMenu TermThemesMenu DynamicPopupAction Function MakeTermThemesMenu
AddToFunc MakeTermThemesMenu
   + I DestroyMenu recreate TermThemesMenu
   + I PipeRead 'fvwm-theme -terms-menu'

AddToMenu MetaThemesMenu DynamicPopupAction Function MakeMetaThemesMenu
AddToFunc MakeMetaThemesMenu
   + I DestroyMenu recreate MetaThemesMenu
   + I PipeRead 'fvwm-theme -meta-themes-menu'
END

    set_theme_from_hash();
}

sub backgrounds_menu {
    generic_menu('Backgrounds', 'BackgroundsMenu', 'bgsub', 'SetBackground',
                 $BACKGROUNDS_DIR, $theme{background}, 0);
}

sub decors_menu {
    generic_menu('Window Decorations', 'DecorsMenu', 'dcsub', 'SetDecor',
                 $DECORS_DIR, $theme{decor}, 1);
}

sub terms_menu {
    generic_menu('Terminal Themes', 'TermThemesMenu', 'ttsub', 'SetTerm',
                 $TERMS_DIR, $theme{term}, 0);
}

sub meta_themes_menu {
    generic_menu('Full Themes', 'MetaThemesMenu', 'ftsub', 'SetTheme',
                 $THEMES_DIR, '', 0);
}

sub set_background {
    my $background = shift;
    $theme{background} = $background;
    system "$BACKGROUND_SETTER $BACKGROUNDS_DIR/$background";
    print "Refresh\n";
}

sub set_decor {
    my $decor = shift;
    my $dir = "$DECORS_DIR/$decor";
    return unless -d $dir;
    for (@BUTTON_SETUP) {
        my $target = $_->[0];
        my $pixmap = $_->[1];
        next unless -e "$dir/$pixmap";
        print "ButtonStyle $target Pixmap $decor/$pixmap\n";
    }
    print "ButtonStyle 1 MiniIcon\n"
        if -e "$DECORS_DIR/$decor/MINI_ICON";
    print "ButtonStyle All -- Flat UseTitleStyle\n";
    for my $state ('ActiveUp', 'ActiveDown', 'Inactive') {
        print "TitleStyle $state MultiPixmap ";
        for (my $i=0; $i < @TITLE_PIXMAPS; $i++) {
            my $pixmap = $TITLE_PIXMAPS[$i];
            my $append = ($state eq 'Inactive' ? 'inactive' : 'active');
            my $pixmap_fn = "${pixmap}_$append.xpm";
            next unless -e "$dir/$pixmap_fn";
            my $pm_name = $PM_NAMES[$i];
            print ", " if $i > 0;
            print "$pm_name ";
            print "(stretched) " if -e "$DECORS_DIR/$decor/STRETCH" &&
                                    ($pixmap eq 'title' || $pixmap eq 'titleunder' ||
                                     $pixmap eq 'titlebt' || $pixmap eq 'titleat');
            print "$decor/$pixmap_fn";
        }
        print "\n";
    }
    print "TitleStyle -- Flat\n";
    open F, "<$dir/decor";
    print while <F>;
    close F;

    $theme{decor} = $decor;
}

sub set_term {
    my $term = shift;
    my %term_info;
    read_hash_file("$TERMS_DIR/$term", \%term_info) or return;
    $theme{term} = $term;
    open XRDB, "|xrdb -merge -" or
        my_die "Can't open a pipe to 'xrdb -merge -' ($!)";
    my $transparent = (exists $term_info{transparent} ? 'true' : 'false');
    my $shading = $term_info{shading} || '100%';
    print XRDB <<"END";
$TERMINAL_PROGRAM.transparent: $transparent
$TERMINAL_PROGRAM.shading: $shading
$TERMINAL_PROGRAM.backgroundPixmap: $term_info{backgroundPixmap}
$TERMINAL_PROGRAM.background: $term_info{background}
$TERMINAL_PROGRAM.foreground: $term_info{foreground}
END
    print XRDB "$TERMINAL_PROGRAM.colorBD: $term_info{bold}\n"
        if $term_info{bold};
    for (my $i=0; $i < @TERM_COLORS; $i++) {
        my $index = $i+1;
        my $value = $term_info{$TERM_COLORS[$i]} or next;
        print XRDB "$TERMINAL_PROGRAM.color${index}: $value\n";
    }
    for (my $i=0; $i < @TERM_COLORS; $i++) {
        my $index = $i+9;
        my $value = $term_info{'bright_' . $TERM_COLORS[$i]} ||
                    $term_info{$TERM_COLORS[$i]} or
                    next;
        print XRDB "$TERMINAL_PROGRAM.color${index}: $value\n";
    }
    close XRDB or
        my_die "Close failed after writing to pipe 'xrdb -merge -' ($!)";
}

sub set_theme {
    my $theme = shift;
    read_hash_file("$THEMES_DIR/$theme", \%theme);
    set_theme_from_hash();
}

############################## Helper Functions ###############################

sub set_theme_from_hash {
    set_background($theme{background});
    set_decor($theme{decor});
    set_term($theme{term});
}

sub generic_menu {
    my ($menu_title, $menu_name, $subname_prefix, $menu_function, $directory, $selected, $directories_are_items) = @_;
    chdir $directory or my_die "Can't chdir to $directory ($!)";
    generic_submenu($menu_title, $menu_name, $subname_prefix, $menu_function,
                    '.', $selected, $directories_are_items);
}

sub generic_submenu {
    my ($menu_title, $menu_name, $subname_prefix, $menu_function, $directory, $selected, $directories_are_items) = @_;
    opendir DIR, $directory or my_die "Can't opendir $directory ($!)";
    my @contents = sort(grep(!/^\./, readdir(DIR)));
    closedir DIR;
    print "DestroyMenu recreate $menu_name\n";
    print "AddToMenu $menu_name '$menu_title' Title\n";
    my @subdirs;
    for my $item (@contents) {
        my $path = ($directory eq '.' ? $item : "$directory/$item");
        my $display_name = make_display_name($item);
        if (-d $path && !$directories_are_items) {
            my $submenu_name = "${subname_prefix}_$path";
            $submenu_name =~ tr|/|_|;
            push @subdirs, [$display_name, $submenu_name, $subname_prefix,
                            $menu_function, $path, $selected];
            print "+ '$display_name' Popup $submenu_name\n";
        }
        else {
            print "+ '$display_name";
            print "%$CHECKMARK_IMAGE%" if $path eq $selected;
            print "' $menu_function $path\n";
        }


    }
    generic_submenu(@$_) for @subdirs;
}    

sub read_hash_file {
    my ($file, $hash) = @_;
    open F, "<$file" or return 0;
    while (<F>) {
        chomp;
        my ($key, $val) = split(/=/, $_, 2);
        $key = trim_whitespace($key);
        $val = trim_whitespace($val);
        $$hash{$key} = $val;
    }
    close F;
    return 1;
}

sub write_hash_file {
    my ($file, $hash) = @_;
    open F, ">$file" or return 0;
    while (my ($key, $val) = each %$hash) {
        print F "$key=$val\n";
    }
    close F;
    return 1;
}

sub trim_whitespace {
    my $str = shift;
    $str =~ s/^\s+//;
    $str =~ s/\s+$//;
    return $str;
}

sub make_display_name {
    my $name = shift;
    $name =~ s/\.[^.]+$//;        # strip extension
    $name =~ tr/_-/ /;            # convert underscores to spaces
    $name =~ s/\b([a-z])/\U$1/g;  # capitalize words
    return $name;
}

sub usage_abort {
    print STDERR <<"END";
Usage:
    fvwm-theme -bg    [background]
    fvwm-theme -decor [window decor]
    fvwm-theme -term  [terminal scheme]
    fvwm-theme -theme [meta-theme name]

    Leave off the extension for [background].

    At fvwm2 startup: fvwm-theme -init

    This will add various bindable menus and functions (most importantly, the
    ThemesMenu menu), and set the theme from ~/.fvwm-theme (or failing that,
    the "default" meta-theme).
END
    exit(1);
}

sub my_die {
    my $msg = shift;
    die "$PROG_NAME: $msg\n";
}