Add experimental css styler

Takes a prepared stylesheet template, inserts the values into it and
puts it into fixed qutebrowser stylesheet directory, calling qutebrowser
to set it automatically.

Much of this is hardcoded and not applicable to different setups!

theme_styles

@@ -0,0 +1,114 @@
+#!/usr/bin/env bash
+# shellcheck disable=2016
+readonly dependency=("samme/base16-styles")
+readonly app="styles"
+
+readonly path="$1"
+readonly package="$2"
+readonly theme="$3"
+readonly permanent="$4"
+
+stylesheet="$HOME/.config/qutebrowser/stylesheets/stylesheet.css"
+styletemplate="css-template.css"
+
+## Main Entrypoint
+#
+#  Finds the right theme template file and starts theme
+#  switching and, if necessary, permanent setting processes.
+main() {
+  dbg_msg $app "Starting Processor"
+  tfile="$path/$package/scss/base16-$theme.scss"
+
+  if ! file_exists "$tfile"; then
+    dbg_msg $app "error" "Theme template $theme not found in package $package"
+    exit 1
+  fi
+
+  if [[ "$permanent" == "true" ]]; then save; fi
+  theme
+
+  dbg_msg $app "Processor Done"
+}
+
+## Theme switcher
+#
+#  Makes sure that if any application instance is
+#  currently running, it switches to new theme.
+theme() {
+  dbg_msg $app "Switching theme"
+  # make sure qutebrowser is running
+  pgrep qutebrowser >/dev/null || {
+    dbg_msg $app "warn" "No instance running, not switching theme"
+    return
+  }
+  qutebrowser --loglevel error ":set content.user_stylesheets $stylesheet"
+  dbg_msg $app "Successfully switched theme"
+}
+
+## Theme setter
+#
+#  Takes care of permanently writing the desired
+#  base16 theme into application settings.
+save() {
+  dbg_msg $app "Saving theme"
+
+  fix_placeholders
+
+  echo "$newsheet" >"$stylesheet"
+
+}
+
+fix_placeholders() {
+  local base00 base01 base02 base03 base04 base05 base06 base07 base08 base09 base0A base0B base0C base0D base0E base0F
+  base00=$(grep -e "\$base00" "$tfile" | sed -e 's/^$base00: \(#[[:alnum:]]\+\);$/\1/')
+  base01=$(grep -e "\$base01" "$tfile" | sed -e 's/^$base01: \(#[[:alnum:]]\+\);$/\1/')
+  base02=$(grep -e "\$base02" "$tfile" | sed -e 's/^$base02: \(#[[:alnum:]]\+\);$/\1/')
+  base03=$(grep -e "\$base03" "$tfile" | sed -e 's/^$base03: \(#[[:alnum:]]\+\);$/\1/')
+  base04=$(grep -e "\$base04" "$tfile" | sed -e 's/^$base04: \(#[[:alnum:]]\+\);$/\1/')
+  base05=$(grep -e "\$base05" "$tfile" | sed -e 's/^$base05: \(#[[:alnum:]]\+\);$/\1/')
+  base06=$(grep -e "\$base06" "$tfile" | sed -e 's/^$base06: \(#[[:alnum:]]\+\);$/\1/')
+  base07=$(grep -e "\$base07" "$tfile" | sed -e 's/^$base07: \(#[[:alnum:]]\+\);$/\1/')
+  base08=$(grep -e "\$base08" "$tfile" | sed -e 's/^$base08: \(#[[:alnum:]]\+\);$/\1/')
+  base09=$(grep -e "\$base09" "$tfile" | sed -e 's/^$base09: \(#[[:alnum:]]\+\);$/\1/')
+  base0A=$(grep -e "\$base0A" "$tfile" | sed -e 's/^$base0A: \(#[[:alnum:]]\+\);$/\1/')
+  base0B=$(grep -e "\$base0B" "$tfile" | sed -e 's/^$base0B: \(#[[:alnum:]]\+\);$/\1/')
+  base0C=$(grep -e "\$base0C" "$tfile" | sed -e 's/^$base0C: \(#[[:alnum:]]\+\);$/\1/')
+  base0D=$(grep -e "\$base0D" "$tfile" | sed -e 's/^$base0D: \(#[[:alnum:]]\+\);$/\1/')
+  base0E=$(grep -e "\$base0E" "$tfile" | sed -e 's/^$base0E: \(#[[:alnum:]]\+\);$/\1/')
+  base0F=$(grep -e "\$base0F" "$tfile" | sed -e 's/^$base0F: \(#[[:alnum:]]\+\);$/\1/')
+
+  newsheet=$(sed -e "s/%base00%/$base00/;s/%base01%/$base01/;s/%base02%/$base02/;s/%base03%/$base03/;s/%base04%/$base04/;s/%base05%/$base05/;s/%base06%/$base06/;s/%base07%/$base07/;s/%base08%/$base08/;s/%base09%/$base09/;s/%base0A%/$base0A/;s/%base0B%/$base0B/;s/%base0C%/$base0C/;s/%base0D%/$base0D/;s/%base0E%/$base0E/;s/%base0F%/$base0F/" "$styletemplate")
+}
+
+## Theme includer
+#
+#  Makes sure that theme is actually included in
+#  default application startup routine.
+#  This is the most invasive step of theming since it
+#  rewrites within existing configuration files.
+include() {
+  local qt_dir="$1"
+  dbg_msg $app "Including theme in configuration"
+
+  if file_exists "$qt_dir/config.py"; then
+    line_exists_or_append "$qt_dir/config.py" "config.source('colorscheme.py')"
+    dbg_msg $app "Successfully included theme in configuration"
+  else
+    dbg_msg $app "warn" "No default configuration file found"
+  fi
+}
+
+# Safe sourcing: https://stackoverflow.com/a/12694189
+DIR="${BASH_SOURCE%/*}"
+if [[ ! -d "$DIR" ]]; then DIR="$PWD"; fi
+# shellcheck source=utilities.sh
+. "$DIR/utilities.sh"
+## Dependency Checker
+#
+#  Makes sure the processor is called for the correct
+#  base16 package, or refuses to run if it is not.
+if printf '%s\n' "${dependency[@]}" | grep -q -P "^$package$"; then
+  main
+else
+  dbg_msg $app "error" "Processor does not work for package $package"
+fi