#!/usr/bin/env bash
readonly dependency=("theova/base16-qutebrowser")
readonly app="qutebrowser"

readonly path="$1"
readonly package="$2"
readonly theme="$3"
readonly permanent="$4"

## 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/$package/themes/default/base16-$theme.config.py"

  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 ":config-source $tfile"
  dbg_msg $app "Successfully switched theme"
}

## Theme setter
#
#  Takes care of permanently writing the desired
#  base16 theme into application settings.
save() {
  dbg_msg $app "Saving theme"
  local qt_dir="${XDG_CONFIG_HOME:-/$HOME/.config}/qutebrowser"

  if [[ -d "$qt_dir" ]]; then
    cat "$tfile" >"$qt_dir/colorscheme.py"
    dbg_msg $app "Saved theme to $qt_dir/colorscheme.py"

    include "$qt_dir"
  else
    dbg_msg $app "warn" "No qutebrowser configuration directory found"
  fi
}

## 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
}

## 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$"; then
  # Safe sourcing: https://stackoverflow.com/a/12694189
  DIR="${BASH_SOURCE%/*}"
  if [[ ! -d "$DIR" ]]; then DIR="$PWD"; fi
  # shellcheck source=utilities.sh
  . "$DIR/utilities.sh"

  main
else
  dbg_msg $app "error" "Processor does not work for package $package"
fi