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

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/$package/colors/base16-$theme.vim"

  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"
  # this whole thing only works when tmux is running

  pgrep tmux >/dev/null || {
    dbg_msg $app "warn" "No instance of tmux running, can not dynamically re-theme vim"
    return
  }

  while read -r l; do
    # we need to close panels that are in a mode and get them out to send keys to vim
    if [ "${l: -1}" = 1 ]; then
      tmux send-keys -t "${l/:*/}" -X cancel && tmux send-keys -t "${l/:*/}" ":source $tfile" "Enter"
      tmux send-keys -t "${l/:*/}" ":AirlineTheme base16" "Enter"
    else
      tmux send-keys -t "${l/:*/}" ":source $tfile" "Enter"
      tmux send-keys -t "${l/:*/}" ":AirlineTheme base16" "Enter"
    fi

    # find all panes which currently have nvim/vim running
  done < <(tmux list-panes -a -F '#D:#T:#{pane_current_command}:#{pane_in_mode}' | grep ':VIM:\|:nvim:')

  dbg_msg $app "Successfully switched theme"
}

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

  for vim_dir in $vim_dirs; do
    if [[ -d "$vim_dir" ]]; then
      foundone=true

      cat "$tfile" >"$vim_dir/colorscheme.vim"
      echo "colorscheme base16-$theme" >>"$vim_dir/colorscheme.vim"
      dbg_msg $app "Saved theme to $vim_dir/colorscheme.vim"

      include "$vim_dir"
    fi
  done

  [[ "$foundone" == false ]] && dbg_msg $app "warn" "No configuration directory found"
}

## 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 vim_dir="$1"
  dbg_msg $app "Including theme in configuration"

  if file_exists "$vim_dir/init.vim"; then
    line_exists_or_append "$vim_dir/init.vim" "runtime colorscheme.vim"
    dbg_msg $app "Successfully included theme in configuration"
  elif file_exists "$HOME/.vimrc"; then
    line_exists_or_append "$HOME/.vimrc" "runtime colorscheme.vim"
    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