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

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

file_exists() {
  if [[ -f "$1" ]]; then
    true
  else
    false
  fi
}
# check for existence of pattern $2 in file $1
line_exists() {
  local file="$1"
  local line="$2"

  if ! file_exists "$file" || ! grep -qe "$line" "$file"; then
    false
  else
    true
  fi
}
# prepare newline at eof to make adding newlines easier
eol_exists_or_append() {
  local file="$1"
  local eof
  eof=$(tail -c 1 "$file")

  if [ -n "$eof" ]; then
    printf "\\n" >>"$file"
  fi
}
# append line $2 to file $1
line_exists_or_append() {
  local file="$1"
  local line="$2"
  local new="${3:-$2}"

  if ! line_exists "$file" "$line"; then
    eol_exists_or_append "$file"
    echo "$new" >>"$file"
  fi
}

theme_vim() {
  dbg_msg="VIM: $package - "
  tfile="$path/$package/colors/base16-$theme.vim"

  check_tfile

  if [[ "$permanent" == "true" ]]; then set_vim_theme; fi
  recolor_vim_w_tmux

  [[ "$DEBUG" == true ]] && echo "$dbg_msg"
}

check_tfile() {
  if ! file_exists "$tfile"; then
    dbg_msg="$dbg_msg theme $theme for vim not found.\n"
    return
  fi
}

recolor_vim_w_tmux() {
  # this whole thing only works when tmux is running
  pgrep tmux >/dev/null || 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 $tfile" "Enter"
    else
      tmux send-keys -t "${l/:*/}" ":source $tfile" "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:')
}

set_vim_theme() {
  local vim_dirs="${XDG_CONFIG_HOME:-/$HOME/.config}/nvim $HOME/.vim"

  for vim_dir in $vim_dirs; do
    if [[ -d "$vim_dir" ]]; then
      cat "$tfile" >"$vim_dir/colorscheme.vim"
      echo "colorscheme base16-$theme" >>"$vim_dir/colorscheme.vim"

      call_from_vim_init

      dbg_msg="$dbg_msg Set theme $theme\n"
    fi
  done
}

# make sure we're calling our new colorscheme whenever starting vim
call_from_vim_init() {
  if file_exists "$vim_dir/init.vim"; then
    line_exists_or_append "$vim_dir/init.vim" "runtime colorscheme.vim"
  elif file_exists "$HOME/.vimrc"; then
    line_exists_or_append "$HOME/.vimrc" "runtime colorscheme.vim"
  fi
}

# Check deps
if printf '%s\n' "${dependency[@]}" | grep -q -P "^$package$"; then
  theme_vim
else
  printf "Processor does not work for %s, please use another." "$package"
fi