#!/bin/bash

set -euo pipefail

CONFIG_PATH="$HOME/.config/omarchy/dell-haptic.conf"
DEFAULT_INTENSITY=100
LOW_INTENSITY=10
MID_INTENSITY=50
HIGH_INTENSITY=100
SERVICE_NAME="dell-xps-touchpad-haptics.service"

usage() {
  printf 'Usage: %s get | set <low|mid|high>\n' "$(basename -- "$0")"
}

clamp_intensity() {
  local value=$1

  if ! [[ $value =~ ^[0-9]+$ ]]; then
    printf '%s\n' "$DEFAULT_INTENSITY"
    return 0
  fi

  if (( value < 0 )); then
    printf '0\n'
  elif (( value > 100 )); then
    printf '100\n'
  else
    printf '%s\n' "$value"
  fi
}

read_intensity() {
  local line=""
  local value=""

  [[ -f $CONFIG_PATH ]] || {
    printf '%s\n' "$DEFAULT_INTENSITY"
    return 0
  }

  while IFS= read -r line; do
    line=${line#${line%%[![:space:]]*}}
    line=${line%${line##*[![:space:]]}}
    [[ -z $line || ${line:0:1} == "#" || $line != *=* ]] && continue

    if [[ ${line%%=*} == "INTENSITY" ]]; then
      value=${line#*=}
      value=${value#${value%%[![:space:]]*}}
      value=${value%${value##*[![:space:]]}}
      clamp_intensity "$value"
      return 0
    fi
  done < "$CONFIG_PATH"

  printf '%s\n' "$DEFAULT_INTENSITY"
}

level_for_intensity() {
  local intensity=$1

  if (( intensity <= 30 )); then
    printf 'low\n'
  elif (( intensity < 75 )); then
    printf 'mid\n'
  else
    printf 'high\n'
  fi
}

intensity_for_level() {
  case "$1" in
  low) printf '%s\n' "$LOW_INTENSITY" ;;
  mid | medium) printf '%s\n' "$MID_INTENSITY" ;;
  high) printf '%s\n' "$HIGH_INTENSITY" ;;
  *)
    echo "Haptic level must be one of: low, mid, high." >&2
    exit 1
    ;;
  esac
}

write_config() {
  local intensity=$1

  install -d -m 755 "$(dirname -- "$CONFIG_PATH")"
  printf '# Dell XPS touchpad haptic intensity.\n# Presets: low=10, mid=50, high=100.\nINTENSITY=%s\n' "$intensity" >"$CONFIG_PATH"
}

service_active() {
  systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null
}

case "${1:-}" in
get)
  if (( $# != 1 )); then
    usage >&2
    exit 1
  fi

  level_for_intensity "$(read_intensity)"
  ;;
set)
  if (( $# != 2 )); then
    usage >&2
    exit 1
  fi

  previous_level=$(level_for_intensity "$(read_intensity)")
  intensity=$(intensity_for_level "$2")
  write_config "$intensity"

  if service_active; then
    printf 'Set Dell XPS touchpad haptics from %s to %s. The running service will apply and verify the new gain in the journal shortly.\n' "$previous_level" "$(level_for_intensity "$intensity")"
  else
    printf 'Set Dell XPS touchpad haptics from %s to %s. Start %s to apply it.\n' "$previous_level" "$(level_for_intensity "$intensity")" "$SERVICE_NAME"
  fi
  ;;
--help | -h)
  usage
  ;;
*)
  usage >&2
  exit 1
  ;;
esac