#!/usr/bin/env bash
set -u

ROOT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
cd "$ROOT_DIR" || exit 1

EXTRA_ARGS=(
  -extra-arg=-isystem
  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0
  -extra-arg=-isystem
  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0/arm-none-eabi
  -extra-arg=-isystem
  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0/backward
  -extra-arg=-isystem
  -extra-arg=/opt/devkitpro/devkitARM/lib/gcc/arm-none-eabi/15.2.0/include
  -extra-arg=-isystem
  -extra-arg=/opt/devkitpro/devkitARM/lib/gcc/arm-none-eabi/15.2.0/include-fixed
  -extra-arg=-isystem
  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include
)

rebuild_tidy_db() {
  mkdir -p .clang-tidy-db
  sed 's/-mthumb-interwork//g' compile_commands.json > .clang-tidy-db/compile_commands.json
}

collect_sources() {
  find source include -type f \( -name '*.c' -o -name '*.cc' -o -name '*.cpp' -o -name '*.cxx' \) 2>/dev/null | sort
}

declare -A mtimes
last_cc_mtime=""

while true; do
  if [[ ! -f compile_commands.json ]]; then
    echo "Waiting for compile_commands.json (run CMake configure/build once)..."
    sleep 2
    continue
  fi

  cc_mtime="$(stat -c %Y compile_commands.json 2>/dev/null || echo 0)"
  db_regenerated=0
  if [[ "$cc_mtime" != "$last_cc_mtime" ]]; then
    rebuild_tidy_db
    last_cc_mtime="$cc_mtime"
    db_regenerated=1
  fi

  mapfile -t files < <(collect_sources)
  changed=()

  for f in "${files[@]}"; do
    m="$(stat -c %Y "$f" 2>/dev/null || echo 0)"
    if [[ "${mtimes[$f]:-}" != "$m" ]]; then
      changed+=("$f")
      mtimes["$f"]="$m"
    fi
  done

  if [[ $db_regenerated -eq 1 && ${#files[@]} -gt 0 ]]; then
    changed=("${files[@]}")
  fi

  if [[ ${#changed[@]} -gt 0 ]]; then
    echo "TIDY-WATCH-BEGIN"
    for f in "${changed[@]}"; do
      clang-tidy -quiet -p .clang-tidy-db "$f" "${EXTRA_ARGS[@]}" || true
    done
    echo "TIDY-WATCH-END"
  fi

  sleep 1
done