#!/usr/bin/env bash

set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
RUN_DIR="$ROOT_DIR/.run"
LOG_DIR="$RUN_DIR/logs"

BACKEND_PID_FILE="$RUN_DIR/backend.pid"
FRONTEND_PID_FILE="$RUN_DIR/frontend.pid"
BACKEND_LOG="$LOG_DIR/backend.log"
FRONTEND_LOG="$LOG_DIR/frontend.log"

BACKEND_HOST="${BACKEND_HOST:-127.0.0.1}"
BACKEND_PORT="${BACKEND_PORT:-8001}"
FRONTEND_HOST="${FRONTEND_HOST:-127.0.0.1}"
FRONTEND_PORT="${FRONTEND_PORT:-3001}"
API_BASE_URL="${NEXT_PUBLIC_API_BASE_URL:-http://${BACKEND_HOST}:${BACKEND_PORT}}"

is_running() {
  local pid_file="$1"
  if [[ -f "$pid_file" ]]; then
    local pid
    pid="$(cat "$pid_file")"
    if [[ -n "$pid" ]] && kill -0 "$pid" 2>/dev/null; then
      return 0
    fi
    rm -f "$pid_file"
  fi
  return 1
}

require_file() {
  local path="$1"
  local label="$2"
  if [[ ! -e "$path" ]]; then
    echo "$label not found: $path" >&2
    exit 1
  fi
}

cmd_start() {
  require_file "$ROOT_DIR/backend/.venv/bin/uvicorn" "Backend virtualenv executable"
  require_file "$ROOT_DIR/frontend/node_modules" "Frontend dependencies"
  mkdir -p "$LOG_DIR"

  if is_running "$BACKEND_PID_FILE"; then
    echo "Backend already running on PID $(cat "$BACKEND_PID_FILE")"
  else
    (
      cd "$ROOT_DIR/backend"
      exec .venv/bin/uvicorn app.main:app --reload --host "$BACKEND_HOST" --port "$BACKEND_PORT"
    ) >"$BACKEND_LOG" 2>&1 &
    echo $! >"$BACKEND_PID_FILE"
    echo "Started backend on http://${BACKEND_HOST}:${BACKEND_PORT} (PID $(cat "$BACKEND_PID_FILE"))"
  fi

  if is_running "$FRONTEND_PID_FILE"; then
    echo "Frontend already running on PID $(cat "$FRONTEND_PID_FILE")"
  else
    (
      cd "$ROOT_DIR/frontend"
      export NEXT_PUBLIC_API_BASE_URL="$API_BASE_URL"
      exec npm run dev -- --hostname "$FRONTEND_HOST" --port "$FRONTEND_PORT"
    ) >"$FRONTEND_LOG" 2>&1 &
    echo $! >"$FRONTEND_PID_FILE"
    echo "Started frontend on http://${FRONTEND_HOST}:${FRONTEND_PORT} (PID $(cat "$FRONTEND_PID_FILE"))"
  fi

  cat <<EOF

Stack status
- Frontend: http://${FRONTEND_HOST}:${FRONTEND_PORT}
- Backend:  http://${BACKEND_HOST}:${BACKEND_PORT}
- Logs:     $LOG_DIR
EOF
}

stop_process() {
  local name="$1"
  local pid_file="$2"
  if [[ ! -f "$pid_file" ]]; then
    echo "$name not running"
    return
  fi

  local pid
  pid="$(cat "$pid_file")"

  if [[ -n "$pid" ]] && kill -0 "$pid" 2>/dev/null; then
    kill "$pid" 2>/dev/null || true
    for _ in {1..20}; do
      if ! kill -0 "$pid" 2>/dev/null; then
        break
      fi
      sleep 0.25
    done
    if kill -0 "$pid" 2>/dev/null; then
      kill -9 "$pid" 2>/dev/null || true
    fi
    echo "Stopped $name (PID $pid)"
  else
    echo "$name pid file was stale"
  fi

  rm -f "$pid_file"
}

cmd_stop() {
  stop_process "frontend" "$FRONTEND_PID_FILE"
  stop_process "backend" "$BACKEND_PID_FILE"
}

cmd_restart() {
  cmd_stop
  cmd_start
}

cmd_status() {
  if is_running "$BACKEND_PID_FILE"; then
    echo "backend   running  PID $(cat "$BACKEND_PID_FILE")  http://${BACKEND_HOST}:${BACKEND_PORT}"
  else
    echo "backend   stopped"
  fi

  if is_running "$FRONTEND_PID_FILE"; then
    echo "frontend  running  PID $(cat "$FRONTEND_PID_FILE")  http://${FRONTEND_HOST}:${FRONTEND_PORT}"
  else
    echo "frontend  stopped"
  fi
}

case "${1:-}" in
  start)   cmd_start ;;
  stop)    cmd_stop ;;
  restart) cmd_restart ;;
  status)  cmd_status ;;
  *)
    echo "Usage: $(basename "$0") {start|stop|restart|status}" >&2
    exit 1
    ;;
esac