#!/usr/bin/env bash
set -euo pipefail

ROOT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)"
RUN_DIR="$ROOT_DIR/run"
ENV_FILE="${APP_ENV_FILE:-$ROOT_DIR/.env}"

if [ -f "$ENV_FILE" ]; then
  set -a
  # shellcheck disable=SC1090
  . "$ENV_FILE"
  set +a
fi

APP_BIND="${APP_BIND:-0.0.0.0}"
APP_PORT="${APP_PORT:-2026}"
TARGETS_FILE="${TARGETS_FILE:-$ROOT_DIR/config/targets.json}"
YUMI_INTERNAL_HOST="${YUMI_INTERNAL_HOST:-127.0.0.1}"
YUMI_INTERNAL_PORT="${YUMI_INTERNAL_PORT:-2027}"
HAIYI_INTERNAL_HOST="${HAIYI_INTERNAL_HOST:-127.0.0.1}"
HAIYI_INTERNAL_PORT="${HAIYI_INTERNAL_PORT:-2028}"
GATEWAY_BIND="$APP_BIND"
GATEWAY_PORT="$APP_PORT"

GATEWAY_SYSTEMD_SERVICE_NAME="hy-app-monitor.service"
YUMI_SYSTEMD_SERVICE_NAME="hy-app-monitor-yumi.service"
HAIYI_SYSTEMD_SERVICE_NAME="hy-app-monitor-haiyi.service"

if [ -x "$ROOT_DIR/.venv/bin/python" ]; then
  PYTHON_BIN_DEFAULT="$ROOT_DIR/.venv/bin/python"
else
  PYTHON_BIN_DEFAULT="python3"
fi

PYTHON_BIN="${PYTHON_BIN:-$PYTHON_BIN_DEFAULT}"

mkdir -p "$RUN_DIR"

suite_service_names() {
  printf '%s\n' gateway yumi haiyi
}

service_display_name() {
  case "$1" in
    gateway) echo "gateway" ;;
    yumi) echo "yumi" ;;
    haiyi) echo "haiyi" ;;
    *)
      echo "unknown service: $1" >&2
      return 1
      ;;
  esac
}

service_unit_name() {
  case "$1" in
    gateway) echo "$GATEWAY_SYSTEMD_SERVICE_NAME" ;;
    yumi) echo "$YUMI_SYSTEMD_SERVICE_NAME" ;;
    haiyi) echo "$HAIYI_SYSTEMD_SERVICE_NAME" ;;
    *)
      echo "unknown service: $1" >&2
      return 1
      ;;
  esac
}

service_entry_file() {
  case "$1" in
    gateway) echo "$ROOT_DIR/server.py" ;;
    yumi) echo "$ROOT_DIR/yumi_server.py" ;;
    haiyi) echo "$ROOT_DIR/haiyi_server.py" ;;
    *)
      echo "unknown service: $1" >&2
      return 1
      ;;
  esac
}

service_bind() {
  case "$1" in
    gateway) echo "$GATEWAY_BIND" ;;
    yumi) echo "$YUMI_INTERNAL_HOST" ;;
    haiyi) echo "$HAIYI_INTERNAL_HOST" ;;
    *)
      echo "unknown service: $1" >&2
      return 1
      ;;
  esac
}

service_port() {
  case "$1" in
    gateway) echo "$GATEWAY_PORT" ;;
    yumi) echo "$YUMI_INTERNAL_PORT" ;;
    haiyi) echo "$HAIYI_INTERNAL_PORT" ;;
    *)
      echo "unknown service: $1" >&2
      return 1
      ;;
  esac
}

service_base_path() {
  case "$1" in
    gateway) echo "" ;;
    yumi) echo "/yumi" ;;
    haiyi) echo "/haiyi" ;;
    *)
      echo "unknown service: $1" >&2
      return 1
      ;;
  esac
}

service_pid_file() {
  echo "$RUN_DIR/hy-app-monitor-$1.pid"
}

service_log_file() {
  echo "$RUN_DIR/hy-app-monitor-$1.log"
}

service_command_pattern() {
  basename "$(service_entry_file "$1")"
}

has_systemd_unit() {
  local name="$1"
  if ! command -v systemctl >/dev/null 2>&1; then
    return 1
  fi
  systemctl cat "$(service_unit_name "$name")" >/dev/null 2>&1
}

has_full_systemd_suite() {
  local name
  for name in $(suite_service_names); do
    if ! has_systemd_unit "$name"; then
      return 1
    fi
  done
  return 0
}

systemd_main_pid() {
  local name="$1"
  local main_pid

  if ! has_systemd_unit "$name"; then
    return 1
  fi

  main_pid="$(systemctl show --property MainPID --value "$(service_unit_name "$name")" 2>/dev/null || true)"
  if [ -z "${main_pid:-}" ] || [ "$main_pid" = "0" ]; then
    return 1
  fi

  echo "$main_pid"
}

pid_matches_project() {
  local name="$1"
  local pid="$2"
  if [ -z "${pid:-}" ] || ! kill -0 "$pid" >/dev/null 2>&1; then
    return 1
  fi

  local command
  command="$(ps -p "$pid" -o command= 2>/dev/null || true)"
  if [[ "$command" != *"$(service_command_pattern "$name")"* ]]; then
    return 1
  fi

  if command -v lsof >/dev/null 2>&1; then
    local expected_port
    expected_port="$(service_port "$name")"
    if ! lsof -a -p "$pid" -iTCP:"$expected_port" -sTCP:LISTEN >/dev/null 2>&1; then
      return 1
    fi
  fi

  if command -v lsof >/dev/null 2>&1; then
    local cwd
    cwd="$(lsof -a -p "$pid" -d cwd -Fn 2>/dev/null | sed -n 's/^n//p' | head -n 1)"
    if [ -n "$cwd" ] && [ "$cwd" != "$ROOT_DIR" ]; then
      return 1
    fi
  fi

  return 0
}

discover_project_pid() {
  local name="$1"
  if ! command -v lsof >/dev/null 2>&1; then
    return 1
  fi

  local pid
  while IFS= read -r pid; do
    if pid_matches_project "$name" "$pid"; then
      echo "$pid"
      return 0
    fi
  done < <(lsof -tiTCP:"$(service_port "$name")" -sTCP:LISTEN 2>/dev/null || true)

  return 1
}

read_pid() {
  local name="$1"
  local pid_file
  pid_file="$(service_pid_file "$name")"

  if [ -f "$pid_file" ]; then
    local pid
    pid="$(cat "$pid_file")"
    if pid_matches_project "$name" "$pid"; then
      echo "$pid"
      return 0
    fi
  fi

  discover_project_pid "$name"
}

is_running() {
  local name="$1"
  local pid
  local pid_file
  pid_file="$(service_pid_file "$name")"
  pid="$(read_pid "$name" || true)"
  if [ -z "${pid:-}" ]; then
    rm -f "$pid_file"
    return 1
  fi
  if ! kill -0 "$pid" >/dev/null 2>&1; then
    rm -f "$pid_file"
    return 1
  fi

  echo "$pid" >"$pid_file"
  return 0
}

stop_legacy_process() {
  local name="$1"
  local pid
  local pid_file
  local managed_pid
  pid_file="$(service_pid_file "$name")"
  pid="$(read_pid "$name" || true)"
  managed_pid="$(systemd_main_pid "$name" || true)"

  if [ -n "${pid:-}" ] && [ -n "${managed_pid:-}" ] && [ "$pid" = "$managed_pid" ]; then
    rm -f "$pid_file"
    return 0
  fi

  if [ -n "${pid:-}" ] && kill -0 "$pid" >/dev/null 2>&1; then
    kill "$pid" >/dev/null 2>&1 || true
    local _i
    for _i in $(seq 1 10); do
      if ! kill -0 "$pid" >/dev/null 2>&1; then
        break
      fi
      sleep 1
    done
    kill -9 "$pid" >/dev/null 2>&1 || true
  fi

  rm -f "$pid_file"
}

stop_all_legacy_processes() {
  local name
  for name in $(suite_service_names); do
    stop_legacy_process "$name"
  done
}

export_service_env() {
  local name="$1"
  export APP_BIND
  export APP_PORT
  export APP_BASE_PATH
  export TARGETS_FILE
  export PYTHONUNBUFFERED=1

  APP_BIND="$(service_bind "$name")"
  APP_PORT="$(service_port "$name")"
  APP_BASE_PATH="$(service_base_path "$name")"
  export APP_BIND APP_PORT APP_BASE_PATH TARGETS_FILE PYTHONUNBUFFERED
}

start_local_service() {
  local name="$1"
  local pid_file
  local log_file
  local entry_file

  if is_running "$name"; then
    echo "$(service_display_name "$name") already running pid=$(read_pid "$name")"
    return 0
  fi

  if [ "$name" = "yumi" ] && [ ! -f "$TARGETS_FILE" ]; then
    echo "targets file not found: $TARGETS_FILE" >&2
    return 1
  fi

  pid_file="$(service_pid_file "$name")"
  log_file="$(service_log_file "$name")"
  entry_file="$(service_entry_file "$name")"

  export_service_env "$name"

  nohup "$PYTHON_BIN" "$entry_file" >>"$log_file" 2>&1 &
  local pid=$!
  echo "$pid" >"$pid_file"

  sleep 1
  if kill -0 "$pid" >/dev/null 2>&1; then
    echo "$(service_display_name "$name") started pid=$pid port=$(service_port "$name")"
    return 0
  fi

  echo "$(service_display_name "$name") failed to start" >&2
  tail -n 40 "$log_file" >&2 || true
  return 1
}

stop_local_service() {
  local name="$1"
  local pid_file
  pid_file="$(service_pid_file "$name")"

  if ! is_running "$name"; then
    echo "$(service_display_name "$name") not running"
    rm -f "$pid_file"
    return 0
  fi

  local pid
  pid="$(read_pid "$name")"
  kill "$pid" >/dev/null 2>&1 || true

  local _i
  for _i in $(seq 1 10); do
    if ! kill -0 "$pid" >/dev/null 2>&1; then
      rm -f "$pid_file"
      echo "$(service_display_name "$name") stopped"
      return 0
    fi
    sleep 1
  done

  kill -9 "$pid" >/dev/null 2>&1 || true
  rm -f "$pid_file"
  echo "$(service_display_name "$name") force stopped"
}

status_local_service() {
  local name="$1"
  if is_running "$name"; then
    echo "$(service_display_name "$name") running pid=$(read_pid "$name") port=$(service_port "$name")"
    return 0
  fi

  echo "$(service_display_name "$name") stopped"
  return 1
}

start_systemd_suite() {
  local name
  for name in yumi haiyi gateway; do
    systemctl start "$(service_unit_name "$name")"
  done
  for name in $(suite_service_names); do
    systemctl is-active "$(service_unit_name "$name")"
  done
}

stop_systemd_suite() {
  local name
  for name in gateway yumi haiyi; do
    systemctl stop "$(service_unit_name "$name")" >/dev/null 2>&1 || true
  done
}

restart_systemd_suite() {
  local name
  for name in yumi haiyi gateway; do
    systemctl restart "$(service_unit_name "$name")"
  done
  for name in $(suite_service_names); do
    systemctl is-active "$(service_unit_name "$name")"
  done
}

status_systemd_suite() {
  local all_active=0
  local name
  for name in $(suite_service_names); do
    if systemctl is-active --quiet "$(service_unit_name "$name")"; then
      echo "$(service_display_name "$name") running under systemd port=$(service_port "$name")"
    else
      echo "$(service_display_name "$name") stopped"
      all_active=1
    fi
  done
  return "$all_active"
}