#!/usr/bin/env bash
# Deploy backend: build release, stop running process gracefully (PID file & pgrep fallback), rotate logs, and start via nohup
# Usage:
#   ENV_FILE=prod ./scripts/deploy_backend.sh
#   ENV_FILE=staging ./scripts/deploy_backend.sh
# Notes:
# - ENV_FILE will be exported for the backend to decide which .env to load (e.g., .env.prod).
# - PID is stored in backend/udmin.pid.

set -euo pipefail

# 获取脚本所在目录的绝对路径
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ROOT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
BACKEND_DIR="$ROOT_DIR/backend"
BIN_PATH="$BACKEND_DIR/target/release/udmin"
LOG_FILE="$BACKEND_DIR/udmin.log"
PID_FILE="$BACKEND_DIR/udmin.pid"
ENV_FILE_VALUE="${ENV_FILE:-prod}"

# 调试信息：打印关键路径
echo "[backend] Script directory: $SCRIPT_DIR"
echo "[backend] Root directory: $ROOT_DIR"
echo "[backend] Backend directory: $BACKEND_DIR"
echo "[backend] Binary path: $BIN_PATH"

# 检查关键目录是否存在
if [ ! -d "$BACKEND_DIR" ]; then
  echo "[backend] ERROR: Backend directory does not exist: $BACKEND_DIR" >&2
  echo "[backend] Please ensure the script is placed in the correct location relative to the project structure" >&2
  exit 1
fi

if [ ! -f "$BACKEND_DIR/Cargo.toml" ]; then
  echo "[backend] ERROR: Cargo.toml not found in backend directory: $BACKEND_DIR" >&2
  echo "[backend] This doesn't appear to be a valid Rust project directory" >&2
  exit 1
fi

cd "$BACKEND_DIR"

echo "[backend] Building release binary..."
cargo build --release

if [ ! -x "$BIN_PATH" ]; then
  echo "[backend] ERROR: Binary not found or not executable: $BIN_PATH" >&2
  exit 1
fi

# Gracefully stop existing process (PID file first)
stop_pid() {
  local pid="$1"
  if [ -z "$pid" ]; then return 0; fi
  if ! ps -p "$pid" >/dev/null 2>&1; then return 0; fi
  echo "[backend] Stopping udmin (pid=$pid) ..."
  kill -TERM "$pid" || true
  for i in {1..10}; do
    if ps -p "$pid" >/dev/null 2>&1; then
      sleep 1
    else
      break
    fi
  done
  if ps -p "$pid" >/dev/null 2>&1; then
    echo "[backend] Force killing udmin (pid=$pid) ..."
    kill -KILL "$pid" || true
  fi
}

# 1) Stop by PID file if present
echo "[backend] Checking for existing PID file: $PID_FILE"
if [ -f "$PID_FILE" ]; then
  PID_CONTENT="$(cat "$PID_FILE" 2>/dev/null || true)"
  if [ -n "$PID_CONTENT" ]; then
    echo "[backend] Found PID file with PID: $PID_CONTENT"
    stop_pid "$PID_CONTENT"
  else
    echo "[backend] PID file exists but is empty"
  fi
  rm -f "$PID_FILE"
  echo "[backend] Removed PID file"
else
  echo "[backend] No PID file found"
fi

# 2) Fallback: stop any process matching the release binary path (safe, avoids killing debug run)
echo "[backend] Searching for existing processes matching: $BIN_PATH"
PGREP_PIDS="$(pgrep -f "$BIN_PATH" 2>/dev/null || true)"
if [ -n "$PGREP_PIDS" ]; then
  echo "[backend] Found existing udmin processes by path: $PGREP_PIDS"
  for p in $PGREP_PIDS; do
    echo "[backend] Stopping process: $p"
    stop_pid "$p"
  done
else
  echo "[backend] No existing processes found matching the binary path"
fi

# Rotate log
TS="$(date +%Y%m%d%H%M%S)"
if [ -f "$LOG_FILE" ]; then
  mv "$LOG_FILE" "$LOG_FILE.$TS" || true
fi

echo "[backend] Starting udmin (ENV_FILE=$ENV_FILE_VALUE) ..."
export ENV_FILE="$ENV_FILE_VALUE"
nohup "$BIN_PATH" > "$LOG_FILE" 2>&1 &
NEW_PID=$!

echo "$NEW_PID" > "$PID_FILE"

echo "[backend] Started with PID: $NEW_PID"
echo "[backend] Logs: $LOG_FILE"
echo "[backend] PID file: $PID_FILE"

# 等待几秒钟验证进程是否成功启动
echo "[backend] Waiting 3 seconds to verify startup..."
sleep 3

if ps -p "$NEW_PID" > /dev/null 2>&1; then
  echo "[backend] ✅ Process is running successfully (PID: $NEW_PID)"
  echo "[backend] Deployment completed successfully!"
else
  echo "[backend] ❌ ERROR: Process failed to start or crashed immediately" >&2
  echo "[backend] Check the log file for details: $LOG_FILE" >&2
  if [ -f "$LOG_FILE" ]; then
    echo "[backend] Last few lines of log:" >&2
    tail -10 "$LOG_FILE" >&2
  fi
  exit 1
fi