feat: add restart_service and start_watcher functions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/dev.sh

@@ -70,6 +70,8 @@ start_service() {
         "$SCRIPT_DIR/$binary" -port=$port > "/tmp/${name}.log" 2>&1 &
     fi
     local pid=$!
+    # 保存 PID 到文件
+    echo $pid > "/tmp/dev_sh_${name}.pid"
 
     sleep 2
 
@@ -101,4 +103,111 @@ build_service() {
         echo -e "${RED}❌ $name 编译失败${NC}"
         return 1
     fi
+}
+
+# 重建并重启单个服务（构建成功后才杀旧进程）
+# 用法: restart_service name dir binary port use_db
+restart_service() {
+    local name=$1
+    local dir=$2
+    local binary=$3
+    local port=$4
+    local use_db=$5
+    local pid_file="/tmp/dev_sh_${name}.pid"
+
+    # Step 1: 编译（先编译，编译成功才杀旧进程）
+    if [ ! -d "$SCRIPT_DIR/$dir" ]; then
+        echo -e "${RED}❌ $dir 目录不存在，跳过${NC}"
+        return 1
+    fi
+
+    cd "$SCRIPT_DIR/$dir"
+    if ! go build -o "$SCRIPT_DIR/$binary" . 2>&1; then
+        echo -e "${RED}❌ [$name] 编译失败，旧进程保持运行${NC}"
+        echo -e "${RED}   查看详细日志: tail -f /tmp/${name}.log${NC}"
+        return 1
+    fi
+    echo -e "${GREEN}✅ [$name] 编译成功${NC}"
+
+    # Step 2: 编译成功后，杀旧进程（从 PID 文件读取）
+    if [ -f "$pid_file" ]; then
+        local old_pid=$(cat "$pid_file")
+        if [ -n "$old_pid" ] && kill -0 "$old_pid" 2>/dev/null; then
+            kill "$old_pid" 2>/dev/null || true
+            echo -e "${YELLOW}🛑 [$name] 旧进程 (PID: $old_pid) 已终止${NC}"
+        fi
+        rm -f "$pid_file"
+    fi
+
+    # Step 3: 启动新进程
+    sleep 1
+    cd "$SCRIPT_DIR"
+    if [ "$use_db" = "1" ]; then
+        "$SCRIPT_DIR/$binary" -port=$port "${DB_ARGS[@]}" > "/tmp/${name}.log" 2>&1 &
+    else
+        "$SCRIPT_DIR/$binary" -port=$port > "/tmp/${name}.log" 2>&1 &
+    fi
+    local new_pid=$!
+    echo $new_pid > "$pid_file"
+    sleep 2
+
+    if ps -p $new_pid > /dev/null 2>&1; then
+        echo -e "${GREEN}✅ [$name] 已重启 (PID: $new_pid)${NC}"
+    else
+        echo -e "${RED}❌ [$name] 重启失败，查看日志: tail -f /tmp/${name}.log${NC}"
+    fi
+}
+
+# 启动文件监听器
+# 用法: start_watcher name dir binary port use_db
+start_watcher() {
+    local name=$1
+    local dir=$2
+    local binary=$3
+    local port=$4
+    local use_db=$5
+    local watch_path="$SCRIPT_DIR/$dir"
+    local restart_marker="/tmp/dev_sh_${name}_restart"
+
+    if [ ! -d "$watch_path" ]; then
+        echo -e "${RED}❌ 监听目录不存在: $watch_path${NC}"
+        return 1
+    fi
+
+    # 清理可能遗留的重启标记
+    rm -f "$restart_marker"
+
+    (
+        if [[ "$(uname)" == "Darwin" ]]; then
+            fswatch -r "$watch_path" --exclude='\.git' --exclude='_test\.go$'
+        else
+            inotifywait -r -m -e modify,create,write "$watch_path" --exclude='\.git' --exclude='_test\.go$'
+        fi | while read event; do
+            # 时间戳防抖：每次事件更新标记文件
+            date +%s%N > "$restart_marker"
+        done
+    ) &
+    local watcher_pid=$!
+    echo "$watcher_pid" >> /tmp/dev_sh_watchers.tmp
+    echo -e "${GREEN}👁️  [$name] 文件监听器已启动 (PID: $watcher_pid)${NC}"
+
+    # 后台防抖循环：每 300ms 检查一次是否需要重启
+    (
+        while true; do
+            sleep 0.3
+            if [ ! -f "$restart_marker" ]; then
+                continue
+            fi
+            local now=$(date +%s%N)
+            local last_time=$(cat "$restart_marker" 2>/dev/null || echo 0)
+            local elapsed=$((now - last_time))
+            if (( elapsed >= 300000000 )); then
+                # 距上次事件已过 300ms，执行重启
+                rm -f "$restart_marker"
+                restart_service "$name" "$dir" "$binary" "$port" "$use_db"
+            fi
+        done
+    ) &
+    local debounce_pid=$!
+    echo "$debounce_pid" >> /tmp/dev_sh_watchers.tmp
 }