# P2P Network Communication - Message Handler Tests
"""
测试消息处理器的基本功能
"""

import pytest
from shared.models import Message, MessageType
from shared.message_handler import (
    MessageHandler,
    MessageValidationError,
    MessageSerializationError,
    MessageRoutingError
)


class TestMessageHandlerSerialization:
    """测试消息处理器的序列化功能"""
    
    def setup_method(self):
        """每个测试方法前初始化"""
        self.handler = MessageHandler()
    
    def test_serialize_text_message(self):
        """测试文本消息序列化"""
        msg = Message(
            msg_type=MessageType.TEXT,
            sender_id="user1",
            receiver_id="user2",
            timestamp=1234567890.0,
            payload=b"Hello, World!"
        )
        
        serialized = self.handler.serialize(msg)
        
        assert isinstance(serialized, bytes)
        assert len(serialized) > MessageHandler.HEADER_SIZE
    
    def test_deserialize_text_message(self):
        """测试文本消息反序列化"""
        original = Message(
            msg_type=MessageType.TEXT,
            sender_id="sender",
            receiver_id="receiver",
            timestamp=9876543210.0,
            payload=b"Test payload"
        )
        
        serialized = self.handler.serialize(original)
        restored = self.handler.deserialize(serialized)
        
        assert restored.msg_type == original.msg_type
        assert restored.sender_id == original.sender_id
        assert restored.receiver_id == original.receiver_id
        assert restored.timestamp == original.timestamp
        assert restored.payload == original.payload
    
    def test_deserialize_short_data_raises_error(self):
        """测试数据过短时抛出错误"""
        with pytest.raises(MessageSerializationError):
            self.handler.deserialize(b"short")
    
    def test_deserialize_invalid_json_raises_error(self):
        """测试无效JSON时抛出错误"""
        import struct
        # 创建有效头部但无效JSON的数据
        invalid_json = b"not valid json"
        header = struct.pack("!II", len(invalid_json), 1)
        
        with pytest.raises(MessageSerializationError):
            self.handler.deserialize(header + invalid_json)


class TestMessageHandlerValidation:
    """测试消息处理器的验证功能"""
    
    def setup_method(self):
        """每个测试方法前初始化"""
        self.handler = MessageHandler()
    
    def test_validate_valid_message(self):
        """测试验证有效消息"""
        msg = Message(
            msg_type=MessageType.TEXT,
            sender_id="user1",
            receiver_id="user2",
            timestamp=1234567890.0,
            payload=b"Valid message"
        )
        
        assert self.handler.validate(msg) is True
    
    def test_validate_empty_sender_raises_error(self):
        """测试空发送者ID时抛出错误"""
        msg = Message(
            msg_type=MessageType.TEXT,
            sender_id="",
            receiver_id="user2",
            timestamp=1234567890.0,
            payload=b"Test"
        )
        
        with pytest.raises(MessageValidationError):
            self.handler.validate(msg)
    
    def test_validate_empty_receiver_raises_error(self):
        """测试空接收者ID时抛出错误"""
        msg = Message(
            msg_type=MessageType.TEXT,
            sender_id="user1",
            receiver_id="",
            timestamp=1234567890.0,
            payload=b"Test"
        )
        
        with pytest.raises(MessageValidationError):
            self.handler.validate(msg)
    
    def test_validate_invalid_timestamp_raises_error(self):
        """测试无效时间戳时抛出错误"""
        msg = Message(
            msg_type=MessageType.TEXT,
            sender_id="user1",
            receiver_id="user2",
            timestamp=-1.0,
            payload=b"Test"
        )
        
        with pytest.raises(MessageValidationError):
            self.handler.validate(msg)


class TestMessageHandlerRouting:
    """测试消息处理器的路由功能"""
    
    def setup_method(self):
        """每个测试方法前初始化"""
        self.handler = MessageHandler()
        self.received_messages = []
    
    def test_register_and_route_handler(self):
        """测试注册和路由处理器"""
        def text_handler(msg):
            self.received_messages.append(msg)
        
        self.handler.register_handler(MessageType.TEXT, text_handler)
        
        msg = Message(
            msg_type=MessageType.TEXT,
            sender_id="user1",
            receiver_id="user2",
            timestamp=1234567890.0,
            payload=b"Routed message"
        )
        
        self.handler.route(msg)
        
        assert len(self.received_messages) == 1
        assert self.received_messages[0].payload == b"Routed message"
    
    def test_route_without_handler_raises_error(self):
        """测试没有处理器时路由抛出错误"""
        msg = Message(
            msg_type=MessageType.FILE_REQUEST,
            sender_id="user1",
            receiver_id="user2",
            timestamp=1234567890.0,
            payload=b"File request"
        )
        
        with pytest.raises(MessageRoutingError):
            self.handler.route(msg)
    
    def test_default_handler(self):
        """测试默认处理器"""
        def default_handler(msg):
            self.received_messages.append(msg)
        
        self.handler.set_default_handler(default_handler)
        
        msg = Message(
            msg_type=MessageType.HEARTBEAT,
            sender_id="user1",
            receiver_id="user2",
            timestamp=1234567890.0,
            payload=b""
        )
        
        self.handler.route(msg)
        
        assert len(self.received_messages) == 1
    
    def test_unregister_handler(self):
        """测试注销处理器"""
        def handler(msg):
            self.received_messages.append(msg)
        
        self.handler.register_handler(MessageType.TEXT, handler)
        self.handler.unregister_handler(MessageType.TEXT)
        
        assert not self.handler.has_handler(MessageType.TEXT)
    
    def test_get_registered_types(self):
        """测试获取已注册的消息类型"""
        self.handler.register_handler(MessageType.TEXT, lambda m: None)
        self.handler.register_handler(MessageType.FILE_REQUEST, lambda m: None)
        
        registered = self.handler.get_registered_types()
        
        assert MessageType.TEXT in registered
        assert MessageType.FILE_REQUEST in registered
        assert len(registered) == 2