"""
Lab 2.9: Context-Aware Agent

Implement sliding window + summarization for long agent sessions.
"""

class ContextManager:
    """Manages the message context with sliding window + summarization."""
    
    def __init__(self, max_recent_turns: int = 5, system_prompt: str = ""):
        self.system_prompt = system_prompt
        self.max_recent_turns = max_recent_turns
        self.summary = ""
        self.recent_messages = []
    
    def add_message(self, role: str, content: str):
        """Add a message and manage context window."""
        # TODO: Add message to recent_messages
        # If recent_messages exceeds max_recent_turns * 2 (for user+assistant pairs):
        #   1. Summarize the oldest messages
        #   2. Update self.summary
        #   3. Remove those messages from recent
        pass
    
    def build_context(self) -> list[dict]:
        """
        Build the full context:
        [system_prompt] + [summary (if exists)] + [recent_messages]
        """
        pass  # TODO
    
    def summarize(self, messages: list[dict]) -> str:
        """Summarize a list of messages into a condensed form."""
        # TODO: Either use LLM summarization or simple truncation
        pass

if __name__ == "__main__":
    cm = ContextManager(system_prompt="You are a helpful assistant.")
    
    # Simulate a long conversation
    for i in range(20):
        user_msg = f"This is user message number {i+1} asking about topic A"
        asst_msg = f"This is assistant response number {i+1}"
        cm.add_message("user", user_msg)
        cm.add_message("assistant", asst_msg)
    
    context = cm.build_context()
    print(f"Context length: {len(context)} messages")
    print(f"Summary: {context[1] if len(context) > 1 else 'No summary'}")