# run_agent.py compression flow (simplified)
# 1. Call memory providers BEFORE compression (good!)
provider_context = self._memory_manager.on_pre_compress(messages)

# 2. Start compression
compressed = self.context_compressor.compress(messages)

# Inside compress():
#   a. _prune_old_tool_results() — cheap removal
#   b. _generate_summary() — LLM summary of middle section
#   c. Replace old messages with summary

---

@dataclass
class CompressionContext:
    """Structured context from memory providers for compression."""
    text: str = ""                          # Freeform context (backward compatible)
    preserve_snippets: List[str] = []       # Text snippets that MUST appear in the summary
    preservation_rules: List[str] = []      # Declarative rules ("keep_last_file_path", "keep_last_error")
    key_facts: List[str] = []              # Facts to inject into the final summary verbatim

---

def _generate_summary(self, messages, provider_contexts):
    prompt = "Summarize the conversation, preserving key information.\n\n"

    # Inject provider key facts (must survive compression)
    for provider, ctx in provider_contexts.items():
        if ctx.key_facts:
            prompt += f"[Context from {provider.name} - PRESERVE VERBATIM]\n"
            for fact in ctx.key_facts:
                prompt += f"- {fact}\n"
            prompt += f"[End {provider.name} context]\n\n"

    if ctx.preservation_rules:
        prompt += "Special preservation rules:\n"
        for rule in ctx.preservation_rules:
            prompt += f"- {rule}\n"
        prompt += "\n"

    prompt += "--- Conversation to summarize ---\n"
    prompt += self._format_messages(messages)

---

# Example rules that providers can specify
PRESERVATION_RULES = {
    "keep_last_file_path": lambda msgs: extract_last_pattern(msgs, r'(/[\w./-]+\.\w+)'),
    "keep_last_error": lambda msgs: extract_last_error_resolution(msgs),
    "keep_last_decision": lambda msgs: extract_last_decision(msgs),
    "keep_user_preferences": lambda msgs: extract_preferences(msgs),
}

---

class MuninnMemoryProvider(MemoryProvider):
    def on_pre_compress(self, messages) -> CompressionContext:
        # Extract and save memories externally (already works)
        self._extract_compression_memories(messages)

        # Build structured context for the compressor
        return CompressionContext(
            text=self._build_compression_digest(messages),
            key_facts=[
                f"Active project: {self._detect_project(messages)}",
                f"Last file modified: {self._find_last_path(messages)}",
            ],
            preservation_rules=[
                "keep_last_file_path",
                "keep_user_preferences",
            ],
        )