"""Agent loop: the core processing engine."""

import asyncio
from contextlib import AsyncExitStack
import json
import json_repair
from pathlib import Path
import re
from typing import Any, Awaitable, Callable

from loguru import logger

from nanobot.bus.events import InboundMessage, OutboundMessage
from nanobot.bus.queue import MessageBus
from nanobot.providers.base import LLMProvider
from nanobot.agent.context import ContextBuilder
from nanobot.agent.tools.registry import ToolRegistry
from nanobot.agent.tools.filesystem import ReadFileTool, WriteFileTool, EditFileTool, ListDirTool
from nanobot.agent.tools.shell import ExecTool
from nanobot.agent.tools.web import WebSearchTool, WebFetchTool
from nanobot.agent.tools.message import MessageTool
from nanobot.agent.tools.spawn import SpawnTool
from nanobot.agent.tools.cron import CronTool
from nanobot.agent.memory import MemoryStore
from nanobot.agent.subagent import SubagentManager
from nanobot.session.manager import Session, SessionManager


class AgentLoop:
    """
    The agent loop is the core processing engine.

    It:
    1. Receives messages from the bus
    2. Builds context with history, memory, skills
    3. Calls the LLM
    4. Executes tool calls
    5. Sends responses back
    """

    def __init__(
        self,
        bus: MessageBus,
        provider: LLMProvider,
        workspace: Path,
        model: str | None = None,
        max_iterations: int = 20,
        temperature: float = 0.7,
        max_tokens: int = 4096,
        memory_window: int = 50,
        brave_api_key: str | None = None,
        exec_config: "ExecToolConfig | None" = None,
        cron_service: "CronService | None" = None,
        restrict_to_workspace: bool = False,
        session_manager: SessionManager | None = None,
        mcp_servers: dict | None = None,
    ):
        from nanobot.config.schema import ExecToolConfig
        from nanobot.cron.service import CronService
        self.bus = bus
        self.provider = provider
        self.workspace = workspace
        self.model = model or provider.get_default_model()
        self.max_iterations = max_iterations
        self.temperature = temperature
        self.max_tokens = max_tokens
        self.memory_window = memory_window
        self.brave_api_key = brave_api_key
        self.exec_config = exec_config or ExecToolConfig()
        self.cron_service = cron_service
        self.restrict_to_workspace = restrict_to_workspace

        self.context = ContextBuilder(workspace)
        self.sessions = session_manager or SessionManager(workspace)
        self.tools = ToolRegistry()
        self.subagents = SubagentManager(
            provider=provider,
            workspace=workspace,
            bus=bus,
            model=self.model,
            temperature=self.temperature,
            max_tokens=self.max_tokens,
            brave_api_key=brave_api_key,
            exec_config=self.exec_config,
            restrict_to_workspace=restrict_to_workspace,
        )
        
        self._running = False
        self._mcp_servers = mcp_servers or {}
        self._mcp_stack: AsyncExitStack | None = None
        self._mcp_connected = False
        self._consolidating: set[str] = set()  # Session keys with consolidation in progress
        self._register_default_tools()
    
    def _register_default_tools(self) -> None:
        """Register the default set of tools."""
        # File tools (workspace for relative paths, restrict if configured)
        allowed_dir = self.workspace if self.restrict_to_workspace else None
        self.tools.register(ReadFileTool(workspace=self.workspace, allowed_dir=allowed_dir))
        self.tools.register(WriteFileTool(workspace=self.workspace, allowed_dir=allowed_dir))
        self.tools.register(EditFileTool(workspace=self.workspace, allowed_dir=allowed_dir))
        self.tools.register(ListDirTool(workspace=self.workspace, allowed_dir=allowed_dir))
        
        # Shell tool
        self.tools.register(ExecTool(
            working_dir=str(self.workspace),
            timeout=self.exec_config.timeout,
            restrict_to_workspace=self.restrict_to_workspace,
        ))
        
        # Web tools
        self.tools.register(WebSearchTool(api_key=self.brave_api_key))
        self.tools.register(WebFetchTool())
        
        # Message tool
        message_tool = MessageTool(send_callback=self.bus.publish_outbound)
        self.tools.register(message_tool)
        
        # Spawn tool (for subagents)
        spawn_tool = SpawnTool(manager=self.subagents)
        self.tools.register(spawn_tool)
        
        # Cron tool (for scheduling)
        if self.cron_service:
            self.tools.register(CronTool(self.cron_service))
    
    async def _connect_mcp(self) -> None:
        """Connect to configured MCP servers (one-time, lazy)."""
        if self._mcp_connected or not self._mcp_servers:
            return
        self._mcp_connected = True
        from nanobot.agent.tools.mcp import connect_mcp_servers
        self._mcp_stack = AsyncExitStack()
        await self._mcp_stack.__aenter__()
        await connect_mcp_servers(self._mcp_servers, self.tools, self._mcp_stack)

    def _set_tool_context(self, channel: str, chat_id: str, message_id: str | None = None) -> None:
        """Update context for all tools that need routing info."""
        if message_tool := self.tools.get("message"):
            if isinstance(message_tool, MessageTool):
                message_tool.set_context(channel, chat_id, message_id)

        if spawn_tool := self.tools.get("spawn"):
            if isinstance(spawn_tool, SpawnTool):
                spawn_tool.set_context(channel, chat_id)

        if cron_tool := self.tools.get("cron"):
            if isinstance(cron_tool, CronTool):
                cron_tool.set_context(channel, chat_id)

    @staticmethod
    def _strip_think(text: str | None) -> str | None:
        """Remove <think>…</think> blocks that some models embed in content."""
        if not text:
            return None
        return re.sub(r"<think>[\s\S]*?</think>", "", text).strip() or None

    @staticmethod
    def _tool_hint(tool_calls: list) -> str:
        """Format tool calls as concise hint, e.g. 'web_search("query")'."""
        def _fmt(tc):
            val = next(iter(tc.arguments.values()), None) if tc.arguments else None
            if not isinstance(val, str):
                return tc.name
            return f'{tc.name}("{val[:40]}…")' if len(val) > 40 else f'{tc.name}("{val}")'
        return ", ".join(_fmt(tc) for tc in tool_calls)

    async def _run_agent_loop(
        self,
        initial_messages: list[dict],
        on_progress: Callable[[str], Awaitable[None]] | None = None,
    ) -> tuple[str | None, list[str]]:
        """
        Run the agent iteration loop.

        Args:
            initial_messages: Starting messages for the LLM conversation.
            on_progress: Optional callback to push intermediate content to the user.

        Returns:
            Tuple of (final_content, list_of_tools_used).
        """
        messages = initial_messages
        iteration = 0
        final_content = None
        tools_used: list[str] = []
        text_only_retried = False

        while iteration < self.max_iterations:
            iteration += 1

            response = await self.provider.chat(
                messages=messages,
                tools=self.tools.get_definitions(),
                model=self.model,
                temperature=self.temperature,
                max_tokens=self.max_tokens,
            )

            if response.has_tool_calls:
                if on_progress:
                    clean = self._strip_think(response.content)
                    await on_progress(clean or self._tool_hint(response.tool_calls))

                tool_call_dicts = [
                    {
                        "id": tc.id,
                        "type": "function",
                        "function": {
                            "name": tc.name,
                            "arguments": json.dumps(tc.arguments, ensure_ascii=False)
                        }
                    }
                    for tc in response.tool_calls
                ]
                messages = self.context.add_assistant_message(
                    messages, response.content, tool_call_dicts,
                    reasoning_content=response.reasoning_content,
                )

                for tool_call in response.tool_calls:
                    tools_used.append(tool_call.name)
                    args_str = json.dumps(tool_call.arguments, ensure_ascii=False)
                    logger.info("Tool call: {}({})", tool_call.name, args_str[:200])
                    result = await self.tools.execute(tool_call.name, tool_call.arguments)
                    messages = self.context.add_tool_result(
                        messages, tool_call.id, tool_call.name, result
                    )
            else:
                final_content = self._strip_think(response.content)
                # Some models send an interim text response before tool calls.
                # Give them one retry; don't forward the text to avoid duplicates.
                if not tools_used and not text_only_retried and final_content:
                    text_only_retried = True
                    logger.debug("Interim text response (no tools used yet), retrying: {}", final_content[:80])
                    messages = self.context.add_assistant_message(
                        messages, response.content,
                        reasoning_content=response.reasoning_content,
                    )
                    final_content = None
                    continue
                break

        return final_content, tools_used

    async def run(self) -> None:
        """Run the agent loop, processing messages from the bus."""
        self._running = True
        await self._connect_mcp()
        logger.info("Agent loop started")

        while self._running:
            try:
                msg = await asyncio.wait_for(
                    self.bus.consume_inbound(),
                    timeout=1.0
                )
                try:
                    response = await self._process_message(msg)
                    if response:
                        await self.bus.publish_outbound(response)
                except Exception as e:
                    logger.error("Error processing message: {}", e)
                    await self.bus.publish_outbound(OutboundMessage(
                        channel=msg.channel,
                        chat_id=msg.chat_id,
                        content=f"Sorry, I encountered an error: {str(e)}"
                    ))
            except asyncio.TimeoutError:
                continue
    
    async def close_mcp(self) -> None:
        """Close MCP connections."""
        if self._mcp_stack:
            try:
                await self._mcp_stack.aclose()
            except (RuntimeError, BaseExceptionGroup):
                pass  # MCP SDK cancel scope cleanup is noisy but harmless
            self._mcp_stack = None

    def stop(self) -> None:
        """Stop the agent loop."""
        self._running = False
        logger.info("Agent loop stopping")
    
    async def _process_message(
        self,
        msg: InboundMessage,
        session_key: str | None = None,
        on_progress: Callable[[str], Awaitable[None]] | None = None,
    ) -> OutboundMessage | None:
        """
        Process a single inbound message.
        
        Args:
            msg: The inbound message to process.
            session_key: Override session key (used by process_direct).
            on_progress: Optional callback for intermediate output (defaults to bus publish).
        
        Returns:
            The response message, or None if no response needed.
        """
        # System messages route back via chat_id ("channel:chat_id")
        if msg.channel == "system":
            return await self._process_system_message(msg)
        
        preview = msg.content[:80] + "..." if len(msg.content) > 80 else msg.content
        logger.info("Processing message from {}:{}: {}", msg.channel, msg.sender_id, preview)
        
        key = session_key or msg.session_key
        session = self.sessions.get_or_create(key)
        
        # Handle slash commands
        cmd = msg.content.strip().lower()
        if cmd == "/new":
            # Capture messages before clearing (avoid race condition with background task)
            messages_to_archive = session.messages.copy()
            session.clear()
            self.sessions.save(session)
            self.sessions.invalidate(session.key)

            async def _consolidate_and_cleanup():
                temp_session = Session(key=session.key)
                temp_session.messages = messages_to_archive
                await self._consolidate_memory(temp_session, archive_all=True)

            asyncio.create_task(_consolidate_and_cleanup())
            return OutboundMessage(channel=msg.channel, chat_id=msg.chat_id,
                                  content="New session started. Memory consolidation in progress.")
        if cmd == "/help":
            return OutboundMessage(channel=msg.channel, chat_id=msg.chat_id,
                                  content="🐈 nanobot commands:\n/new — Start a new conversation\n/help — Show available commands")
        
        if len(session.messages) > self.memory_window and session.key not in self._consolidating:
            self._consolidating.add(session.key)

            async def _consolidate_and_unlock():
                try:
                    await self._consolidate_memory(session)
                finally:
                    self._consolidating.discard(session.key)

            asyncio.create_task(_consolidate_and_unlock())

        self._set_tool_context(msg.channel, msg.chat_id, msg.metadata.get("message_id"))
        initial_messages = self.context.build_messages(
            history=session.get_history(max_messages=self.memory_window),
            current_message=msg.content,
            media=msg.media if msg.media else None,
            channel=msg.channel,
            chat_id=msg.chat_id,
        )

        async def _bus_progress(content: str) -> None:
            await self.bus.publish_outbound(OutboundMessage(
                channel=msg.channel, chat_id=msg.chat_id, content=content,
                metadata=msg.metadata or {},
            ))

        final_content, tools_used = await self._run_agent_loop(
            initial_messages, on_progress=on_progress or _bus_progress,
        )

        if final_content is None:
            final_content = "I've completed processing but have no response to give."
        
        preview = final_content[:120] + "..." if len(final_content) > 120 else final_content
        logger.info("Response to {}:{}: {}", msg.channel, msg.sender_id, preview)
        
        session.add_message("user", msg.content)
        session.add_message("assistant", final_content,
                            tools_used=tools_used if tools_used else None)
        self.sessions.save(session)
        
        return OutboundMessage(
            channel=msg.channel,
            chat_id=msg.chat_id,
            content=final_content,
            metadata=msg.metadata or {},  # Pass through for channel-specific needs (e.g. Slack thread_ts)
        )
    
    async def _process_system_message(self, msg: InboundMessage) -> OutboundMessage | None:
        """
        Process a system message (e.g., subagent announce).
        
        The chat_id field contains "original_channel:original_chat_id" to route
        the response back to the correct destination.
        """
        logger.info("Processing system message from {}", msg.sender_id)
        
        # Parse origin from chat_id (format: "channel:chat_id")
        if ":" in msg.chat_id:
            parts = msg.chat_id.split(":", 1)
            origin_channel = parts[0]
            origin_chat_id = parts[1]
        else:
            # Fallback
            origin_channel = "cli"
            origin_chat_id = msg.chat_id
        
        session_key = f"{origin_channel}:{origin_chat_id}"
        session = self.sessions.get_or_create(session_key)
        self._set_tool_context(origin_channel, origin_chat_id, msg.metadata.get("message_id"))
        initial_messages = self.context.build_messages(
            history=session.get_history(max_messages=self.memory_window),
            current_message=msg.content,
            channel=origin_channel,
            chat_id=origin_chat_id,
        )
        final_content, _ = await self._run_agent_loop(initial_messages)

        if final_content is None:
            final_content = "Background task completed."
        
        session.add_message("user", f"[System: {msg.sender_id}] {msg.content}")
        session.add_message("assistant", final_content)
        self.sessions.save(session)
        
        return OutboundMessage(
            channel=origin_channel,
            chat_id=origin_chat_id,
            content=final_content
        )
    
    async def _consolidate_memory(self, session, archive_all: bool = False) -> None:
        """Consolidate old messages into MEMORY.md + HISTORY.md.

        Args:
            archive_all: If True, clear all messages and reset session (for /new command).
                       If False, only write to files without modifying session.
        """
        memory = MemoryStore(self.workspace)

        if archive_all:
            old_messages = session.messages
            keep_count = 0
            logger.info("Memory consolidation (archive_all): {} total messages archived", len(session.messages))
        else:
            keep_count = self.memory_window // 2
            if len(session.messages) <= keep_count:
                logger.debug("Session {}: No consolidation needed (messages={}, keep={})", session.key, len(session.messages), keep_count)
                return

            messages_to_process = len(session.messages) - session.last_consolidated
            if messages_to_process <= 0:
                logger.debug("Session {}: No new messages to consolidate (last_consolidated={}, total={})", session.key, session.last_consolidated, len(session.messages))
                return

            old_messages = session.messages[session.last_consolidated:-keep_count]
            if not old_messages:
                return
            logger.info("Memory consolidation started: {} total, {} new to consolidate, {} keep", len(session.messages), len(old_messages), keep_count)

        lines = []
        for m in old_messages:
            if not m.get("content"):
                continue
            tools = f" [tools: {', '.join(m['tools_used'])}]" if m.get("tools_used") else ""
            lines.append(f"[{m.get('timestamp', '?')[:16]}] {m['role'].upper()}{tools}: {m['content']}")
        conversation = "\n".join(lines)
        current_memory = memory.read_long_term()

        prompt = f"""You are a memory consolidation agent. Process this conversation and return a JSON object with exactly two keys:

1. "history_entry": A paragraph (2-5 sentences) summarizing the key events/decisions/topics. Start with a timestamp like [YYYY-MM-DD HH:MM]. Include enough detail to be useful when found by grep search later.

2. "memory_update": The updated long-term memory content. Add any new facts: user location, preferences, personal info, habits, project context, technical decisions, tools/services used. If nothing new, return the existing content unchanged.

## Current Long-term Memory
{current_memory or "(empty)"}

## Conversation to Process
{conversation}

**IMPORTANT**: Both values MUST be strings, not objects or arrays.

Example:
{{
  "history_entry": "[2026-02-14 22:50] User asked about...",
  "memory_update": "- Host: HARRYBOOK-T14P\n- Name: Nado"
}}

Respond with ONLY valid JSON, no markdown fences."""

        try:
            response = await self.provider.chat(
                messages=[
                    {"role": "system", "content": "You are a memory consolidation agent. Respond only with valid JSON."},
                    {"role": "user", "content": prompt},
                ],
                model=self.model,
            )
            text = (response.content or "").strip()
            if not text:
                logger.warning("Memory consolidation: LLM returned empty response, skipping")
                return
            if text.startswith("```"):
                text = text.split("\n", 1)[-1].rsplit("```", 1)[0].strip()
            result = json_repair.loads(text)
            if not isinstance(result, dict):
                logger.warning("Memory consolidation: unexpected response type, skipping. Response: {}", text[:200])
                return

            if entry := result.get("history_entry"):
                # Defensive: ensure entry is a string (LLM may return dict)
                if not isinstance(entry, str):
                    entry = json.dumps(entry, ensure_ascii=False)
                memory.append_history(entry)
            if update := result.get("memory_update"):
                # Defensive: ensure update is a string
                if not isinstance(update, str):
                    update = json.dumps(update, ensure_ascii=False)
                if update != current_memory:
                    memory.write_long_term(update)

            if archive_all:
                session.last_consolidated = 0
            else:
                session.last_consolidated = len(session.messages) - keep_count
            logger.info("Memory consolidation done: {} messages, last_consolidated={}", len(session.messages), session.last_consolidated)
        except Exception as e:
            logger.error("Memory consolidation failed: {}", e)

    async def process_direct(
        self,
        content: str,
        session_key: str = "cli:direct",
        channel: str = "cli",
        chat_id: str = "direct",
        on_progress: Callable[[str], Awaitable[None]] | None = None,
    ) -> str:
        """
        Process a message directly (for CLI or cron usage).
        
        Args:
            content: The message content.
            session_key: Session identifier (overrides channel:chat_id for session lookup).
            channel: Source channel (for tool context routing).
            chat_id: Source chat ID (for tool context routing).
            on_progress: Optional callback for intermediate output.
        
        Returns:
            The agent's response.
        """
        await self._connect_mcp()
        msg = InboundMessage(
            channel=channel,
            sender_id="user",
            chat_id=chat_id,
            content=content
        )
        
        response = await self._process_message(msg, session_key=session_key, on_progress=on_progress)
        return response.content if response else ""