"""
Multi-agent coordination engine.

Orchestrates delegation from Tatlock to expert agents (Librarian, etc.)
based on Steward recommendations. Handles:
- Routing tasks to appropriate agents
- Parallel and sequential execution
- Result aggregation
- Error handling and graceful degradation
"""
import asyncio
import time
from typing import Any, AsyncGenerator, Optional

from src.agents.librarian import run_librarian, run_librarian_stream
from src.agents.protocol import (
    AgentError,
    AgentRequest,
    AgentResponse,
    AgentTimeoutError,
    AgentUnavailableError,
    CoordinationResult,
    DelegationIntent,
    DelegationReason,
    ToolCallRecord,
)
from src.core.household_registry import get_household_registry
from src.core.logging_config import get_logger

logger = get_logger(__name__)


# Agent execution functions registry
AGENT_EXECUTORS: dict[str, Any] = {
    "librarian": run_librarian,
}

AGENT_STREAM_EXECUTORS: dict[str, Any] = {
    "librarian": run_librarian_stream,
}


class CoordinationEngine:
    """
    Coordinates multi-agent task execution.

    Routes tasks from Tatlock to appropriate expert agents,
    handles execution, and aggregates results.
    """

    def __init__(self):
        """Initialize the coordination engine."""
        self.registry = get_household_registry()
        logger.info("coordination_engine_initialized")

    def get_available_agents(self) -> list[str]:
        """
        Get list of available expert agents.

        Returns:
            List of agent names that can accept delegations
        """
        available = []
        for name in self.registry.list_members():
            member = self.registry.get_member(name)
            if member and member.agent is not None:
                available.append(name)
        return available

    def can_delegate_to(self, agent_name: str) -> bool:
        """
        Check if delegation to an agent is possible.

        Args:
            agent_name: Name of the target agent

        Returns:
            True if agent is available and can accept tasks
        """
        if agent_name not in AGENT_EXECUTORS:
            return False

        member = self.registry.get_member(agent_name)
        return member is not None and member.agent is not None

    async def execute_delegation(
        self,
        intent: DelegationIntent,
        context: str = "",
        message_history: Optional[list[Any]] = None,
    ) -> AgentResponse:
        """
        Execute a single delegation to an expert agent.

        Args:
            intent: The delegation intent with task details
            context: Additional context for the agent
            message_history: Optional conversation history

        Returns:
            AgentResponse with results

        Raises:
            AgentUnavailableError: If agent is not available
            AgentTimeoutError: If execution times out
            AgentError: For other execution errors
        """
        start_time = time.time()
        agent_name = intent.target_agent

        logger.info(
            "delegation_started",
            agent=agent_name,
            task=intent.task[:100],
            reason=intent.reason.value,
        )

        # Check if agent is available
        if not self.can_delegate_to(agent_name):
            raise AgentUnavailableError(
                f"Agent '{agent_name}' is not available for delegation",
                agent_name=agent_name,
            )

        # Get the executor
        executor = AGENT_EXECUTORS.get(agent_name)
        if not executor:
            raise AgentUnavailableError(
                f"No executor found for agent '{agent_name}'",
                agent_name=agent_name,
            )

        try:
            # Build the request
            request = AgentRequest(
                task=intent.task,
                context=context,
                delegation_reason=intent.reason,
            )

            # Execute with timeout
            timeout = request.timeout_seconds or 60

            result = await asyncio.wait_for(
                executor(
                    task=request.task,
                    context=request.context,
                    message_history=message_history,
                ),
                timeout=timeout,
            )

            duration_ms = int((time.time() - start_time) * 1000)

            logger.info(
                "delegation_completed",
                agent=agent_name,
                duration_ms=duration_ms,
                output_length=len(result),
            )

            return AgentResponse(
                success=True,
                result=result,
                reasoning=f"Delegated to {agent_name}: {intent.expected_outcome}",
                duration_ms=duration_ms,
            )

        except asyncio.TimeoutError:
            duration_ms = int((time.time() - start_time) * 1000)
            logger.error(
                "delegation_timeout",
                agent=agent_name,
                duration_ms=duration_ms,
            )
            raise AgentTimeoutError(
                f"Agent '{agent_name}' timed out after {duration_ms}ms",
                agent_name=agent_name,
            )

        except Exception as e:
            duration_ms = int((time.time() - start_time) * 1000)
            logger.error(
                "delegation_error",
                agent=agent_name,
                error=str(e),
                duration_ms=duration_ms,
                exc_info=True,
            )
            return AgentResponse(
                success=False,
                result="",
                error_message=str(e),
                duration_ms=duration_ms,
            )

    async def execute_delegation_stream(
        self,
        intent: DelegationIntent,
        context: str = "",
        message_history: Optional[list[Any]] = None,
    ) -> AsyncGenerator[str, None]:
        """
        Execute a delegation with streaming output.

        Args:
            intent: The delegation intent with task details
            context: Additional context for the agent
            message_history: Optional conversation history

        Yields:
            Text deltas from the agent

        Raises:
            AgentUnavailableError: If agent is not available
        """
        agent_name = intent.target_agent

        logger.info(
            "delegation_stream_started",
            agent=agent_name,
            task=intent.task[:100],
        )

        # Check if agent is available
        if agent_name not in AGENT_STREAM_EXECUTORS:
            raise AgentUnavailableError(
                f"Agent '{agent_name}' does not support streaming",
                agent_name=agent_name,
            )

        executor = AGENT_STREAM_EXECUTORS[agent_name]

        try:
            async for delta in executor(
                task=intent.task,
                context=context,
                message_history=message_history,
            ):
                yield delta

            logger.info("delegation_stream_completed", agent=agent_name)

        except Exception as e:
            logger.error(
                "delegation_stream_error",
                agent=agent_name,
                error=str(e),
                exc_info=True,
            )
            yield f"\n\n[Error from {agent_name}: {str(e)}]"

    async def coordinate(
        self,
        intents: list[DelegationIntent],
        context: str = "",
        message_history: Optional[list[Any]] = None,
    ) -> CoordinationResult:
        """
        Coordinate execution of multiple delegations.

        Handles parallel execution for independent tasks and
        sequential execution for dependent tasks.

        Args:
            intents: List of delegation intents to execute
            context: Shared context for all agents
            message_history: Optional conversation history

        Returns:
            CoordinationResult with aggregated results
        """
        start_time = time.time()
        agent_responses: dict[str, AgentResponse] = {}
        agents_consulted: list[str] = []

        logger.info(
            "coordination_started",
            intent_count=len(intents),
            agents=[i.target_agent for i in intents],
        )

        # Sort by priority
        sorted_intents = sorted(intents, key=lambda x: x.priority)

        # Group by dependencies (simple version: sequential for now)
        # TODO: Implement parallel execution for independent tasks
        for intent in sorted_intents:
            try:
                response = await self.execute_delegation(
                    intent=intent,
                    context=context,
                    message_history=message_history,
                )
                agent_responses[intent.target_agent] = response
                if response.success:
                    agents_consulted.append(intent.target_agent)

            except AgentError as e:
                agent_responses[intent.target_agent] = AgentResponse(
                    success=False,
                    result="",
                    error_message=str(e),
                )

        # Aggregate results
        successful_results = [
            r.result for r in agent_responses.values() if r.success and r.result
        ]

        final_response = "\n\n---\n\n".join(successful_results) if successful_results else ""

        total_duration = int((time.time() - start_time) * 1000)

        logger.info(
            "coordination_completed",
            total_duration_ms=total_duration,
            agents_consulted=agents_consulted,
            success_count=len(successful_results),
        )

        return CoordinationResult(
            final_response=final_response,
            agent_responses=agent_responses,
            delegation_intents=intents,
            total_duration_ms=total_duration,
            agents_consulted=agents_consulted,
        )


# Global coordination engine instance
_coordination_engine: Optional[CoordinationEngine] = None


def get_coordination_engine() -> CoordinationEngine:
    """Get the global coordination engine instance."""
    global _coordination_engine
    if _coordination_engine is None:
        _coordination_engine = CoordinationEngine()
    return _coordination_engine


async def delegate_to_librarian(
    task: str,
    context: str = "",
    reason: DelegationReason = DelegationReason.DOMAIN_EXPERTISE,
    message_history: Optional[list[Any]] = None,
) -> AgentResponse:
    """
    Convenience function to delegate a task to The Librarian.

    Args:
        task: Research task description
        context: Additional context
        reason: Why delegating to Librarian
        message_history: Optional conversation history

    Returns:
        AgentResponse with research results
    """
    engine = get_coordination_engine()

    intent = DelegationIntent(
        target_agent="librarian",
        task=task,
        reason=reason,
        expected_outcome="Research findings and relevant information",
    )

    return await engine.execute_delegation(
        intent=intent,
        context=context,
        message_history=message_history,
    )


async def delegate_to_librarian_stream(
    task: str,
    context: str = "",
    message_history: Optional[list[Any]] = None,
) -> AsyncGenerator[str, None]:
    """
    Convenience function to delegate to Librarian with streaming.

    Args:
        task: Research task description
        context: Additional context
        message_history: Optional conversation history

    Yields:
        Text deltas from The Librarian
    """
    engine = get_coordination_engine()

    intent = DelegationIntent(
        target_agent="librarian",
        task=task,
        reason=DelegationReason.DOMAIN_EXPERTISE,
        expected_outcome="Research findings",
    )

    async for delta in engine.execute_delegation_stream(
        intent=intent,
        context=context,
        message_history=message_history,
    ):
        yield delta