"""Agent memory facade — unified API for persistent agent memory.

Delegates to the ``agent_memory`` plugin (pgvector semantic search) and
provides the canonical function signatures used by the agent framework
(``store_agent_memory``, ``retrieve_agent_memory``, ``search_agent_memory``).

Used by:
- ``app/ai/agent_loop.py`` — memory retrieval during ReAct loops
- ``app/plugins/builtins/automation`` — agent memory tools
"""

from __future__ import annotations

import logging
import uuid
from typing import Any

from sqlalchemy.ext.asyncio import AsyncSession

logger = logging.getLogger(__name__)

# Memory types supported by the agent memory system.
MEMORY_TYPES = ("observation", "preference", "fact", "context")


def _memory_type(value: str | None) -> str:
    """Normalize a memory type to a supported value."""
    if value in MEMORY_TYPES:
        return value
    return "fact"


async def store_agent_memory(
    db: AsyncSession,
    tenant_id: uuid.UUID,
    agent_id: uuid.UUID,
    memory_type: str,
    content: str,
    metadata: dict[str, Any] | None = None,
) -> uuid.UUID:
    """Store a new agent memory with semantic embedding.

    Args:
        db: Database session.
        tenant_id: Tenant UUID.
        agent_id: Agent UUID.
        memory_type: One of ``observation``, ``preference``, ``fact``, ``context``.
        content: Memory content text.
        metadata: Optional metadata dict (stored as JSONB on the memory row).

    Returns:
        The UUID of the created memory.
    """
    from app.plugins.builtins.agent_memory.services import store_memory

    result = await store_memory(
        db=db,
        tenant_id=tenant_id,
        agent_id=agent_id,
        content=content,
        memory_type=_memory_type(memory_type),
    )
    memory_id = uuid.UUID(result["id"])

    # Persist optional metadata on the memory row.
    if metadata:
        from sqlalchemy import update

        from app.plugins.builtins.agent_memory.models import AgentMemory

        await db.execute(
            update(AgentMemory)
            .where(AgentMemory.id == memory_id)
            .values(metadata_=metadata)
        )
        await db.flush()

    return memory_id


async def retrieve_agent_memory(
    db: AsyncSession,
    tenant_id: uuid.UUID,
    agent_id: uuid.UUID,
    memory_type: str | None = None,
    limit: int = 10,
) -> list[dict[str, Any]]:
    """Retrieve recent memories for an agent, optionally filtered by type.

    Args:
        db: Database session.
        tenant_id: Tenant UUID.
        agent_id: Agent UUID.
        memory_type: Optional memory type filter.
        limit: Maximum number of results (default 10).

    Returns:
        List of memory dicts, newest first.
    """
    from sqlalchemy import select

    from app.plugins.builtins.agent_memory.models import AgentMemory

    stmt = (
        select(AgentMemory)
        .where(
            AgentMemory.tenant_id == tenant_id,
            AgentMemory.agent_id == agent_id,
            AgentMemory.deleted_at.is_(None),
        )
        .order_by(AgentMemory.created_at.desc())
        .limit(limit)
    )
    if memory_type:
        stmt = stmt.where(AgentMemory.memory_type == _memory_type(memory_type))

    result = await db.execute(stmt)
    memories = result.scalars().all()
    return [
        {
            "id": str(m.id),
            "agent_id": str(m.agent_id),
            "memory_type": m.memory_type,
            "content": m.content,
            "metadata": getattr(m, "metadata_", None) or {},
            "created_at": m.created_at.isoformat() if m.created_at else None,
        }
        for m in memories
    ]


async def search_agent_memory(
    db: AsyncSession,
    tenant_id: uuid.UUID,
    agent_id: uuid.UUID,
    query: str,
    limit: int = 5,
) -> list[dict[str, Any]]:
    """Semantic search over agent memories using pgvector embeddings.

    Falls back to recent-memory retrieval when embedding generation is
    unavailable (e.g. no embedding model configured).

    Args:
        db: Database session.
        tenant_id: Tenant UUID.
        agent_id: Agent UUID.
        query: Natural language query.
        limit: Maximum number of results (default 5).

    Returns:
        List of memory dicts with similarity scores, sorted by relevance.
    """
    from app.plugins.builtins.agent_memory.services import retrieve_relevant_memories

    return await retrieve_relevant_memories(
        db=db,
        tenant_id=tenant_id,
        agent_id=agent_id,
        query=query,
        limit=limit,
        min_score=0.0,
    )


def register_agent_memory_tools(registry) -> None:
    """Register agent memory tools in the global ToolRegistry.

    Registers ``search_agent_memory`` so AI agents can query their own
    persistent memory during ReAct loops.
    """
    import json

    async def search_agent_memory_handler(
        arguments: dict[str, Any], context: dict[str, Any]
    ) -> str:
        """Handle search_agent_memory tool call from an AI agent."""
        from app.core.db import get_session_factory

        query = arguments.get("query", "")
        limit = arguments.get("limit", 5)
        agent_id_str = context.get("agent_id", "")
        tenant_id_str = context.get("tenant_id", "")

        if not query:
            return json.dumps({"error": "Missing query"})
        try:
            tenant_id = uuid.UUID(tenant_id_str) if tenant_id_str else uuid.uuid4()
            agent_id = uuid.UUID(agent_id_str) if agent_id_str else uuid.uuid4()
        except (ValueError, TypeError):
            return json.dumps({"error": "Invalid tenant_id or agent_id"})

        factory = get_session_factory()
        async with factory() as db:
            results = await search_agent_memory(
                db=db,
                tenant_id=tenant_id,
                agent_id=agent_id,
                query=query,
                limit=limit,
            )
        return json.dumps({"memories": results, "count": len(results)}, default=str)

    registry.register(
        name="search_agent_memory",
        description=(
            "Semantische Suche über das persistente Gedächtnis eines Agents. "
            "Findet relevante frühere Beobachtungen, Fakten und Präferenzen."
        ),
        parameters={
            "type": "object",
            "properties": {
                "query": {
                    "type": "string",
                    "description": "Natürlichsprachliche Suchanfrage",
                },
                "limit": {
                    "type": "integer",
                    "default": 5,
                    "description": "Maximale Anzahl Ergebnisse",
                },
            },
            "required": ["query"],
        },
        handler=search_agent_memory_handler,
        plugin_name="agent_memory",
        required_permission="agent_memory:read",
        category="memory",
    )
    logger.info("Agent memory tool 'search_agent_memory' registered")


def unregister_agent_memory_tools(registry) -> None:
    """Unregister agent memory tools from the global ToolRegistry."""
    registry.unregister("search_agent_memory")
    logger.info("Agent memory tool 'search_agent_memory' unregistered")