from __future__ import annotations

from typing import Any

from django.db.models import Q
from django.utils import timezone

from core.memory.search_backend import get_memory_search_backend
from core.models import MemoryItem


def _coerce_statuses(value: Any, default: tuple[str, ...]) -> tuple[str, ...]:
    if isinstance(value, (list, tuple, set)):
        items = [str(item or "").strip().lower() for item in value]
    else:
        items = [item.strip().lower() for item in str(value or "").split(",")]
    cleaned = tuple(item for item in items if item)
    return cleaned or default


def _base_queryset(
    *,
    user_id: int,
    person_id: str = "",
    conversation_id: str = "",
    statuses: tuple[str, ...] = ("active",),
):
    now = timezone.now()
    queryset = MemoryItem.objects.filter(user_id=int(user_id))
    if statuses:
        queryset = queryset.filter(status__in=list(statuses))
    queryset = queryset.filter(Q(expires_at__isnull=True) | Q(expires_at__gt=now))
    if person_id:
        queryset = queryset.filter(person_id=person_id)
    if conversation_id:
        queryset = queryset.filter(conversation_id=conversation_id)
    return queryset


def retrieve_memories_for_prompt(
    *,
    user_id: int,
    query: str = "",
    person_id: str = "",
    conversation_id: str = "",
    statuses: tuple[str, ...] = ("active",),
    limit: int = 20,
) -> list[dict[str, Any]]:
    statuses = _coerce_statuses(statuses, ("active",))
    safe_limit = max(1, min(200, int(limit or 20)))
    search_text = str(query or "").strip()

    if search_text:
        backend = get_memory_search_backend()
        hits = backend.search(
            user_id=int(user_id),
            query=search_text,
            conversation_id=conversation_id,
            limit=safe_limit,
            include_statuses=statuses,
        )
        ids = [
            str(hit.memory_id or "").strip()
            for hit in hits
            if str(hit.memory_id or "").strip()
        ]
        scoped = _base_queryset(
            user_id=int(user_id),
            person_id=person_id,
            conversation_id=conversation_id,
            statuses=statuses,
        ).filter(id__in=ids)
        by_id = {str(item.id): item for item in scoped}
        rows = []
        for hit in hits:
            item = by_id.get(str(hit.memory_id))
            if not item:
                continue
            rows.append(
                {
                    "id": str(item.id),
                    "memory_kind": str(item.memory_kind or ""),
                    "status": str(item.status or ""),
                    "person_id": str(item.person_id or ""),
                    "conversation_id": str(item.conversation_id or ""),
                    "content": item.content or {},
                    "provenance": item.provenance or {},
                    "confidence_score": float(item.confidence_score or 0.0),
                    "expires_at": (
                        item.expires_at.isoformat() if item.expires_at else ""
                    ),
                    "last_verified_at": (
                        item.last_verified_at.isoformat()
                        if item.last_verified_at
                        else ""
                    ),
                    "updated_at": (
                        item.updated_at.isoformat() if item.updated_at else ""
                    ),
                    "search_score": float(hit.score or 0.0),
                    "search_summary": str(hit.summary or ""),
                }
            )
        return rows

    queryset = _base_queryset(
        user_id=int(user_id),
        person_id=person_id,
        conversation_id=conversation_id,
        statuses=statuses,
    ).order_by("-last_verified_at", "-updated_at")
    rows = []
    for item in queryset[:safe_limit]:
        rows.append(
            {
                "id": str(item.id),
                "memory_kind": str(item.memory_kind or ""),
                "status": str(item.status or ""),
                "person_id": str(item.person_id or ""),
                "conversation_id": str(item.conversation_id or ""),
                "content": item.content or {},
                "provenance": item.provenance or {},
                "confidence_score": float(item.confidence_score or 0.0),
                "expires_at": item.expires_at.isoformat() if item.expires_at else "",
                "last_verified_at": (
                    item.last_verified_at.isoformat() if item.last_verified_at else ""
                ),
                "updated_at": item.updated_at.isoformat() if item.updated_at else "",
                "search_score": 0.0,
                "search_summary": "",
            }
        )
    return rows