"""CatalogReader — loads + filters catalog by source_hint.

For typical users (≤50 tables), returns the FULL catalog with no slicing.
Catalog-level search is added later if catalog grows past the limit.
"""

from datetime import UTC, datetime
from typing import Literal

from src.middlewares.logging import get_logger

from .models import Catalog, Source
from .store import CatalogStore

logger = get_logger("catalog_reader")

SourceHint = Literal["chat", "unstructured", "structured"]


def _filter_sources(catalog: Catalog, source_hint: SourceHint) -> Catalog:
    """Return a copy of `catalog` keeping only the sources matching `source_hint`."""
    filtered: list[Source]
    if source_hint == "chat":
        filtered = []
    elif source_hint == "structured":
        filtered = [s for s in catalog.sources if s.source_type in {"schema", "tabular"}]
    else:  # "unstructured"
        filtered = [s for s in catalog.sources if s.source_type == "unstructured"]
    return catalog.model_copy(update={"sources": filtered})


class CatalogReader:
    """Loads the user's catalog and filters by source_hint.

    On miss, returns an empty Catalog (never raises) — query path is
    responsible for handling "no data registered yet" gracefully.
    Returned Catalog is always a copy; the underlying stored catalog
    is never mutated.
    """

    def __init__(self, store: CatalogStore) -> None:
        self._store = store

    async def read(self, user_id: str, source_hint: SourceHint) -> Catalog:
        catalog = await self._store.get(user_id)
        if catalog is None:
            return Catalog(user_id=user_id, generated_at=datetime.now(UTC))

        return _filter_sources(catalog, source_hint)


class MemoizingCatalogReader(CatalogReader):
    """Request-scoped CatalogReader that caches each ``read`` by source_hint.

    One per request. The same per-user catalog is otherwise fetched from the
    catalog DB 4-5x during a single slow-path run (planner load, then
    check_data's structured read + check_knowledge's unstructured read, then
    retrieve_data's structured read). Wrapping the base reader collapses those
    to one round-trip
    per distinct source_hint and pins a single consistent snapshot for the whole
    request (plan-time and execution-time catalogs can no longer diverge).
    """

    def __init__(self, inner: CatalogReader) -> None:
        # `read` is fully overridden below and delegates to `inner`, so the parent's
        # `_store` is never used — carry it through only so this stays a real
        # CatalogReader (any inner with a `read` works, including test fakes).
        super().__init__(getattr(inner, "_store", None))
        self._inner = inner
        self._cache: dict[SourceHint, Catalog] = {}

    async def read(self, user_id: str, source_hint: SourceHint) -> Catalog:
        cached = self._cache.get(source_hint)
        if cached is None:
            cached = await self._inner.read(user_id, source_hint)
            self._cache[source_hint] = cached
        return cached


class AnalysisScopedCatalogReader(CatalogReader):
    """Reads the analysis-scope catalog, falling back to the user-scope reader.

    Used by the `check` skill so "what data do I have" inside a room reflects
    that analysis's bound sources — structured AND documents — with their real
    names. A database shows as "xl test" (analysis-scope) instead of the
    auto-generated `postgres_<hash>` placeholder, and documents show at all
    (the user-scope catalog holds no `unstructured` sources, so reading them from
    user-scope always came back empty).

    Fallback rule (tightened 2026-07-13): the user-scope reader is used ONLY when
    there is no `analysis_id` at all (a legacy room with no analysis concept).
    When an `analysis_id` IS present but its catalog row is missing (legacy
    analysis created before catalog materialization, or Go hasn't rebuilt the
    binding yet) or the read fails, this returns an EMPTY catalog — NOT the
    user-scope catalog. Previously it degraded to user-scope, which silently
    surfaced sources that are NOT bound to this analysis as if they were (e.g. a
    room bound to a CSV answered "check" with the account's unrelated XLSX). An
    empty result reads correctly as "nothing bound yet — re-save / rebuild the
    binding to materialize the analysis catalog". Every outcome is logged so a
    miss is diagnosable instead of silent.
    """

    def __init__(self, inner: CatalogReader, analysis_id: str | None) -> None:
        # `inner` is a real CatalogReader (constructed at the check call site), so
        # its `_store` is the live CatalogStore we need for the analysis read.
        super().__init__(inner._store)
        self._inner = inner
        self._analysis_id = analysis_id

    async def read(self, user_id: str, source_hint: SourceHint) -> Catalog:
        # No analysis_id at all → legacy room with no analysis-scope concept; fall
        # back to the user-scope reader (unchanged behavior).
        if not self._analysis_id:
            return await self._inner.read(user_id, source_hint)

        # Analysis-scoped room: read its OWN catalog. Analysis-scope rows carry the
        # real DB names AND the room's documents (`source_type='unstructured'`),
        # unlike the user-scope rows (`postgres_<hash>` names, no documents).
        try:
            catalog = await self._store.get_by_analysis(self._analysis_id)
        except Exception as e:  # noqa: BLE001 — never block check on the analysis read
            logger.warning(
                "analysis catalog read failed — returning empty",
                analysis_id=self._analysis_id,
                error=str(e),
            )
            catalog = None

        if catalog is not None:
            logger.info(
                "analysis catalog hit",
                analysis_id=self._analysis_id,
                sources=len(catalog.sources),
            )
            return _filter_sources(catalog, source_hint)

        # analysis_id present but no catalog row (or read failed): return EMPTY,
        # NOT the user-scope catalog. Surfacing user-scope sources here reads as
        # "these are your bound sources" when they are not (the misleading-XLSX bug).
        logger.info(
            "analysis catalog miss — returning empty (no user-scope fallback)",
            analysis_id=self._analysis_id,
        )
        return Catalog(user_id=user_id, generated_at=datetime.now(UTC))