"""StructuredPipeline — builds a catalog for DB / tabular sources.

Steps (per source, end-to-end):
  1. introspect (caller-supplied — DatabaseIntrospector or TabularIntrospector)
  2. merge     (replace any existing source with the same source_id)
  3. validate  (catalog/validator.py)
  4. upsert    (catalog/store.py)

LLM-driven enrichment was removed: the planner relies on stats + sample
rows + column names directly. Source/table/column `description` fields stay
in the model but are not populated by this pipeline.

Source-type-agnostic: the caller picks the introspector. Triggers in
`pipeline/triggers.py` know which one to use based on the upload event.
"""

from __future__ import annotations

from datetime import UTC, datetime
from typing import TYPE_CHECKING

from src.catalog.introspect.base import BaseIntrospector
from src.catalog.models import Catalog, Source
from src.middlewares.logging import get_logger

if TYPE_CHECKING:
    from src.catalog.store import CatalogStore
    from src.catalog.validator import CatalogValidator

logger = get_logger("structured_pipeline")


class StructuredPipeline:
    """Orchestrates introspect → merge → validate → store.

    Dependencies are injected (no concrete imports at class-definition time)
    so tests can pass mocks without constructing Settings or opening DB
    connections.
    """

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

    async def run(
        self,
        introspector: BaseIntrospector,
        location_ref: str,
        user_id: str,
    ) -> Source:
        source = await introspector.introspect(location_ref)
        merged = await self._merge_with_existing(user_id, source)
        self._validator.validate(merged)
        await self._store.upsert(merged)
        logger.info(
            "structured pipeline complete",
            user_id=user_id,
            source_id=source.source_id,
            source_type=source.source_type,
            tables=len(source.tables),
        )
        return source

    async def _merge_with_existing(self, user_id: str, new_source: Source) -> Catalog:
        existing = await self._store.get(user_id)
        now = datetime.now(UTC)
        if existing is None:
            return Catalog(user_id=user_id, generated_at=now, sources=[new_source])
        kept = [s for s in existing.sources if s.source_id != new_source.source_id]
        return existing.model_copy(
            update={"sources": [*kept, new_source]}
        )


def default_structured_pipeline() -> StructuredPipeline:
    """Build the production pipeline with default deps.

    Lazy imports keep `from src.pipeline.structured_pipeline import …` cheap
    and side-effect-free for tests.
    """
    from src.catalog.store import CatalogStore
    from src.catalog.validator import CatalogValidator

    return StructuredPipeline(
        validator=CatalogValidator(),
        store=CatalogStore(),
    )