"""Load a :class:`DataSourceProfile` from ``src/configs/datasets/<name>.yaml``.

The active profile defaults to ``va_cdw`` (today's VA behaviour) and is
overridable via the ``SAGE_DATASOURCE_PROFILE`` environment variable, so the
same pipeline targets MIMIC with ``SAGE_DATASOURCE_PROFILE=mimiciv_duckdb``.
"""

from __future__ import annotations

import functools
import os
from pathlib import Path

import yaml

from .profile import CanonicalView, DataSourceProfile, SourceSpec

# src/profiles/loader.py -> parents[1] == src
SRC_ROOT = Path(__file__).resolve().parents[1]
DATASETS_DIR = SRC_ROOT / "configs" / "datasets"

DEFAULT_PROFILE_NAME = "va_cdw"
ACTIVE_PROFILE_ENV = "SAGE_DATASOURCE_PROFILE"


def _build_source(source_id: str, spec: dict) -> SourceSpec:
    return SourceSpec(
        source_id=source_id,
        path=str(spec["path"]),
        source_type=str(spec.get("source_type", "csv")),
        meaning=str(spec.get("meaning", "")),
        search_columns=tuple(spec.get("search_columns", []) or []),
        display_columns=tuple(spec.get("display_columns", []) or []),
    )


def load_profile(name: str) -> DataSourceProfile:
    path = DATASETS_DIR / f"{name}.yaml"
    if not path.exists():
        available = sorted(p.stem for p in DATASETS_DIR.glob("*.yaml"))
        raise FileNotFoundError(
            f"No data-source profile {name!r} at {path}. Available: {available}"
        )
    raw = yaml.safe_load(path.read_text(encoding="utf-8")) or {}

    sources = {
        sid: _build_source(sid, spec)
        for sid, spec in (raw.get("sources") or {}).items()
    }
    concept_sources_by_domain = {
        domain: tuple(source_ids)
        for domain, source_ids in (raw.get("concept_sources_by_domain") or {}).items()
    }
    domain_concept_keys = {
        domain: tuple(keys)
        for domain, keys in (raw.get("domain_concept_keys") or {}).items()
    }
    canonical_views = {
        domain: CanonicalView(
            domain=domain,
            relation=str(cv.get("relation", "")),
            roles=dict(cv.get("roles") or {}),
            create_view_sql=cv.get("create_view_sql"),
        )
        for domain, cv in (raw.get("canonical_views") or {}).items()
    }

    return DataSourceProfile(
        name=str(raw.get("name", name)),
        dialect=str(raw.get("dialect", "tsql")),
        retrieval_mode=str(raw.get("retrieval_mode", "discover")),
        sources=sources,
        concept_sources_by_domain=concept_sources_by_domain,
        domain_concept_keys=domain_concept_keys,
        canonical_views=canonical_views,
        capabilities=dict(raw.get("capabilities") or {}),
        raw=raw,
    )


@functools.lru_cache(maxsize=None)
def _load_cached(name: str) -> DataSourceProfile:
    return load_profile(name)


def active_profile_name() -> str:
    return (os.environ.get(ACTIVE_PROFILE_ENV) or DEFAULT_PROFILE_NAME).strip() or DEFAULT_PROFILE_NAME


def get_active_profile() -> DataSourceProfile:
    """The profile selected by ``$SAGE_DATASOURCE_PROFILE`` (default ``va_cdw``)."""

    return _load_cached(active_profile_name())