import uuid

from fastapi import APIRouter, Depends, Query
from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from app.db import get_session
from app.models import Prediction, Variant
from app.schemas import VariantPage

router = APIRouter()


@router.get("", response_model=VariantPage)
async def list_variants(
    job_id: uuid.UUID,
    gene: str | None = None,
    impact: str | None = Query(None, pattern="^(HIGH|MODERATE|LOW|MODIFIER)$"),
    max_af: float | None = Query(None, ge=0, le=1),
    min_score: float | None = Query(None, ge=0, le=1),
    limit: int = Query(50, le=500),
    offset: int = 0,
    session: AsyncSession = Depends(get_session),
):
    stmt = select(Variant).where(Variant.job_id == job_id)
    if gene:
        stmt = stmt.where(Variant.gene == gene.upper())
    if impact:
        stmt = stmt.where(Variant.impact == impact)
    if max_af is not None:
        stmt = stmt.where((Variant.gnomad_af.is_(None)) | (Variant.gnomad_af <= max_af))
    if min_score is not None:
        stmt = stmt.join(Prediction, Prediction.variant_id == Variant.id).where(Prediction.score >= min_score)

    total = await session.scalar(select(func.count()).select_from(stmt.subquery()))
    rows = await session.scalars(
        stmt.options(selectinload(Variant.prediction))
        .order_by(Variant.chrom, Variant.pos)
        .limit(limit)
        .offset(offset)
    )
    return VariantPage(items=rows.all(), total=total or 0, limit=limit, offset=offset)