"""
Public share router — no authentication required.
Serves shareable read-only views for briefs and collections.
"""
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from app.database import get_db
from app.models.bill import Bill, BillDocument
from app.models.brief import BillBrief
from app.models.collection import Collection, CollectionBill
from app.schemas.schemas import (
    BillSchema,
    BriefSchema,
    BriefShareResponse,
    CollectionDetailSchema,
)

router = APIRouter()


# ── Brief share ───────────────────────────────────────────────────────────────

@router.get("/brief/{token}", response_model=BriefShareResponse)
async def get_shared_brief(
    token: str,
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(BillBrief)
        .options(
            selectinload(BillBrief.bill).selectinload(Bill.sponsor),
            selectinload(BillBrief.bill).selectinload(Bill.briefs),
            selectinload(BillBrief.bill).selectinload(Bill.trend_scores),
        )
        .where(BillBrief.share_token == token)
    )
    brief = result.scalar_one_or_none()
    if not brief:
        raise HTTPException(status_code=404, detail="Brief not found")

    bill = brief.bill
    bill_schema = BillSchema.model_validate(bill)
    if bill.briefs:
        bill_schema.latest_brief = bill.briefs[0]
    if bill.trend_scores:
        bill_schema.latest_trend = bill.trend_scores[0]

    doc_result = await db.execute(
        select(BillDocument.bill_id).where(BillDocument.bill_id == bill.bill_id).limit(1)
    )
    bill_schema.has_document = doc_result.scalar_one_or_none() is not None

    return BriefShareResponse(
        brief=BriefSchema.model_validate(brief),
        bill=bill_schema,
    )


# ── Collection share ──────────────────────────────────────────────────────────

@router.get("/collection/{token}", response_model=CollectionDetailSchema)
async def get_shared_collection(
    token: str,
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(Collection)
        .options(
            selectinload(Collection.collection_bills).selectinload(CollectionBill.bill).selectinload(Bill.briefs),
            selectinload(Collection.collection_bills).selectinload(CollectionBill.bill).selectinload(Bill.trend_scores),
            selectinload(Collection.collection_bills).selectinload(CollectionBill.bill).selectinload(Bill.sponsor),
        )
        .where(Collection.share_token == token)
    )
    collection = result.scalar_one_or_none()
    if not collection:
        raise HTTPException(status_code=404, detail="Collection not found")

    cb_list = collection.collection_bills
    bills = [cb.bill for cb in cb_list]
    bill_ids = [b.bill_id for b in bills]

    if bill_ids:
        doc_result = await db.execute(
            select(BillDocument.bill_id).where(BillDocument.bill_id.in_(bill_ids)).distinct()
        )
        bills_with_docs = {row[0] for row in doc_result}
    else:
        bills_with_docs = set()

    bill_schemas = []
    for bill in bills:
        bs = BillSchema.model_validate(bill)
        if bill.briefs:
            bs.latest_brief = bill.briefs[0]
        if bill.trend_scores:
            bs.latest_trend = bill.trend_scores[0]
        bs.has_document = bill.bill_id in bills_with_docs
        bill_schemas.append(bs)

    return CollectionDetailSchema(
        id=collection.id,
        name=collection.name,
        slug=collection.slug,
        is_public=collection.is_public,
        share_token=collection.share_token,
        bill_count=len(cb_list),
        created_at=collection.created_at,
        bills=bill_schemas,
    )