from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy import func, select, text
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.dependencies import get_current_admin
from app.database import get_db
from app.models import Bill, BillBrief, BillDocument, Follow
from app.models.user import User
from app.schemas.schemas import UserResponse

router = APIRouter()


# ── User Management ───────────────────────────────────────────────────────────

class UserWithStats(UserResponse):
    follow_count: int


@router.get("/users", response_model=list[UserWithStats])
async def list_users(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_admin),
):
    """List all users with their follow counts."""
    users_result = await db.execute(select(User).order_by(User.created_at))
    users = users_result.scalars().all()

    counts_result = await db.execute(
        select(Follow.user_id, func.count(Follow.id).label("cnt"))
        .group_by(Follow.user_id)
    )
    counts = {row.user_id: row.cnt for row in counts_result}

    return [
        UserWithStats(
            id=u.id,
            email=u.email,
            is_admin=u.is_admin,
            notification_prefs=u.notification_prefs or {},
            created_at=u.created_at,
            follow_count=counts.get(u.id, 0),
        )
        for u in users
    ]


@router.delete("/users/{user_id}", status_code=204)
async def delete_user(
    user_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_admin),
):
    """Delete a user account (cascades to their follows). Cannot delete yourself."""
    if user_id == current_user.id:
        raise HTTPException(status_code=400, detail="Cannot delete your own account")
    user = await db.get(User, user_id)
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    await db.delete(user)
    await db.commit()


@router.patch("/users/{user_id}/toggle-admin", response_model=UserResponse)
async def toggle_admin(
    user_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_admin),
):
    """Promote or demote a user's admin status."""
    if user_id == current_user.id:
        raise HTTPException(status_code=400, detail="Cannot change your own admin status")
    user = await db.get(User, user_id)
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    user.is_admin = not user.is_admin
    await db.commit()
    await db.refresh(user)
    return user


# ── Analysis Stats ────────────────────────────────────────────────────────────

@router.get("/stats")
async def get_stats(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_admin),
):
    """Return analysis pipeline progress counters."""
    total_bills = (await db.execute(select(func.count()).select_from(Bill))).scalar()
    docs_fetched = (await db.execute(
        select(func.count()).select_from(BillDocument).where(BillDocument.raw_text.isnot(None))
    )).scalar()
    total_briefs = (await db.execute(select(func.count()).select_from(BillBrief))).scalar()
    full_briefs = (await db.execute(
        select(func.count()).select_from(BillBrief).where(BillBrief.brief_type == "full")
    )).scalar()
    amendment_briefs = (await db.execute(
        select(func.count()).select_from(BillBrief).where(BillBrief.brief_type == "amendment")
    )).scalar()
    uncited_briefs = (await db.execute(
        text("""
            SELECT COUNT(*) FROM bill_briefs
            WHERE key_points IS NOT NULL
              AND jsonb_array_length(key_points) > 0
              AND jsonb_typeof(key_points->0) = 'string'
        """)
    )).scalar()
    return {
        "total_bills": total_bills,
        "docs_fetched": docs_fetched,
        "briefs_generated": total_briefs,
        "full_briefs": full_briefs,
        "amendment_briefs": amendment_briefs,
        "uncited_briefs": uncited_briefs,
        "remaining": total_bills - total_briefs,
    }


# ── Celery Tasks ──────────────────────────────────────────────────────────────

@router.post("/backfill-citations")
async def backfill_citations(current_user: User = Depends(get_current_admin)):
    """Delete pre-citation briefs and re-queue LLM processing using stored document text."""
    from app.workers.llm_processor import backfill_brief_citations
    task = backfill_brief_citations.delay()
    return {"task_id": task.id, "status": "queued"}


@router.post("/backfill-sponsors")
async def backfill_sponsors(current_user: User = Depends(get_current_admin)):
    from app.workers.congress_poller import backfill_sponsor_ids
    task = backfill_sponsor_ids.delay()
    return {"task_id": task.id, "status": "queued"}


@router.post("/trigger-poll")
async def trigger_poll(current_user: User = Depends(get_current_admin)):
    from app.workers.congress_poller import poll_congress_bills
    task = poll_congress_bills.delay()
    return {"task_id": task.id, "status": "queued"}


@router.post("/trigger-member-sync")
async def trigger_member_sync(current_user: User = Depends(get_current_admin)):
    from app.workers.congress_poller import sync_members
    task = sync_members.delay()
    return {"task_id": task.id, "status": "queued"}


@router.post("/trigger-fetch-actions")
async def trigger_fetch_actions(current_user: User = Depends(get_current_admin)):
    from app.workers.congress_poller import fetch_actions_for_active_bills
    task = fetch_actions_for_active_bills.delay()
    return {"task_id": task.id, "status": "queued"}


@router.post("/trigger-trend-scores")
async def trigger_trend_scores(current_user: User = Depends(get_current_admin)):
    from app.workers.trend_scorer import calculate_all_trend_scores
    task = calculate_all_trend_scores.delay()
    return {"task_id": task.id, "status": "queued"}


@router.post("/bills/{bill_id}/reprocess")
async def reprocess_bill(bill_id: str, current_user: User = Depends(get_current_admin)):
    """Queue document and action fetches for a specific bill. Useful for debugging."""
    from app.workers.document_fetcher import fetch_bill_documents
    from app.workers.congress_poller import fetch_bill_actions
    doc_task = fetch_bill_documents.delay(bill_id)
    actions_task = fetch_bill_actions.delay(bill_id)
    return {"task_ids": {"documents": doc_task.id, "actions": actions_task.id}}


@router.get("/task-status/{task_id}")
async def get_task_status(task_id: str, current_user: User = Depends(get_current_admin)):
    from app.workers.celery_app import celery_app
    result = celery_app.AsyncResult(task_id)
    return {
        "task_id": task_id,
        "status": result.status,
        "result": result.result if result.ready() else None,
    }