homeschool/backend/app/routers/sessions.py

from datetime import date

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from sqlalchemy.orm import selectinload

from app.dependencies import get_db, get_current_user
from app.models.child import Child
from app.models.schedule import ScheduleBlock, ScheduleTemplate
from app.models.session import DailySession, TimerEvent
from app.models.user import User
from app.schemas.session import DailySessionOut, SessionStart, TimerAction
from app.websocket.manager import manager

router = APIRouter(prefix="/api/sessions", tags=["sessions"])


async def _broadcast_session(db: AsyncSession, session: DailySession) -> None:
    """Build a snapshot dict and broadcast it to all connected TVs for this child."""
    # Load template blocks if available
    blocks = []
    if session.template_id:
        result = await db.execute(
            select(ScheduleBlock)
            .where(ScheduleBlock.template_id == session.template_id)
            .order_by(ScheduleBlock.order_index)
        )
        blocks = [{"id": b.id, "subject_id": b.subject_id, "time_start": str(b.time_start),
                   "time_end": str(b.time_end), "label": b.label, "order_index": b.order_index}
                  for b in result.scalars().all()]

    # Gather completed block IDs from timer events
    events_result = await db.execute(
        select(TimerEvent).where(
            TimerEvent.session_id == session.id,
            TimerEvent.event_type == "complete",
        )
    )
    completed_ids = [e.block_id for e in events_result.scalars().all() if e.block_id]

    payload = {
        "event": "session_update",
        "session": {
            "id": session.id,
            "child_id": session.child_id,
            "session_date": str(session.session_date),
            "is_active": session.is_active,
            "current_block_id": session.current_block_id,
        },
        "blocks": blocks,
        "completed_block_ids": completed_ids,
    }
    await manager.broadcast(session.child_id, payload)


@router.post("", response_model=DailySessionOut, status_code=status.HTTP_201_CREATED)
async def start_session(
    body: SessionStart,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    # Verify child belongs to user
    child_result = await db.execute(
        select(Child).where(Child.id == body.child_id, Child.user_id == current_user.id)
    )
    if not child_result.scalar_one_or_none():
        raise HTTPException(status_code=404, detail="Child not found")

    session_date = body.session_date or date.today()

    # Deactivate any existing active session for this child today
    existing = await db.execute(
        select(DailySession).where(
            DailySession.child_id == body.child_id,
            DailySession.session_date == session_date,
            DailySession.is_active == True,
        )
    )
    for old in existing.scalars().all():
        old.is_active = False

    session = DailySession(
        child_id=body.child_id,
        template_id=body.template_id,
        session_date=session_date,
        is_active=True,
    )
    db.add(session)
    await db.commit()
    await db.refresh(session)
    await _broadcast_session(db, session)
    return session


@router.get("/{session_id}", response_model=DailySessionOut)
async def get_session(
    session_id: int,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(DailySession)
        .join(Child)
        .where(DailySession.id == session_id, Child.user_id == current_user.id)
        .options(selectinload(DailySession.current_block))
    )
    session = result.scalar_one_or_none()
    if not session:
        raise HTTPException(status_code=404, detail="Session not found")
    return session


@router.post("/{session_id}/timer", response_model=DailySessionOut)
async def timer_action(
    session_id: int,
    body: TimerAction,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(DailySession)
        .join(Child)
        .where(DailySession.id == session_id, Child.user_id == current_user.id)
        .options(selectinload(DailySession.current_block))
    )
    session = result.scalar_one_or_none()
    if not session:
        raise HTTPException(status_code=404, detail="Session not found")

    # Update current block if provided
    if body.block_id is not None:
        session.current_block_id = body.block_id

    # Record the timer event
    event = TimerEvent(
        session_id=session.id,
        block_id=body.block_id or session.current_block_id,
        event_type=body.event_type,
    )
    db.add(event)

    # Mark session complete if event is session-level complete
    if body.event_type == "complete" and body.block_id is None:
        session.is_active = False

    await db.commit()
    await db.refresh(session)

    # Broadcast the timer event to all TV clients
    ws_payload = {
        "event": body.event_type,
        "session_id": session.id,
        "block_id": event.block_id,
        "current_block_id": session.current_block_id,
        "is_active": session.is_active,
    }
    await manager.broadcast(session.child_id, ws_payload)

    return session