"""
Public dashboard endpoint — no authentication required.
Used by the TV view to get the initial session snapshot before WebSocket connects.
"""
from datetime import date, datetime

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

from app.dependencies import get_db
from app.models.child import Child
from app.models.schedule import ScheduleBlock, ScheduleTemplate
from app.models.subject import Subject  # noqa: F401 — needed for selectinload chain
from app.models.session import DailySession, TimerEvent
from app.schemas.session import DashboardSnapshot

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


@router.get("/{child_id}", response_model=DashboardSnapshot)
async def get_dashboard(child_id: int, db: AsyncSession = Depends(get_db)):
    child_result = await db.execute(select(Child).where(Child.id == child_id, Child.is_active == True))
    child = child_result.scalar_one_or_none()
    if not child:
        raise HTTPException(status_code=404, detail="Child not found")

    # Get today's active session
    session_result = await db.execute(
        select(DailySession)
        .where(
            DailySession.child_id == child_id,
            DailySession.session_date == date.today(),
            DailySession.is_active == True,
        )
        .options(selectinload(DailySession.current_block))
        .limit(1)
    )
    session = session_result.scalar_one_or_none()

    blocks = []
    completed_ids = []
    block_elapsed_seconds = 0
    day_start_time = None
    day_end_time = None

    if session and session.template_id:
        blocks_result = await db.execute(
            select(ScheduleBlock)
            .where(ScheduleBlock.template_id == session.template_id)
            .options(selectinload(ScheduleBlock.subject).selectinload(Subject.options))
            .order_by(ScheduleBlock.time_start)
        )
        blocks = blocks_result.scalars().all()

        template_result = await db.execute(
            select(ScheduleTemplate).where(ScheduleTemplate.id == session.template_id)
        )
        template = template_result.scalar_one_or_none()
        if template:
            day_start_time = template.day_start_time
            day_end_time = template.day_end_time

        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]

    # Compute elapsed seconds for the current block from timer_events
    if session and session.current_block_id:
        tick_result = await db.execute(
            select(TimerEvent)
            .where(
                TimerEvent.session_id == session.id,
                TimerEvent.block_id == session.current_block_id,
                TimerEvent.event_type.in_(["start", "resume", "pause"]),
            )
            .order_by(TimerEvent.occurred_at)
        )
        tick_events = tick_result.scalars().all()
        last_start = None
        elapsed = 0.0
        for e in tick_events:
            if e.event_type in ("start", "resume"):
                last_start = e.occurred_at
            elif e.event_type == "pause" and last_start:
                elapsed += (e.occurred_at - last_start).total_seconds()
                last_start = None
        if last_start:
            elapsed += (datetime.utcnow() - last_start).total_seconds()
        block_elapsed_seconds = int(elapsed)

    return DashboardSnapshot(
        session=session,
        child=child,
        blocks=blocks,
        completed_block_ids=completed_ids,
        block_elapsed_seconds=block_elapsed_seconds,
        day_start_time=day_start_time,
        day_end_time=day_end_time,
    )