from datetime import datetime, time, timedelta
from typing import List, Optional
from fastapi import APIRouter, Depends, Query
from sqlmodel.ext.asyncio.session import AsyncSession
from app.database import get_session
from app.crud import get_sessions
from app.schemas import DailySummaryResponse, TimetableResponse, WakeupBedtimeResponse
from app.utils.time_utils import get_day_night_splits

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


@router.get("/daily-summary", response_model=DailySummaryResponse)
async def get_daily_summary(
    from_date: datetime,
    to_date: datetime,
    day_start: str = Query("07:00"),
    day_end: str = Query("20:00"),
    session: AsyncSession = Depends(get_session),
):
    try:
        day_start_time = time.fromisoformat(day_start)
        day_end_time = time.fromisoformat(day_end)
    except ValueError:
        return {"days": []}

    adj_from_date = from_date - timedelta(days=1)
    sessions, _ = await get_sessions(session, from_date=adj_from_date, to_date=to_date)
    summary_map = {}

    for s in sessions:
        if not s.end_time:
            continue
        segments = get_day_night_splits(
            s.start_time, s.end_time, day_start_time, day_end_time
        )
        for seg in segments:
            if not (from_date.date() <= seg["start"].date() <= to_date.date()):
                continue
            date_str = seg["start"].strftime("%Y-%m-%d")
            if date_str not in summary_map:
                summary_map[date_str] = {"day": 0.0, "night": 0.0}
            duration = (seg["end"] - seg["start"]).total_seconds() / 60.0
            if seg["type"] == "day":
                summary_map[date_str]["day"] += duration
            else:
                summary_map[date_str]["night"] += duration

    days = []
    for date_str in sorted(summary_map.keys()):
        data = summary_map[date_str]
        days.append(
            {
                "date": date_str,
                "total_minutes": int(round(data["day"] + data["night"])),
                "day_minutes": int(round(data["day"])),
                "night_minutes": int(round(data["night"])),
            }
        )
    return {"days": days}


@router.get("/timetable", response_model=TimetableResponse)
async def get_timetable(
    from_date: datetime,
    to_date: datetime,
    day_start: str = Query("07:00"),
    day_end: str = Query("20:00"),
    session: AsyncSession = Depends(get_session),
):
    adj_from_date = from_date - timedelta(days=1)
    sessions, _ = await get_sessions(session, from_date=adj_from_date, to_date=to_date)
    slots = []
    current_date = from_date.date()
    while current_date <= to_date.date():
        date_str = current_date.strftime("%Y-%m-%d")
        for i in range(96):
            slot_start_time = datetime.combine(current_date, time(0, 0)) + timedelta(
                minutes=i * 15
            )
            slot_end_time = slot_start_time + timedelta(minutes=15)
            slot_start_str = slot_start_time.strftime("%H:%M")
            slot_end_str = slot_end_time.strftime("%H:%M")
            is_sleeping = False
            for s in sessions:
                if s.start_time <= slot_end_time and (
                    s.end_time is None or s.end_time >= slot_start_time
                ):
                    is_sleeping = True
                    break
            slots.append(
                {
                    "date": date_str,
                    "slot_start": slot_start_str,
                    "slot_end": slot_end_str,
                    "sleeping": is_sleeping,
                }
            )
        current_date += timedelta(days=1)
    return {"slots": slots}


@router.get("/wake-sleep-times", response_model=WakeupBedtimeResponse)
async def get_wake_sleep_times(
    from_date: datetime,
    to_date: datetime,
    wakeup_ref: str = Query("04:00"),
    bedtime_ref: str = Query("19:00"),
    session: AsyncSession = Depends(get_session),
):
    try:
        w_ref_time = time.fromisoformat(wakeup_ref)
        b_ref_time = time.fromisoformat(bedtime_ref)
    except ValueError:
        return {"days": []}

    # Fetch sessions starting from one day before to catch night sleep ending on from_date
    adj_from_date = from_date - timedelta(days=1)
    sessions, _ = await get_sessions(session, from_date=adj_from_date, to_date=to_date)
    days_data = []
    current_date = from_date.date()
    while current_date <= to_date.date():
        date_str = current_date.strftime("%Y-%m-%d")
        wakeup_min = None
        bedtime_min = None

        midnight_today = datetime.combine(current_date, time(0, 0))
        
        night_session = None
        for s in sessions:
            # A session that runs over midnight into current_date
            if s.start_time < midnight_today and s.end_time and s.end_time >= midnight_today:
                night_session = s
                break
        
        if night_session:
            # Bedtime offset from b_ref_time on the day it started
            s_start_date = night_session.start_time.date()
            ref_datetime_bedtime = datetime.combine(s_start_date, b_ref_time)
            bedtime_min = int((night_session.start_time - ref_datetime_bedtime).total_seconds() / 60.0)
            
            # Wakeup offset from w_ref_time on the current day
            ref_datetime_wakeup = datetime.combine(current_date, w_ref_time)
            wakeup_min = int((night_session.end_time - ref_datetime_wakeup).total_seconds() / 60.0)

        days_data.append(
            {
                "date": date_str,
                "wakeup_minutes": wakeup_min,
                "bedtime_minutes": bedtime_min,
            }
        )
        current_date += timedelta(days=1)
    return {"days": days_data}