"""
Presence Management Routes
User presence marking and admin management
"""
from typing import List
from datetime import datetime, timedelta
from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy.orm import Session
import uuid

from database.connection import get_db
from database.models import UserPresence, User, DailyParkingAssignment
from utils.auth_middleware import get_current_user, require_manager_or_admin
from services.parking import handle_presence_change, get_spot_display_name

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


# Request/Response Models
class PresenceMarkRequest(BaseModel):
    date: str  # YYYY-MM-DD
    status: str  # present, remote, absent


class AdminPresenceMarkRequest(BaseModel):
    user_id: str
    date: str
    status: str


class BulkPresenceRequest(BaseModel):
    start_date: str
    end_date: str
    status: str
    days: List[int] | None = None  # Optional: [0,1,2,3,4] for Mon-Fri


class AdminBulkPresenceRequest(BaseModel):
    user_id: str
    start_date: str
    end_date: str
    status: str
    days: List[int] | None = None


class PresenceResponse(BaseModel):
    id: str
    user_id: str
    date: str
    status: str
    created_at: str | None
    updated_at: str | None
    parking_spot_number: str | None = None

    class Config:
        from_attributes = True


# Helper functions
def validate_status(status: str):
    if status not in ["present", "remote", "absent"]:
        raise HTTPException(status_code=400, detail="Status must be: present, remote, or absent")


def parse_date(date_str: str) -> datetime:
    try:
        return datetime.strptime(date_str, "%Y-%m-%d")
    except ValueError:
        raise HTTPException(status_code=400, detail="Invalid date format. Use YYYY-MM-DD")


def check_manager_access(current_user: User, target_user: User, db: Session):
    """Check if current_user has access to target_user"""
    if current_user.role == "admin":
        return True

    if current_user.role == "manager":
        # Manager can access users they manage
        if target_user.manager_id == current_user.id:
            return True
        raise HTTPException(status_code=403, detail="User is not managed by you")

    raise HTTPException(status_code=403, detail="Access denied")


def _mark_presence_for_user(
    user_id: str,
    date: str,
    status: str,
    db: Session,
    target_user: User
) -> UserPresence:
    """
    Core presence marking logic - shared by user and admin routes.
    """
    validate_status(status)
    parse_date(date)

    existing = db.query(UserPresence).filter(
        UserPresence.user_id == user_id,
        UserPresence.date == date
    ).first()

    now = datetime.utcnow().isoformat()
    old_status = existing.status if existing else None

    if existing:
        existing.status = status
        existing.updated_at = now
        db.commit()
        db.refresh(existing)
        presence = existing
    else:
        presence = UserPresence(
            id=str(uuid.uuid4()),
            user_id=user_id,
            date=date,
            status=status,
            created_at=now,
            updated_at=now
        )
        db.add(presence)
        db.commit()
        db.refresh(presence)

    # Handle parking assignment
    # Use manager_id if user has one, or user's own id if they are a manager
    parking_manager_id = target_user.manager_id
    if not parking_manager_id and target_user.role == "manager":
        # Manager is part of their own team for parking purposes
        parking_manager_id = target_user.id

    if old_status != status and parking_manager_id:
        try:
            handle_presence_change(
                user_id, date,
                old_status or "absent", status,
                parking_manager_id, db
            )
        except Exception as e:
            print(f"Warning: Parking handler failed: {e}")

    return presence


def _bulk_mark_presence(
    user_id: str,
    start_date: str,
    end_date: str,
    status: str,
    days: List[int] | None,
    db: Session,
    target_user: User
) -> List[UserPresence]:
    """
    Core bulk presence marking logic - shared by user and admin routes.
    """
    validate_status(status)
    start = parse_date(start_date)
    end = parse_date(end_date)

    if end < start:
        raise HTTPException(status_code=400, detail="End date must be after start date")
    if (end - start).days > 90:
        raise HTTPException(status_code=400, detail="Range cannot exceed 90 days")

    results = []
    current_date = start
    now = datetime.utcnow().isoformat()

    while current_date <= end:
        if days is None or current_date.weekday() in days:
            date_str = current_date.strftime("%Y-%m-%d")

            existing = db.query(UserPresence).filter(
                UserPresence.user_id == user_id,
                UserPresence.date == date_str
            ).first()

            old_status = existing.status if existing else None

            if existing:
                existing.status = status
                existing.updated_at = now
                results.append(existing)
            else:
                presence = UserPresence(
                    id=str(uuid.uuid4()),
                    user_id=user_id,
                    date=date_str,
                    status=status,
                    created_at=now,
                    updated_at=now
                )
                db.add(presence)
                results.append(presence)

            # Handle parking for each date
            # Use manager_id if user has one, or user's own id if they are a manager
            parking_manager_id = target_user.manager_id
            if not parking_manager_id and target_user.role == "manager":
                parking_manager_id = target_user.id

            if old_status != status and parking_manager_id:
                try:
                    handle_presence_change(
                        user_id, date_str,
                        old_status or "absent", status,
                        parking_manager_id, db
                    )
                except Exception:
                    pass

        current_date += timedelta(days=1)

    db.commit()
    return results


def _delete_presence(
    user_id: str,
    date: str,
    db: Session,
    target_user: User
) -> dict:
    """
    Core presence deletion logic - shared by user and admin routes.
    """
    parse_date(date)

    presence = db.query(UserPresence).filter(
        UserPresence.user_id == user_id,
        UserPresence.date == date
    ).first()

    if not presence:
        raise HTTPException(status_code=404, detail="Presence not found")

    old_status = presence.status
    db.delete(presence)
    db.commit()

    # Use manager_id if user has one, or user's own id if they are a manager
    parking_manager_id = target_user.manager_id
    if not parking_manager_id and target_user.role == "manager":
        parking_manager_id = target_user.id

    if parking_manager_id:
        try:
            handle_presence_change(
                user_id, date,
                old_status, "absent",
                parking_manager_id, db
            )
        except Exception:
            pass

    return {"message": "Presence deleted"}


# User Routes
@router.post("/mark", response_model=PresenceResponse)
def mark_presence(data: PresenceMarkRequest, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
    """Mark presence for a date"""
    return _mark_presence_for_user(current_user.id, data.date, data.status, db, current_user)


@router.post("/mark-bulk", response_model=List[PresenceResponse])
def mark_bulk_presence(data: BulkPresenceRequest, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
    """Mark presence for a date range"""
    return _bulk_mark_presence(
        current_user.id, data.start_date, data.end_date,
        data.status, data.days, db, current_user
    )


@router.get("/my-presences", response_model=List[PresenceResponse])
def get_my_presences(start_date: str = None, end_date: str = None, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
    """Get current user's presences"""
    query = db.query(UserPresence).filter(UserPresence.user_id == current_user.id)

    if start_date:
        parse_date(start_date)
        query = query.filter(UserPresence.date >= start_date)
    if end_date:
        parse_date(end_date)
        query = query.filter(UserPresence.date <= end_date)

    return query.order_by(UserPresence.date.desc()).all()


@router.delete("/{date}")
def delete_presence(date: str, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
    """Delete presence for a date"""
    return _delete_presence(current_user.id, date, db, current_user)


# Admin/Manager Routes
@router.post("/admin/mark", response_model=PresenceResponse)
def admin_mark_presence(data: AdminPresenceMarkRequest, db: Session = Depends(get_db), current_user=Depends(require_manager_or_admin)):
    """Mark presence for any user (manager/admin)"""
    target_user = db.query(User).filter(User.id == data.user_id).first()
    if not target_user:
        raise HTTPException(status_code=404, detail="User not found")

    check_manager_access(current_user, target_user, db)
    return _mark_presence_for_user(data.user_id, data.date, data.status, db, target_user)


@router.post("/admin/mark-bulk", response_model=List[PresenceResponse])
def admin_mark_bulk_presence(data: AdminBulkPresenceRequest, db: Session = Depends(get_db), current_user=Depends(require_manager_or_admin)):
    """Bulk mark presence for any user (manager/admin)"""
    target_user = db.query(User).filter(User.id == data.user_id).first()
    if not target_user:
        raise HTTPException(status_code=404, detail="User not found")

    check_manager_access(current_user, target_user, db)
    return _bulk_mark_presence(
        data.user_id, data.start_date, data.end_date,
        data.status, data.days, db, target_user
    )


@router.delete("/admin/{user_id}/{date}")
def admin_delete_presence(user_id: str, date: str, db: Session = Depends(get_db), current_user=Depends(require_manager_or_admin)):
    """Delete presence for any user (manager/admin)"""
    target_user = db.query(User).filter(User.id == user_id).first()
    if not target_user:
        raise HTTPException(status_code=404, detail="User not found")

    check_manager_access(current_user, target_user, db)
    return _delete_presence(user_id, date, db, target_user)


@router.get("/team")
def get_team_presences(start_date: str, end_date: str, manager_id: str = None, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
    """Get team presences with parking info, filtered by manager.
    - Admins can see all teams
    - Managers see their own team
    - Employees can only see their own team (read-only view)
    """
    parse_date(start_date)
    parse_date(end_date)

    # Get users based on permissions and manager filter
    # Note: Manager is part of their own team (for parking assignment purposes)
    if current_user.role == "employee":
        # Employees can only see their own team (users with same manager_id + the manager)
        if not current_user.manager_id:
            return []  # No manager assigned, no team to show
        users = db.query(User).filter(
            (User.manager_id == current_user.manager_id) | (User.id == current_user.manager_id)
        ).all()
    elif manager_id:
        # Filter by specific manager (for admins/managers) - include the manager themselves
        users = db.query(User).filter(
            (User.manager_id == manager_id) | (User.id == manager_id)
        ).all()
    elif current_user.role == "admin":
        # Admin sees all users
        users = db.query(User).all()
    else:
        # Manager sees their team + themselves
        users = db.query(User).filter(
            (User.manager_id == current_user.id) | (User.id == current_user.id)
        ).all()

    # Batch query presences and parking for all users
    user_ids = [u.id for u in users]
    presences = db.query(UserPresence).filter(
        UserPresence.user_id.in_(user_ids),
        UserPresence.date >= start_date,
        UserPresence.date <= end_date
    ).all()

    parking_assignments = db.query(DailyParkingAssignment).filter(
        DailyParkingAssignment.user_id.in_(user_ids),
        DailyParkingAssignment.date >= start_date,
        DailyParkingAssignment.date <= end_date
    ).all()

    # Build lookups
    parking_lookup = {}
    parking_info_lookup = {}
    for p in parking_assignments:
        if p.user_id not in parking_lookup:
            parking_lookup[p.user_id] = []
            parking_info_lookup[p.user_id] = []
        parking_lookup[p.user_id].append(p.date)
        spot_display_name = get_spot_display_name(p.spot_id, p.manager_id, db)
        parking_info_lookup[p.user_id].append({
            "id": p.id,
            "date": p.date,
            "spot_id": p.spot_id,
            "spot_display_name": spot_display_name
        })

    # Build manager lookup for display
    manager_ids = list(set(u.manager_id for u in users if u.manager_id))
    managers = db.query(User).filter(User.id.in_(manager_ids)).all() if manager_ids else []
    manager_lookup = {m.id: m.name for m in managers}

    # Build response
    result = []
    for user in users:
        user_presences = [p for p in presences if p.user_id == user.id]

        result.append({
            "id": user.id,
            "name": user.name,
            "manager_id": user.manager_id,
            "manager_name": manager_lookup.get(user.manager_id),
            "presences": [{"date": p.date, "status": p.status} for p in user_presences],
            "parking_dates": parking_lookup.get(user.id, []),
            "parking_info": parking_info_lookup.get(user.id, [])
        })

    return result


@router.get("/admin/{user_id}")
def get_user_presences(user_id: str, start_date: str = None, end_date: str = None, db: Session = Depends(get_db), current_user=Depends(require_manager_or_admin)):
    """Get any user's presences with parking info (manager/admin)"""
    target_user = db.query(User).filter(User.id == user_id).first()
    if not target_user:
        raise HTTPException(status_code=404, detail="User not found")

    check_manager_access(current_user, target_user, db)

    query = db.query(UserPresence).filter(UserPresence.user_id == user_id)

    if start_date:
        parse_date(start_date)
        query = query.filter(UserPresence.date >= start_date)
    if end_date:
        parse_date(end_date)
        query = query.filter(UserPresence.date <= end_date)

    presences = query.order_by(UserPresence.date.desc()).all()

    # Batch query parking assignments
    date_strs = [p.date for p in presences]
    parking_map = {}
    if date_strs:
        assignments = db.query(DailyParkingAssignment).filter(
            DailyParkingAssignment.user_id == user_id,
            DailyParkingAssignment.date.in_(date_strs)
        ).all()
        for a in assignments:
            parking_map[a.date] = get_spot_display_name(a.spot_id, a.manager_id, db)

    # Build response
    result = []
    for presence in presences:
        result.append({
            "id": presence.id,
            "user_id": presence.user_id,
            "date": presence.date,
            "status": presence.status,
            "created_at": presence.created_at,
            "updated_at": presence.updated_at,
            "parking_spot_number": parking_map.get(presence.date)
        })

    return result