from fastapi import APIRouter, Depends, HTTPException, Path, Query
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, or_
from datetime import datetime, timezone
from typing import Optional, List
import asyncio
import json
import urllib.request
import urllib.parse
import logging

from app.database import get_db
from app.models.location import Location
from app.schemas.location import LocationCreate, LocationUpdate, LocationResponse, LocationSearchResult
from app.routers.auth import get_current_user
from app.models.user import User

logger = logging.getLogger(__name__)

router = APIRouter()


@router.get("/search", response_model=List[LocationSearchResult])
async def search_locations(
    q: str = Query(..., min_length=1),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Search locations from local DB and Nominatim OSM."""
    results: List[LocationSearchResult] = []

    # Local DB search — scoped to user's locations
    local_query = (
        select(Location)
        .where(
            Location.user_id == current_user.id,
            or_(
                Location.name.ilike(f"%{q}%"),
                Location.address.ilike(f"%{q}%"),
            ),
        )
        .limit(5)
    )
    local_result = await db.execute(local_query)
    local_locations = local_result.scalars().all()

    for loc in local_locations:
        results.append(
            LocationSearchResult(
                source="local",
                location_id=loc.id,
                name=loc.name,
                address=loc.address,
            )
        )

    # Nominatim proxy search (run in thread executor to avoid blocking event loop)
    def _fetch_nominatim() -> list:
        encoded_q = urllib.parse.quote(q)
        url = f"https://nominatim.openstreetmap.org/search?q={encoded_q}&format=json&limit=5"
        req = urllib.request.Request(url, headers={"User-Agent": "UMBRA-LifeManager/1.0"})
        with urllib.request.urlopen(req, timeout=5) as resp:
            return json.loads(resp.read().decode())

    try:
        loop = asyncio.get_running_loop()
        osm_data = await loop.run_in_executor(None, _fetch_nominatim)
        for item in osm_data:
            display_name = item.get("display_name", "")
            name_parts = display_name.split(",", 1)
            name = name_parts[0].strip()
            address = name_parts[1].strip() if len(name_parts) > 1 else display_name
            results.append(
                LocationSearchResult(
                    source="nominatim",
                    name=name,
                    address=address,
                )
            )
    except Exception as e:
        logger.warning(f"Nominatim search failed: {e}")

    return results


@router.get("/", response_model=List[LocationResponse])
async def get_locations(
    category: Optional[str] = Query(None),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get all locations with optional category filter."""
    query = select(Location).where(Location.user_id == current_user.id)

    if category:
        query = query.where(Location.category == category)

    query = query.order_by(Location.name.asc())

    result = await db.execute(query)
    locations = result.scalars().all()

    return locations


@router.post("/", response_model=LocationResponse, status_code=201)
async def create_location(
    location: LocationCreate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Create a new location."""
    new_location = Location(**location.model_dump(), user_id=current_user.id)
    db.add(new_location)
    await db.commit()
    await db.refresh(new_location)

    return new_location


@router.get("/{location_id}", response_model=LocationResponse)
async def get_location(
    location_id: int = Path(ge=1, le=2147483647),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get a specific location by ID."""
    result = await db.execute(
        select(Location).where(Location.id == location_id, Location.user_id == current_user.id)
    )
    location = result.scalar_one_or_none()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    return location


@router.put("/{location_id}", response_model=LocationResponse)
async def update_location(
    location_id: int = Path(ge=1, le=2147483647),
    location_update: LocationUpdate = ...,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Update a location."""
    result = await db.execute(
        select(Location).where(Location.id == location_id, Location.user_id == current_user.id)
    )
    location = result.scalar_one_or_none()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    update_data = location_update.model_dump(exclude_unset=True)

    for key, value in update_data.items():
        setattr(location, key, value)

    # Guarantee timestamp refresh regardless of DB driver behaviour
    location.updated_at = datetime.now(timezone.utc).replace(tzinfo=None)

    await db.commit()
    await db.refresh(location)

    return location


@router.delete("/{location_id}", status_code=204)
async def delete_location(
    location_id: int = Path(ge=1, le=2147483647),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Delete a location."""
    result = await db.execute(
        select(Location).where(Location.id == location_id, Location.user_id == current_user.id)
    )
    location = result.scalar_one_or_none()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    await db.delete(location)
    await db.commit()

    return None