"""Worlds router - CRUD for game worlds."""

from typing import Annotated

from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel, Field
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from app.database import get_db
from app.dependencies import CurrentUser
from app.models.world import World, WorldVisibility

router = APIRouter()

DbDep = Annotated[AsyncSession, Depends(get_db)]


# --- Pydantic schemas ---

class WorldCreate(BaseModel):
    """Schema for creating a world."""
    name: str = Field(..., min_length=1, max_length=255)
    description: str | None = None
    visibility: WorldVisibility = WorldVisibility.PUBLIC


class WorldUpdate(BaseModel):
    """Schema for updating a world."""
    name: str | None = Field(None, min_length=1, max_length=255)
    description: str | None = None
    visibility: WorldVisibility | None = None


class WorldResponse(BaseModel):
    """Schema for world responses."""
    id: int
    name: str
    description: str | None
    visibility: WorldVisibility
    owner_id: int
    created_at: str | None = None

    model_config = {"from_attributes": True}


# --- Endpoints ---

@router.get("/", response_model=list[WorldResponse])
async def list_worlds(
    current_user: CurrentUser,
    db: DbDep,
    skip: int = Query(0, ge=0),
    limit: int = Query(50, ge=1, le=100),
    visibility: WorldVisibility | None = None,
):
    """List worlds visible to the current user.

    PUBLIC worlds are visible to everyone.
    PRIVATE/FRIENDS_ONLY worlds are visible to their owner.
    """
    query = select(World).options(selectinload(World.owner))

    # Filter by visibility if specified
    if visibility:
        query = query.where(World.visibility == visibility)
        if visibility != WorldVisibility.PUBLIC:
            # Requesting a non-public visibility explicitly must not bypass
            # ownership — otherwise any authenticated user could list every
            # PRIVATE/FRIENDS_ONLY world in the system just by passing the
            # filter, defeating the point of the check below.
            query = query.where(World.owner_id == current_user.id)
    else:
        # Show PUBLIC worlds + owner's own worlds
        query = query.where(
            (World.visibility == WorldVisibility.PUBLIC)
            | (World.owner_id == current_user.id)
        )

    query = query.offset(skip).limit(limit).order_by(World.created_at.desc())
    result = await db.execute(query)
    worlds = result.scalars().all()
    return worlds


@router.get("/{world_id}", response_model=WorldResponse)
async def get_world(
    world_id: int,
    current_user: CurrentUser,
    db: DbDep,
):
    """Get a single world by ID, respecting visibility."""
    result = await db.execute(
        select(World).where(World.id == world_id).options(selectinload(World.owner))
    )
    world = result.scalar_one_or_none()
    if not world:
        raise HTTPException(status_code=404, detail="World not found")

    # Allow access if world is PUBLIC or owned by current user
    if world.visibility != WorldVisibility.PUBLIC and world.owner_id != current_user.id:
        raise HTTPException(status_code=404, detail="World not found")

    return world


@router.post("/", response_model=WorldResponse, status_code=201)
async def create_world(
    world_data: WorldCreate,
    current_user: CurrentUser,
    db: DbDep,
):
    """Create a new world."""
    world = World(
        name=world_data.name,
        description=world_data.description,
        owner_id=current_user.id,
        visibility=world_data.visibility,
    )
    db.add(world)
    await db.commit()
    await db.refresh(world)
    return world


@router.put("/{world_id}", response_model=WorldResponse)
async def update_world(
    world_id: int,
    world_data: WorldUpdate,
    current_user: CurrentUser,
    db: DbDep,
):
    """Update an existing world."""
    result = await db.execute(select(World).where(World.id == world_id))
    world = result.scalar_one_or_none()
    if not world:
        raise HTTPException(status_code=404, detail="World not found")

    if world.owner_id != current_user.id:
        raise HTTPException(status_code=403, detail="Not owner of this world")

    update_data = world_data.model_dump(exclude_unset=True)
    for field, value in update_data.items():
        setattr(world, field, value)

    await db.commit()
    await db.refresh(world)
    return world


@router.delete("/{world_id}", status_code=204)
async def delete_world(
    world_id: int,
    current_user: CurrentUser,
    db: DbDep,
):
    """Delete a world."""
    result = await db.execute(select(World).where(World.id == world_id))
    world = result.scalar_one_or_none()
    if not world:
        raise HTTPException(status_code=404, detail="World not found")

    if world.owner_id != current_user.id:
        raise HTTPException(status_code=403, detail="Not owner of this world")

    await db.delete(world)
    await db.commit()