from contextlib import asynccontextmanager

from fastapi import Depends, FastAPI, File, HTTPException, UploadFile
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from sqlalchemy.orm import Session

from .database import Base, engine, get_db
from .models import MapObject, ObjectMedia
from .schemas import MapObjectCreate, MapObjectRead, MapObjectUpdate, ObjectMediaRead
from .seed import seed_objects
from .storage import (
    ALLOWED_CONTENT_TYPES,
    MAX_FILE_SIZE,
    build_stored_name,
    ensure_upload_dir,
    is_allowed_content_type,
    media_file_path,
    remove_media_file,
)


def media_to_read(media: ObjectMedia) -> ObjectMediaRead:
    return ObjectMediaRead(
        id=media.id,
        object_id=media.object_id,
        original_name=media.original_name,
        content_type=media.content_type,
        size=media.size,
        created_at=media.created_at,
        url=f"/api/media/{media.id}/file",
    )


@asynccontextmanager
async def lifespan(_: FastAPI):
    ensure_upload_dir()
    Base.metadata.create_all(bind=engine)
    db = next(get_db())
    try:
        seed_objects(db)
    finally:
        db.close()
    yield


app = FastAPI(title="MapMil API", lifespan=lifespan)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.get("/api/health")
def health():
    return {"status": "ok"}


@app.get("/api/objects", response_model=list[MapObjectRead])
def list_objects(db: Session = Depends(get_db)):
    return db.query(MapObject).order_by(MapObject.id).all()


@app.get("/api/objects/{object_id}", response_model=MapObjectRead)
def get_object(object_id: int, db: Session = Depends(get_db)):
    obj = db.query(MapObject).filter(MapObject.id == object_id).first()
    if not obj:
        raise HTTPException(status_code=404, detail="Объект не найден")
    return obj


@app.post("/api/objects", response_model=MapObjectRead, status_code=201)
def create_object(payload: MapObjectCreate, db: Session = Depends(get_db)):
    data = payload.model_dump()
    created_at = data.pop("created_at", None)
    obj = MapObject(**data)
    if created_at is not None:
        obj.created_at = created_at
    db.add(obj)
    db.commit()
    db.refresh(obj)
    return obj


@app.patch("/api/objects/{object_id}", response_model=MapObjectRead)
def update_object(
    object_id: int,
    payload: MapObjectUpdate,
    db: Session = Depends(get_db),
):
    obj = db.query(MapObject).filter(MapObject.id == object_id).first()
    if not obj:
        raise HTTPException(status_code=404, detail="Объект не найден")

    for field, value in payload.model_dump(exclude_unset=True).items():
        setattr(obj, field, value)

    db.commit()
    db.refresh(obj)
    return obj


@app.delete("/api/objects/{object_id}", status_code=204)
def delete_object(object_id: int, db: Session = Depends(get_db)):
    obj = db.query(MapObject).filter(MapObject.id == object_id).first()
    if not obj:
        raise HTTPException(status_code=404, detail="Объект не найден")

    for media in obj.media:
        remove_media_file(media.stored_name)

    db.delete(obj)
    db.commit()


@app.get("/api/objects/{object_id}/media", response_model=list[ObjectMediaRead])
def list_object_media(object_id: int, db: Session = Depends(get_db)):
    obj = db.query(MapObject).filter(MapObject.id == object_id).first()
    if not obj:
        raise HTTPException(status_code=404, detail="Объект не найден")

    media_items = (
        db.query(ObjectMedia)
        .filter(ObjectMedia.object_id == object_id)
        .order_by(ObjectMedia.id)
        .all()
    )
    return [media_to_read(item) for item in media_items]


@app.post("/api/objects/{object_id}/media", response_model=ObjectMediaRead, status_code=201)
async def upload_object_media(
    object_id: int,
    file: UploadFile = File(...),
    db: Session = Depends(get_db),
):
    obj = db.query(MapObject).filter(MapObject.id == object_id).first()
    if not obj:
        raise HTTPException(status_code=404, detail="Объект не найден")

    content_type = file.content_type or "application/octet-stream"
    if not is_allowed_content_type(content_type):
        raise HTTPException(
            status_code=400,
            detail=f"Неподдерживаемый тип файла. Разрешены: {', '.join(sorted(ALLOWED_CONTENT_TYPES))}",
        )

    content = await file.read()
    if len(content) > MAX_FILE_SIZE:
        raise HTTPException(status_code=400, detail="Файл слишком большой (макс. 20 МБ)")

    original_name = file.filename or "file"
    stored_name = build_stored_name(original_name)
    path = media_file_path(stored_name)
    path.write_bytes(content)

    media = ObjectMedia(
        object_id=object_id,
        stored_name=stored_name,
        original_name=original_name,
        content_type=content_type,
        size=len(content),
    )
    db.add(media)
    db.commit()
    db.refresh(media)
    return media_to_read(media)


@app.get("/api/media/{media_id}/file")
def get_media_file(media_id: int, db: Session = Depends(get_db)):
    media = db.query(ObjectMedia).filter(ObjectMedia.id == media_id).first()
    if not media:
        raise HTTPException(status_code=404, detail="Медиафайл не найден")

    path = media_file_path(media.stored_name)
    if not path.exists():
        raise HTTPException(status_code=404, detail="Файл не найден на диске")

    return FileResponse(path, media_type=media.content_type, filename=media.original_name)


@app.delete("/api/media/{media_id}", status_code=204)
def delete_media(media_id: int, db: Session = Depends(get_db)):
    media = db.query(ObjectMedia).filter(ObjectMedia.id == media_id).first()
    if not media:
        raise HTTPException(status_code=404, detail="Медиафайл не найден")

    remove_media_file(media.stored_name)
    db.delete(media)
    db.commit()