__init__.py

from typing import List, Optional

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from sqlalchemy import select
from sqlalchemy.orm import Session, subqueryload

from .config import settings
from .database import SessionLocal
from .enum import FilterEnum
from .dynamic_routes import create_dynamic_router
from .models import Schema, AttributeDefinition, AttrType
from .general_routes import router


def load_schemas(db: Session) -> List[models.Schema]:
    schemas = db.execute(
        select(Schema)
        .options(
            subqueryload(Schema.attr_defs)
        )
    ).scalars().all()
    return schemas


def generate_api_description() -> str:
    description = '# Filters\n\n**Filters list**:'
    for filter in FilterEnum:
        description += '\n* `{}` - {}'.format(filter.value.name, filter.value.description)

    description += '\n\n**Available filters for each type**:'
    for atype in AttrType:
        description += '\n* `{}`: {}'.format(atype.name, ', '.join([f'`{i.value.name}`' for i in atype.value.filters]))
    return description


def load_dynamic_routes(db: Session, app: FastAPI):
    schemas = load_schemas(db)
    for schema in schemas:
        create_dynamic_router(schema=schema, app=app)


def create_app(session: Optional[Session] = None) -> FastAPI:
    app = FastAPI(description=generate_api_description())
    origins = ['*']
    app.add_middleware(CORSMiddleware,
        allow_origins=origins,
        allow_credentials=True,
        allow_methods=['*'],
        allow_headers=['*'])

    if session:
        load_dynamic_routes(db=session, app=app)
    else:
        with SessionLocal() as db:
            load_dynamic_routes(db=db, app=app)

    app.include_router(router)
    return app