from fastapi import FastAPI

app = FastAPI()


@app.get("/new_session")
async def new_session():
    """Start a new session"""
    # add session to the database
    # return new session cookie
    return {"session_id": 42}


@app.get("/next_picture/{session_id}")
async def next_picture(session_id: int):
    """Request new picture to rate."""
    # take not rated picture from the database
    # do not insert anything in the database yet
    # return this picture
    pass


@app.get("/rate_picture/{session_id}/{picture_id}/{mark}")
async def rate_picture(session_id: int, picture_id: int, mark: int):
    """Submit a rating for the picture"""
    # check if session is valid
    # add new mark to the session table
    pass