import json
from datetime import datetime, timezone
from typing import Optional

import nanoid
from sqlalchemy import Engine
from sqlmodel import Field, Relationship, Session, SQLModel, create_engine

from settings import settings


class Podcast(SQLModel, table=True):
    id: str = Field(primary_key=True, default_factory=lambda: nanoid.generate())
    name: str
    description: str
    explicit: bool = Field(default=True)
    image_filename: Optional[str] = Field(default=None)
    owner_id: Optional[str] = Field(default=None)

    episodes: list["PodcastEpisode"] = Relationship(back_populates="podcast")


class PodcastEpisode(SQLModel, table=True):
    id: str = Field(primary_key=True, default_factory=lambda: nanoid.generate())
    name: str
    duration: Optional[float] = Field(default=None)
    description: Optional[float] = Field(default=None)
    file_hash: str
    file_size: int
    publish_date: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))

    podcast_id: str = Field(foreign_key="podcast.id")
    podcast: Podcast = Relationship(back_populates="episodes")


def setup_db(engine: Engine):
    SQLModel.metadata.create_all(engine)

    # try and migrate old data
    old_data = settings.directory / "data.json"
    if old_data.is_file():
        try:
            session = Session(engine)

            with open(old_data, "r") as f:
                data = json.load(f)

            for id, item in data["podcasts"].items():
                podcast = Podcast(
                    id=id,
                    name=item.get("name"),
                    description=item.get("description"),
                    explicit=item.get("explicit"),
                    image_filename=item.get("image_filename"),
                )
                session.add(podcast)
                session.commit()

                for episode in item["episodes"]:
                    ep = PodcastEpisode.model_validate(
                        {**episode, "podcast_id": podcast.id, "id": nanoid.generate()}
                    )
                    session.add(ep)

                session.commit()

            old_data.unlink()
        except Exception as ex:
            print("Failed to migrate old data", ex)


engine = create_engine(f"sqlite:///{settings.directory / 'data.db'}")