from os import read
import sqlite3
from dataclasses import dataclass
from datetime import datetime
from typing import Tuple


@dataclass
class Link:
    link: str
    user_id: str
    id: int = None
    read_at: datetime = None
    added_at: datetime = None

    def create(self, db: sqlite3.Connection):
        self.added_at = datetime.now()
        cur = db.cursor()
        rows = (cur.execute(
            "INSERT INTO links(link, user_id, added_at) VALUES(?, ?, ?) RETURNING id;",
            (self.link, self.user_id, self.added_at)
        ))
        r = list(rows)
        assert len(r) == 1
        assert len(r[0]) == 1
        assert int(r[0][0])
        self.id = r[0][0]

    @classmethod
    def _from_tuple(cls, tuple) -> 'Link':
        id, link, user_id, read_at, added_at = tuple
        return cls(
            id=id,
            link=link,
            user_id=user_id,
            read_at=read_at,
            added_at=added_at
        )

    @classmethod
    def _get(cls, db: sqlite3.Connection, where: str, values: Tuple = ()) -> 'Link':
        cur = db.cursor()
        rows = cur.execute(f"SELECT * FROM links WHERE {where}", values)
        return map(cls._from_tuple, rows)

    @classmethod
    def get_unread(cls, db: sqlite3.Connection, user_id: str):
        return cls._get(db, "user_id = ? AND read_at IS NULL", (user_id,))