import sqlite3
from dataclasses import dataclass
from typing import Optional, List

@dataclass
class ParticipantModel:
    conversation_id: Optional[int] = None
    user_id: Optional[int] = None
    joined_at: Optional[str] = None

class Participants:
    def __init__(self, db_path="instance/app_database.db"):
        self.db_path = db_path
        self._create_tables()

    def _create_tables(self):
        with sqlite3.connect(self.db_path) as conn:
            cursor = conn.cursor()
            cursor.execute("""
                CREATE TABLE IF NOT EXISTS participants (
                    conversation_id INTEGER,
                    user_id INTEGER,
                    joined_at DATETIME DEFAULT CURRENT_TIMESTAMP,
                    PRIMARY KEY (conversation_id, user_id),
                    FOREIGN KEY (conversation_id) REFERENCES conversations(id) ON DELETE CASCADE,
                    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
                );
            """)
            conn.commit()

    def add_user(self, conversation_id: int, user_id: int):
        with sqlite3.connect(self.db_path) as conn:
            conn.execute(
                "INSERT OR IGNORE INTO participants (conversation_id, user_id) VALUES (?, ?)",
                (conversation_id, user_id)
            )

    def get_conversation_members(self, conversation_id: int) -> List[int]:
        with sqlite3.connect(self.db_path) as conn:
            cursor = conn.cursor()
            cursor.execute("SELECT user_id FROM participants WHERE conversation_id = ?", (conversation_id,))
            return [row[0] for row in cursor.fetchall()]

    def remove_user(self, conversation_id: int, user_id: int):
        with sqlite3.connect(self.db_path) as conn:
            conn.execute(
                "DELETE FROM participants WHERE conversation_id = ? AND user_id = ?",
                (conversation_id, user_id)
            )