/**
 * Copyright (C) 2026 Sofía Aritz and contributors
 *
 * This file is part of Everest.
 *
 * Everest is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * Everest is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * Everest. If not, see <https://www.gnu.org/licenses/>.
 */

import { Kysely, PostgresDialect } from "kysely";
import { Pool } from "pg";

let db: Kysely<DatabaseSchema> | null = null;

export function getDb() {
    if (!db) {
        const databaseUrl = process.env.DATABASE_URL;
        if (!databaseUrl) throw new Error("Environment variable DATABASE_URL is required");

        const connectionUrl = new URL(databaseUrl);
        if (connectionUrl.protocol !== "postgresql:") throw new Error("DATABASE_URL's protocol must be 'postgresql'");

        const pool = new Pool({
            host: connectionUrl.hostname,
            port: connectionUrl.port ? Number(connectionUrl.port) : 5434,
            user: connectionUrl.username,
            password: connectionUrl.password,
            database: connectionUrl.pathname.substring(1),
        });

        db = new Kysely<DatabaseSchema>({
            dialect: new PostgresDialect({ pool }),
        });
    }

    return db;
}

export interface DatabaseSchema {
    atproto_auth_state: AtProtoAuthStateTable;
    atproto_auth_session: AtProtoAuthSessionTable;
    account: AccountTable;
    entry: EntryTable;
    follow: FollowTable;
}

export interface AtProtoAuthStateTable {
    key: string;
    value: string;
}

export interface AtProtoAuthSessionTable {
    key: string;
    value: string;
}

export interface AccountTable {
    did: string;
    email?: string;
    handle: string;
    avatar?: string;
    active: boolean;
}

export interface EntryTable {
    uri: string;
    authorDid: string;
    website: string;
    note?: string;
    tags: string[];
    createdAt: Date;
    indexedAt: Date;
}

export interface FollowTable {
    uri: string;
    follower: string;
    following: string;
    createdAt: Date;
    indexedAt: Date;
}