import log from "@shared/utils/logger.ts";
import * as mariadb from "npm:mariadb";
import { getMessageFromError } from "@shared/utils/result.ts";

interface MariaDBConfig {
    user: string;
    password: string;
    host: string;
    port: number;
    database: string;
}

export function loadMariaDBConfigFromEnv(): MariaDBConfig {
    const requiredVars = [
        "KBRG_MYSQL_USER",
        "KBRG_MYSQL_PASSWORD",
        "KBRG_MYSQL_DATABASE",
    ];

    const missingVars = requiredVars.filter(
        (varName) => !Deno.env.has(varName),
    );

    if (missingVars.length > 0) {
        log.critical(
            `Missing required environment variables: ${missingVars.join(", ")}`,
        );
        Deno.exit(1);
    }

    const host = Deno.env.get("KBRG_MYSQL_HOST") || "localhost";
    const user = Deno.env.get("KBRG_MYSQL_USER")!;
    const password = Deno.env.get("KBRG_MYSQL_PASSWORD")!;
    const database = Deno.env.get("KBRG_MYSQL_DATABASE")!;
    const port = parseInt(Deno.env.get("KBRG_MYSQL_PORT") || "3306");

    if (isNaN(port)) {
        log.critical(`Invalid port number for KBRG_MYSQL_PORT: ${port}`);
        Deno.exit(1);
    }

    return { user, password, host, port, database };
}

export async function createAndTestMariaDBPool(
    config: MariaDBConfig,
): Promise<mariadb.Pool> {
    const { user, password, host, port, database } = config;

    try {
        const pool = mariadb.createPool({
            host,
            port,
            user,
            password,
            database,
            connectionLimit: 10,
        });

        // Test Connection
        const connection = await pool.getConnection();
        connection.release();

        log.info("Successfully connected to MySQL");

        return pool;
    } catch (e) {
        const errorMessage = getMessageFromError(e);
        log.critical(`Failed to create MySQL pool: ${errorMessage}`);
        Deno.exit(1);
    }
}