import { promisify } from 'util';
import zlib from 'zlib';

import * as Sentry from '@sentry/node';
import SQL from 'sql-template-strings';
import * as sqlite from 'sqlite';
import sqlite3 from 'sqlite3';
import { ulid } from 'ulid';

import type { UserRow } from './express/user.ts';

import { rootDir } from '~/server/paths.ts';

interface Payload {
    userId?: string;
    [key: string]: unknown;
}

let connection: sqlite.Database | null = null;
const connect = async (): Promise<sqlite.Database> => {
    if (!connection) {
        connection = await sqlite.open({
            filename: `${rootDir}/audit.sqlite`,
            driver: sqlite3.Database,
        });

        // we don't want to replicate the migration setup just for this, so a little workaround here.
        // it's already executed on live db, so only creating the table on dev
        if (process.env.NODE_ENV === 'development') {
            await connection.exec(`
                CREATE TABLE IF NOT EXISTS audit_log
                (
                    id          TEXT NOT NULL PRIMARY KEY,
                    userId      TEXT,
                    username    TEXT,
                    aboutUserId TEXT NULL,
                    event       TEXT NOT NULL,
                    payload     BLOB NULL
                );
                CREATE INDEX IF NOT EXISTS "audit_log_userId" ON "audit_log" ("userId");
                CREATE INDEX IF NOT EXISTS "audit_log_username" ON "audit_log" ("username");
                CREATE INDEX IF NOT EXISTS "audit_log_aboutUserId" ON "audit_log" ("aboutUserId");
            `);
        }
    }

    return connection;
};

export const closeAuditLogConnection = async () => {
    if (connection) {
        await connection.close();
        connection = null;
    }
};

const gzip = promisify(zlib.gzip);
const gunzip = promisify(zlib.gunzip);

export const auditLog = async (
    req: { user?: Pick<UserRow, 'id' | 'username'> | null; rawUser?: Pick<UserRow, 'id' | 'username'> | undefined },
    event: string,
    payload: Payload | null = null,
): Promise<void> => {
    const db = await connect();

    try {
        const compressedPayload = payload
            ? await gzip(Buffer.from(JSON.stringify(payload)) as Uint8Array)
            : null;

        const user = req.user || req.rawUser || { id: null, username: null };
        await db.get(SQL`INSERT INTO audit_log (id, userId, aboutUserId, username, event, payload) VALUES (
            ${ulid()}, ${user.id}, ${payload?.userId || null}, ${user.username}, ${event}, ${compressedPayload}
        )`);
    } catch (error) {
        Sentry.captureException(error);
    }
};

export const fetchAuditLog = async (username: string, userId: string, aboutUserId: string) => {
    const db = await connect();

    const entries = await db.all(SQL`
        SELECT * FROM audit_log
        WHERE username = ${username} OR userId = ${userId} OR aboutUserId = ${aboutUserId}
        ORDER BY id DESC
    `);

    return await Promise.all(entries.map(async (entry) => {
        const payload = entry.payload ? JSON.parse((await gunzip(entry.payload)).toString()) : null;
        return { ...entry, payload };
    }));
};