import Knex from 'knex';

import config from '../knexfile';

export interface Pg {
    userGetId: (id: UUID) => Promise<User>,
    userGetName: (name: string) => Promise<User>,
    userUpsert: (user: User) => Promise<User>,
    userWants: (user: User) => Promise<Want[]>,

    wantUpsert: (want: Want, user: User) => Promise<Want>,
    listingUpsert: (listing: Listing, want: Want) => Promise<Listing>,
    listingGet: (id: number) => Promise<Listing>,
}

export default function createPg(): Pg {
    const pg = Knex(config);

    async function userGetId(id): Promise<User> {
        return pg('users')
            .where({ id })
            .first();
    }

    async function userGetName(name): Promise<User> {
        return pg('users')
            .where({ discogs: name })
            .first();
    }

    async function userWants(user: User): Promise<Want[]> {
        return pg('wants')
            .where({ user: user.id });
    }

    async function userUpsert(user): Promise<User> {
        const [row] = await pg('users')
            .insert({
                discogs: user.username,
                data: user,
            })
            .onConflict('id')
            .merge()
            .onConflict('discogs')
            .merge()
            .returning('*');

        return row;
    }

    async function wantUpsert(want, user): Promise<Want> {
        const [row] = await pg('wants')
            .insert({
                data: want,
                release: want.id,
                user: user.id,
            })
            .onConflict('id')
            .merge()
            .onConflict(['user', 'release'])
            .merge()
            .returning('*');

        return row;
    }

    async function listingUpsert(listing, want): Promise<Listing> {
        const [row] = await pg('listings')
            .insert({
                id: listing.id,
                want: want.id,
                seller: listing.seller.id,
                data: listing,
            })
            .onConflict('id')
            .merge()
            .returning('*');

        return row;
    }

    async function listingGet(id): Promise<Listing> {
        return pg('listings')
            .where({ id })
            .first();
    }

    return {
        userGetId,
        userGetName,
        userUpsert,
        userWants,

        wantUpsert,
        listingUpsert,
        listingGet,
    };
}