import * as Knex from "knex";

/*
This migration converts the storeLinks column from JSON to plain text.
The reason is that there are too many differences between the JSON support
of different back-ends, making plain text easier to deal with.
*/

async function castStoreLinks(table: string, knex: any) {
    await knex.schema.alterTable(table, (t: any) => {
        t.string('storeLinksTemp');
    });
    await knex(table).update({
        storeLinksTemp: knex.raw('CAST("storeLinks" AS VARCHAR(255))')
    })
    await knex.schema.alterTable(table, (t: any) => {
        t.dropColumn('storeLinks');
    });
    await knex.schema.alterTable(table, (t: any) => {
        t.renameColumn('storeLinksTemp', 'storeLinks');
    });
}

async function revertStoreLinks(table: string, knex: any) {
    await knex.schema.alterTable(table, (t: any) => {
        t.json('storeLinksTemp');
    });
    if (knex.client.config.client === 'sqlite3') {
        await knex(table).update({
            storeLinksTemp: knex.raw('"storeLinks"')
        })
    } else {
        await knex(table).update({
            storeLinksTemp: knex.raw('CAST("storeLinks" AS json)')
        })
    }
    await knex.schema.alterTable(table, (t: any) => {
        t.dropColumn('storeLinks');
    });
    await knex.schema.alterTable(table, (t: any) => {
        t.renameColumn('storeLinksTemp', 'storeLinks');
    });
}

export async function up(knex: Knex): Promise<void> {
    console.log("Knex client:", knex.client.config);
    await castStoreLinks('songs', knex);
    await castStoreLinks('albums', knex);
    await castStoreLinks('artists', knex);
}


export async function down(knex: Knex): Promise<void> {
    await revertStoreLinks('songs', knex);
    await revertStoreLinks('albums', knex);
    await revertStoreLinks('artists', knex);
}