exports.up = function (knex, Promise) {
    return knex.schema.createTable('messages_announcements', function (table) {
        table.increments('mid'); //autoincrementing (non-nullable) primary key
        table.timestamps(true, true); //adds timestamptz-type (a PostgresQL data type) updated_at and created_at columns

        table.string('title').notNullable();
        table.text('content');
        table.integer('views').defaultTo(0);
        
        /*
        Les auteurs et destinataires des annonces sont dans les tables announcements_authors et announcements_recipients
        table.string('recipient',128).notNullable().defaultTo('noone')
            .references('gid').inTable('groups')
            .onDelete('SET DEFAULT'); //if recipient is deleted, direct to the special "no-one" group
        //TODO: for now, we support only 1 author (where as graphql schema indicates support for [Group] authors)
        table.string('author',128).notNullable()
            .references('gid').inTable('groups')
            .onDelete('CASCADE'); //delete message if author is deleted
        */

        /* 
        we cannot declare this column yet, as table 'message_events' is not yet created.
        it will be declared in the migration for the 'message_events' table.
        table.integer('for_event')
            .references('mid').inTable('message_events')
            .onDelete('SET NULL');
        */

    });
};

exports.down = function (knex, Promise) {
    return knex.schema.dropTable('messages_announcements');
};