import {Connection} from '../connection/Connection'
import {Awaitable} from '../../util'
import {TableBuilder} from './TableBuilder'

/**
 * Represents a SQL-schema implementation.
 */
export abstract class Schema {
    constructor(
        /** The SQL connection to execute against. */
        protected readonly connection: Connection,
    ) { }

    /**
     * Resolve true if the schema has a table with the given name.
     * @param name
     */
    public abstract hasTable(name: string): Awaitable<boolean>

    /**
     * Resolve true if the schema table with the given name has a column with the given name.
     * @param table
     * @param name
     */
    public abstract hasColumn(table: string, name: string): Awaitable<boolean>

    /**
     * Resolve true if the schema table with the given name has all the specified columns.
     * @param table
     * @param name
     */
    public abstract hasColumns(table: string, name: string[]): Awaitable<boolean>

    /**
     * Get a TableBuilder instance for a table on the schema.
     * @param table
     */
    public abstract table(table: string): Awaitable<TableBuilder>

    /**
     * Apply the table to the schema.
     * @param schema
     */
    public async commit(schema: TableBuilder): Promise<void> {
        const query = this.connection
            .dialect()
            .renderCommitSchemaTransaction(schema)

        await this.connection.query(query)
    }
}