import {QueryRow} from '../../types'
import {Builder} from '../Builder'
import {Connection} from '../../connection/Connection'
import {AbstractResultIterable} from './AbstractResultIterable'
import {Collection} from '../../../util'

/**
 * Implementation of AbstractResultIterable that yields simple QueryRow instances (objects).
 */
export class ResultIterable extends AbstractResultIterable<QueryRow> {
    constructor(
        public readonly builder: Builder,
        public readonly connection: Connection,
    ) {
        super(builder, connection)
    }

    public get selectSQL(): string {
        return this.connection.dialect().renderSelect(this.builder)
    }

    async at(i: number): Promise<QueryRow | undefined> {
        const query = this.connection.dialect().renderRangedSelect(this.selectSQL, i, i + 1)
        return (await this.connection.query(query)).rows.first()
    }

    async range(start: number, end: number): Promise<Collection<QueryRow>> {
        const query = this.connection.dialect().renderRangedSelect(this.selectSQL, start, end)
        return (await this.connection.query(query)).rows
    }

    async count(): Promise<number> {
        const query = this.connection.dialect().renderCount(this.selectSQL)
        const result = (await this.connection.query(query)).rows.first()
        return result?.extollo_render_count ?? 0
    }

    async all(): Promise<Collection<QueryRow>> {
        const result = await this.connection.query(this.selectSQL)
        return result.rows
    }

    clone(): ResultIterable {
        return new ResultIterable(this.builder, this.connection)
    }
}