import {Model} from "./Model";
import {AbstractResultIterable} from "../builder/result/AbstractResultIterable";
import {Connection} from "../connection/Connection";
import {ModelBuilder} from "./ModelBuilder";
import {Container, Instantiable} from "../../di";
import {QueryRow} from "../types";
import {Collection} from "../../util";

/**
 * Implementation of the result iterable that returns query results as instances of the defined model.
 */
export class ModelResultIterable<T extends Model<T>> extends AbstractResultIterable<T> {
    constructor(
        public readonly builder: ModelBuilder<T>,
        public readonly connection: Connection,
        /** The model that should be instantiated for each row. */
        protected readonly ModelClass: Instantiable<T>
    ) { super(builder, connection) }

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

    async at(i: number) {
        const query = this.connection.dialect().renderRangedSelect(this.selectSQL, i, i + 1)
        const row = (await this.connection.query(query)).rows.first()

        if ( row ) {
            return this.inflateRow(row)
        }
    }

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

    async count() {
        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<T>> {
        const result = await this.connection.query(this.selectSQL)
        return result.rows.promiseMap<T>(row => this.inflateRow(row))
    }

    /**
     * Given a query row, create an instance of the configured model class from it.
     * @param row
     * @protected
     */
    protected async inflateRow(row: QueryRow): Promise<T> {
        return Container.getContainer().make<T>(this.ModelClass).assumeFromSource(row)
    }

    clone() {
        return new ModelResultIterable(this.builder, this.connection, this.ModelClass)
    }
}