import { Connection, ConnectionNotReadyError } from './Connection.ts'
import { Client } from '../../../lib/src/external/db.ts'
import {collect, Collection} from '../../../lib/src/collection/Collection.ts'
import { QueryResult, QueryRow } from './types.ts'
import { logger } from '../../../lib/src/service/logging/global.ts'

export default class PostgresConnection extends Connection {
    private _client?: Client

    public async init() {
        this._client = new Client(this.config)

        logger.info(`Opening PostgreSQL database for connection: ${this.name}`)
        await this._client.connect()
    }

    public async query(query: string) {
        if ( !this._client ) throw new ConnectionNotReadyError(this.name)
        const result = await this._client.query(query)

        let base_i = 0
        const cols = collect(result?.rowDescription?.columns || []).sortBy('index').map(col => {
            col.index = base_i
            base_i += 1
            return col
        })

        const rows = new Collection<QueryRow>()
        for ( const row of result.rows ) {
            const row_obj: { [key: string]: any } = {}
            for ( const col of cols ) {
                // @ts-ignore
                row_obj[col.name] = row[col.index]
            }
            rows.push(row_obj)
        }

        logger.verbose(`Query result returned ${result.rowCount} row(s).`)
        return {
            rows,
            row_count: result.rowCount,
        } as QueryResult
    }

    public async close() {
        if ( this._client )
            await this._client.end()
    }

}