import Builder from "./Builder";
import Binding from "./Library";
import { encodeRequest, decodeRows, decodeResponse } from "./Protocol";
import type { ExecResult } from "./Protocol";

type Options = {
  database: string;
};

/**
 * Allows to use SQLite databases in a NodeJS process.
 */
export default class CBuilder<
  I extends abstract new (...args: any) => any,
> extends Builder<I> {
  constructor(opts: Options) {
    super({ database: opts.database, url: "" });
  }
  /**
   * TODO: handle responses
   */
  async *Rows<T = InstanceType<I>>(): AsyncGenerator<T> {
    this.formatRequest();
    const req = Buffer.from(encodeRequest(this.request));
    const iter = Binding.rowIterator(req);
    for (;;) {
      const response = iter.next();
      const rows = decodeRows(response);
      if (rows.length === 0) {
        iter.cleanup();
        break;
      }
      for (const row of rows) {
        if (this.headerRow === null) {
          this.headerRow = row.r;
          continue;
        }
        yield this.formatRow(row.r);
      }
    }
  }
  async Query<T = InstanceType<I>>(): Promise<T[]> {
    const rows = this.Rows();
    const result: T[] = [];
    for await (const row of rows) {
      result.push(row);
    }
    return result;
  }
  async Exec(): Promise<ExecResult> {
    this.formatRequest();
    const req = Buffer.from(encodeRequest(this.request));
    const iter = Binding.rowIterator(req);
    const response = iter.next();
    return decodeResponse(response);
  }
}