import Papa from "papaparse";
import iconv from "iconv-lite";
import { createParser } from "@/parser";
import { Actual, ActualImportResult } from "@/backend";
import { Config } from "@/types/config";
import { Readable } from "stream";
import { Transaction } from "@/types/transaction";

export type ImportResult = {
  transactions: Transaction[];
  result: ActualImportResult;
  skipped: string[][];
};

export async function importTransactions(stream: Readable, profile: string, server: string, config: Config, dryRun?: boolean): Promise<ImportResult> {  
  return new Promise((resolve, reject) => {
    const profileConfig = config.profiles[profile];

    if (!profileConfig) {
      throw new Error(`Unknown profile: ${profile}`);
    }

    const serverConfig = config.servers[server];
    if(!serverConfig) {
      throw new Error(`Unknown server: ${server}`);
    }

    const parser = createParser(profileConfig, serverConfig);

    const actualServer = new Actual(serverConfig, dryRun);
    const skipped: string[][] = [];

    const handleRow = async (data: string[]) => {
      const pushed = await parser.pushTransaction(data);
      
      if (!pushed) {
        skipped.push(data);
      }
    };

    const handleClose = async () => {
      try {
        const transactions = await parser.reconcile();      
        const result = await actualServer.submit(transactions);

        resolve({
          transactions,
          result,
          skipped
        });
                    
      } catch (e) {
        console.error(e);
        reject(e);
      }
    };
    
    stream
      .pipe(iconv.decodeStream(profileConfig.encoding ?? "utf8"))    
      .pipe(Papa.parse(Papa.NODE_STREAM_INPUT))
      .on('data', handleRow)
      .on('close', handleClose);
  });
};