import { Injectable } from '@nestjs/common';

import {
  decimalFromString,
  divide,
  formatDecimal,
  multiply,
  subtract,
} from '../../../../../common/decimal';
import { ISO_DATE_LENGTH, ISO_DATE_START } from '../../../../../common/time';
import { decimal } from '../../../../../integrations/tbank/decimal';
import { CandleService } from '../../application/candle.service';
import {
  CatalogEnrichmentService,
  type CatalogPayload,
} from '../../application/catalog-enrichment.service';
import { timestamp } from '../../application/instrument-market';
import {
  StockCandlesQueryDto,
  StockQuoteDto,
  StockQuoteResourceDto,
} from '../presentation/stock.dto';

const ZERO_AMOUNT = 0n;

const CHANGE_PERCENT_DECIMAL_PLACES = 6;
@Injectable()
export class StockMarketService {
  constructor(
    private readonly history: CandleService,
    private readonly sources: CatalogEnrichmentService,
  ) {}

  async quote(
    userId: string,
    uid: string,
    observe = false,
  ): Promise<StockQuoteResourceDto> {
    const result = await this.sources.section(
      userId,
      'share',
      uid,
      'quote',
      observe,
    );
    return {
      data: result.values.instrument
        ? stockQuote(result.values, result.unavailable, result.observedAt)
        : null,
      meta: result.meta,
    };
  }

  candles(
    userId: string,
    uid: string,
    period: StockCandlesQueryDto['period'] = 'month',
    observe = false,
  ) {
    return this.history.read(
      userId,
      { uid, instrumentType: 'share', period },
      observe,
    );
  }
}

export function stockQuote(
  values: CatalogPayload,
  unavailable: string[],
  observedAt: string,
): StockQuoteDto {
  const { price: last, candle: previous, tradingStatus = null } = values;
  const share = values.instrument;
  const priceAt = timestamp(last?.time);
  const currency = share?.currency?.toUpperCase();
  const price =
    last?.price && currency
      ? { currency, value: formatDecimal(decimal(last.price)) }
      : null;
  const previousPrice =
    previous?.close && currency
      ? { currency, value: formatDecimal(decimal(previous.close)) }
      : null;
  const difference =
    price && previousPrice
      ? subtract(
          decimalFromString(price.value),
          decimalFromString(previousPrice.value),
        )
      : null;
  return {
    price,
    priceAt,
    tradingStatus,
    previousCloseDate: timestamp(previous?.time)?.slice(ISO_DATE_START, ISO_DATE_LENGTH) ?? null,
    previousClose: previousPrice,
    change:
      difference && currency
        ? { currency, value: formatDecimal(difference) }
        : null,
    changePercent:
      difference &&
      previousPrice &&
      decimalFromString(previousPrice.value).value > ZERO_AMOUNT
        ? formatDecimal(
            divide(
              multiply(difference, decimalFromString('100')),
              decimalFromString(previousPrice.value),
              CHANGE_PERCENT_DECIMAL_PLACES,
            ),
          )
        : null,
    unavailable,
    observedAt,
  };
}