import { fetchRate } from "./api.js";
import { insertIntoDB } from "./db.js";

export class Bot {
  constructor(pair, interval, threshold) {
    this.pair = pair;
    this.interval = interval;
    this.threshold = threshold;
    this.lastPrice = null;
    this.running = null;
    this.timer = null;
  }

  start() {
    if (!this.running) {
      this.running = true;

      console.log(`[STARTED] Monitoring ${this.pair}`);

      this.check().catch((err) =>
        console.error(
          `[ERROR] Initialization failed for ${this.pair}: ${err.message}`,
        ),
      );

      this.timer = setInterval(async () => {
        try {
          await this.check();
        } catch (err) {
          console.error(`[ERROR] ${this.pair}: ${err.message}`);
        }
      }, this.interval);
    }
  }

  stop() {
    this.isRunning = false;
    if (this.timer) {
      clearInterval(this.timer);
    }
  }

  async check() {
    const currentPrice = await fetchRate(this.pair);

    if (!this.lastPrice) {
      this.lastPrice = currentPrice;
      console.log(`[INIT] ${this.pair} set to ${currentPrice.toFixed(2)}`);
      return;
    }

    const diff = currentPrice.minus(this.lastPrice);
    const percentDiff = diff.dividedBy(this.lastPrice).multipliedBy(100);

    if (percentDiff.abs().gte(this.threshold)) {
      const direction = diff.isPositive() ? "UP" : "DOWN";
      const priceStr = currentPrice.toFixed(2);
      const prevPriceStr = this.lastPrice.toFixed(2);
      const pctNum = percentDiff.toNumber();

      this.alert(direction, priceStr, pctNum);
      insertIntoDB({
        pair: this.pair,
        direction,
        previousPrice: prevPriceStr,
        newPrice: priceStr,
        percentChange: pctNum,
        interval: this.interval,
        threshold: this.threshold,
      });

      this.lastPrice = currentPrice;
    }
  }

  alert(direction, priceStr, percentChange) {
    const sign = direction === "UP" ? "+" : "-";
    console.log(
      `[ALERT] ${this.pair} ${direction} ${sign}${percentChange.toFixed(2)}% | Price: ${priceStr}`,
    );
  }
}