import { env } from "../env";
import winston from "winston";
import { getCurrentSpan } from "./instrumentation";
import { propagation, context } from "@opentelemetry/api";

const tracingFormat = function () {
  return winston.format((info) => {
    const span = getCurrentSpan();
    if (span) {
      const { spanId, traceId } = span.spanContext();
      const traceIdEnd = traceId.slice(traceId.length / 2);
      info["dd.trace_id"] = BigInt(`0x${traceIdEnd}`).toString();
      info["dd.span_id"] = BigInt(`0x${spanId}`).toString();
      info["trace_id"] = traceId;
      info["span_id"] = spanId;
    }
    const baggage = propagation.getBaggage(context.active());
    if (baggage) {
      const headerObj: Record<string, string> = {};
      baggage.getAllEntries().forEach(([k, v]) => (headerObj[k] = v.value));
      if (Object.keys(headerObj).length) info = { ...headerObj, ...info };
    }
    return info;
  })();
};

const getWinstonLogger = (
  nodeEnv: "development" | "production" | "test",
  minLevel = "info",
) => {
  const textLoggerFormat = winston.format.combine(
    winston.format.errors({ stack: true }),
    winston.format.timestamp(),
    winston.format.align(),
    winston.format.printf((info) => {
      const logMessage = `${info.timestamp} ${info.level} ${info.message}`;
      return info.stack ? `${logMessage}\n${info.stack}` : logMessage;
    }),
  );

  const jsonLoggerFormat = winston.format.combine(
    winston.format.errors({ stack: true }),
    winston.format.timestamp(),
    tracingFormat(),
    winston.format.json(),
  );

  const format =
    env.LANGFUSE_LOG_FORMAT === "text" ? textLoggerFormat : jsonLoggerFormat;
  return winston.createLogger({
    level: minLevel,
    format: format,
    transports: [new winston.transports.Console()],
  });
};

export const logger = getWinstonLogger(env.NODE_ENV, env.LANGFUSE_LOG_LEVEL);