import { dev } from "$app/environment";
import { configure, getConsoleSink, type LogRecord } from "@logtape/logtape";
import { requestContext } from "$lib/server/context";

interface RailwayLogEntry {
  timestamp: string;
  level: string;
  message: string;
  target: string;
  [key: string]: unknown;
}

function railwayFormatter(record: LogRecord): string {
  const ctx = requestContext.getStore();
  const categoryTarget = record.category.join(":");
  const entry: RailwayLogEntry = {
    timestamp: new Date().toISOString(),
    level: record.level.toLowerCase(),
    message: record.message.join(" "),
    target: categoryTarget ? `bun:${categoryTarget}` : "bun",
    ...(ctx?.requestId && { req_id: ctx.requestId }),
  };

  if (record.properties && Object.keys(record.properties).length > 0) {
    Object.assign(entry, record.properties);
  }

  return JSON.stringify(entry) + "\n";
}

export async function initLogger() {
  const useJsonLogs =
    process.env.LOG_JSON === "true" || process.env.LOG_JSON === "1";

  const logLevel = (process.env.LOG_LEVEL?.toLowerCase() ??
    (dev ? "debug" : "info")) as "debug" | "info" | "warning" | "error";

  const jsonSink = (record: LogRecord) => {
    process.stdout.write(railwayFormatter(record));
  };
  const consoleSink = getConsoleSink();

  try {
    await configure({
      sinks: {
        json: useJsonLogs ? jsonSink : consoleSink,
        console: useJsonLogs ? jsonSink : consoleSink,
      },
      filters: {},
      loggers: [
        {
          category: ["logtape", "meta"],
          lowestLevel: "warning",
          sinks: [useJsonLogs ? "json" : "console"],
        },
        {
          category: [],
          lowestLevel: logLevel,
          sinks: [useJsonLogs ? "json" : "console"],
        },
      ],
    });
  } catch (error) {
    if (
      error instanceof Error &&
      error.message.includes("Already configured")
    ) {
      return;
    }
    throw error;
  }
}