/**
 * @file Frontend logger that forwards console output to the backend telemetry service.
 * @copyright nhcarrigan
 * @license Naomi's Public License
 * @author Naomi Carrigan
 */
/* eslint-disable no-console -- This file intentionally overrides console methods */

type Level = "debug" | "info" | "warn";

const post = (path: string, body: object): void => {
  void fetch(path, {
    body:    JSON.stringify(body),
    // eslint-disable-next-line @typescript-eslint/naming-convention -- HTTP header names use kebab-case
    headers: { "Content-Type": "application/json" },
    method:  "POST",
  }).catch(() => {
    // Intentionally swallowed — we cannot log logger failures without infinite recursion.
  });
};

/**
 * Overrides the global console.log and console.error methods so that all
 * frontend log output is forwarded to the backend telemetry endpoints.
 * Must be called once at application startup before any other code runs.
 */
const initialiseFrontendLogger = (): void => {
  const originalLog = console.log.bind(console);
  const originalError = console.error.bind(console);

  console.log = (...consoleArguments: Array<unknown>): void => {
    originalLog(...consoleArguments);
    const level: Level = "info";
    const message = consoleArguments.map((argument) => {
      return typeof argument === "string"
        ? argument
        : JSON.stringify(argument);
    }).join(" ");
    post("/api/fe/log", { level, message });
  };

  console.error = (...consoleArguments: Array<unknown>): void => {
    originalError(...consoleArguments);
    const message = consoleArguments.map((argument) => {
      if (argument instanceof Error) {
        return `${argument.message}\n${argument.stack ?? ""}`;
      }
      return typeof argument === "string"
        ? argument
        : JSON.stringify(argument);
    }).join(" ");

    /*
     * Ignore errors originating entirely from third-party scripts (e.g. AdSense).
     * Stack frames from our own code reference elysium.nhcarrigan.com or localhost;
     * if none are present but external URLs are, the error is not actionable.
     */
    const hasExternalUrl = (/https?:\/\//u).test(message);
    const hasOurDomain = message.includes("elysium.nhcarrigan.com");
    const hasOwnFrame = hasOurDomain || message.includes("localhost");
    if (hasExternalUrl && !hasOwnFrame) {
      return;
    }
    const context = "console.error";
    post("/api/fe/error", { context, message });
  };

  console.warn = (...consoleArguments: Array<unknown>): void => {
    originalLog(...consoleArguments);
    const level: Level = "warn";
    const message = consoleArguments.map((argument) => {
      return typeof argument === "string"
        ? argument
        : JSON.stringify(argument);
    }).join(" ");
    post("/api/fe/log", { level, message });
  };
};

export { initialiseFrontendLogger };