type LogLevel = "debug" | "info" | "warn" | "error";

interface LogEntry {
  level: LogLevel;
  message: string;
  timestamp: string;
  requestId?: string;
  module?: string;
  [key: string]: unknown;
}

const LOG_LEVELS: Record<LogLevel, number> = {
  debug: 0,
  info: 1,
  warn: 2,
  error: 3,
};

const currentLevel: LogLevel =
  (process.env.LOG_LEVEL as LogLevel) ?? (process.env.NODE_ENV === "production" ? "info" : "debug");

let requestIdCounter = 0;

export function generateRequestId(): string {
  requestIdCounter += 1;
  return `${Date.now().toString(36)}-${requestIdCounter.toString(36)}`;
}

function shouldLog(level: LogLevel): boolean {
  // eslint-disable-next-line security/detect-object-injection -- LOG_LEVELS keyed by LogLevel union
  return LOG_LEVELS[level] >= LOG_LEVELS[currentLevel];
}

function formatLog(entry: LogEntry): string {
  return JSON.stringify(entry);
}

function writeLog(entry: LogEntry): void {
  if (!shouldLog(entry.level)) return;

  const formatted = formatLog(entry);

  switch (entry.level) {
    case "error":
      console.error(formatted);
      break;
    case "warn":
      console.warn(formatted);
      break;
    default:
      console.log(formatted);
      break;
  }
}

export const logger = {
  debug(message: string, meta: Record<string, unknown> = {}): void {
    writeLog({ level: "debug", message, timestamp: new Date().toISOString(), ...meta });
  },

  info(message: string, meta: Record<string, unknown> = {}): void {
    writeLog({ level: "info", message, timestamp: new Date().toISOString(), ...meta });
  },

  warn(message: string, meta: Record<string, unknown> = {}): void {
    writeLog({ level: "warn", message, timestamp: new Date().toISOString(), ...meta });
  },

  error(message: string, meta: Record<string, unknown> = {}): void {
    writeLog({ level: "error", message, timestamp: new Date().toISOString(), ...meta });
  },
};