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

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

function getMinLevel(): Level {
  const env = process.env.LOG_LEVEL as Level | undefined;
  if (env && env in PRIORITY) return env;
  const appEnv = process.env.APP_ENV;
  return appEnv === "production" ? "info" : "debug";
}

function shouldLog(level: Level): boolean {
  return PRIORITY[level] >= PRIORITY[getMinLevel()];
}

function write(
  level: Level,
  ctx: string,
  message: string,
  data?: Record<string, unknown>
): void {
  if (!shouldLog(level)) return;
  const ts = new Date().toISOString();
  const tag = level.toUpperCase().padEnd(5);
  const line = data
    ? `[${ts}] [${tag}] [${ctx}] ${message} ${JSON.stringify(data)}`
    : `[${ts}] [${tag}] [${ctx}] ${message}`;
  if (level === "warn" || level === "error") {
    console.error(line);
  } else {
    console.log(line);
  }
}

export const logger = {
  debug: (ctx: string, message: string, data?: Record<string, unknown>) =>
    write("debug", ctx, message, data),
  info: (ctx: string, message: string, data?: Record<string, unknown>) =>
    write("info", ctx, message, data),
  warn: (ctx: string, message: string, data?: Record<string, unknown>) =>
    write("warn", ctx, message, data),
  error: (ctx: string, message: string, data?: Record<string, unknown>) =>
    write("error", ctx, message, data),
  isEnabled: (level: Level): boolean => shouldLog(level),
};