import { useState } from "react";
import { Circle, CircleCheck } from "lucide-react";

import { Text } from "@/components/ui/text";
import { evaluatePasswordRules, type PasswordRuleResult } from "@/domain/auth/password-policy";
import { cn } from "@/lib/utils";

export type PasswordChecklistProps = {
  password: string;
  id?: string;
  className?: string;
};

function describeChanges(previous: PasswordRuleResult[], next: PasswordRuleResult[]): string {
  return next
    .filter((rule, index) => rule.met !== previous[index]?.met)
    .map((rule) => `${rule.label}: ${rule.met ? "requirement met" : "requirement not met"}`)
    .join(". ");
}

/**
 * Live, per-rule feedback for the shared password policy. A polite status region
 * announces only the rules whose state changed, so screen-reader users hear
 * progress while typing without the whole list being re-read on each keystroke.
 */
export function PasswordChecklist({ password, id, className }: PasswordChecklistProps) {
  const results = evaluatePasswordRules(password);
  const signature = results.map((rule) => (rule.met ? "1" : "0")).join("");
  const [previous, setPrevious] = useState({ signature, results });
  const [announcement, setAnnouncement] = useState("");

  if (previous.signature !== signature) {
    setPrevious({ signature, results });
    setAnnouncement(describeChanges(previous.results, results));
  }

  return (
    <>
      <ul
        id={id}
        aria-label="Password requirements"
        className={cn("m-0 mt-2 grid list-none gap-1 p-0", className)}
      >
        {results.map(({ id: ruleId, label, met }) => (
          <li key={ruleId} data-rule={ruleId} data-met={met} className="flex items-center gap-1.5">
            {met ? (
              <CircleCheck size={13} aria-hidden="true" className="text-(--color-success)" />
            ) : (
              <Circle size={13} aria-hidden="true" className="text-(--color-text-muted)" />
            )}
            <Text variant="caption" tone={met ? "success" : "muted"}>
              {label}
            </Text>
            <span className="sr-only">{met ? "requirement met" : "requirement not met"}</span>
          </li>
        ))}
      </ul>
      <Text variant="feedback" className="sr-only">
        {announcement}
      </Text>
    </>
  );
}