"use client";

import type { ReactNode, FormEvent } from "react";
import { Lock } from "lucide-react";
import Link from "next/link";
import { useRouter } from "next/navigation";
import { useId, useState } from "react";
import { apiUnlockPost, apiUnlockPostPassword } from "@/lib/api";
import { CSRF_COOKIE } from "@/lib/cookies";
import { toast } from "@/lib/toast";
import { hideKindLabel, type HideKind } from "@/lib/hideBlocks";

/** 若浏览器尚无 CSRF cookie，请求公开接口以触发后端签发 */
async function ensureGuestCSRF() {
  if (typeof document === "undefined") return;
  const escaped = CSRF_COOKIE.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
  if (new RegExp(`(?:^|;\\s*)${escaped}=`).test(document.cookie)) return;
  try {
    await fetch("/api/me", { credentials: "include", cache: "no-store" });
  } catch {
    /* 忽略：后续解锁会报 CSRF 错误 */
  }
}

type MdHideBlockProps = {
  kind: HideKind;
  points?: number;
  locked?: boolean;
  postId?: number;
  loggedIn?: boolean;
  children?: ReactNode;
};

/** 正文内嵌隐藏块：已解锁显示徽章容器；locked 显示就地门禁 */
export default function MdHideBlock({
  kind,
  points = 0,
  locked = false,
  postId,
  loggedIn = false,
  children,
}: MdHideBlockProps) {
  const router = useRouter();
  const pwdErrId = useId();
  const [busy, setBusy] = useState(false);
  const [pwd, setPwd] = useState("");
  const [pwdError, setPwdError] = useState("");
  const label = hideKindLabel(kind);

  if (locked) {
    const unlockPoints = async () => {
      if (!postId) return;
      setBusy(true);
      try {
        const res = await apiUnlockPost(String(postId));
        if (res.post) {
          toast("已解锁隐藏内容", "ok");
          router.refresh();
        } else {
          toast(res.error || "解锁失败", "error");
        }
      } catch {
        toast("解锁失败", "error");
      } finally {
        setBusy(false);
      }
    };

    const unlockPassword = async (e: FormEvent) => {
      e.preventDefault();
      if (!postId) return;
      const password = pwd.trim();
      if (!password) {
        setPwdError("请输入密码");
        return;
      }
      setBusy(true);
      setPwdError("");
      try {
        // 游客可能尚无 CSRF：先打一次公开 GET 让后端签发，再提交解锁
        await ensureGuestCSRF();
        const res = await apiUnlockPostPassword(String(postId), password);
        if (res.post) {
          toast("密码正确，已解锁", "ok");
          setPwd("");
          setPwdError("");
          router.refresh();
        } else {
          setPwdError(res.error || "密码错误，请重试");
        }
      } catch {
        setPwdError("验证失败，请稍后重试");
      } finally {
        setBusy(false);
      }
    };

    return (
      <aside
        className="j13-hide-gate"
        role="note"
        aria-label={`${label}（未解锁）`}
      >
        <Lock size={22} className="j13-hide-gate-icon" aria-hidden />
        <p className="j13-hide-gate-title">此段内容{label}</p>
        <p className="j13-hide-gate-desc meta">
          {kind === "points"
            ? `支付 ${points || 0} 积分后可阅读此段`
            : kind === "reply"
              ? loggedIn
                ? "发表一条回复后即可阅读此段"
                : "登录并发表一条回复后即可阅读此段"
              : kind === "password"
                ? "输入正确密码后可阅读此段"
                : "登录后即可阅读此段"}
        </p>
        <div className="j13-hide-gate-actions">
          {kind === "login" && !loggedIn && postId && (
            <Link
              href={`/login?redirect=${encodeURIComponent(`/post/${postId}`)}`}
              className="btn btn-primary"
            >
              去登录
            </Link>
          )}
          {kind === "points" && loggedIn && postId && (
            <button
              type="button"
              className="btn btn-primary"
              disabled={busy}
              onClick={() => void unlockPoints()}
            >
              {busy ? "解锁中…" : `支付 ${points || 0} 积分解锁`}
            </button>
          )}
          {kind === "points" && !loggedIn && postId && (
            <Link
              href={`/login?redirect=${encodeURIComponent(`/post/${postId}`)}`}
              className="btn btn-primary"
            >
              登录后解锁
            </Link>
          )}
          {kind === "reply" && postId && !loggedIn && (
            <Link
              href={`/login?redirect=${encodeURIComponent(`/post/${postId}#comment-input`)}`}
              className="btn btn-primary"
            >
              登录后去回复
            </Link>
          )}
          {kind === "reply" && loggedIn && (
            <a
              href="#comment-input"
              className="btn btn-primary"
              onClick={(e) => {
                e.preventDefault();
                const el = document.getElementById("comment-input");
                if (!(el instanceof HTMLTextAreaElement)) {
                  document.getElementById("comments")?.scrollIntoView({
                    behavior: "smooth",
                    block: "start",
                  });
                  return;
                }
                el.scrollIntoView({ behavior: "smooth", block: "center" });
                window.setTimeout(() => {
                  el.focus({ preventScroll: true });
                }, 280);
              }}
            >
              去回复
            </a>
          )}
          {kind === "password" && postId && (
            <div className="j13-hide-pwd-wrap">
              <form className="j13-hide-pwd-form" onSubmit={(e) => void unlockPassword(e)}>
                <input
                  type="password"
                  className={`j13-hide-pwd-input${pwdError ? " is-invalid" : ""}`}
                  placeholder="输入密码"
                  value={pwd}
                  maxLength={64}
                  autoComplete="off"
                  disabled={busy}
                  aria-invalid={pwdError ? true : undefined}
                  aria-describedby={pwdError ? pwdErrId : undefined}
                  onChange={(e) => {
                    setPwd(e.target.value);
                    if (pwdError) setPwdError("");
                  }}
                  aria-label="隐藏内容密码"
                />
                <button type="submit" className="btn btn-primary" disabled={busy}>
                  {busy ? "验证中…" : "查看"}
                </button>
              </form>
              {pwdError && (
                <p id={pwdErrId} className="j13-hide-pwd-error" role="alert">
                  {pwdError}
                </p>
              )}
            </div>
          )}
        </div>
      </aside>
    );
  }

  return (
    <div className="j13-hide-block" data-hide-kind={kind}>
      <div className="j13-hide-block-bar">
        <span className="j13-hide-badge">{label}</span>
        {kind === "points" && points > 0 && (
          <span className="meta text-[12px]">{points} 积分</span>
        )}
      </div>
      <div className="j13-hide-block-body">{children}</div>
    </div>
  );
}