"use client";

import { useEffect, useRef, useState, type FormEvent } from "react";
import styles from "../vip.module.css";

type LoginFormProps = {
  onVerify: (userId: string) => Promise<boolean>;
  onVerifyByEmail?: (
    email: string,
    password: string,
    user_id?: string
  ) => Promise<boolean | { ok: boolean; error?: string }>;
  onSuccess: () => void;
  autoFocus?: boolean;
  /** 验证请求进行中（用于全屏 loading 等） */
  onBusyChange?: (busy: boolean) => void;
};

export function LoginForm({
  onVerify,
  onVerifyByEmail,
  onSuccess,
  autoFocus,
  onBusyChange,
}: LoginFormProps) {
  const [mode, setMode] = useState<"user_id" | "email">("user_id");
  const [userId, setUserId] = useState("");
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const inputRef = useRef<HTMLInputElement>(null);

  const getCandidateUserId = (): string => {
    if (typeof window === "undefined") return "";
    const fromMemos = localStorage.getItem("memosAccount")?.trim() || "";
    if (/^user\d+$/.test(fromMemos)) return fromMemos;
    const fromUserId = localStorage.getItem("userId")?.trim() || "";
    if (/^user\d+$/.test(fromUserId)) return fromUserId;
    return "";
  };

  useEffect(() => {
    if (autoFocus) inputRef.current?.focus();
  }, [autoFocus, mode]);

  useEffect(() => {
    onBusyChange?.(loading);
  }, [loading, onBusyChange]);

  const handleUserIdSubmit = async (e: FormEvent) => {
    e.preventDefault();
    const trimmed = userId.trim();
    if (!trimmed) {
      setError("请输入您的账号");
      return;
    }

    setError(null);
    setLoading(true);
    let succeeded = false;
    try {
      const ok = await onVerify(trimmed);
      if (ok) {
        succeeded = true;
        onSuccess();
      } else {
        setError("未找到该账号的会员记录，请确认账号正确");
      }
    } catch {
      setError("验证失败，请稍后重试");
    } finally {
      if (!succeeded) setLoading(false);
    }
  };

  const handleEmailSubmit = async (e: FormEvent) => {
    e.preventDefault();
    if (!onVerifyByEmail) return;

    const trimmedEmail = email.trim();
    const trimmedPassword = password.trim();
    if (!trimmedEmail) {
      setError("请输入邮箱");
      return;
    }
    if (!trimmedPassword) {
      setError("请输入密码");
      return;
    }

    setError(null);
    setLoading(true);
    let succeeded = false;
    try {
      const candidateUserId = getCandidateUserId();
      const result = await onVerifyByEmail(
        trimmedEmail,
        trimmedPassword,
        candidateUserId || undefined
      );
      const ok = typeof result === "object" ? result.ok : result;
      const errMsg = typeof result === "object" ? result.error : undefined;
      if (ok) {
        succeeded = true;
        onSuccess();
      } else {
        setError(errMsg || "邮箱或密码错误，或未找到关联的会员记录");
      }
    } catch {
      setError("验证失败，请稍后重试");
    } finally {
      if (!succeeded) setLoading(false);
    }
  };

  const inputStyle = {
    width: "100%" as const,
    padding: "0.75rem 1rem",
    fontSize: "1rem",
    border: "1px solid var(--border)",
    borderRadius: "8px",
    background: "var(--background)",
    color: "var(--foreground)",
    marginBottom: "0.75rem",
  };

  return (
    <>
      <div className="mb-3 flex gap-2">
        <button
          type="button"
          onClick={() => {
            setMode("user_id");
            setError(null);
          }}
          className={`flex-1 rounded-lg py-2 text-sm font-medium ${
            mode === "user_id"
              ? "bg-[var(--primary)] text-[var(--primary-foreground)]"
              : "bg-[var(--muted)] text-[var(--muted-foreground)]"
          }`}
        >
          账号
        </button>
        <button
          type="button"
          onClick={() => {
            setMode("email");
            setError(null);
          }}
          className={`flex-1 rounded-lg py-2 text-sm font-medium ${
            mode === "email"
              ? "bg-[var(--primary)] text-[var(--primary-foreground)]"
              : "bg-[var(--muted)] text-[var(--muted-foreground)]"
          }`}
        >
          邮箱
        </button>
      </div>

      {mode === "user_id" ? (
        <form onSubmit={handleUserIdSubmit}>
          <input
            ref={inputRef}
            type="text"
            value={userId}
            onChange={(e) => setUserId(e.target.value)}
            placeholder="例如：user1773315608560"
            disabled={loading}
            style={inputStyle}
          />
          {error && (
            <p style={{ fontSize: "0.85rem", color: "#ef4444", marginBottom: "0.75rem" }}>
              {error}
            </p>
          )}
          <button
            type="submit"
            disabled={loading}
            className={`${styles.btnPrimary} ${styles.btnLarge}`}
            style={{ width: "100%" }}
          >
            {loading ? "验证中..." : "验证并登录"}
          </button>
        </form>
      ) : onVerifyByEmail ? (
        <form onSubmit={handleEmailSubmit}>
          <input
            ref={inputRef}
            type="email"
            value={email}
            onChange={(e) => setEmail(e.target.value)}
            placeholder="your@email.com"
            disabled={loading}
            style={inputStyle}
          />
          <input
            type="password"
            value={password}
            onChange={(e) => setPassword(e.target.value)}
            placeholder="请输入密码"
            disabled={loading}
            style={inputStyle}
          />
          {error && (
            <p style={{ fontSize: "0.85rem", color: "#ef4444", marginBottom: "0.75rem" }}>
              {error}
            </p>
          )}
          <button
            type="submit"
            disabled={loading}
            className={`${styles.btnPrimary} ${styles.btnLarge}`}
            style={{ width: "100%" }}
          >
            {loading ? "验证中..." : "验证并登录"}
          </button>
        </form>
      ) : (
        <form onSubmit={handleUserIdSubmit}>
          <input
            ref={inputRef}
            type="text"
            value={userId}
            onChange={(e) => setUserId(e.target.value)}
            placeholder="例如：user1773315608560"
            disabled={loading}
            style={inputStyle}
          />
          {error && (
            <p style={{ fontSize: "0.85rem", color: "#ef4444", marginBottom: "0.75rem" }}>
              {error}
            </p>
          )}
          <button
            type="submit"
            disabled={loading}
            className={`${styles.btnPrimary} ${styles.btnLarge}`}
            style={{ width: "100%" }}
          >
            {loading ? "验证中..." : "验证并登录"}
          </button>
        </form>
      )}
    </>
  );
}