import * as React from "react";
import Link from "next/link";

import { Button } from "@/components/ui/button";
import { Checkbox } from "@/components/ui/checkbox";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { CaptchaField } from "@/components/auth/captcha-field";

export function LoginForm(props: {
  clientId: string;
  tenantId: string;
  callback: string;
  initialEmail: string;
  prefillPassword?: string;
  disabled?: boolean;
  externalError?: string | null;
  onClearExternalError?: () => void;
  captcha: string;
  onCaptchaChange: (next: string) => void;
  captchaKey: string;
  onRefreshCaptcha: () => void;
}) {
  const [email, setEmail] = React.useState(props.initialEmail);
  const [password, setPassword] = React.useState("");
  const [rememberMe, setRememberMe] = React.useState(
    Boolean(props.initialEmail),
  );
  const [submitting, setSubmitting] = React.useState(false);
  const [error, setError] = React.useState<string | null>(null);

  React.useEffect(() => {
    setEmail(props.initialEmail);
    setRememberMe(Boolean(props.initialEmail));
  }, [props.initialEmail]);

  React.useEffect(() => {
    if (props.prefillPassword) {
      setPassword(props.prefillPassword);
    }
  }, [props.prefillPassword]);

  const missingParams = !props.clientId || !props.tenantId || !props.callback;

  async function onSubmit(e: React.FormEvent) {
    e.preventDefault();
    setError(null);
    props.onClearExternalError?.();
    setSubmitting(true);
    try {
      const res = await fetch("/api/auth/login", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          clientId: props.clientId,
          tenantId: props.tenantId,
          callback: props.callback,
          email,
          password,
          captcha: props.captcha,
          rememberMe,
        }),
      });
      const json = (await res.json()) as {
        redirectTo?: string;
        message?: string;
      };
      if (!res.ok || !json.redirectTo) {
        throw new Error(json.message || "登录失败");
      }
      window.location.href = json.redirectTo;
    } catch (err) {
      setError(err instanceof Error ? err.message : "登录失败");
      props.onCaptchaChange("");
      props.onRefreshCaptcha();
    } finally {
      setSubmitting(false);
    }
  }

  const disabled = Boolean(props.disabled) || submitting;

  return (
    <form onSubmit={onSubmit} className="space-y-4">
      {missingParams ? (
        <div className="text-sm text-destructive">
          缺少 clientId、tenantId 或 callback 参数，无法继续登录
        </div>
      ) : null}
      {props.externalError ? (
        <div className="text-sm text-destructive">{props.externalError}</div>
      ) : null}
      {error ? <div className="text-sm text-destructive">{error}</div> : null}

      <div className="space-y-2">
        <Label htmlFor="email">用户名</Label>
        <Input
          id="email"
          autoComplete="username"
          value={email}
          onChange={(e) => setEmail(e.target.value)}
          placeholder="user@example.com"
          disabled={disabled}
          required
        />
      </div>

      <div className="space-y-2">
        <Label htmlFor="password">密码</Label>
        <Input
          id="password"
          type="password"
          autoComplete="current-password"
          value={password}
          onChange={(e) => setPassword(e.target.value)}
          disabled={disabled}
          required
        />
      </div>

      <CaptchaField
        captcha={props.captcha}
        onCaptchaChange={props.onCaptchaChange}
        captchaKey={props.captchaKey}
        onRefresh={props.onRefreshCaptcha}
        disabled={disabled}
      />

      <div className="flex items-center justify-between">
        <label className="flex items-center gap-2 text-sm">
          <Checkbox
            checked={rememberMe}
            onCheckedChange={(v) => setRememberMe(Boolean(v))}
            disabled={disabled}
          />
          记住我
        </label>
        <Link
          className="text-sm underline underline-offset-4"
          href={`/forgot-password?tenantId=${encodeURIComponent(props.tenantId)}`}
        >
          忘记密码
        </Link>
      </div>

      <Button
        type="submit"
        className="w-full"
        disabled={disabled || missingParams}
      >
        {submitting ? "登录中..." : "登录"}
      </Button>
    </form>
  );
}