import { useState } from "react";
import { GOOGLE_AUTH_URL, AUTH_STATUS_URL } from "../lib/config";

type AuthMode = 'google' | 'csv-only';

interface AuthStatusProps {
  teacherEmail: string;
  setTeacherEmail: (email: string) => void;
  isAuthenticated: boolean;
  setIsAuthenticated: (auth: boolean) => void;
}

export function AuthStatus({
  teacherEmail,
  setTeacherEmail,
  isAuthenticated,
  setIsAuthenticated,
}: AuthStatusProps) {
  const [emailInput, setEmailInput] = useState("");
  const [isChecking, setIsChecking] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [authMode, setAuthMode] = useState<AuthMode | null>(null);

  const checkAuthStatus = async (email: string) => {
    try {
      setIsChecking(true);
      const response = await fetch(`${AUTH_STATUS_URL}?teacher_email=${encodeURIComponent(email)}`);
      const data = await response.json();
      
      if (data.authenticated) {
        setTeacherEmail(email);
        setIsAuthenticated(true);
      }
      return data.authenticated;
    } catch (err) {
      console.error("Error checking auth status:", err);
      return false;
    } finally {
      setIsChecking(false);
    }
  };

  const handleConnect = async (e: React.FormEvent) => {
    e.preventDefault();
    setError(null);
    
    if (!emailInput.trim()) {
      setError("請輸入您的電子郵件地址");
      return;
    }
    
    // Check if already authenticated
    const alreadyAuth = await checkAuthStatus(emailInput);
    if (alreadyAuth) {
      return;
    }
    
    // Try to start OAuth - catch errors if not configured
    try {
      const response = await fetch(`${GOOGLE_AUTH_URL}?teacher_email=${encodeURIComponent(emailInput)}`, {
        method: 'GET',
        redirect: 'manual'
      });
      
      // If we get a redirect, OAuth is configured - follow it
      if (response.type === 'opaqueredirect' || response.status === 302) {
        window.location.href = `${GOOGLE_AUTH_URL}?teacher_email=${encodeURIComponent(emailInput)}`;
      } else if (response.status === 500) {
        const data = await response.json();
        if (data.detail?.includes('not configured')) {
          setAuthMode('csv-only');
          setError("Google OAuth 未設定。您仍可在聊天中直接上傳 CSV 檔案使用應用程式！");
          // Set as "connected" with just email for CSV fallback
          setTeacherEmail(emailInput);
          setIsAuthenticated(true);
        } else {
          setAuthMode('google');
          setError(data.detail || "Failed to connect");
        }
      } else {
        // Redirect to OAuth
        window.location.href = `${GOOGLE_AUTH_URL}?teacher_email=${encodeURIComponent(emailInput)}`;
      }
    } catch (err) {
      // Network error or CORS - just redirect
      window.location.href = `${GOOGLE_AUTH_URL}?teacher_email=${encodeURIComponent(emailInput)}`;
    }
  };

  const handleDisconnect = async () => {
    try {
      await fetch(`/auth/disconnect?teacher_email=${encodeURIComponent(teacherEmail)}`, {
        method: 'POST'
      });
      setIsAuthenticated(false);
      setTeacherEmail("");
    } catch (err) {
      console.error("Error disconnecting:", err);
    }
  };

  return (
    <section id="connect" className="py-20 px-6">
      <div className="max-w-xl mx-auto">
        <div className="card p-8">
          <div className="text-center mb-8">
            <div className="w-16 h-16 mx-auto mb-4 rounded-2xl bg-gradient-to-br from-[var(--color-primary)] to-[var(--color-primary-light)] flex items-center justify-center shadow-lg">
              <svg className="w-8 h-8 text-white" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z" />
              </svg>
            </div>
            <h2 className="font-display text-2xl font-bold text-[var(--color-text)] mb-2">
              {isAuthenticated ? "已連接！" : "連接您的 Google 帳號"}
            </h2>
            <p className="text-[var(--color-text-muted)]">
              {isAuthenticated 
                ? "您的 Google 帳號已連結。現在可以分析考試答案了。"
                : "我們只會存取您的 Google 表單回應試算表。不會在我們的伺服器上儲存任何資料。"}
            </p>
          </div>

          {isAuthenticated ? (
            <div className="space-y-4">
          <div className="flex items-center justify-center gap-3 p-4 rounded-xl bg-[var(--color-success)]/10 border border-[var(--color-success)]/20">
            <div className="w-10 h-10 rounded-full bg-[var(--color-success)]/20 flex items-center justify-center">
              <svg className="w-5 h-5 text-[var(--color-success)]" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
              </svg>
            </div>
            <div className="text-left">
              <div className="font-medium text-[var(--color-text)]">{teacherEmail}</div>
              <div className="text-sm text-[var(--color-text-muted)]">
                {authMode === 'csv-only' ? 'CSV 上傳模式（Google OAuth 未設定）' : 'Google 帳號已連接'}
              </div>
            </div>
          </div>
          
          {authMode === 'csv-only' && (
            <div className="p-3 rounded-lg bg-amber-50 border border-amber-200 text-amber-700 text-sm">
              <strong>注意：</strong>您可以在聊天中直接貼上 CSV 資料，或設定 Google OAuth 從 Google 表單取得資料。
            </div>
          )}
              
              <button
                onClick={handleDisconnect}
                className="w-full btn btn-outline text-red-500 border-red-200 hover:border-red-500 hover:text-red-600"
              >
                斷開帳號
              </button>
            </div>
          ) : (
            <form onSubmit={handleConnect} className="space-y-4">
              <div>
                <label htmlFor="email" className="block text-sm font-medium text-[var(--color-text)] mb-2">
                  您的學校電子郵件
                </label>
                <input
                  type="email"
                  id="email"
                  value={emailInput}
                  onChange={(e) => setEmailInput(e.target.value)}
                  placeholder="teacher@school.edu"
                  className="input"
                  required
                />
              </div>
              
              {error && (
                <div className="p-3 rounded-lg bg-red-50 border border-red-200 text-red-600 text-sm">
                  {error}
                </div>
              )}
              
              <button 
                type="submit" 
                className="w-full btn btn-primary"
                disabled={isChecking}
              >
                {isChecking ? (
                  <>
                    <svg className="w-5 h-5 animate-spin" fill="none" viewBox="0 0 24 24">
                      <circle className="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="4" />
                      <path className="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z" />
                    </svg>
                    檢查中...
                  </>
                ) : (
                  <>
                    <svg className="w-5 h-5" viewBox="0 0 24 24" fill="currentColor">
                      <path d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92c-.26 1.37-1.04 2.53-2.21 3.31v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.09z"/>
                      <path d="M12 23c2.97 0 5.46-.98 7.28-2.66l-3.57-2.77c-.98.66-2.23 1.06-3.71 1.06-2.86 0-5.29-1.93-6.16-4.53H2.18v2.84C3.99 20.53 7.7 23 12 23z"/>
                      <path d="M5.84 14.09c-.22-.66-.35-1.36-.35-2.09s.13-1.43.35-2.09V7.07H2.18C1.43 8.55 1 10.22 1 12s.43 3.45 1.18 4.93l2.85-2.22.81-.62z"/>
                      <path d="M12 5.38c1.62 0 3.06.56 4.21 1.64l3.15-3.15C17.45 2.09 14.97 1 12 1 7.7 1 3.99 3.47 2.18 7.07l3.66 2.84c.87-2.6 3.3-4.53 6.16-4.53z"/>
                    </svg>
                    使用 Google 繼續
                  </>
                )}
              </button>
              
              <p className="text-center text-xs text-[var(--color-text-muted)]">
                連接即表示您同意我們的{" "}
                <a href="#" className="underline hover:text-[var(--color-primary)]">服務條款</a>
                {" "}和{" "}
                <a href="#" className="underline hover:text-[var(--color-primary)]">隱私政策</a>
              </p>
            </form>
          )}
        </div>
      </div>
    </section>
  );
}