import { useState, useEffect } from "react";
import { Link, useNavigate, useLocation } from "react-router-dom";
import { ChevronLeftIcon, EyeCloseIcon, EyeIcon } from "../../icons";
import Label from "../form/Label";
import Input from "../form/input/InputField";
import Checkbox from "../form/input/Checkbox";
import Button from "../ui/button/Button";
import { useAuthStore } from "../../store/authStore";

interface LogoutReason {
  code: string;
  message: string;
  path: string;
  context?: any;
  timestamp: string;
  source: string;
}

export default function SignInForm() {
  const [showPassword, setShowPassword] = useState(false);
  const [isChecked, setIsChecked] = useState(false);
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");
  const [error, setError] = useState("");
  const [logoutReason, setLogoutReason] = useState<LogoutReason | null>(null);
  const [showLogoutDetails, setShowLogoutDetails] = useState(false);
  const [sessionConflict, setSessionConflict] = useState<{
    message: string;
    existingUser: { email: string; username: string; id: number };
    requestedUser: { email: string; username: string; id: number };
  } | null>(null);
  
  const navigate = useNavigate();
  const location = useLocation();
  const { login, loading } = useAuthStore();

  // Check for logout reason on component mount
  useEffect(() => {
    try {
      const storedReason = localStorage.getItem('logout_reason');
      
      if (storedReason) {
        const reason = JSON.parse(storedReason);
        setLogoutReason(reason);
        
        // Check if we've already logged this (prevent StrictMode duplicates)
        const loggedKey = 'logout_reason_logged';
        const alreadyLogged = sessionStorage.getItem(loggedKey);
        
        if (!alreadyLogged) {
          // Single consolidated log
          console.error('🚨 LOGOUT:', reason.code, '-', reason.message, 'on', reason.path);
          sessionStorage.setItem(loggedKey, 'true');
        }
      }
    } catch (e) {
      console.error('Failed to read logout reason:', e);
    }
  }, []);

  const handleSubmit = async (e: React.FormEvent, forceLogout = false) => {
    e.preventDefault();
    setError("");
    setSessionConflict(null);

    if (!email || !password) {
      setError("Please enter both email and password");
      return;
    }

    try {
      await login(email, password, isChecked, forceLogout);
      // Redirect to the page user was trying to access, or home
      const from = (location.state as any)?.from?.pathname || "/";
      navigate(from, { replace: true });
    } catch (err: any) {
      // Handle session conflict
      if (err?.type === 'SESSION_CONFLICT') {
        setSessionConflict({
          message: err.message,
          existingUser: err.existingUser,
          requestedUser: err.requestedUser,
        });
        return;
      }
      
      if (err?.code === 'PLAN_REQUIRED') {
        window.location.href = 'https://igny8.com/pricing';
        return;
      }
      setError(err.message || "Login failed. Please check your credentials.");
    }
  };
  
  const handleForceLogout = async (e: React.FormEvent) => {
    e.preventDefault();
    await handleSubmit(e, true);
  };
  
  return (
    <div className="flex flex-col flex-1">
      <div className="w-full max-w-md pt-10 mx-auto">
        {/* Back link removed - users shouldn't go back to dashboard when not logged in */}
      </div>
      <div className="flex flex-col justify-center flex-1 w-full max-w-md mx-auto">
        <div>
          <div className="mb-5 sm:mb-8">
            <h1 className="mb-2 font-semibold text-gray-800 text-title-sm dark:text-white/90 sm:text-title-md">
              Sign In
            </h1>
            <p className="text-sm text-gray-500 dark:text-gray-400">
              Enter your email and password to sign in!
            </p>
          </div>
          <div>
            <div className="grid grid-cols-1 gap-3 sm:grid-cols-2 sm:gap-5">
              <Button variant="outline" tone="neutral" size="md" className="gap-3">
                <svg
                  width="20"
                  height="20"
                  viewBox="0 0 20 20"
                  fill="none"
                  xmlns="http://www.w3.org/2000/svg"
                >
                  <path
                    d="M18.7511 10.1944C18.7511 9.47495 18.6915 8.94995 18.5626 8.40552H10.1797V11.6527H15.1003C15.0011 12.4597 14.4654 13.675 13.2749 14.4916L13.2582 14.6003L15.9087 16.6126L16.0924 16.6305C17.7788 15.1041 18.7511 12.8583 18.7511 10.1944Z"
                    fill="#4285F4"
                  />
                  <path
                    d="M10.1788 18.75C12.5895 18.75 14.6133 17.9722 16.0915 16.6305L13.274 14.4916C12.5201 15.0068 11.5081 15.3666 10.1788 15.3666C7.81773 15.3666 5.81379 13.8402 5.09944 11.7305L4.99473 11.7392L2.23868 13.8295L2.20264 13.9277C3.67087 16.786 6.68674 18.75 10.1788 18.75Z"
                    fill="#34A853"
                  />
                  <path
                    d="M5.10014 11.7305C4.91165 11.186 4.80257 10.6027 4.80257 9.99992C4.80257 9.3971 4.91165 8.81379 5.09022 8.26935L5.08523 8.1534L2.29464 6.02954L2.20333 6.0721C1.5982 7.25823 1.25098 8.5902 1.25098 9.99992C1.25098 11.4096 1.5982 12.7415 2.20333 13.9277L5.10014 11.7305Z"
                    fill="#FBBC05"
                  />
                  <path
                    d="M10.1789 4.63331C11.8554 4.63331 12.9864 5.34303 13.6312 5.93612L16.1511 3.525C14.6035 2.11528 12.5895 1.25 10.1789 1.25C6.68676 1.25 3.67088 3.21387 2.20264 6.07218L5.08953 8.26943C5.81381 6.15972 7.81776 4.63331 10.1789 4.63331Z"
                    fill="#EB4335"
                  />
                </svg>
                Sign in with Google
              </Button>
              <Button variant="outline" tone="neutral" size="md" className="gap-3">
                <svg
                  width="21"
                  className="fill-current"
                  height="20"
                  viewBox="0 0 21 20"
                  fill="none"
                  xmlns="http://www.w3.org/2000/svg"
                >
                  <path d="M15.6705 1.875H18.4272L12.4047 8.75833L19.4897 18.125H13.9422L9.59717 12.4442L4.62554 18.125H1.86721L8.30887 10.7625L1.51221 1.875H7.20054L11.128 7.0675L15.6705 1.875ZM14.703 16.475H16.2305L6.37054 3.43833H4.73137L14.703 16.475Z" />
                </svg>
                Sign in with X
              </Button>
            </div>
            <div className="relative py-3 sm:py-5">
              <div className="absolute inset-0 flex items-center">
                <div className="w-full border-t border-gray-200 dark:border-gray-800"></div>
              </div>
              <div className="relative flex justify-center text-sm">
                <span className="p-2 text-gray-400 bg-white dark:bg-gray-900 sm:px-5 sm:py-2">
                  Or
                </span>
              </div>
            </div>
            <form onSubmit={handleSubmit}>
              <div className="space-y-6">
                {/* Logout Reason Display */}
                {logoutReason && (
                  <div className="p-4 bg-warning-50 border border-warning-200 rounded-lg dark:bg-warning-900/20 dark:border-warning-800">
                    <div className="flex items-start justify-between">
                      <div className="flex-1">
                        <div className="flex items-center gap-2 mb-2">
                          <svg className="w-5 h-5 text-warning-600 dark:text-warning-400" fill="currentColor" viewBox="0 0 20 20">
                            <path fillRule="evenodd" d="M8.257 3.099c.765-1.36 2.722-1.36 3.486 0l5.58 9.92c.75 1.334-.213 2.98-1.742 2.98H4.42c-1.53 0-2.493-1.646-1.743-2.98l5.58-9.92zM11 13a1 1 0 11-2 0 1 1 0 012 0zm-1-8a1 1 0 00-1 1v3a1 1 0 002 0V6a1 1 0 00-1-1z" clipRule="evenodd" />
                          </svg>
                          <h4 className="font-semibold text-warning-800 dark:text-warning-300">
                            Session Ended
                          </h4>
                        </div>
                        <p className="text-sm text-warning-700 dark:text-warning-400 mb-2">
                          {logoutReason.message}
                        </p>
                        {logoutReason.path && logoutReason.path !== '/signin' && (
                          <p className="text-xs text-warning-600 dark:text-warning-500">
                            Original page: <span className="font-mono">{logoutReason.path}</span>
                          </p>
                        )}
                      </div>
                      <button
                        type="button"
                        onClick={() => setShowLogoutDetails(!showLogoutDetails)}
                        className="ml-2 p-1 text-warning-600 hover:text-warning-800 dark:text-warning-400 dark:hover:text-warning-300"
                        title="Toggle technical details"
                      >
                        <svg className="w-5 h-5" fill="currentColor" viewBox="0 0 20 20">
                          <path fillRule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7-4a1 1 0 11-2 0 1 1 0 012 0zM9 9a1 1 0 000 2v3a1 1 0 001 1h1a1 1 0 100-2v-3a1 1 0 00-1-1H9z" clipRule="evenodd" />
                        </svg>
                      </button>
                    </div>
                    
                    {/* Expandable Technical Details */}
                    {showLogoutDetails && (
                      <div className="mt-3 pt-3 border-t border-warning-300 dark:border-warning-700">
                        <p className="text-xs font-semibold text-warning-800 dark:text-warning-300 mb-2">
                          Technical Details:
                        </p>
                        <div className="space-y-1 text-xs font-mono text-warning-700 dark:text-warning-400">
                          <div><span className="font-bold">Code:</span> {logoutReason.code}</div>
                          <div><span className="font-bold">Source:</span> {logoutReason.source}</div>
                          <div><span className="font-bold">Time:</span> {new Date(logoutReason.timestamp).toLocaleString()}</div>
                          {logoutReason.context && Object.keys(logoutReason.context).length > 0 && (
                            <div className="mt-2">
                              <span className="font-bold">Context:</span>
                              <pre className="mt-1 p-2 bg-warning-100 dark:bg-warning-900/30 rounded text-xs overflow-x-auto">
                                {JSON.stringify(logoutReason.context, null, 2)}
                              </pre>
                            </div>
                          )}
                        </div>
                      </div>
                    )}
                  </div>
                )}
                
                {/* Session Conflict Alert */}
                {sessionConflict && (
                  <div className="p-4 bg-warning-50 border border-warning-200 rounded-lg dark:bg-warning-900/20 dark:border-warning-800">
                    <div className="flex items-center gap-2 mb-3">
                      <svg className="w-5 h-5 text-warning-600 dark:text-warning-400" fill="currentColor" viewBox="0 0 20 20">
                        <path fillRule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z" clipRule="evenodd" />
                      </svg>
                      <h4 className="font-semibold text-warning-800 dark:text-warning-300">
                        Active Session Detected
                      </h4>
                    </div>
                    <p className="text-sm text-warning-700 dark:text-warning-400 mb-2">
                      You have an active session for:
                    </p>
                    <p className="text-sm font-semibold text-warning-800 dark:text-warning-300 mb-3">
                      {sessionConflict.existingUser.email}
                    </p>
                    <p className="text-sm text-warning-700 dark:text-warning-400 mb-4">
                      You're trying to login as: <strong>{sessionConflict.requestedUser.email}</strong>
                    </p>
                    <div className="flex gap-3">
                      <Button
                        type="button"
                        variant="primary"
                        tone="warning"
                        size="sm"
                        onClick={handleForceLogout}
                        disabled={loading}
                        className="flex-1"
                      >
                        {loading ? 'Logging out...' : 'Logout Previous & Continue'}
                      </Button>
                      <Button
                        type="button"
                        variant="outline"
                        tone="warning"
                        size="sm"
                        onClick={() => setSessionConflict(null)}
                        className="flex-1"
                      >
                        Cancel
                      </Button>
                    </div>
                  </div>
                )}
                
                {error && (
                  <div className="p-3 text-sm text-error-600 bg-error-50 border border-error-200 rounded-lg dark:bg-error-900/20 dark:text-error-400 dark:border-error-800">
                    {error}
                  </div>
                )}
                <div>
                  <Label>
                    Email <span className="text-error-500">*</span>{" "}
                  </Label>
                  <Input 
                    type="email"
                    value={email}
                    onChange={(e) => setEmail(e.target.value)}
                    placeholder="info@gmail.com"
                    required
                  />
                </div>
                <div>
                  <Label>
                    Password <span className="text-error-500">*</span>{" "}
                  </Label>
                  <div className="relative">
                    <Input
                      type={showPassword ? "text" : "password"}
                      value={password}
                      onChange={(e) => setPassword(e.target.value)}
                      placeholder="Enter your password"
                      required
                    />
                    <span
                      onClick={() => setShowPassword(!showPassword)}
                      className="absolute z-30 -translate-y-1/2 cursor-pointer right-4 top-1/2"
                    >
                      {showPassword ? (
                        <EyeIcon className="fill-gray-500 dark:fill-gray-400 size-5" />
                      ) : (
                        <EyeCloseIcon className="fill-gray-500 dark:fill-gray-400 size-5" />
                      )}
                    </span>
                  </div>
                </div>
                <div className="flex items-center justify-between">
                  <div className="flex items-center gap-3">
                    <Checkbox checked={isChecked} onChange={setIsChecked} />
                    <span className="block font-normal text-gray-700 text-theme-sm dark:text-gray-400">
                      Keep me logged in
                    </span>
                  </div>
                  <Link
                    to="/reset-password"
                    className="text-sm text-brand-500 hover:text-brand-600 dark:text-brand-400"
                  >
                    Forgot password?
                  </Link>
                </div>
                <div>
                  <Button 
                    className="w-full" 
                    size="sm" 
                    type="submit"
                    disabled={loading}
                  >
                    {loading ? "Signing in..." : "Sign in"}
                  </Button>
                </div>
              </div>
            </form>

            <div className="mt-5">
              <p className="text-sm font-normal text-center text-gray-700 dark:text-gray-400 sm:text-start">
                Don&apos;t have an account? {""}
                <Link
                  to="/signup"
                  className="text-brand-500 hover:text-brand-600 dark:text-brand-400"
                >
                  Sign Up
                </Link>
              </p>
            </div>
          </div>
        </div>
      </div>
    </div>
  );
}