'use client';

import React, { useEffect, useState } from 'react';
import Link from 'next/link';
import { onAuthStateChanged } from 'firebase/auth';
import { firebaseAuth } from '../../lib/firebase-client';

interface OperationsErrorStateProps {
  status: 401 | 403 | 404 | 503 | 'disabled' | 'network' | number;
  message?: string;
  onRetry?: () => void;
}

export function OperationsErrorState({
  status,
  message,
  onRetry,
}: OperationsErrorStateProps) {
  const [authenticating, setAuthenticating] = useState(false);

  useEffect(() => {
    if (status !== 401) return;
    const unsubscribe = onAuthStateChanged(firebaseAuth, async (user) => {
      if (user) {
        setAuthenticating(true);
        try {
          const idToken = await user.getIdToken();
          const res = await fetch('/api/auth/firebase-login', {
            method: 'POST',
            headers: { 'content-type': 'application/json' },
            body: JSON.stringify({ id_token: idToken }),
          });
          if (res.ok) {
            window.location.reload();
            return;
          }
        } catch {
          // Ignore and remain on error state
        } finally {
          setAuthenticating(false);
        }
      }
    });
    return () => unsubscribe();
  }, [status]);

  let title = 'Operations Error';
  let description = authenticating
    ? 'Verifying operator credentials and activating session...'
    : (message ?? 'An unexpected error occurred in the Operations console.');
  let icon = authenticating ? 'sync' : 'error';
  let showSignIn = false;
  let showRetry = true;

  if (status === 401) {
    title = authenticating ? 'Authenticating Operator...' : 'Authentication Required';
    description = authenticating
      ? 'Verifying operator credentials and establishing secure session...'
      : (message ?? 'Your Operations session has expired or is unauthenticated.');
    icon = authenticating ? 'sync' : 'lock';
    showSignIn = !authenticating;
    showRetry = false;
  } else if (status === 403) {
    title = 'Access Restricted';
    description = message ?? 'You do not have sufficient authority to access Operations.';
    icon = 'gavel';
    showSignIn = false;
    showRetry = false;
  } else if (status === 404) {
    title = 'Resource Not Found';
    description = message ?? 'The requested Operations resource does not exist.';
    icon = 'search_off';
  } else if (status === 503 || status === 'network') {
    title = 'Operations Temporarily Unavailable';
    description = message ?? 'Unable to communicate with the Operations API. Try again in a few moments.';
    icon = 'cloud_off';
  } else if (status === 'disabled') {
    title = 'Operations Disabled';
    description = message ?? 'The Operations platform is currently disabled by system policy.';
    icon = 'block';
    showRetry = false;
  }

  return (
    <div className="p-8 rounded-xl bg-surface-container-low border border-outline-variant/30 text-center max-w-lg mx-auto my-12 space-y-4 shadow-sm">
      <div className="w-12 h-12 rounded-full bg-surface-container-high border border-outline-variant/40 flex items-center justify-center text-outline mx-auto">
        <span className="material-symbols-outlined text-[24px]">{icon}</span>
      </div>

      <div className="space-y-1">
        <span className="text-[10px] font-mono text-outline font-semibold">
          Status {status}
        </span>
        <h2 className="text-lg font-bold text-on-surface">{title}</h2>
        <p className="text-xs text-on-surface-variant leading-relaxed">
          {description}
        </p>
      </div>

      <div className="pt-4 border-t border-outline-variant/20 flex items-center justify-center gap-3">
        {showSignIn && (
          <Link
            href="/login?returnTo=/admin"
            className="inline-flex items-center gap-1.5 px-4 py-2 rounded-lg bg-primary-container text-on-primary-container text-xs font-bold shadow-sm hover:brightness-105 transition-all focus-visible:ring-2 focus-visible:ring-primary-container focus-visible:outline-none"
          >
            <span className="material-symbols-outlined text-[16px]">login</span>
            <span>Sign In</span>
          </Link>
        )}

        {showRetry && onRetry && (
          <button
            type="button"
            onClick={onRetry}
            className="inline-flex items-center gap-1.5 px-4 py-2 rounded-lg bg-surface-container-high hover:bg-surface-bright text-on-surface border border-outline-variant/30 text-xs font-semibold transition-all focus-visible:ring-2 focus-visible:ring-primary-container focus-visible:outline-none"
          >
            <span className="material-symbols-outlined text-[16px]">refresh</span>
            <span>Retry</span>
          </button>
        )}

        <Link
          href="/"
          className="inline-flex items-center gap-1.5 px-3 py-2 rounded-lg text-xs font-medium text-on-surface-variant hover:text-on-surface transition-colors"
        >
          Return Home
        </Link>
      </div>
    </div>
  );
}