'use client';

import { useEffect, useMemo, useState } from 'react';
import { usePathname, useRouter } from 'next/navigation';
import { motion } from 'framer-motion';
import { z } from 'zod';
import { useAuth } from '@/contexts/AuthContext';
import Link from 'next/link';
import {
  Bell,
  CreditCard,
  Lock,
  Mail,
  Phone,
  ShieldCheck,
  SlidersHorizontal,
  User,
} from 'lucide-react';
import { getAuth, sendPasswordResetEmail, updateProfile } from 'firebase/auth';
import { app } from '@/lib/firebase';
import { getPurchasesByUser, updateUserOnboardingCompleted } from '@/lib/firestore';
import toast from 'react-hot-toast';

const profileSchema = z.object({
  displayName: z.string().trim().min(2, 'Display name must be at least 2 characters.'),
  phone: z
    .string()
    .trim()
    .optional()
    .transform((value) => (value ? value : undefined))
    .refine(
      (value) => !value || /^\+?[0-9\s\-()]{7,20}$/.test(value),
      'Enter a valid phone number.'
    ),
});

const containerVariants = {
  hidden: { opacity: 0 },
  show: { opacity: 1, transition: { staggerChildren: 0.08 } },
};

const cardVariants = {
  hidden: { opacity: 0, y: 14 },
  show: { opacity: 1, y: 0, transition: { duration: 0.4 } },
};

export default function SettingsPage() {
  const { user, isLoading } = useAuth();
  const router = useRouter();
  const pathname = usePathname();
  const auth = getAuth(app);
  const firebaseUser = auth.currentUser;

  const [profileForm, setProfileForm] = useState({
    displayName: user?.name || '',
    phone: user?.phoneNumber || '',
  });
  const [profileErrors, setProfileErrors] = useState<{ displayName?: string; phone?: string }>(
    {}
  );
  const [isSavingProfile, setIsSavingProfile] = useState(false);
  const [resetStatus, setResetStatus] = useState<string | null>(null);

  const [emailNotifications, setEmailNotifications] = useState(true);
  const [callAlerts, setCallAlerts] = useState(true);
  const [weeklyReports, setWeeklyReports] = useState(false);

  const [totalCreditsPurchased, setTotalCreditsPurchased] = useState<number | null>(null);

  useEffect(() => {
    if (!isLoading && !user) {
      router.push('/auth');
    }
  }, [user, isLoading, router]);

  useEffect(() => {
    if (user) {
      getPurchasesByUser(user.uid)
        .then((purchases) => {
          const total = purchases.reduce((sum, purchase) => sum + (purchase.credits || 0), 0);
          setTotalCreditsPurchased(total);
        })
        .catch((error) => {
          console.error('Failed to load purchases', error);
          toast.error('Unable to load purchases.');
          setTotalCreditsPurchased(0);
        });
    }
  }, [user]);

  const creationDate = useMemo(() => {
    const createdAt = firebaseUser?.metadata?.creationTime;
    if (!createdAt) return 'Unknown';
    return new Date(createdAt).toLocaleDateString();
  }, [firebaseUser]);

  const handleProfileChange = (key: 'displayName' | 'phone', value: string) => {
    setProfileForm((prev) => ({ ...prev, [key]: value }));
    setProfileErrors((prev) => ({ ...prev, [key]: undefined }));
  };

  const handleSaveProfile = async () => {
    if (!firebaseUser) return;
    const result = profileSchema.safeParse(profileForm);
    if (!result.success) {
      const errors: { displayName?: string; phone?: string } = {};
      result.error.issues.forEach((issue) => {
        const field = issue.path[0] as 'displayName' | 'phone';
        errors[field] = issue.message;
      });
      setProfileErrors(errors);
      return;
    }

    setIsSavingProfile(true);
    try {
      await updateProfile(firebaseUser, { displayName: result.data.displayName.trim() });
      setProfileForm((prev) => ({ ...prev, displayName: result.data.displayName.trim() }));
      toast.success('Profile updated.');
    } catch (error) {
      console.error('Error updating profile', error);
      setProfileErrors({ displayName: 'Failed to update profile. Try again.' });
      toast.error('Unable to update profile.');
    } finally {
      setIsSavingProfile(false);
    }
  };

  const handlePasswordReset = async () => {
    if (!firebaseUser?.email) return;
    setResetStatus(null);
    try {
      await sendPasswordResetEmail(auth, firebaseUser.email);
      setResetStatus('Password reset email sent.');
      toast.success('Password reset email sent.');
    } catch (error) {
      console.error('Password reset failed', error);
      setResetStatus('Unable to send reset email. Try again.');
      toast.error('Unable to send reset email.');
    }
  };

  const handleRestartTour = async () => {
    if (!user) return;
    try {
      await updateUserOnboardingCompleted(user.uid, false);
      toast.success('Tour restarted. Redirecting...');
      router.push('/dashboard');
    } catch (error) {
      console.error('Failed to restart tour', error);
      toast.error('Unable to restart tour.');
    }
  };

  if (isLoading) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-[#0f0b1a] via-[#1b1330] to-[#0f1b3d] text-white">
        <div className="animate-pulse text-lg">Loading...</div>
      </div>
    );
  }

  if (!user) return null;

  const navLinks = [
    { label: 'Dashboard', href: '/dashboard' },
    { label: 'Scheduled Calls', href: '/dashboard/scheduled-calls' },
    { label: 'Voice Agent', href: '/dashboard/agent-settings' },
    { label: 'Credits', href: '/dashboard/credits' },
    { label: 'Notifications', href: '/dashboard/notifications' },
  ];

  return (
    <div className="min-h-screen bg-gradient-to-br from-[#0f0b1a] via-[#1b1330] to-[#0f1b3d] text-white px-6 py-10">
      <motion.div
        className="max-w-5xl mx-auto space-y-6"
        variants={containerVariants}
        initial="hidden"
        animate="show"
      >
        <motion.header
          variants={cardVariants}
          className="flex flex-wrap items-center justify-between gap-4"
        >
          <div className="flex items-center gap-3">
            <div className="h-10 w-10 rounded-2xl bg-[#8b5cf6]/20 border border-[#8b5cf6]/40 flex items-center justify-center">
              <SlidersHorizontal className="h-5 w-5 text-[#8b5cf6]" />
            </div>
            <div>
              <h1 className="text-2xl font-semibold">Settings</h1>
              <p className="text-xs text-[#9ca3af]">Manage preferences and account details</p>
            </div>
          </div>
          <div className="flex flex-wrap gap-2">
            {navLinks.map((link) => {
              const isActive = pathname === link.href;
              return (
                <Link
                  key={link.href}
                  href={link.href}
                  className={`px-3 py-1.5 rounded-full border text-xs transition ${
                    isActive
                      ? 'bg-[#8b5cf6]/20 border-[#8b5cf6]/40 text-white'
                      : 'bg-white/5 border-white/10 text-[#9ca3af] hover:text-white'
                  }`}
                >
                  {link.label}
                </Link>
              );
            })}
          </div>
        </motion.header>

        <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
          <motion.div variants={cardVariants} className="lg:col-span-2 space-y-6">
            <div className="bg-[#1a1625] border border-white/10 rounded-3xl p-6 shadow-2xl space-y-5">
              <h2 className="text-lg font-semibold flex items-center gap-2">
                <User className="h-5 w-5 text-[#8b5cf6]" />
                User Profile
              </h2>
              <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                <div className="bg-[#0f0b1a] border border-white/10 rounded-2xl p-4">
                  <p className="text-xs uppercase text-[#9ca3af] flex items-center gap-2">
                    <Mail className="h-4 w-4" />
                    Email
                  </p>
                  <p className="text-sm mt-2">{user.email}</p>
                </div>
                <div className="bg-[#0f0b1a] border border-white/10 rounded-2xl p-4">
                  <p className="text-xs uppercase text-[#9ca3af] flex items-center gap-2">
                    <User className="h-4 w-4" />
                    Display Name
                  </p>
                  <input
                    value={profileForm.displayName}
                    onChange={(event) => handleProfileChange('displayName', event.target.value)}
                    className="mt-2 w-full rounded-xl bg-transparent border border-white/10 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-[#8b5cf6]"
                    placeholder="Your name"
                  />
                  {profileErrors.displayName && (
                    <p className="text-xs text-red-300 mt-2">{profileErrors.displayName}</p>
                  )}
                </div>
                <div className="bg-[#0f0b1a] border border-white/10 rounded-2xl p-4 md:col-span-2">
                  <p className="text-xs uppercase text-[#9ca3af] flex items-center gap-2">
                    <Phone className="h-4 w-4" />
                    Phone
                  </p>
                  <input
                    value={profileForm.phone}
                    onChange={(event) => handleProfileChange('phone', event.target.value)}
                    className="mt-2 w-full rounded-xl bg-transparent border border-white/10 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-[#8b5cf6]"
                    placeholder="+34 600 000 000"
                  />
                  {profileErrors.phone && (
                    <p className="text-xs text-red-300 mt-2">{profileErrors.phone}</p>
                  )}
                </div>
              </div>
              <button
                onClick={handleSaveProfile}
                disabled={isSavingProfile}
                className="px-4 py-2 rounded-2xl bg-[#8b5cf6] text-white font-semibold shadow-2xl hover:bg-[#7c3aed] transition disabled:opacity-60"
              >
                {isSavingProfile ? 'Saving...' : 'Save Profile'}
              </button>
            </div>

            <div className="bg-[#1a1625] border border-white/10 rounded-3xl p-6 shadow-2xl space-y-5">
              <h2 className="text-lg font-semibold flex items-center gap-2">
                <ShieldCheck className="h-5 w-5 text-[#8b5cf6]" />
                Security
              </h2>
              <p className="text-sm text-[#9ca3af]">
                Reset your password to keep your account secure.
              </p>
              <button
                onClick={handlePasswordReset}
                className="w-full md:w-auto px-4 py-2 rounded-2xl bg-white/5 border border-white/10 text-white hover:bg-white/10 transition flex items-center gap-2"
              >
                <Lock className="h-4 w-4" />
                Change Password
              </button>
              {resetStatus && <p className="text-xs text-[#9ca3af]">{resetStatus}</p>}
            </div>

            <div className="bg-[#1a1625] border border-white/10 rounded-3xl p-6 shadow-2xl space-y-5">
              <h2 className="text-lg font-semibold flex items-center gap-2">
                <Bell className="h-5 w-5 text-[#8b5cf6]" />
                Notification Preferences
              </h2>
              {[
                {
                  key: 'email',
                  label: 'Email notifications',
                  value: emailNotifications,
                  setter: setEmailNotifications,
                },
                {
                  key: 'calls',
                  label: 'Call alerts',
                  value: callAlerts,
                  setter: setCallAlerts,
                },
                {
                  key: 'reports',
                  label: 'Weekly usage reports',
                  value: weeklyReports,
                  setter: setWeeklyReports,
                },
              ].map((item) => (
                <div key={item.key} className="flex items-center justify-between">
                  <p className="text-sm">{item.label}</p>
                  <button
                    type="button"
                    onClick={() => item.setter(!item.value)}
                    className={`h-6 w-12 rounded-full transition flex items-center ${
                      item.value ? 'bg-[#8b5cf6]' : 'bg-white/10'
                    }`}
                  >
                    <span
                      className={`h-5 w-5 rounded-full bg-white shadow transform transition ${
                        item.value ? 'translate-x-6' : 'translate-x-1'
                      }`}
                    />
                  </button>
                </div>
              ))}
              <p className="text-xs text-[#9ca3af]">
                Preferences save locally for now. TODO: persist in Firestore.
              </p>
            </div>
          </motion.div>

          <motion.div variants={cardVariants} className="space-y-6">
            <div className="bg-[#1a1625] border border-white/10 rounded-3xl p-6 shadow-2xl space-y-4">
              <h2 className="text-lg font-semibold flex items-center gap-2">
                <CreditCard className="h-5 w-5 text-[#8b5cf6]" />
                Account Info
              </h2>
              <div className="bg-[#0f0b1a] border border-white/10 rounded-2xl p-4 space-y-2">
                <p className="text-xs uppercase text-[#9ca3af]">Member Since</p>
                <p className="text-sm">{creationDate}</p>
              </div>
              <div className="bg-[#0f0b1a] border border-white/10 rounded-2xl p-4 space-y-2">
                <p className="text-xs uppercase text-[#9ca3af]">Total Credits Purchased</p>
                <p className="text-sm">
                  {totalCreditsPurchased === null ? 'Loading…' : totalCreditsPurchased}
                </p>
              </div>
              <button
                onClick={() => router.push('/dashboard/credits')}
                className="w-full px-4 py-2 rounded-2xl bg-[#8b5cf6] text-white font-semibold shadow-2xl hover:bg-[#7c3aed] transition"
              >
                Go to Billing & Credits
              </button>
              <button
                onClick={handleRestartTour}
                className="w-full px-4 py-2 rounded-2xl bg-white/5 border border-white/10 text-white hover:bg-white/10 transition"
              >
                Restart Tour
              </button>
            </div>
          </motion.div>
        </div>
      </motion.div>
    </div>
  );
}