import { useState } from "react";
import type { FormEvent } from "react";
import { useNavigate } from "react-router-dom";
import { useAuthStore } from "../../stores/authStore";
import {
  Loader2,
  Mail,
  Lock,
  User,
  ImageIcon,
  BookOpen,
  Star,
  Zap,
  Trophy,
} from "lucide-react";

const STYLES = `
  @import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;700;800;900&family=Nunito+Sans:wght@400;600;700&display=swap');

  *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

  .rg-root {
    min-height: 100vh;
    display: flex;
    font-family: 'Nunito', sans-serif;
    background: #fffbf4;
  }

  /* ─── LEFT PANEL ─── */
  .rg-left {
    position: relative;
    width: 50%;
    min-height: 100vh;
    background: linear-gradient(150deg, #1e1b4b 0%, #3b1d8a 50%, #6d28d9 100%);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    padding: 3rem 3.5rem;
    overflow: hidden;
    flex-shrink: 0;
  }

  /* Blobs inside left panel */
  .rg-panel-blob {
    position: absolute; pointer-events: none; border-radius: 50%;
    opacity: 0.18;
  }
  .rg-panel-blob-1 {
    width: 420px; height: 420px;
    background: #a855f7;
    top: -140px; right: -100px;
    animation: blobDrift1 16s ease-in-out infinite;
  }
  .rg-panel-blob-2 {
    width: 300px; height: 300px;
    background: #f97316;
    bottom: -100px; left: -80px;
    animation: blobDrift2 18s ease-in-out infinite;
  }
  .rg-panel-blob-3 {
    width: 200px; height: 200px;
    background: #22c55e;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    animation: blobDrift1 14s ease-in-out infinite reverse;
  }
  @keyframes blobDrift1 {
    0%,100% { transform: translate(0,0) scale(1); }
    50%      { transform: translate(24px, 32px) scale(1.08); }
  }
  @keyframes blobDrift2 {
    0%,100% { transform: translate(0,0) scale(1); }
    50%      { transform: translate(-20px, -28px) scale(1.06); }
  }

  /* Floating decorative shapes */
  .rg-shape {
    position: absolute; pointer-events: none;
    animation: floatShape 8s ease-in-out infinite;
  }
  @keyframes floatShape {
    0%,100% { transform: translateY(0) rotate(0deg); }
    50%      { transform: translateY(-16px) rotate(12deg); }
  }

  /* Stars scattered */
  .rg-star {
    position: absolute; pointer-events: none;
    color: #fde68a; opacity: 0.55;
    animation: twinkle 3s ease-in-out infinite;
  }
  @keyframes twinkle {
    0%,100% { opacity: 0.55; transform: scale(1); }
    50%      { opacity: 0.9; transform: scale(1.3); }
  }

  /* Left panel content */
  .rg-panel-content {
    position: relative; z-index: 1;
    display: flex; flex-direction: column;
    align-items: flex-start; gap: 2.5rem;
    width: 100%;
  }

  .rg-panel-logo {
    display: flex; align-items: center; gap: 0.75rem;
  }
  .rg-panel-logo-badge {
    width: 48px; height: 48px; border-radius: 14px;
    background: linear-gradient(135deg, #f97316, #ef4444);
    display: flex; align-items: center; justify-content: center;
    box-shadow: 0 6px 0 rgba(0,0,0,0.25), 0 8px 20px rgba(249,115,22,0.4);
    font-size: 1.4rem;
  }
  .rg-panel-logo-text {
    font-size: 1.4rem; font-weight: 900;
    color: white; letter-spacing: -0.02em;
  }

  .rg-panel-headline {
    display: flex; flex-direction: column; gap: 0.75rem;
  }
  .rg-panel-headline h2 {
    font-size: 2.4rem; font-weight: 900; line-height: 1.15;
    color: white; letter-spacing: -0.03em;
  }
  .rg-panel-headline h2 span {
    background: linear-gradient(90deg, #fde68a, #f97316);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  }
  .rg-panel-headline p {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 1rem; font-weight: 600; color: #c4b5fd; line-height: 1.6;
  }

  /* Feature pills */
  .rg-features { display: flex; flex-direction: column; gap: 0.85rem; }
  .rg-feature {
    display: flex; align-items: center; gap: 0.85rem;
    background: rgba(255,255,255,0.07);
    border: 1.5px solid rgba(255,255,255,0.12);
    border-radius: 14px; padding: 0.85rem 1.1rem;
    backdrop-filter: blur(8px);
    animation: fadeSlideIn 0.5s ease both;
  }
  .rg-feature:nth-child(1) { animation-delay: 0.1s; }
  .rg-feature:nth-child(2) { animation-delay: 0.2s; }
  .rg-feature:nth-child(3) { animation-delay: 0.3s; }
  @keyframes fadeSlideIn {
    from { opacity: 0; transform: translateX(-16px); }
    to   { opacity: 1; transform: translateX(0); }
  }
  .rg-feature-icon {
    width: 36px; height: 36px; border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    flex-shrink: 0;
  }
  .rg-feature-text strong {
    display: block; font-size: 0.85rem; font-weight: 800; color: white;
  }
  .rg-feature-text span {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.75rem; font-weight: 600; color: #a5b4fc;
  }

  /* Social proof */
  .rg-social-proof {
    display: flex; align-items: center; gap: 0.75rem;
    padding: 0.1rem 0;
  }
  .rg-avatars { display: flex; }
  .rg-av {
    width: 30px; height: 30px; border-radius: 50%;
    border: 2px solid #3b1d8a;
    background: linear-gradient(135deg, #a855f7, #6d28d9);
    margin-left: -8px; display: flex; align-items: center;
    justify-content: center; font-size: 0.65rem; font-weight: 800; color: white;
  }
  .rg-av:first-child { margin-left: 0; }
  .rg-social-proof p {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.78rem; font-weight: 700; color: #c4b5fd;
  }
  .rg-social-proof p strong { color: #fde68a; }

  /* ─── RIGHT PANEL (form) ─── */
  .rg-right {
    flex: 1;
    display: flex; align-items: center; justify-content: center;
    padding: 3rem 4rem;
    position: relative; overflow: hidden;
  }

  /* Subtle bg dots on right */
  .rg-bg-dot {
    position: absolute; border-radius: 50%; pointer-events: none; opacity: 0.10;
    animation: bgDotFloat 9s ease-in-out infinite;
  }
  @keyframes bgDotFloat {
    0%,100% { transform: translateY(0); }
    50%      { transform: translateY(-12px); }
  }

  .rg-form-wrap {
    position: relative; z-index: 1;
    width: 100%; max-width: 420px;
    display: flex; flex-direction: column; gap: 2rem;
    animation: formPopIn 0.55s cubic-bezier(0.34,1.56,0.64,1) both;
  }
  @keyframes formPopIn {
    from { opacity: 0; transform: translateY(24px) scale(0.97); }
    to   { opacity: 1; transform: translateY(0) scale(1); }
  }

  /* Form header */
  .rg-form-header { display: flex; flex-direction: column; gap: 0.4rem; }
  .rg-form-header h1 {
    font-size: 2rem; font-weight: 900; color: #1e1b4b;
    letter-spacing: -0.03em; line-height: 1.2;
  }
  .rg-form-header p {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.88rem; font-weight: 600; color: #9ca3af;
  }

  /* Avatar row */
  .rg-avatar-row {
    display: flex; align-items: center; gap: 1.1rem;
    background: #f9fafb; border: 2.5px solid #f3f4f6;
    border-radius: 18px; padding: 0.9rem 1.1rem;
    transition: border-color 0.2s;
  }
  .rg-avatar-row:focus-within { border-color: #c4b5fd; background: white; }
  .rg-avatar-ring {
    width: 52px; height: 52px; border-radius: 50%;
    border: 2.5px dashed #e5e7eb;
    display: flex; align-items: center; justify-content: center;
    overflow: hidden; background: white; flex-shrink: 0;
    transition: border-color 0.25s, border-style 0.25s;
  }
  .rg-avatar-ring.filled { border-style: solid; border-color: #a855f7; }
  .rg-avatar-ring img { width: 100%; height: 100%; object-fit: cover; }
  .rg-avatar-input-col { flex: 1; display: flex; flex-direction: column; gap: 0.2rem; }
  .rg-avatar-label {
    font-size: 0.68rem; font-weight: 800; letter-spacing: 0.1em;
    text-transform: uppercase; color: #6b7280;
  }
  .rg-avatar-input {
    background: transparent; border: none; outline: none;
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.85rem; font-weight: 600; color: #1e1b4b;
    width: 100%;
  }
  .rg-avatar-input::placeholder { color: #d1d5db; }
  .rg-avatar-hint {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.7rem; font-weight: 600; color: #c4b5fd;
  }

  /* Fields grid */
  .rg-fields { display: flex; flex-direction: column; gap: 1rem; }
  .rg-row { display: flex; gap: 1rem; }
  .rg-row .rg-field { flex: 1; }

  .rg-field { display: flex; flex-direction: column; gap: 0.4rem; }
  .rg-label {
    font-size: 0.7rem; font-weight: 800; letter-spacing: 0.1em;
    text-transform: uppercase; color: #6b7280; padding-left: 0.2rem;
  }
  .rg-input-wrap { position: relative; }
  .rg-input-icon {
    position: absolute; left: 0.9rem; top: 50%;
    transform: translateY(-50%); pointer-events: none; color: #9ca3af;
    transition: color 0.2s;
  }
  .rg-input {
    width: 100%; padding: 0.85rem 1rem 0.85rem 2.6rem;
    background: #f9fafb; border: 2.5px solid #f3f4f6;
    border-radius: 14px;
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.88rem; font-weight: 600; color: #1e1b4b;
    outline: none; transition: all 0.2s;
  }
  .rg-input:focus {
    background: white; border-color: #c4b5fd;
    box-shadow: 0 0 0 3.5px rgba(168,85,247,0.1);
  }
  .rg-input:focus + .rg-input-icon { color: #a855f7; }
  .rg-input:disabled { opacity: 0.5; cursor: not-allowed; }
  .rg-input::placeholder { color: #d1d5db; }

  /* Strength */
  .rg-strength-bar { display: flex; gap: 5px; margin-top: 0.4rem; }
  .rg-strength-seg {
    flex: 1; height: 4px; border-radius: 999px;
    background: #f3f4f6; transition: background 0.3s;
  }
  .rg-strength-seg.weak   { background: #f43f5e; }
  .rg-strength-seg.medium { background: #eab308; }
  .rg-strength-seg.strong { background: #22c55e; }
  .rg-strength-hint {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.7rem; font-weight: 700; margin-top: 0.2rem; padding-left: 0.1rem;
    color: #9ca3af;
  }
  .rg-strength-hint.weak   { color: #f43f5e; }
  .rg-strength-hint.medium { color: #eab308; }
  .rg-strength-hint.strong { color: #22c55e; }

  /* Error */
  .rg-error {
    background: #fff1f2; border: 2px solid #fecdd3;
    border-radius: 14px; padding: 0.8rem 1rem;
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.82rem; font-weight: 700; color: #e11d48;
    display: flex; align-items: center; gap: 0.5rem;
  }

  /* Submit */
  .rg-btn {
    width: 100%; padding: 1rem;
    background: #a855f7; color: white; border: none;
    border-radius: 100px; cursor: pointer;
    font-family: 'Nunito', sans-serif; font-size: 1rem; font-weight: 900;
    display: flex; align-items: center; justify-content: center; gap: 0.5rem;
    box-shadow: 0 6px 0 #7c3aed, 0 10px 24px rgba(168,85,247,0.3);
    transition: transform 0.1s, box-shadow 0.1s;
    letter-spacing: 0.01em;
  }
  .rg-btn:hover  { transform: translateY(-2px); box-shadow: 0 8px 0 #7c3aed, 0 14px 28px rgba(168,85,247,0.35); }
  .rg-btn:active { transform: translateY(3px);  box-shadow: 0 3px 0 #7c3aed; }
  .rg-btn:disabled {
    background: #e5e7eb; color: #9ca3af;
    cursor: not-allowed; box-shadow: 0 4px 0 #d1d5db;
  }
  .rg-btn:disabled:hover { transform: none; box-shadow: 0 4px 0 #d1d5db; }

  .rg-spinner { animation: spin 0.8s linear infinite; }
  @keyframes spin { to { transform: rotate(360deg); } }

  .rg-form-footer {
    text-align: center;
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.8rem; font-weight: 600; color: #9ca3af;
  }
  .rg-link {
    color: #a855f7; font-weight: 800; text-decoration: none;
  }
  .rg-link:hover { color: #7c3aed; }

  /* Responsive */
  @media (max-width: 860px) {
    .rg-left { display: none; }
    .rg-right { padding: 2rem 1.5rem; }
  }
`;

function getStrength(p: string): 0 | 1 | 2 | 3 {
  if (!p) return 0;
  let s = 0;
  if (p.length >= 8) s++;
  if (/[A-Z]/.test(p) && /[a-z]/.test(p)) s++;
  if (/[0-9]/.test(p) || /[^A-Za-z0-9]/.test(p)) s++;
  return s as 0 | 1 | 2 | 3;
}
const S_LABEL = ["", "Weak", "Medium", "Strong"];
const S_CLASS = ["", "weak", "medium", "strong"];

const FEATURES = [
  {
    icon: <BookOpen size={18} color="#fff" />,
    bg: "#a855f7",
    title: "Adaptive Practice",
    sub: "Questions tailored to your skill level",
  },
  {
    icon: <Zap size={18} color="#fff" />,
    bg: "#f97316",
    title: "Instant Feedback",
    sub: "Know exactly where you went wrong",
  },
  {
    icon: <Trophy size={18} color="#fff" />,
    bg: "#22c55e",
    title: "Score Tracking",
    sub: "Watch your SAT score climb over time",
  },
];

const PANEL_DOTS = [
  {
    size: 70,
    color: "#f97316",
    top: "15%",
    left: "65%",
    delay: "0s",
    dur: "9s",
  },
  {
    size: 45,
    color: "#22c55e",
    top: "62%",
    left: "10%",
    delay: "1s",
    dur: "11s",
  },
  {
    size: 30,
    color: "#fde68a",
    top: "35%",
    left: "75%",
    delay: "0.5s",
    dur: "7s",
  },
  {
    size: 20,
    color: "#a855f7",
    top: "78%",
    left: "50%",
    delay: "2s",
    dur: "13s",
  },
];

const BG_DOTS = [
  {
    size: 180,
    color: "#a855f7",
    top: "5%",
    right: "5%",
    delay: "0s",
    dur: "12s",
  },
  {
    size: 100,
    color: "#f97316",
    bottom: "10%",
    left: "2%",
    delay: "1.5s",
    dur: "10s",
  },
  {
    size: 60,
    color: "#22c55e",
    top: "50%",
    right: "3%",
    delay: "0.8s",
    dur: "8s",
  },
];

const INITIALS = ["JD", "AS", "MK", "RP", "LL"];

export const Register = () => {
  const [name, setName] = useState("");
  const [email, setEmail] = useState("");
  const [avatarUrl, setAvatarUrl] = useState("");
  const [password, setPassword] = useState("");
  const [avatarError, setAvatarError] = useState(false);

  const navigate = useNavigate();
  const { register, isLoading, error, clearError } = useAuthStore();

  const strength = getStrength(password);
  const isValid = name.trim() && email.trim() && password.length >= 6;

  const handleSubmit = async (e: FormEvent<HTMLButtonElement>) => {
    e.preventDefault();
    clearError();
    const success = await register({
      email,
      name,
      avatar_url: avatarUrl,
      password,
    });
    if (success) navigate("/student/home", { replace: true });
  };

  return (
    <div className="rg-root">
      <style>{STYLES}</style>

      {/* ── LEFT PANEL ── */}
      <div className="rg-left">
        <div className="rg-panel-blob rg-panel-blob-1" />
        <div className="rg-panel-blob rg-panel-blob-2" />
        <div className="rg-panel-blob rg-panel-blob-3" />

        {/* Decorative floating dots */}
        {PANEL_DOTS.map((d, i) => (
          <div
            key={i}
            className="rg-shape"
            style={
              {
                width: d.size,
                height: d.size,
                background: d.color,
                borderRadius: "50%",
                opacity: 0.12,
                top: d.top,
                left: d.left,
                animationDelay: d.delay,
                animationDuration: d.dur,
              } as React.CSSProperties
            }
          />
        ))}

        {/* Stars */}
        {[
          { top: "14%", left: "20%", size: 14, delay: "0s" },
          { top: "28%", left: "78%", size: 10, delay: "0.7s" },
          { top: "52%", left: "30%", size: 12, delay: "1.3s" },
          { top: "70%", left: "65%", size: 8, delay: "0.4s" },
          { top: "88%", left: "22%", size: 10, delay: "1.8s" },
        ].map((s, i) => (
          <Star
            key={i}
            className="rg-star"
            size={s.size}
            style={
              {
                top: s.top,
                left: s.left,
                animationDelay: s.delay,
                fill: "#fde68a",
              } as React.CSSProperties
            }
          />
        ))}

        {/* Decorative ring shapes */}
        {[
          { size: 90, top: "72%", left: "5%", delay: "0.2s", dur: "10s" },
          { size: 60, top: "8%", left: "55%", delay: "1.1s", dur: "13s" },
        ].map((r, i) => (
          <div
            key={i}
            className="rg-shape"
            style={
              {
                width: r.size,
                height: r.size,
                border: "2.5px solid rgba(255,255,255,0.1)",
                borderRadius: "50%",
                top: r.top,
                left: r.left,
                animationDelay: r.delay,
                animationDuration: r.dur,
              } as React.CSSProperties
            }
          />
        ))}

        <div className="rg-panel-content">
          {/* Logo */}
          <div className="rg-panel-logo">
            <div className="rg-panel-logo-badge">📚</div>
            <span className="rg-panel-logo-text">EdBridge</span>
          </div>

          {/* Headline */}
          <div className="rg-panel-headline">
            <h2>
              Ace the SAT.
              <br />
              <span>Start for free.</span>
            </h2>
            <p>
              Join thousands of students who improved their
              <br />
              SAT scores with personalized practice.
            </p>
          </div>

          {/* Feature pills */}
          <div className="rg-features">
            {FEATURES.map((f, i) => (
              <div className="rg-feature" key={i}>
                <div className="rg-feature-icon" style={{ background: f.bg }}>
                  {f.icon}
                </div>
                <div className="rg-feature-text">
                  <strong>{f.title}</strong>
                  <span>{f.sub}</span>
                </div>
              </div>
            ))}
          </div>

          {/* Social proof */}
          <div className="rg-social-proof">
            <div className="rg-avatars">
              {INITIALS.map((s, i) => (
                <div className="rg-av" key={i}>
                  {s}
                </div>
              ))}
            </div>
            <p>
              <strong>2,400+</strong> students already enrolled
            </p>
          </div>
        </div>
      </div>

      {/* ── RIGHT PANEL ── */}
      <div className="rg-right">
        {BG_DOTS.map((d, i) => (
          <div
            key={i}
            className="rg-bg-dot"
            style={
              {
                width: d.size,
                height: d.size,
                background: d.color,
                top: (d as any).top,
                right: (d as any).right,
                bottom: (d as any).bottom,
                left: (d as any).left,
                animationDelay: d.delay,
                animationDuration: d.dur,
              } as React.CSSProperties
            }
          />
        ))}

        <div className="rg-form-wrap">
          {/* Header */}
          <div className="rg-form-header">
            <h1>Create your account ✨</h1>
            <p>Fill in the details below to get started</p>
          </div>

          {/* Avatar URL row */}
          <div className="rg-avatar-row">
            <div
              className={`rg-avatar-ring ${avatarUrl && !avatarError ? "filled" : ""}`}
            >
              {avatarUrl && !avatarError ? (
                <img
                  src={avatarUrl}
                  alt="Avatar"
                  onError={() => setAvatarError(true)}
                />
              ) : (
                <ImageIcon size={20} color="#d1d5db" />
              )}
            </div>
            <div className="rg-avatar-input-col">
              <span className="rg-avatar-label">
                Avatar URL{" "}
                <span
                  style={{
                    fontWeight: 600,
                    textTransform: "none",
                    letterSpacing: 0,
                    color: "#c4b5fd",
                    fontSize: "0.68rem",
                  }}
                >
                  (optional)
                </span>
              </span>
              <input
                className="rg-avatar-input"
                type="url"
                placeholder="https://example.com/photo.jpg"
                value={avatarUrl}
                onChange={(e) => {
                  setAvatarUrl(e.target.value);
                  setAvatarError(false);
                }}
                disabled={isLoading}
              />
              <span className="rg-avatar-hint">
                Paste any image URL to set your profile photo
              </span>
            </div>
          </div>

          {/* Fields */}
          <div className="rg-fields">
            {/* Name + Email row */}
            <div className="rg-row">
              <div className="rg-field">
                <label className="rg-label" htmlFor="name">
                  Full Name
                </label>
                <div className="rg-input-wrap">
                  <input
                    id="name"
                    type="text"
                    className="rg-input"
                    style={{ paddingLeft: "1rem" }}
                    placeholder="Jane Doe"
                    value={name}
                    onChange={(e) => setName(e.target.value)}
                    disabled={isLoading}
                  />
                </div>
              </div>
            </div>

            {/* Email */}
            <div className="rg-field">
              <label className="rg-label" htmlFor="email">
                Email
              </label>
              <div className="rg-input-wrap">
                <Mail size={15} className="rg-input-icon" />
                <input
                  id="email"
                  type="email"
                  className="rg-input"
                  placeholder="you@example.com"
                  value={email}
                  onChange={(e) => setEmail(e.target.value)}
                  disabled={isLoading}
                />
              </div>
            </div>

            {/* Password */}
            <div className="rg-field">
              <label className="rg-label" htmlFor="password">
                Password
              </label>
              <div className="rg-input-wrap">
                <Lock size={15} className="rg-input-icon" />
                <input
                  id="password"
                  type="password"
                  className="rg-input"
                  placeholder="Min. 6 characters"
                  value={password}
                  onChange={(e) => setPassword(e.target.value)}
                  disabled={isLoading}
                />
              </div>
              {password && (
                <>
                  <div className="rg-strength-bar">
                    {[1, 2, 3].map((seg) => (
                      <div
                        key={seg}
                        className={`rg-strength-seg ${strength >= seg ? S_CLASS[strength] : ""}`}
                      />
                    ))}
                  </div>
                  <p className={`rg-strength-hint ${S_CLASS[strength]}`}>
                    {S_LABEL[strength]} password
                  </p>
                </>
              )}
            </div>

            {/* Error */}
            {error && (
              <div className="rg-error">
                <span>⚠️</span> {error}
              </div>
            )}

            {/* Submit */}
            <button
              className="rg-btn"
              onClick={handleSubmit}
              disabled={isLoading || !isValid}
            >
              {isLoading ? (
                <>
                  <Loader2 size={18} className="rg-spinner" /> Creating
                  account...
                </>
              ) : (
                "Create Account →"
              )}
            </button>
          </div>

          <p className="rg-form-footer">
            Already have an account?{" "}
            <a href="/login" className="rg-link">
              Sign in
            </a>
          </p>
        </div>
      </div>
    </div>
  );
};