"use client";

import React, { useEffect, useState } from "react";
import Link from "next/link";
import Image from "next/image";
import { ArrowLeft } from "lucide-react";
import { ThemeToggle } from "@/lib/theme-toggle";

interface AuthLayoutProps {
  title: string;
  subtitle: string;
  children: React.ReactNode;
  footerText?: string;
  footerLinkText?: string;
  footerLinkHref?: string;
}

/* Waveform design — "Golden Studio": the auth visual column is a dim
   control room: amber record light (pulsing LED + mono timecode), a live
   waveform as the single hero object, and the tail of the guest pipeline
   fading into canvas at the bottom. Collapses below 900px per the design
   system (§5.4) — the form is never broken.

   Bar heights are a fixed, hand-tuned array (never Math.random — would
   cause hydration mismatches between SSR and client). */
const WAVE_HEIGHTS = [
  12, 18, 26, 20, 34, 48, 42, 60, 84, 72, 96, 120, 104, 132, 116, 140, 124, 108,
  128, 96, 112, 78, 88, 60, 68, 44, 52, 32, 40, 24, 28, 16, 20, 12,
];

const PIPELINE_CARDS = [
  { label: "Prospect", count: 8, color: "var(--status-prospect)", rotate: "-2deg" },
  { label: "Contacted", count: 5, color: "var(--status-contacted)", rotate: "1.5deg" },
  { label: "Scheduled", count: 3, color: "var(--status-scheduled)", rotate: "-1deg" },
];

function formatTimecode(totalSeconds: number): string {
  const h = Math.floor(totalSeconds / 3600);
  const m = Math.floor((totalSeconds % 3600) / 60);
  const s = totalSeconds % 60;
  return `${h}:${String(m).padStart(2, "0")}:${String(s).padStart(2, "0")}`;
}

export function AuthLayout({
  title,
  subtitle,
  children,
  footerText,
  footerLinkText,
  footerLinkHref,
}: AuthLayoutProps) {
  return (
    <div className="auth-layout-container">
      <style>{authStyles}</style>
      <AuthFormColumn title={title} subtitle={subtitle}>
        {children}
        {footerText && footerLinkText && footerLinkHref && (
          <p className="auth-form-footer">
            {footerText}{" "}
            <Link href={footerLinkHref} style={{ color: "var(--color-primary)", fontWeight: 600, textDecoration: "none" }}>
              {footerLinkText}
            </Link>
          </p>
        )}
      </AuthFormColumn>
      <AuthVisualColumn />
    </div>
  );
}

/* ─── Form column (left, 40%) ──────────────────────────────── */

function AuthFormColumn({
  title,
  subtitle,
  children,
}: {
  title: string;
  subtitle: string;
  children: React.ReactNode;
}) {
  return (
    <div className="auth-form-col">
      <div className="auth-form-brand">
        <Link href="/" className="auth-brand-link">
          <Image src="/logo.png" alt="MicProtocol" width={40} height={40} style={{ borderRadius: "var(--radius-md)", objectFit: "contain" }} />
          <span className="auth-brand-name">MicProtocol</span>
        </Link>
        <ThemeToggle className="auth-theme-toggle" />
      </div>

      <div className="auth-form-center">
        <div style={{ width: "100%", maxWidth: 420 }}>
          <Link
            href="/"
            className="auth-back-link"
          >
            <ArrowLeft size={14} />
            <span>Back to home</span>
          </Link>
        </div>
        <div className="auth-card texture-surface texture-surface--fluted-glass">
          <h1 className="auth-title">{title}</h1>
          <p className="auth-subtitle">{subtitle}</p>
          {children}
        </div>
      </div>

      <div className="auth-form-meta">
        <span>&copy; {new Date().getFullYear()} MicProtocol</span>
        <div className="auth-form-meta-links">
          <Link href="/privacy">Privacy</Link>
          <Link href="/terms">Terms</Link>
          <Link href="/security">Security</Link>
        </div>
      </div>
    </div>
  );
}

/* ─── Visual column (right, 60%) ───────────────────────────── */

function AuthVisualColumn() {
  const [seconds, setSeconds] = useState(0);

  useEffect(() => {
    const id = window.setInterval(() => {
      setSeconds((prev) => prev + 1);
    }, 1000);
    return () => window.clearInterval(id);
  }, []);

  return (
    <div className="auth-visual-col texture-surface texture-surface--speckled-graphite" aria-hidden="true">
      <div className="auth-visual-bg" />

      {/* Record light */}
      <div className="auth-rec-indicator">
        <span className="auth-rec-dot" />
        <span className="auth-rec-time">REC {formatTimecode(seconds)}</span>
      </div>

      {/* Live waveform — the hero object */}
      <div className="auth-waveform">
        {WAVE_HEIGHTS.map((height, i) => (
          <span
            key={i}
            className="auth-waveform-bar"
            style={{ height, animationDelay: `${(i % 12) * -160}ms` }}
          />
        ))}
      </div>

      {/* Pipeline tail */}
      <div className="auth-pipeline-stack">
        {PIPELINE_CARDS.map(({ label, count, color, rotate }) => (
          <div key={label} className="auth-pipeline-card" style={{ transform: `rotate(${rotate})` }}>
            <span className="auth-pipeline-dot" style={{ backgroundColor: color }} />
            <span className="auth-pipeline-label">{label}</span>
            <span className="auth-pipeline-count">{count}</span>
          </div>
        ))}
      </div>

    </div>
  );
}

/* ─── Styles ───────────────────────────────────────────────── */

const authStyles = `
  .auth-layout-container {
    display: grid;
    grid-template-columns: 1fr;
    min-height: 100vh;
    background: var(--bg-primary);
  }

  /* ── Form column ── */
  .auth-form-col {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    padding: clamp(1.5rem, 4vw, 2.5rem);
  }

  .auth-form-brand {
    width: 100%;
    max-width: 420px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .auth-theme-toggle {
    padding: var(--space-2);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
  }

  .auth-theme-toggle:hover {
    background: var(--bg-elevated);
    border-color: var(--color-primary);
  }

  .auth-brand-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-3);
    color: inherit;
    text-decoration: none;
  }

  .auth-brand-name {
    font-family: var(--font-display);
    font-size: var(--text-lg);
    font-weight: 700;
    letter-spacing: -0.02em;
  }

  .auth-form-center {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
  }

  .auth-form-meta {
    width: 100%;
    max-width: 420px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: var(--text-xs);
    color: var(--text-tertiary);
  }

  .auth-form-meta-links {
    display: flex;
    gap: var(--space-4);
  }

  .auth-form-meta-links a {
    color: var(--text-tertiary);
    text-decoration: none;
    transition: color var(--transition-fast);
  }

  .auth-form-meta-links a:hover {
    color: var(--text-secondary);
  }

  .auth-card {
    width: 100%;
    max-width: 420px;
    padding: clamp(1.5rem, 4vw, 2.5rem);
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    animation: auth-card-in 0.45s var(--ease-out-expo);
  }

  @keyframes auth-card-in {
    from {
      opacity: 0;
      transform: translateY(10px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  .auth-title {
    font-family: var(--font-display);
    font-size: var(--text-2xl);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    color: var(--text-primary);
    margin: 0 0 var(--space-2);
  }

  .auth-subtitle {
    font-size: var(--text-sm);
    line-height: 1.55;
    color: var(--text-secondary);
    margin: 0 0 var(--space-6);
  }

  .auth-form-footer {
    margin: var(--space-6) 0 0;
    text-align: center;
    font-size: var(--text-xs);
    color: var(--text-secondary);
  }

  /* ── Visual column ── */
  .auth-visual-col {
    display: none;
    position: relative;
    overflow: hidden;
    background: var(--bg-secondary);
  }

  /* Dim control-room backdrop: low amber light source bottom-center
     (the "record light" spilling onto the desk), cool top read */
  .auth-visual-bg {
    position: absolute;
    inset: 0;
    background:
      radial-gradient(ellipse 60% 45% at 50% 92%, color-mix(in srgb, var(--color-primary) 10%, transparent), transparent 70%),
      radial-gradient(ellipse 80% 60% at 50% 45%, color-mix(in srgb, var(--color-primary) 4%, transparent), transparent 70%),
      var(--bg-secondary);
  }

  .auth-visual-bg::after {
    content: "";
    position: absolute;
    inset: 0;
    opacity: 0.4;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.6' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.05'/%3E%3C/svg%3E");
    pointer-events: none;
  }

  .auth-rec-indicator {
    position: absolute;
    top: clamp(1.5rem, 3vw, 2.5rem);
    right: clamp(1.5rem, 3vw, 2.5rem);
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 8px 14px;
    border-radius: var(--radius-full);
    border: 1px solid var(--border-color);
    background: color-mix(in srgb, var(--bg-primary) 70%, transparent);
    z-index: 2;
  }

  .auth-rec-dot {
    width: 8px;
    height: 8px;
    border-radius: var(--radius-full);
    background: var(--color-primary);
    animation: auth-rec-pulse 1.5s ease-in-out infinite;
  }

  @keyframes auth-rec-pulse {
    0%, 100% {
      box-shadow: 0 0 4px color-mix(in srgb, var(--color-primary) 60%, transparent);
      opacity: 1;
    }
    50% {
      box-shadow: 0 0 12px color-mix(in srgb, var(--color-primary) 90%, transparent);
      opacity: 0.75;
    }
  }

  .auth-rec-time {
    font-family: var(--font-mono);
    font-variant-numeric: tabular-nums;
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--text-secondary);
    letter-spacing: 0.02em;
  }

  /* Waveform — centered hero object */
  .auth-waveform {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -55%);
    display: flex;
    align-items: center;
    gap: 4px;
    width: min(560px, 72%);
    justify-content: center;
    z-index: 1;
  }

  .auth-waveform-bar {
    flex: 1;
    max-width: 6px;
    min-width: 2px;
    border-radius: var(--radius-full);
    background: linear-gradient(
      180deg,
      color-mix(in srgb, var(--color-primary) 55%, var(--bg-secondary)) 0%,
      var(--color-primary) 100%
    );
    opacity: 0.85;
    animation: auth-wave-motion 1.6s ease-in-out infinite alternate;
  }

  @keyframes auth-wave-motion {
    from {
      transform: scaleY(0.85);
      opacity: 0.55;
    }
    to {
      transform: scaleY(1.12);
      opacity: 0.95;
    }
  }

  /* Pipeline tail — three stage cards drifting down-right, fading out */
  .auth-pipeline-stack {
    position: absolute;
    bottom: 0;
    left: clamp(1.5rem, 4vw, 3rem);
    width: min(280px, 55%);
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    padding-bottom: var(--space-6);
    -webkit-mask-image: linear-gradient(180deg, #000 30%, transparent 98%);
    mask-image: linear-gradient(180deg, #000 30%, transparent 98%);
    z-index: 1;
  }

  .auth-pipeline-card {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
  }

  .auth-pipeline-dot {
    width: 8px;
    height: 8px;
    border-radius: var(--radius-full);
    flex-shrink: 0;
  }

  .auth-pipeline-label {
    flex: 1;
    font-size: var(--text-xs);
    font-weight: 600;
    color: var(--text-secondary);
  }

  .auth-pipeline-count {
    font-family: var(--font-display);
    font-size: var(--text-sm);
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    color: var(--text-primary);
  }

  /* ── Split at 900px: form + visual columns ── */
  @media (min-width: 900px) {
    .auth-layout-container {
      grid-template-columns: 2fr 3fr;
    }

    .auth-visual-col {
      display: block;
    }
  }

  /* ── Big screens (>= 1200px): balanced form + visual, no container shrink ── */
  @media (min-width: 1200px) {
    .auth-layout-container {
      grid-template-columns: 1fr 1fr;
    }

    .auth-form-col {
      padding: clamp(2rem, 5vw, 3rem);
    }

    .auth-card {
      max-width: 420px;
      margin: 0 auto;
    }

    .auth-visual-col {
      min-width: 0;
    }
  }

  /* ── Reduced motion: calm the room ── */
  @media (prefers-reduced-motion: reduce) {
    .auth-waveform-bar,
    .auth-rec-dot,
    .auth-card {
      animation: none;
    }

    .auth-rec-indicator {
      background: var(--bg-primary);
    }
  }

  /* ── Small screens: stricter rhythm ── */
  @media (max-width: 480px) {
    .auth-form-col {
      padding: var(--space-4);
    }

    .auth-form-meta {
      justify-content: center;
      gap: var(--space-4);
    }
  }
`;