import { A } from '@solidjs/router';
import { For, Show, createMemo, createSignal, onCleanup, onMount } from 'solid-js';
import PublicBackground from '~/components/PublicBackground';
import PublicFooter from '~/components/PublicFooter';
import PublicHeader from '~/components/PublicHeader';

const chapters = [
  { id: 'chapter-problem', title: '01 The problem' },
  { id: 'chapter-built', title: '02 What we built' },
  { id: 'chapter-trust', title: '03 How trust works' },
  { id: 'chapter-principles', title: '04 Principles' },
  { id: 'chapter-timeline', title: '05 Timeline' },
] as const;

const trustSequence = [
  { num: '01', title: 'Submission', body: 'A user submits profile, job, or requirement details with required context.' },
  { num: '02', title: 'Human Review', body: 'A reviewer checks quality, relevance, and verification requirements.' },
  { num: '03', title: 'Approval', body: 'Validated submissions are approved and moved to publish-ready state.' },
  { num: '04', title: 'Visible to Marketplace', body: 'Approved entities become discoverable and can receive responses.' },
] as const;

const milestones = [
  { title: 'Research', body: 'Mapped trust breakdowns in hiring and service discovery journeys.' },
  { title: 'MVP', body: 'Built a marketplace core with structured onboarding and review signals.' },
  { title: 'Private pilot', body: 'Tested operational workflows with role-specific submissions.' },
  { title: 'Launch', body: 'Released trust-layered marketplace experience to wider users.' },
  { title: 'Next: expanding categories', body: 'Adding more categories while keeping quality controls strong.' },
] as const;
const chapterFourNarrative = [
  'We didn’t build another marketplace.',
  'We built a filter.',
  'A review layer.',
  'Clarity replaces noise.',
] as const;
const chapterTwoRows = ['Profile status', 'Requirement status', 'Activity transparency'] as const;

export default function AboutPage() {
  const [showBackToTop, setShowBackToTop] = createSignal(false);
  const [reduceMotion, setReduceMotion] = createSignal(false);
  const [activeChapter, setActiveChapter] = createSignal(0);
  const [scrollY, setScrollY] = createSignal(0);

  // Initialize visible for SSR - all content renders on server, client hydration just updates visibility for animations
  const [heroVisible, setHeroVisible] = createSignal(true);
  const [problemVisible, setProblemVisible] = createSignal(true);
  const [builtVisible, setBuiltVisible] = createSignal(true);
  const [trustVisible, setTrustVisible] = createSignal(true);
  const [principlesVisible, setPrinciplesVisible] = createSignal(true);
  const [timelineVisible, setTimelineVisible] = createSignal(true);
  const [closingVisible, setClosingVisible] = createSignal(true);

  const [problemProgress, setProblemProgress] = createSignal(0);
  const [trustProgress, setTrustProgress] = createSignal(0);
  const [principleProgress, setPrincipleProgress] = createSignal(0);
  const [builtTilt, setBuiltTilt] = createSignal({ x: 0, y: 0 });

  let heroRef: HTMLElement | undefined;
  let chapterProblemRef: HTMLElement | undefined;
  let chapterBuiltRef: HTMLElement | undefined;
  let chapterTrustRef: HTMLElement | undefined;
  let chapterPrinciplesRef: HTMLElement | undefined;
  let chapterTimelineRef: HTMLElement | undefined;
  let closingRef: HTMLElement | undefined;

  onMount(() => {
    const media = window.matchMedia('(prefers-reduced-motion: reduce)');
    const syncMotion = () => setReduceMotion(media.matches);
    syncMotion();

    const chapterRefs = () => [chapterProblemRef, chapterBuiltRef, chapterTrustRef, chapterPrinciplesRef, chapterTimelineRef];

    const revealMap = new Map<HTMLElement, (visible: boolean) => void>();
    if (heroRef) revealMap.set(heroRef, setHeroVisible);
    if (chapterProblemRef) revealMap.set(chapterProblemRef, setProblemVisible);
    if (chapterBuiltRef) revealMap.set(chapterBuiltRef, setBuiltVisible);
    if (chapterTrustRef) revealMap.set(chapterTrustRef, setTrustVisible);
    if (chapterPrinciplesRef) revealMap.set(chapterPrinciplesRef, setPrinciplesVisible);
    if (chapterTimelineRef) revealMap.set(chapterTimelineRef, setTimelineVisible);
    if (closingRef) revealMap.set(closingRef, setClosingVisible);

    const observer = new IntersectionObserver(
      (entries) => {
        entries.forEach((entry) => {
          if (!entry.isIntersecting) return;
          const setter = revealMap.get(entry.target as HTMLElement);
          if (setter) setter(true);
        });
      },
      { threshold: 0.12 }
    );
    revealMap.forEach((_, el) => observer.observe(el));

    const onScroll = () => {
      setShowBackToTop(window.scrollY > 500);
      setScrollY(window.scrollY || 0);

      const middle = window.innerHeight * 0.42;
      let nextActive = 0;
      chapterRefs().forEach((section, index) => {
        if (!section) return;
        const rect = section.getBoundingClientRect();
        if (rect.top <= middle) nextActive = index;
      });
      setActiveChapter(nextActive);

      if (chapterProblemRef && !reduceMotion()) {
        const rect = chapterProblemRef.getBoundingClientRect();
        const viewport = window.innerHeight;
        const start = viewport * 0.9;
        const end = viewport * 0.18;
        const range = rect.height + (start - end);
        const raw = (start - rect.top) / range;
        setProblemProgress(Math.max(0, Math.min(1, raw)));
      } else if (reduceMotion()) {
        setProblemProgress(1);
      }

      if (chapterTrustRef && !reduceMotion()) {
        const rect = chapterTrustRef.getBoundingClientRect();
        const viewport = window.innerHeight;
        const start = viewport * 0.75;
        const end = viewport * 0.18;
        const range = rect.height + (start - end);
        const raw = (start - rect.top) / range;
        setTrustProgress(Math.max(0, Math.min(1, raw)));
      } else if (reduceMotion()) {
        setTrustProgress(1);
      }

      if (chapterPrinciplesRef && !reduceMotion()) {
        const rect = chapterPrinciplesRef.getBoundingClientRect();
        const viewport = window.innerHeight;
        const sectionTopAbs = window.scrollY + rect.top;
        const start = sectionTopAbs - viewport * 0.9;
        const end = sectionTopAbs + rect.height - viewport * 0.52;
        const range = Math.max(1, end - start);
        const raw = (window.scrollY - start) / range;
        setPrincipleProgress(Math.max(0, Math.min(1, raw)));
      } else if (reduceMotion()) {
        setPrincipleProgress(1);
      }
    };

    onScroll();
    window.addEventListener('scroll', onScroll, { passive: true });
    media.addEventListener('change', syncMotion);
    onCleanup(() => {
      window.removeEventListener('scroll', onScroll);
      media.removeEventListener('change', syncMotion);
      observer.disconnect();
    });
  });

  const progress = createMemo(() => {
    if (chapters.length <= 1) return 0;
    return (activeChapter() / (chapters.length - 1)) * 100;
  });

  const progressBetween = (value: number, start: number, end: number) => {
    const span = Math.max(0.001, end - start);
    return Math.max(0, Math.min(1, (value - start) / span));
  };

  const effectiveProblemProgress = createMemo(() => (reduceMotion() ? 1 : problemProgress()));
  const effectiveTrustProgress = createMemo(() => (reduceMotion() ? 1 : trustProgress()));
  const effectivePrincipleProgress = createMemo(() => (reduceMotion() ? 1 : principleProgress()));

  const chapterOneHeadlineIn = createMemo(() => progressBetween(effectiveProblemProgress(), 0.12, 0.42));
  const chapterOneBodyIn = createMemo(() => progressBetween(effectiveProblemProgress(), 0.24, 0.56));
  const chapterOneShapeFade = createMemo(() => (reduceMotion() ? 0 : 0.08 * (1 - effectiveProblemProgress())));

  const principleStage = createMemo(() => {
    const p = effectivePrincipleProgress();
    if (p < 0.25) return 0;
    if (p < 0.5) return 1;
    if (p < 0.75) return 2;
    return 3;
  });
  const stateTwoUnderline = createMemo(() => progressBetween(effectivePrincipleProgress(), 0.26, 0.46));
  const stateThreeLine = createMemo(() => progressBetween(effectivePrincipleProgress(), 0.52, 0.74));
  const chapterFourMotion = (idx: number) => {
    const p = effectivePrincipleProgress();
    const center = (idx + 0.5) / chapterFourNarrative.length;
    const preWindow = 0.14;

    // Once a line has crossed center, keep it bright and glowing.
    if (p >= center) {
      return {
        opacity: 1,
        y: 0,
        glow: 52,
      };
    }

    // Before center: approach from dim to bright, but no glow yet.
    const distanceToCenter = Math.max(0, center - p);
    const t = Math.max(0, Math.min(1, 1 - distanceToCenter / preWindow));

    return {
      opacity: 0.46 + t * 0.54,
      y: 0,
      glow: 0,
    };
  };
  const chapterFourBackdropGlow = createMemo(() => {
    // Keep chapter backdrop glow once the first narrative line reaches center.
    const firstCenter = 0.5 / chapterFourNarrative.length;
    return effectivePrincipleProgress() >= firstCenter ? 1 : 0;
  });
  const scrollToChapter = (chapterId: string) => {
    const target = document.getElementById(chapterId);
    if (!target) return;
    const offset = window.innerWidth >= 1280 ? 180 : 150;
    const top = target.getBoundingClientRect().top + window.scrollY - offset;
    window.scrollTo({ top: Math.max(0, top), behavior: reduceMotion() ? 'auto' : 'smooth' });
  };

  return (
    <main class="lp-main about-page-root">
      <PublicBackground scrollY={scrollY()} reduceMotion={reduceMotion()} meshFactor={0.12} ribbonFactor={0.22} meshCap={40} ribbonCap={55} />

      <div class="lp-content about-content about-with-rail">
        <PublicHeader />

        <aside class="about-chapter-rail">
          <div class="about-chapter-track">
            <span class="about-chapter-progress" style={{ height: `${progress()}%` }} />
          </div>
          <ul class="about-chapter-list">
            <For each={chapters}>
              {(chapter, idx) => (
                <li class={idx() === activeChapter() ? 'about-chapter-item-active' : 'about-chapter-item'}>
                  <a
                    href={`#${chapter.id}`}
                    onClick={(event) => {
                      event.preventDefault();
                      scrollToChapter(chapter.id);
                    }}
                  >
                    {chapter.title}
                  </a>
                </li>
              )}
            </For>
          </ul>
        </aside>

        <section ref={heroRef} class="about-hero">
          <div class="container">
            <div class={`about-hero-inner about-reveal-init ${heroVisible() ? 'about-reveal-show' : ''}`}>
              <div>
                <p class="about-kicker">Brand Story</p>
                <h1 class="about-title">Trust-first hiring and services.</h1>
                <p class="about-copy">
                  Nxtgauge is built to reduce noise, improve quality, and help people connect with confidence.
                </p>
                <div class="hero-actions">
                  <A class="lp-primary-btn" href="/contact">Contact us</A>
                </div>
              </div>

              <aside class="about-manifesto-card">
                <h2>Our manifesto</h2>
                <ul>
                  <li>Verify what matters</li>
                  <li>Reduce spam and guesswork</li>
                  <li>Match people faster</li>
                </ul>
                <span class="about-sheen-sweep" />
              </aside>
            </div>
          </div>
        </section>

        <section
          id="chapter-problem"
          ref={chapterProblemRef}
          class="about-section-tight about-chapter-problem-section"
        >
          <div class="container">
            <article class={`about-problem-stage about-reveal-init ${problemVisible() ? 'about-reveal-show' : ''}`}>
              <span class="about-problem-halo" style={{ opacity: 0.16 + effectiveProblemProgress() * 0.32 }} />
              <span
                class="about-problem-shape-a"
                style={{
                  opacity: chapterOneShapeFade(),
                  transform: `translate3d(${-14 * effectiveProblemProgress()}px, ${10 * effectiveProblemProgress()}px, 0)`,
                }}
              />
              <span
                class="about-problem-shape-b"
                style={{
                  opacity: chapterOneShapeFade(),
                  transform: `translate3d(${16 * effectiveProblemProgress()}px, ${-8 * effectiveProblemProgress()}px, 0)`,
                }}
              />
              <span
                class="about-problem-shape-c"
                style={{
                  opacity: chapterOneShapeFade(),
                  transform: `translate3d(${12 * effectiveProblemProgress()}px, ${11 * effectiveProblemProgress()}px, 0)`,
                }}
              />
              <span
                class="about-problem-shape-d"
                style={{
                  opacity: chapterOneShapeFade(),
                  transform: `translate3d(${-12 * effectiveProblemProgress()}px, ${-10 * effectiveProblemProgress()}px, 0)`,
                }}
              />
              <p class="about-chapter-label about-chapter-label-light">Chapter 01</p>
              <h2 class="about-chapter-title about-chapter-title-dark">The Problem</h2>
              <h3
                class="about-problem-headline"
                style={{
                  opacity: chapterOneHeadlineIn(),
                  filter: `blur(${(1 - chapterOneHeadlineIn()) * 5}px)`,
                }}
              >
                The hardest part isn’t finding options.
              </h3>
              <p
                class="about-problem-body"
                style={{
                  opacity: chapterOneBodyIn(),
                  filter: `blur(${(1 - chapterOneBodyIn()) * 3}px)`,
                }}
              >
                It’s knowing which one deserves your time.
                <br />
                Scrolling. Comparing. Second-guessing. Starting over.
                <br />
                The real cost isn’t money.
                <br />
                It’s momentum.
              </p>
            </article>
          </div>
        </section>

        <section
          id="chapter-built"
          ref={chapterBuiltRef}
          class="about-section-tight"
        >
          <div class="container">
            <article class={`about-glass-light about-chapter-two-shell about-reveal-init ${builtVisible() ? 'about-reveal-show' : ''}`}>
              <p class="about-chapter-label about-chapter-label-orange">Chapter 02</p>
              <h2 class="about-chapter-title about-chapter-title-light">What We Built</h2>
              <div class="about-chapter-two-grid">
                <div
                  class="about-chapter-two-text"
                  style={{
                    opacity: builtVisible() ? 1 : 0,
                    transform: builtVisible() ? 'translate3d(0,0,0)' : 'translate3d(0,8px,0)',
                  }}
                >
                  <h2 class="about-chapter-two-heading">We wanted to reduce hesitation.</h2>
                  <p class="about-chapter-two-body">
                    Not by adding more choices.
                    <br />
                    But by designing fewer, stronger ones.
                    <br />
                    Nxtgauge is built around one idea:
                    <br />
                    Confidence should come before commitment.
                  </p>
                </div>
                <aside
                  class="about-chapter-two-panel"
                  onMouseMove={(event) => {
                    if (reduceMotion()) return;
                    const rect = event.currentTarget.getBoundingClientRect();
                    const px = (event.clientX - rect.left) / rect.width - 0.5;
                    const py = (event.clientY - rect.top) / rect.height - 0.5;
                    setBuiltTilt({ x: -(py * 2), y: px * 2 });
                  }}
                  onMouseLeave={() => setBuiltTilt({ x: 0, y: 0 })}
                  style={{
                    opacity: builtVisible() ? 1 : 0,
                    transform: reduceMotion()
                      ? builtVisible()
                        ? 'translate3d(0,0,0)'
                        : 'translate3d(0,8px,0)'
                      : builtVisible()
                        ? `perspective(980px) rotateX(${builtTilt().x}deg) rotateY(${builtTilt().y}deg) scale(1)`
                        : 'perspective(980px) rotateX(0deg) rotateY(0deg) scale(0.95)',
                    filter: builtVisible() && !reduceMotion() ? 'blur(0px)' : 'blur(3px)',
                    transitionDelay: builtVisible() ? '150ms' : '0ms',
                  }}
                >
                  <span class="about-chapter-two-panel-glow" />
                  <span class="about-chapter-two-reflection" style={{ animation: builtVisible() && !reduceMotion() ? 'chapterTwoSweep 900ms ease-out 1' : 'none' }} />
                  <div class="about-chapter-two-panel-inner">
                    <p class="about-chapter-two-panel-label">HOW IT SHOWS UP</p>
                    <h3 class="about-chapter-two-panel-title">
                      Before you decide,
                      <br />
                      you see signals.
                    </h3>
                    <span class="about-chapter-two-divider" />
                    <div class="about-chapter-two-rows">
                      <For each={chapterTwoRows}>
                        {(row, idx) => (
                          <div
                            class="about-chapter-two-row"
                            style={{
                              opacity: builtVisible() ? 1 : 0,
                              transform: builtVisible() ? 'translate3d(0,0,0)' : 'translate3d(0,8px,0)',
                              'transition-delay': builtVisible() ? `${200 + idx() * 100}ms` : '0ms',
                            }}
                          >
                            <span class="about-chapter-two-row-dot" />
                            {row}
                          </div>
                        )}
                      </For>
                    </div>
                    <p class="about-chapter-two-closing">Clarity before commitment.</p>
                  </div>
                </aside>
              </div>
            </article>
          </div>
        </section>

        <section
          id="chapter-trust"
          ref={chapterTrustRef}
          class="about-section-tight"
        >
          <div class="container">
            <article class={`about-glass-dark about-trust-shell about-reveal-init ${trustVisible() ? 'about-reveal-show' : ''}`}>
              <p class="about-chapter-label about-chapter-label-light">Chapter 03</p>
              <h2 class="about-chapter-title about-chapter-title-dark">The Trust Layer</h2>
              <p class="about-trust-sub">Most reviews complete within 24-48 hours.</p>
              <div class="about-trust-sequence">
                <div class="about-trust-sequence-list">
                  <For each={trustSequence}>
                    {(step, idx) => (
                      <article
                        class="about-trust-sequence-card"
                        style={{
                          opacity: effectiveTrustProgress() >= (idx() / trustSequence.length) * 0.85 ? 1 : 0.3,
                          transform: effectiveTrustProgress() >= (idx() / trustSequence.length) * 0.85 ? 'translate3d(0,0,0)' : 'translate3d(0,10px,0)',
                        }}
                      >
                        <div class="about-trust-sequence-row">
                          <span class="about-trust-sequence-icon">
                            <span class="about-trust-sequence-dot" />
                          </span>
                          <div>
                            <p class="about-trust-num">{step.num}</p>
                            <h3>{step.title}</h3>
                            <p>{step.body}</p>
                          </div>
                        </div>
                      </article>
                    )}
                  </For>
                </div>
              </div>
            </article>
          </div>
        </section>

        <section
          id="chapter-principles"
          ref={chapterPrinciplesRef}
          class="about-section-tight about-principles-section"
        >
          <div class="container">
            <article class={`about-glass-dark about-trust-shell about-principle-narrative-section about-reveal-init ${principlesVisible() ? 'about-reveal-show' : ''}`}>
              <p class="about-chapter-label about-chapter-label-light">Chapter 04</p>
              <h2 class="about-chapter-title about-chapter-title-dark">Principles</h2>
              <div class="about-narrative-stage-root">
                <Show
                  when={!reduceMotion()}
                  fallback={
                    <div class="about-narrative-stack">
                      <p class="about-narrative-headline about-narrative-item-active">We didn’t build another marketplace.</p>
                      <div>
                        <p class="about-narrative-headline about-narrative-item-active">We built a <span class="about-orange-word">filter</span>.</p>
                        <span class="about-filter-underline-static" />
                      </div>
                      <div>
                        <p class="about-narrative-headline about-narrative-item-active">
                          A review layer.
                          <span class="about-principles-subline-inline">Profiles. Jobs. Requirements.</span>
                        </p>
                        <span class="about-review-line-static" />
                      </div>
                      <p class="about-narrative-headline about-narrative-item-active">Clarity replaces noise.</p>
                    </div>
                  }
                >
                  <div class="about-narrative-viewport">
                    <span
                      class="about-narrative-glow"
                      style={{
                        opacity: chapterFourBackdropGlow() * 0.78,
                      }}
                    />
                    <div class="about-narrative-stack">
                      <For each={chapterFourNarrative}>
                        {(line, idx) => (
                          <div
                            class={principleStage() === idx() ? 'about-narrative-item-active' : 'about-narrative-item-inactive'}
                            style={{
                              opacity: chapterFourMotion(idx()).opacity,
                              transform: `translate3d(0, ${chapterFourMotion(idx()).y}px, 0)`,
                              'text-shadow': chapterFourMotion(idx()).glow > 0
                                ? `0 0 ${chapterFourMotion(idx()).glow}px rgba(253, 98, 22, 0.34)`
                                : 'none',
                            }}
                          >
                            <p class="about-narrative-headline">
                              {idx() === 1 ? (
                                <>
                                  We built a <span class="about-orange-word">filter</span>.
                                </>
                              ) : (
                                line
                              )}
                            </p>
                            <Show when={idx() === 1}>
                              <span class="about-filter-underline" style={{ transform: `scaleX(${stateTwoUnderline()})` }} />
                            </Show>
                            <Show when={idx() === 2}>
                              <>
                                <span class="about-principles-subline-inline">Profiles. Jobs. Requirements.</span>
                                <span class="about-review-line" style={{ transform: `scaleX(${stateThreeLine()})` }} />
                              </>
                            </Show>
                          </div>
                        )}
                      </For>
                    </div>
                  </div>
                </Show>
                </div>
            </article>
          </div>
        </section>

        <section
          id="chapter-timeline"
          ref={chapterTimelineRef}
          class="about-section-tight about-timeline-section-tight"
        >
          <div class="container">
            <div class={`about-glass-light about-timeline-mask-init ${timelineVisible() ? 'about-timeline-mask-show' : ''}`}>
              <p class="about-kicker about-kicker-orange">Chapter 05</p>
              <h2 class="about-section-title-light">Timeline</h2>
              <div class="about-timeline-wrap">
                <span class="about-timeline-spine-glow" />
                <For each={milestones}>
                  {(milestone, index) => (
                    <article
                      class={`about-timeline-milestone ${timelineVisible() ? 'about-timeline-milestone-visible' : ''}`}
                      style={{ 'transition-delay': `${index() * 90}ms` }}
                    >
                      <span class="about-timeline-index">{index() + 1}</span>
                      <h3>{milestone.title}</h3>
                      <p>{milestone.body}</p>
                    </article>
                  )}
                </For>
              </div>
            </div>
          </div>
        </section>

        <section ref={closingRef} class="about-section-mid">
          <div class="container">
            <div class={`about-glass-dark about-closing-card about-reveal-init ${closingVisible() ? 'about-reveal-show' : ''}`}>
              <h2>Have a question or want to partner?</h2>
              <div class="hero-actions">
                <A class="lp-primary-btn" href="/contact">Contact us</A>
                <A class="lp-ghost-btn lp-ghost-btn-dark" href="/">Back to home</A>
              </div>
            </div>
          </div>
        </section>

        <Show when={showBackToTop()}>
          <button class="back-top" onClick={() => window.scrollTo({ top: 0, behavior: reduceMotion() ? 'auto' : 'smooth' })}>
            ↑
          </button>
        </Show>

        <PublicFooter />
      </div>
    </main>
  );
}