"use client";

import { useState, useEffect } from "react";
import { useTranslation } from "@/app/hooks/useTranslation";
import ReadyToJoin from "./ReadyToJoin";

const BASE = process.env.NEXT_PUBLIC_BASE_PATH || "";

type EventItem = {
  id: number;
  title: string;
  location: string;
  date: string;
  description: string;
  images: string[];
  googleDriveUrl: string;
};

export default function GalleryPageClient() {
  const { gallery, lang } = useTranslation();

  // Active Event Index (0: latest event, 7: oldest event)
  const [activeEventIndex, setActiveEventIndex] = useState(0);

  // Lightbox State
  const [lightboxImageIndex, setLightboxImageIndex] = useState<number | null>(null);

  // Active event object
  const activeEvent = gallery.events[activeEventIndex] as EventItem;

  // Helper to format image source path
  const getImgSrc = (src: string) => {
    if (src.startsWith("http")) return src;
    return `${BASE}${src}`;
  };

  // Keyboard navigation for Lightbox
  useEffect(() => {
    if (lightboxImageIndex === null || !activeEvent) return;

    const handleKeyDown = (e: KeyboardEvent) => {
      if (e.key === "Escape") {
        closeLightbox();
      } else if (e.key === "ArrowRight") {
        setLightboxImageIndex((prev) => (prev! + 1) % activeEvent.images.length);
      } else if (e.key === "ArrowLeft") {
        setLightboxImageIndex((prev) => (prev! - 1 + activeEvent.images.length) % activeEvent.images.length);
      }
    };

    window.addEventListener("keydown", handleKeyDown);
    return () => {
      window.removeEventListener("keydown", handleKeyDown);
    };
  }, [lightboxImageIndex, activeEvent]);

  const openLightbox = (imgIndex: number) => {
    setLightboxImageIndex(imgIndex);
    document.body.style.overflow = "hidden";
  };

  const closeLightbox = () => {
    setLightboxImageIndex(null);
    document.body.style.overflow = "";
  };

  const goToNewerEvent = () => {
    if (activeEventIndex > 0) {
      setActiveEventIndex(activeEventIndex - 1);
    }
  };

  const goToOlderEvent = () => {
    if (activeEventIndex < gallery.events.length - 1) {
      setActiveEventIndex(activeEventIndex + 1);
    }
  };

  const activeImage = activeEvent && lightboxImageIndex !== null
    ? activeEvent.images[lightboxImageIndex]
    : null;

  // Helper to determine CSS classes for the dynamic mosaic
  const getMosaicClasses = (i: number, total: number) => {
    // If very few images, keep it simple
    if (total < 3) {
      return "h-[240px] sm:h-[320px]";
    }

    // Dynamic grid classes
    switch (i) {
      case 0:
        // Spotlight spans 2 columns & 2 rows on desktop
        return "md:col-span-2 md:row-span-2 h-[260px] sm:h-[360px] md:h-[500px]";
      default:
        // Adjust the last image to prevent layout gaps
        if (i === total - 1) {
          if (total === 4 || total === 7) {
            return "md:col-span-2 h-[180px] sm:h-[240px]";
          }
          if (total === 5 || total === 8) {
            return "md:col-span-2 h-[180px] sm:h-[240px]";
          }
          if (total === 10) {
            return "md:col-span-3 h-[200px] sm:h-[280px]";
          }
        }
        return "h-[180px] sm:h-[240px]";
    }
  };

  return (
    <main className="pt-16 lg:pt-20 min-h-screen bg-background text-on-surface">
      {/* Hero Header */}
      <section className="hero-glow py-20 lg:py-32 px-[var(--spacing-gutter)] text-center">
        <div className="max-w-4xl mx-auto">
          <span className="font-[var(--font-label-caps)] text-xs lg:text-sm text-primary block mb-4 lg:mb-6 tracking-[0.25em] uppercase">
            {gallery.hero.eyebrow}
          </span>
          <h1 className="font-[var(--font-display-lg)] text-on-surface text-[clamp(2.5rem,6vw+1rem,5.5rem)] leading-none tracking-tight">
            {gallery.hero.title}
          </h1>
          <p className="font-[var(--font-body-base)] text-on-surface-variant text-base lg:text-[20px] max-w-3xl mx-auto opacity-70 leading-relaxed mt-6">
            {gallery.hero.description}
          </p>
        </div>
      </section>

      {/* Gallery Section */}
      <section className="py-12 lg:py-20 px-[var(--spacing-gutter)] max-w-hd mx-auto">

        {/* Step Timeline Navigation */}
        <div className="mb-10 max-w-4xl mx-auto px-4">
          <div className="relative flex justify-between items-center">
            {/* Timeline track behind steps */}
            <div className="absolute left-0 right-0 h-[2px] bg-white/10 -z-10" />
            <div
              className="absolute left-0 h-[2px] bg-primary transition-all duration-500 -z-10"
              style={{ width: `${(activeEventIndex / (gallery.events.length - 1)) * 100}%` }}
            />

            {gallery.events.map((event: EventItem, idx: number) => {
              const isActive = idx === activeEventIndex;
              const isPassed = idx < activeEventIndex;

              return (
                <button
                  key={event.id}
                  type="button"
                  onClick={() => setActiveEventIndex(idx)}
                  className="flex flex-col items-center group cursor-pointer relative focus:outline-none"
                  title={event.title}
                >
                  {/* Step circle */}
                  <div
                    className={[
                      "w-8 h-8 rounded-full flex items-center justify-center font-[var(--font-label-caps)] text-xs font-bold transition-all duration-300 border-2 z-10",
                      isActive
                        ? "bg-background border-primary text-primary status-led shadow-[0_0_12px_rgba(197,160,89,0.6)] scale-110"
                        : isPassed
                          ? "bg-primary border-primary text-on-primary"
                          : "bg-surface-container-high border-white/10 text-on-surface-variant/40 hover:border-white/30 hover:text-on-surface"
                    ].join(" ")}
                  >
                    {idx + 1}
                  </div>
                </button>
              );
            })}
          </div>
        </div>

        {/* Active Event Grid Container */}
        {activeEvent && (
          <div className="glass-panel p-6 sm:p-10 lg:p-16 rounded-[2rem] lg:rounded-[3rem] border border-primary/20 hover:border-primary/30 shadow-2xl transition-all duration-300">

            {/* Top Navigation Control Header */}
            <div className="flex justify-between items-center mb-10 border-b border-white/5 pb-6">
              <button
                type="button"
                onClick={goToNewerEvent}
                disabled={activeEventIndex === 0}
                className="flex items-center gap-1.5 text-xs sm:text-sm font-bold uppercase tracking-wider text-on-surface-variant/60 hover:text-primary disabled:opacity-20 disabled:pointer-events-none transition-colors duration-200 focus:outline-none"
              >
                <span className="material-symbols-outlined text-lg">arrow_back</span>
                <span className="hidden sm:inline">{lang === "vi" ? "Sự kiện mới hơn" : "Newer Event"}</span>
              </button>

              <span className="font-[var(--font-label-caps)] text-xs sm:text-sm text-primary tracking-widest bg-primary/5 border border-primary/20 px-4 py-2 rounded-xl">
                {lang === "vi"
                  ? `SỰ KIỆN ${activeEventIndex + 1} / ${gallery.events.length}`
                  : `EVENT ${activeEventIndex + 1} OF ${gallery.events.length}`
                }
              </span>

              <button
                type="button"
                onClick={goToOlderEvent}
                disabled={activeEventIndex === gallery.events.length - 1}
                className="flex items-center gap-1.5 text-xs sm:text-sm font-bold uppercase tracking-wider text-on-surface-variant/60 hover:text-primary disabled:opacity-20 disabled:pointer-events-none transition-colors duration-200 focus:outline-none"
              >
                <span className="hidden sm:inline">{lang === "vi" ? "Sự kiện cũ hơn" : "Older Event"}</span>
                <span className="material-symbols-outlined text-lg">arrow_forward</span>
              </button>
            </div>

            {/* Event Info Header */}
            <div className="max-w-4xl mb-12">
              <h2 className="text-2xl sm:text-3xl lg:text-4xl font-[var(--font-display-lg)] text-primary mb-4 leading-tight">
                {activeEvent.title}
              </h2>

              <div className="flex flex-wrap items-center gap-4 text-xs uppercase tracking-wider text-on-surface-variant/50 font-[var(--font-label-caps)] mb-6">
                <div className="flex items-center gap-1.5 bg-surface-container-high px-3.5 py-2 rounded-xl border border-white/5">
                  <span className="material-symbols-outlined text-base text-primary">calendar_today</span>
                  <span>{activeEvent.date}</span>
                </div>

                {activeEvent.googleDriveUrl && activeEvent.googleDriveUrl.trim() !== "" && (
                  <a
                    href={activeEvent.googleDriveUrl}
                    target="_blank"
                    rel="noopener noreferrer"
                    className="flex items-center gap-2 bg-surface-container-high hover:bg-surface-container-highest px-3.5 py-2 rounded-xl border border-white/5 text-primary text-xs font-bold transition-all duration-200 focus:outline-none"
                  >
                    <i className="fab fa-google-drive text-sm"></i>
                    <span>{lang === "vi" ? "Xem Full Album trên Drive" : "View Full Album on Drive"}</span>
                  </a>
                )}
              </div>
            </div>

            {/* Dynamic Mosaic Grid or Coming Soon Placeholder */}
            {activeEvent.images.length === 0 ? (
              <div className="flex flex-col items-center justify-center py-20 px-6 border border-white/5 bg-white/[0.01] rounded-2xl">
                <span className="material-symbols-outlined text-5xl text-primary/45 mb-4">image</span>
                <p className="text-on-surface-variant/60 font-sans text-sm sm:text-base text-center max-w-md">
                  {lang === "vi"
                    ? "Hình ảnh nổi bật cho sự kiện này hiện đang được cập nhật."
                    : "Highlight images for this event are currently being updated."
                  }
                </p>
              </div>
            ) : (
              <div className="grid grid-cols-1 sm:grid-cols-2 md:grid-cols-3 gap-6">
                {activeEvent.images.map((imgUrl, i) => (
                  <div
                    key={i}
                    className={[
                      getMosaicClasses(i, activeEvent.images.length),
                      "overflow-hidden rounded-2xl border border-white/10 group cursor-pointer relative",
                    ].join(" ")}
                    onClick={() => openLightbox(i)}
                  >
                    {/* eslint-disable-next-line @next/next/no-img-element */}
                    <img
                      src={getImgSrc(imgUrl)}
                      alt={`${activeEvent.title} Highlight ${i + 1}`}
                      className="w-full h-full object-cover transition-transform duration-700 group-hover:scale-105"
                      loading="lazy"
                    />
                    <div className="absolute inset-0 bg-black/40 opacity-0 group-hover:opacity-100 transition-opacity duration-300 flex items-center justify-center">
                      <div className="w-12 h-12 rounded-full bg-primary/20 backdrop-blur-md flex items-center justify-center border border-primary/50 text-white shadow-lg">
                        <span className="material-symbols-outlined text-2xl">zoom_in</span>
                      </div>
                    </div>
                  </div>
                ))}
              </div>
            )}

          </div>
        )}
      </section>

      {/* Invitation Section */}
      <ReadyToJoin data={gallery.join} />

      {/* Lightbox Overlay */}
      {lightboxImageIndex !== null && activeEvent && activeImage && (
        <div
          className="fixed inset-0 z-[100] flex flex-col justify-center items-center bg-black/95 backdrop-blur-md transition-opacity duration-300"
          onClick={closeLightbox}
        >
          {/* Close button */}
          <button
            type="button"
            className="absolute top-6 right-6 text-white/70 hover:text-white transition-colors p-2 z-[110] focus:outline-none"
            onClick={closeLightbox}
            aria-label="Close Lightbox"
          >
            <span className="material-symbols-outlined text-4xl">close</span>
          </button>

          {/* Lightbox content container */}
          <div
            className="relative flex items-center justify-between w-full max-w-6xl px-4 md:px-12 h-[60vh] sm:h-[70vh] md:h-[80vh]"
            onClick={(e) => e.stopPropagation()}
          >
            {/* Prev arrow */}
            <button
              type="button"
              className="w-12 h-12 md:w-16 md:h-16 rounded-full bg-white/5 hover:bg-white/10 border border-white/10 text-white flex items-center justify-center transition-colors mr-2 active:scale-95 focus:outline-none"
              onClick={() => setLightboxImageIndex((prev) => (prev! - 1 + activeEvent.images.length) % activeEvent.images.length)}
              aria-label="Previous Image"
            >
              <span className="material-symbols-outlined text-2xl md:text-3xl">chevron_left</span>
            </button>

            {/* Active Image */}
            <div className="flex-1 flex items-center justify-center h-full relative overflow-hidden select-none px-4">
              {/* eslint-disable-next-line @next/next/no-img-element */}
              <img
                src={getImgSrc(activeImage)}
                alt={`${activeEvent.title} Full Highlight`}
                className="max-w-full max-h-full object-contain rounded-lg border border-white/5 shadow-2xl transition-all duration-300 animate-in fade-in zoom-in-95 duration-200"
              />
            </div>

            {/* Next arrow */}
            <button
              type="button"
              className="w-12 h-12 md:w-16 md:h-16 rounded-full bg-white/5 hover:bg-white/10 border border-white/10 text-white flex items-center justify-center transition-colors ml-2 active:scale-95 focus:outline-none"
              onClick={() => setLightboxImageIndex((prev) => (prev! + 1) % activeEvent.images.length)}
              aria-label="Next Image"
            >
              <span className="material-symbols-outlined text-2xl md:text-3xl">chevron_right</span>
            </button>
          </div>

          {/* Info bar below image */}
          <div
            className="text-center mt-6 px-6 max-w-2xl select-none"
            onClick={(e) => e.stopPropagation()}
          >
            <h3 className="font-[var(--font-display-lg)] text-primary text-base sm:text-lg mb-1.5">
              {activeEvent.title}
            </h3>
            <p className="text-on-surface-variant/60 text-xs sm:text-sm uppercase tracking-wider font-[var(--font-label-caps)]">
              {lang === "vi"
                ? `Hình ảnh ${lightboxImageIndex + 1} trên ${activeEvent.images.length}`
                : `Image ${lightboxImageIndex + 1} of ${activeEvent.images.length}`
              }
            </p>
          </div>
        </div>
      )}
    </main>
  );
}