import { useEffect, useLayoutEffect, useMemo, useRef, useState } from "react";
import { motion } from "framer-motion";
import { convertFileSrc } from "@tauri-apps/api/core";
import { ExploreTagEntry, TagCloudEntry, useGalleryStore } from "../store";

const ACCENTS = [
  "#60a5fa",
  "#c084fc",
  "#4ade80",
  "#fbbf24",
  "#f472b4",
  "#2dd4bf",
  "#fb923c",
  "#a78bfa",
  "#34d399",
  "#f87171",
];

const GOLDEN_ANGLE = Math.PI * (3 - Math.sqrt(5));

function seeded(n: number): number {
  const x = Math.sin(n * 9301 + 49297) * 233280;
  return x - Math.floor(x);
}

interface PlacedNode {
  entry: TagCloudEntry;
  index: number;
  x: number;
  y: number;
  w: number;
  h: number;
  accent: string;
  driftX: number;
  driftY: number;
  driftDuration: number;
  rotateSeed: number;
}

function buildCloud(entries: TagCloudEntry[], containerW: number, containerH: number): PlacedNode[] {
  if (!entries.length || containerW <= 0 || containerH <= 0) return [];

  const maxCount = Math.max(...entries.map((e) => e.count));
  const cx = containerW / 2;
  const cy = containerH / 2;
  // Spread ellipse shrinks slightly to leave room for card half-widths at the edges
  const spreadX = containerW * 0.42;
  const spreadY = containerH * 0.36;
  const n = entries.length;

  // 1. Build initial positions using phyllotaxis spiral
  const nodes: PlacedNode[] = entries.map((entry, i) => {
    const ratio = Math.max(entry.count / maxCount, 0.08);
    // Cards scale from 110px to 230px wide; height is 3/4 of width
    const w = 110 + Math.sqrt(ratio) * 120;
    const h = w * 0.75;
    const radialRatio = Math.sqrt((i + 0.5) / n);
    const angle = i * GOLDEN_ANGLE;

    return {
      entry,
      index: i,
      x: cx + Math.cos(angle) * radialRatio * spreadX,
      y: cy + Math.sin(angle) * radialRatio * spreadY,
      w,
      h,
      accent: ACCENTS[i % ACCENTS.length],
      driftX: (seeded(i + 11) - 0.5) * 18,
      driftY: (seeded(i + 17) - 0.5) * 14,
      driftDuration: 8 + seeded(i + 23) * 7,
      rotateSeed: (seeded(i + 31) - 0.5) * 4,
    };
  });

  // 2. Iterative overlap resolution — no physics, just push apart
  const PAD = 24;
  for (let iter = 0; iter < 80; iter++) {
    for (let a = 0; a < nodes.length; a++) {
      const na = nodes[a];
      for (let b = a + 1; b < nodes.length; b++) {
        const nb = nodes[b];
        const dx = nb.x - na.x;
        const dy = nb.y - na.y;
        const overlapX = (na.w + nb.w) / 2 + PAD - Math.abs(dx);
        const overlapY = (na.h + nb.h) / 2 + PAD - Math.abs(dy);
        if (overlapX <= 0 || overlapY <= 0) continue;
        // Push along the smaller overlap axis
        if (overlapX < overlapY) {
          const push = overlapX * 0.5 * (dx >= 0 ? 1 : -1);
          nb.x += push;
          na.x -= push;
        } else {
          const push = overlapY * 0.5 * (dy >= 0 ? 1 : -1);
          nb.y += push;
          na.y -= push;
        }
      }
      // Pull gently back toward anchor to prevent runaway drift
      na.x += (cx + Math.cos(na.index * GOLDEN_ANGLE) * Math.sqrt((na.index + 0.5) / n) * spreadX - na.x) * 0.05;
      na.y += (cy + Math.sin(na.index * GOLDEN_ANGLE) * Math.sqrt((na.index + 0.5) / n) * spreadY - na.y) * 0.05;
    }
  }

  // 3. Clamp so cards never poke outside the container
  return nodes.map((node) => ({
    ...node,
    x: Math.min(Math.max(node.x, node.w / 2 + 16), containerW - node.w / 2 - 16),
    y: Math.min(Math.max(node.y, node.h / 2 + 16), containerH - node.h / 2 - 16),
  }));
}

function CloudCard({ node, onOpen }: { node: PlacedNode; onOpen: (imageIds: number[]) => void }) {
  const src = node.entry.thumbnail_path ? convertFileSrc(node.entry.thumbnail_path) : null;
  const { w, h, accent } = node;

  return (
    <motion.button
      className="group absolute overflow-hidden rounded-2xl border border-white/8 bg-white/[0.04] text-left shadow-[0_8px_40px_rgba(0,0,0,0.5)] focus:outline-none focus-visible:ring-2 focus-visible:ring-white/30"
      style={{ width: w, height: h, left: node.x - w / 2, top: node.y - h / 2 }}
      initial={{ opacity: 0, scale: 0.75 }}
      animate={{
        opacity: 1,
        scale: 1,
        x: [0, node.driftX, 0],
        y: [0, node.driftY, 0],
        rotate: [node.rotateSeed, node.rotateSeed + 1.4, node.rotateSeed],
      }}
      transition={{
        opacity: { duration: 0.3, delay: Math.min(node.index * 0.035, 0.7) },
        scale:   { duration: 0.3, delay: Math.min(node.index * 0.035, 0.7) },
        x:       { duration: node.driftDuration, repeat: Infinity, ease: "easeInOut", delay: seeded(node.index + 41) * 3 },
        y:       { duration: node.driftDuration + 1.6, repeat: Infinity, ease: "easeInOut", delay: seeded(node.index + 51) * 3 },
        rotate:  { duration: node.driftDuration + 0.9, repeat: Infinity, ease: "easeInOut" },
      }}
      whileHover={{ scale: 1.06, rotate: 0, transition: { duration: 0.18 } }}
      onClick={() => onOpen(node.entry.image_ids)}
      title={`Open cluster — ${node.entry.count.toLocaleString()} images`}
    >
      {src ? (
        <img
          src={src}
          alt=""
          className="absolute inset-0 h-full w-full object-cover transition-transform duration-500 group-hover:scale-105"
          draggable={false}
        />
      ) : (
        <div className="absolute inset-0 bg-gradient-to-br from-white/[0.07] to-transparent" />
      )}
      <div className="absolute inset-0 bg-gradient-to-t from-black/85 via-black/20 to-transparent" />
      {/* Accent glow on hover */}
      <div
        className="absolute inset-0 opacity-0 transition-opacity duration-300 group-hover:opacity-100"
        style={{ background: `radial-gradient(ellipse at bottom, ${accent}25, transparent 70%)` }}
      />
      <div className="absolute inset-x-0 bottom-0 p-3">
        <div className="mb-2 h-px rounded-full" style={{ background: `linear-gradient(to right, ${accent}80, transparent)` }} />
        <div className="flex items-end justify-between gap-2">
          <div>
            <p className="text-[9px] uppercase tracking-[0.18em] text-white/35">Cluster</p>
            <p className="text-base font-semibold leading-none text-white">{node.entry.count.toLocaleString()}</p>
          </div>
          <span
            className="rounded-full border px-2 py-0.5 text-[9px] uppercase tracking-[0.1em] opacity-0 transition-opacity duration-200 group-hover:opacity-100"
            style={{ borderColor: `${accent}50`, color: accent, backgroundColor: `${accent}12` }}
          >
            Open
          </span>
        </div>
      </div>
    </motion.button>
  );
}

// Actual tag cloud — word size driven by log-scaled frequency
function TagWord({
  entry,
  index,
  logMin,
  logRange,
  onSearch,
}: {
  entry: ExploreTagEntry;
  index: number;
  logMin: number;
  logRange: number;
  onSearch: (tag: string) => void;
}) {
  const ratio = logRange > 0 ? (Math.log(Math.max(entry.count, 1)) - logMin) / logRange : 0.5;
  const fontSize = 11 + ratio * 28; // 11px – 39px
  const accent = ACCENTS[index % ACCENTS.length];
  const tilt = (seeded(index + 5) - 0.5) * 7;

  return (
    <motion.button
      initial={{ opacity: 0, scale: 0.6 }}
      animate={{ opacity: 0.4 + ratio * 0.6, scale: 1 }}
      transition={{ delay: Math.min(index * 0.008, 0.55), duration: 0.22 }}
      whileHover={{ scale: 1.2, opacity: 1, rotate: 0, transition: { duration: 0.14 } }}
      className="group inline-flex items-center gap-1 rounded-full px-2 py-1 transition-colors hover:bg-white/[0.07]"
      style={{ fontSize, rotate: tilt }}
      onClick={() => onSearch(entry.tag)}
      title={`${entry.tag} — ${entry.count.toLocaleString()} images`}
    >
      <span
        className="font-medium leading-none"
        style={{ color: ratio > 0.55 ? accent : "rgba(255,255,255,0.82)" }}
      >
        {entry.tag}
      </span>
      <span
        className="rounded-full px-1.5 py-0.5 text-[9px] tabular-nums opacity-0 transition-opacity group-hover:opacity-100"
        style={{ backgroundColor: `${accent}22`, color: accent }}
      >
        {entry.count.toLocaleString()}
      </span>
    </motion.button>
  );
}

function Spinner() {
  return (
    <motion.div
      className="h-5 w-5 rounded-full border-2 border-white/15 border-t-white/50"
      animate={{ rotate: 360 }}
      transition={{ duration: 0.85, repeat: Infinity, ease: "linear" }}
    />
  );
}

// Separate component so its useLayoutEffect fires when the canvas is actually
// mounted — not at TagCloud mount time when the container may still be hidden
// behind a loading state.
function ClusterCloud({
  entries,
  onOpen,
}: {
  entries: TagCloudEntry[];
  onOpen: (imageIds: number[]) => void;
}) {
  const canvasRef = useRef<HTMLDivElement>(null);
  const [canvasSize, setCanvasSize] = useState({ w: 0, h: 0 });

  useLayoutEffect(() => {
    const el = canvasRef.current;
    if (!el) return;
    const update = () => {
      const r = el.getBoundingClientRect();
      setCanvasSize({ w: r.width, h: r.height });
    };
    update();
    const ro = new ResizeObserver(update);
    ro.observe(el);
    return () => ro.disconnect();
  }, []);

  const nodes = useMemo(
    () => buildCloud(entries, canvasSize.w, canvasSize.h),
    [entries, canvasSize.w, canvasSize.h],
  );

  return (
    <div ref={canvasRef} className="relative min-h-0 flex-1 overflow-hidden">
      <div className="pointer-events-none absolute inset-0 opacity-[0.07] [background-image:radial-gradient(circle,rgba(255,255,255,0.6)_1px,transparent_1px)] [background-size:28px_28px]" />
      {nodes.map((node) => (
        <CloudCard key={`${node.entry.representative_image_id}:${node.index}`} node={node} onOpen={onOpen} />
      ))}
    </div>
  );
}

export function TagCloud() {
  const exploreMode = useGalleryStore((state) => state.exploreMode);
  const setExploreMode = useGalleryStore((state) => state.setExploreMode);
  const tagCloudEntries = useGalleryStore((state) => state.tagCloudEntries);
  const tagCloudLoading = useGalleryStore((state) => state.tagCloudLoading);
  const loadTagCloud = useGalleryStore((state) => state.loadTagCloud);
  const exploreTagEntries = useGalleryStore((state) => state.exploreTagEntries);
  const exploreTagLoading = useGalleryStore((state) => state.exploreTagLoading);
  const loadExploreTags = useGalleryStore((state) => state.loadExploreTags);
  const showVisualCluster = useGalleryStore((state) => state.showVisualCluster);
  const searchForTag = useGalleryStore((state) => state.searchForTag);
  const selectedFolderId = useGalleryStore((state) => state.selectedFolderId);

  useEffect(() => {
    if (exploreMode === "visual") void loadTagCloud();
    else void loadExploreTags();
  }, [exploreMode, selectedFolderId, loadTagCloud, loadExploreTags]);

  const { logMin, logRange } = useMemo(() => {
    if (!exploreTagEntries.length) return { logMin: 0, logRange: 1 };
    const logs = exploreTagEntries.map((e) => Math.log(Math.max(e.count, 1)));
    const lo = Math.min(...logs);
    const hi = Math.max(...logs);
    return { logMin: lo, logRange: hi - lo || 1 };
  }, [exploreTagEntries]);

  const loading = exploreMode === "visual" ? tagCloudLoading : exploreTagLoading;
  const hasEntries = exploreMode === "visual" ? tagCloudEntries.length > 0 : exploreTagEntries.length > 0;
  const entryCount = exploreMode === "visual" ? tagCloudEntries.length : exploreTagEntries.length;

  return (
    <div className="flex min-h-0 flex-1 flex-col overflow-hidden bg-[radial-gradient(ellipse_at_top,rgba(59,130,246,0.08),transparent_50%),radial-gradient(ellipse_at_80%_75%,rgba(168,85,247,0.07),transparent_40%),#07080f]">
      {/* Header */}
      <div className="shrink-0 border-b border-white/[0.05] px-6 py-4">
        <div className="flex items-center justify-between gap-4">
          <div className="min-w-0">
            <h2 className="text-[15px] font-semibold text-white">Explore</h2>
            <p className="mt-0.5 truncate text-[11px] text-white/30">
              {loading
                ? exploreMode === "visual" ? "Computing visual clusters…" : "Loading tags…"
                : hasEntries
                  ? exploreMode === "visual"
                    ? `${entryCount} cluster${entryCount !== 1 ? "s" : ""} — click any to open`
                    : `${entryCount} tag${entryCount !== 1 ? "s" : ""} — click any to search`
                  : exploreMode === "visual"
                    ? "No clusters — images need embeddings first"
                    : "No tags — run the AI tagger or add tags manually"}
            </p>
          </div>
          <div className="flex shrink-0 rounded-lg border border-white/8 bg-white/[0.03] p-0.5">
            <button
              className={`rounded-md px-3 py-1.5 text-xs transition-colors ${
                exploreMode === "visual" ? "bg-white/10 text-white" : "text-gray-500 hover:text-gray-300"
              }`}
              onClick={() => setExploreMode("visual")}
            >
              Clusters
            </button>
            <button
              className={`rounded-md px-3 py-1.5 text-xs transition-colors ${
                exploreMode === "tags" ? "bg-white/10 text-white" : "text-gray-500 hover:text-gray-300"
              }`}
              onClick={() => setExploreMode("tags")}
            >
              Tag Cloud
            </button>
          </div>
        </div>
      </div>

      {loading ? (
        <div className="flex flex-1 items-center justify-center gap-3 text-white/25">
          <Spinner />
          <span className="text-sm">{exploreMode === "visual" ? "Computing clusters…" : "Loading tags…"}</span>
        </div>
      ) : !hasEntries ? (
        <div className="flex flex-1 items-center justify-center px-8">
          <p className="max-w-xs text-center text-sm leading-relaxed text-white/25">
            {exploreMode === "visual"
              ? "No visual clusters yet. Images need embeddings before they can be grouped. Check indexing progress in the sidebar."
              : "No tags yet. Run the AI tagger from Settings, or add tags manually in the image preview."}
          </p>
        </div>
      ) : exploreMode === "visual" ? (
        <ClusterCloud entries={tagCloudEntries} onOpen={showVisualCluster} />
      ) : (
        /* Tag cloud — words sized by log-scaled frequency, wrapped freely */
        <div className="overflow-y-auto px-8 py-8">
          <div className="flex flex-wrap items-center justify-center gap-x-0.5 gap-y-1 leading-none">
            {exploreTagEntries.map((entry, index) => (
              <TagWord
                key={entry.tag}
                entry={entry}
                index={index}
                logMin={logMin}
                logRange={logRange}
                onSearch={searchForTag}
              />
            ))}
          </div>
        </div>
      )}
    </div>
  );
}