import { useEffect, useState } from "react";
import { useQuery } from "@tanstack/react-query";
import { cn } from "@/lib/utils";
import {
  iconComponent,
  imageIconKey,
  resolveStackIcon,
  suggestIconName,
} from "@/lib/stackIcons";
import type { IconStack } from "@/lib/stackIcons";
import { stacksApi } from "@/api/stacks";
import type { StackStatus } from "@/types";

/**
 * A stack's icon, wearing its status as a coloured glow.
 *
 * This replaces the status dot in the stacks list: the same information, but
 * carried by the thing the eye lands on anyway. The status is still spelled out
 * in the badge next to it and in the tooltip here, so the colour is never the
 * only way to read it.
 *
 * The icon is either an image the server holds — the app's real logo, or an
 * upload — or a glyph derived from the name. Images are fetched through the API
 * client because that endpoint needs the bearer token.
 */

type Size = "sm" | "md" | "lg";

const SIZES: Record<Size, { box: string; glyph: string; radius: string }> = {
  sm: { box: "h-7 w-7", glyph: "h-3.5 w-3.5", radius: "rounded-[9px]" },
  md: { box: "h-9 w-9", glyph: "h-[18px] w-[18px]", radius: "rounded-[11px]" },
  lg: { box: "h-12 w-12", glyph: "h-6 w-6", radius: "rounded-[15px]" },
};

/** Ring + halo per status. Kept as whole class strings because Tailwind only
 *  sees classes it can find literally in the source. */
const STATUS_STYLE: Record<StackStatus, { ring: string; halo: string; glyph: string }> = {
  running: {
    ring: "ring-green-500/60 dark:ring-green-400/60",
    halo: "bg-green-500/40 dark:bg-green-400/40",
    glyph: "text-green-600 dark:text-green-400",
  },
  partial: {
    ring: "ring-yellow-500/60 dark:ring-yellow-400/60",
    halo: "bg-yellow-500/40 dark:bg-yellow-400/40",
    glyph: "text-yellow-600 dark:text-yellow-400",
  },
  stopped: {
    ring: "ring-slate-400/50 dark:ring-slate-500/50",
    halo: "bg-slate-400/20 dark:bg-slate-500/20",
    glyph: "text-slate-500 dark:text-slate-400",
  },
  error: {
    ring: "ring-red-500/60 dark:ring-red-400/60",
    halo: "bg-red-500/45 dark:bg-red-400/45",
    glyph: "text-red-600 dark:text-red-400",
  },
  updating: {
    ring: "ring-sky-500/60 dark:ring-sky-400/60",
    halo: "bg-sky-500/45 dark:bg-sky-400/45",
    glyph: "text-sky-600 dark:text-sky-400",
  },
  unknown: {
    ring: "ring-slate-300/60 dark:ring-slate-600/60",
    halo: "bg-slate-300/20 dark:bg-slate-600/20",
    glyph: "text-slate-400 dark:text-slate-500",
  },
};

export function StackIcon({
  stack,
  status,
  size = "md",
  previewUrl,
  className,
}: {
  stack: IconStack;
  status: StackStatus;
  size?: Size;
  /** Shows this image instead of the stored icon — used to preview a file that
   *  has been chosen but not uploaded yet (a stack being created). */
  previewUrl?: string | null;
  className?: string;
}) {
  const resolved = resolveStackIcon(stack);
  const dims = SIZES[size];
  const tone = STATUS_STYLE[status] ?? STATUS_STYLE.unknown;
  const stored = useStackImageUrl(
    stack.id,
    resolved.kind === "image" && !previewUrl ? imageIconKey(stack) : null
  );
  const custom = previewUrl ?? stored;
  // The glyph doubles as the fallback for an image that cannot be fetched (a
  // logo the server has not got yet), so derive it from the name either way
  // rather than landing on the generic mark.
  const Glyph = iconComponent(
    resolved.kind === "builtin" ? resolved.name : suggestIconName(stack.name, stack.id)
  );

  return (
    <span
      className={cn("relative inline-flex shrink-0", dims.box, className)}
      role="img"
      aria-label={`${stack.name} — ${status}`}
      title={status}
    >
      {/* The status "shimmer": a blurred copy of the status colour bleeding out
          from behind the tile. Pulses while an operation is running. */}
      <span
        aria-hidden
        className={cn(
          "pointer-events-none absolute -inset-[3px] blur-[5px]",
          dims.radius,
          tone.halo,
          status === "updating" && "animate-pulse"
        )}
      />
      <span
        className={cn(
          "relative inline-flex h-full w-full items-center justify-center overflow-hidden",
          "bg-sp-surface-2 ring-2",
          dims.radius,
          tone.ring
        )}
      >
        {custom ? (
          // Logos are drawn for a light ground and many are dark line art, so
          // the tile stays light in both themes rather than swallowing them.
          // `contain`, not `cover`: a logo must not be cropped.
          <img
            src={custom}
            alt=""
            className="h-full w-full bg-white object-contain p-0.5"
          />
        ) : (
          <Glyph className={cn(dims.glyph, tone.glyph)} strokeWidth={2} />
        )}
      </span>
    </span>
  );
}

/**
 * Object URL for a stack's image icon, or null while there is none.
 *
 * The icon endpoint needs the bearer token, so the bytes are fetched through
 * the API client and handed to the browser as a blob. `icon` is part of the
 * query key: an upload carries a version and a logo carries its slug, so
 * changing either retires the previous image instead of leaving a stale one on
 * screen. `retry: false` matters here — a stack whose logo the server cannot
 * fetch (no internet yet) must fall through to its glyph quietly.
 */
function useStackImageUrl(stackId: string, icon: string | null | undefined): string | null {
  const { data: blob } = useQuery({
    queryKey: ["stack-icon", stackId, icon],
    queryFn: () => stacksApi.icon(stackId),
    enabled: Boolean(icon),
    staleTime: Infinity,
    gcTime: 60 * 60 * 1000,
    retry: false,
  });
  const [url, setUrl] = useState<string | null>(null);

  useEffect(() => {
    if (!blob) {
      setUrl(null);
      return;
    }
    const objectUrl = URL.createObjectURL(blob);
    setUrl(objectUrl);
    // Every mount makes its own URL; without this each row would leak one for
    // the lifetime of the tab.
    return () => URL.revokeObjectURL(objectUrl);
  }, [blob]);

  return url;
}