import { useMutation, useQueryClient } from "@tanstack/react-query";
import { ScanSearch } from "lucide-react";
import { useState } from "react";
import { Link } from "react-router-dom";

import { Button, Spinner } from "@/components/ui";
import { api, errorMessage } from "@/lib/api";
import { cn } from "@/lib/cn";
import {
  e621ErrorMessage,
  effectiveCredentials,
  iqdbSearch,
  RATING_LABELS,
  type E621IqdbResult,
} from "@/lib/e621";
import type { MediaItem } from "@/lib/types";
import { useE621 } from "@/store/e621";

const ratingPill: Record<string, string> = {
  s: "bg-ctp-green text-ctp-crust",
  q: "bg-ctp-peach text-ctp-crust",
  e: "bg-ctp-red text-ctp-crust",
};

type Notice = { kind: "ok" | "warn" | "error"; text: string } | null;

export function IqdbCard({
  item,
  canLink,
}: {
  item: MediaItem;
  canLink: boolean;
}) {
  const queryClient = useQueryClient();
  const credentials = useE621((state) => state.credentials);
  const [busy, setBusy] = useState(false);
  const [candidates, setCandidates] = useState<E621IqdbResult[] | null>(null);
  const [selected, setSelected] = useState<E621IqdbResult | null>(null);
  const [notice, setNotice] = useState<Notice>(null);

  const isImage = item.kind === "image";
  const configured = Boolean(credentials?.configured);

  async function search() {
    setBusy(true);
    setNotice(null);
    setSelected(null);
    setCandidates(null);
    try {
      const response = await fetch(item.raw_url);
      if (!response.ok) {
        throw new Error(`Could not load the file (HTTP ${response.status}).`);
      }
      const blob = await response.blob();
      const results = await iqdbSearch(
        effectiveCredentials(credentials),
        blob,
        item.filename,
      );
      setCandidates(results);
      if (results.length === 0) {
        setNotice({ kind: "warn", text: "No similar posts found on e621." });
      }
    } catch (error) {
      setNotice({ kind: "error", text: e621ErrorMessage(error) });
    } finally {
      setBusy(false);
    }
  }

  const linkMutation = useMutation({
    mutationFn: (postId: number) =>
      api<MediaItem & { md5_match?: boolean }>(
        `/api/files/${item.j_id}/match/`,
        { method: "POST", json: { post_id: postId } },
      ),
    onSuccess: (data) => {
      void queryClient.invalidateQueries({ queryKey: ["file", item.j_id] });
      void queryClient.invalidateQueries({ queryKey: ["files"] });
      void queryClient.invalidateQueries({ queryKey: ["tag-cloud"] });
      setSelected(null);
      setNotice(
        data.md5_match
          ? {
              kind: "ok",
              text: `Linked to post #${data.e621_post_id} — MD5 matches.`,
            }
          : {
              kind: "warn",
              text: `Linked to post #${data.e621_post_id}, but its MD5 differs from this file.`,
            },
      );
    },
    onError: (error) =>
      setNotice({ kind: "error", text: errorMessage(error) }),
  });

  return (
    <section className="rounded-lg border border-ctp-surface0 bg-ctp-base p-4">
      <div className="flex items-center justify-between gap-2">
        <h2 className="text-sm font-semibold text-ctp-subtext1">IQDB search</h2>
        {candidates && candidates.length > 0 ? (
          <span className="font-mono text-[11px] text-ctp-overlay0">
            {candidates.length} candidates
          </span>
        ) : null}
      </div>

      <p className="mt-2 text-xs text-ctp-overlay0">
        Reverse-search e621 with this file to find its original post.
      </p>

      <Button
        variant="secondary"
        className="mt-3 w-full"
        disabled={busy || !isImage || !configured}
        onClick={() => void search()}
      >
        {busy ? (
          <Spinner className="h-3.5 w-3.5" />
        ) : (
          <ScanSearch className="h-4 w-4" />
        )}
        {busy ? "Searching…" : "Search e621"}
      </Button>

      {!configured ? (
        <p className="mt-2 text-[11px] text-ctp-overlay0">
          Configure e621 credentials in Account to use IQDB.
        </p>
      ) : !isImage ? (
        <p className="mt-2 text-[11px] text-ctp-overlay0">
          IQDB works on images only.
        </p>
      ) : null}

      {notice ? (
        <p
          className={cn(
            "mt-2 text-xs",
            notice.kind === "ok"
              ? "text-ctp-green"
              : notice.kind === "warn"
                ? "text-ctp-yellow"
                : "text-ctp-red",
          )}
        >
          {notice.text}
        </p>
      ) : null}

      {candidates && candidates.length > 0 ? (
        <div className="mt-3 grid grid-cols-3 gap-1.5">
          {candidates.map((candidate) => {
            const exact = candidate.md5 !== null && candidate.md5 === item.md5;
            return (
              <button
                key={`${candidate.post_id}-${candidate.md5}`}
                type="button"
                disabled={linkMutation.isPending || candidate.post_id === null}
                onClick={() => setSelected(candidate)}
                className={cn(
                  "overflow-hidden rounded-md border bg-ctp-mantle text-left transition",
                  selected?.post_id === candidate.post_id
                    ? "border-ctp-mauve ring-2 ring-ctp-mauve/40"
                    : "border-ctp-surface0 hover:border-ctp-surface2",
                )}
              >
                <span className="relative block aspect-square overflow-hidden">
                  {candidate.preview_url ? (
                    <img
                      src={candidate.preview_url}
                      alt={`Post #${candidate.post_id}`}
                      loading="lazy"
                      className="h-full w-full object-cover"
                    />
                  ) : (
                    <span className="flex h-full w-full items-center justify-center text-[10px] text-ctp-overlay0">
                      No preview
                    </span>
                  )}
                  {candidate.rating ? (
                    <span
                      className={cn(
                        "absolute left-1 top-1 rounded-full px-1 py-0.5 font-mono text-[9px] font-semibold uppercase",
                        ratingPill[candidate.rating] ??
                          "bg-ctp-surface1 text-ctp-text",
                      )}
                    >
                      {candidate.rating}
                    </span>
                  ) : null}
                  {exact ? (
                    <span className="absolute right-1 top-1 rounded-full bg-ctp-green/90 px-1 py-0.5 font-mono text-[9px] font-semibold uppercase text-ctp-crust">
                      MD5
                    </span>
                  ) : null}
                </span>
                <span className="block px-1 py-0.5 font-mono text-[10px] text-ctp-overlay0">
                  #{candidate.post_id}
                  {candidate.score !== null
                    ? ` · ${Math.round(candidate.score)}%`
                    : ""}
                </span>
              </button>
            );
          })}
        </div>
      ) : null}

      {selected ? (
        <div className="mt-3 rounded-md border border-ctp-surface0 bg-ctp-surface0/40 p-3">
          <div className="flex items-center justify-between gap-2">
            <p className="font-mono text-xs text-ctp-subtext1">
              Post #{selected.post_id}
            </p>
            {selected.md5 === item.md5 ? (
              <span className="rounded-full bg-ctp-green/15 px-1.5 py-0.5 font-mono text-[9px] font-semibold uppercase text-ctp-green">
                MD5 match
              </span>
            ) : null}
          </div>
          <p className="mt-1 text-xs text-ctp-overlay0">
            {selected.rating
              ? (RATING_LABELS[selected.rating] ?? selected.rating)
              : "Unknown rating"}
            {selected.score_total !== null
              ? ` · ▲ ${selected.score_total}`
              : ""}
            {selected.fav_count !== null ? ` · ${selected.fav_count} favs` : ""}
            {selected.width && selected.height
              ? ` · ${selected.width}×${selected.height}`
              : ""}
          </p>
          {selected.tags_preview.length > 0 ? (
            <div className="mt-2 flex flex-wrap gap-1">
              {selected.tags_preview.map((tag) => (
                <span
                  key={tag}
                  className="rounded border border-ctp-surface1 px-1 py-0.5 font-mono text-[10px] text-ctp-subtext0"
                >
                  {tag}
                </span>
              ))}
            </div>
          ) : null}
          <div className="mt-3 flex items-center gap-3">
            <Button
              disabled={
                !canLink || linkMutation.isPending || selected.post_id === null
              }
              onClick={() =>
                selected.post_id !== null &&
                linkMutation.mutate(selected.post_id)
              }
            >
              {linkMutation.isPending ? "Linking…" : "Link selected post"}
            </Button>
            <Link
              to={`/detail/${selected.post_id}`}
              target="_blank"
              className="text-xs text-ctp-blue hover:underline"
            >
              View post
            </Link>
          </div>
          <p className="mt-2 text-[11px] text-ctp-overlay0">
            {canLink
              ? "Linking stores this post's metadata on the item."
              : "Only the uploader or staff can link posts."}
          </p>
        </div>
      ) : null}

      {candidates && candidates.length > 0 && !selected ? (
        <p className="mt-2 text-[11px] text-ctp-overlay0">
          Select a candidate first, then confirm the link.
        </p>
      ) : null}
    </section>
  );
}