import { useQuery } from "@tanstack/react-query";
import { useRef, useState } from "react";
import { Link, useLocation } from "wouter";
import { ApiError, api, type EntryView } from "../api.ts";
import { addTag, removeTag } from "../edits.ts";
import { engagementNouns, formatPartialDate, friendlyError, mediaTypeLabel, shortDate, STATUSES, statusLabel } from "../format.ts";
import { changesFor, useEntryPatch, usePendingChanges, useSources } from "../hooks.ts";
import { useRatingScale } from "../settings.ts";
import { Cover } from "./Cover.tsx";
import { AttachmentsBox, ChildrenBox, CopyBox, CustomFieldsBox, EngagementsBox, ReviewBox, SourcesBox } from "./DetailBoxes.tsx";
import { HistoryDrawer } from "./HistoryDrawer.tsx";
import { Icon } from "./Icon.tsx";
import { LinkToCatalogue } from "./LinkToCatalogue.tsx";
import { StarRating } from "./StarRating.tsx";

const TIMES = ["", "once", "twice", "three times"];

export function EntryDetail({ id }: { id: string }) {
  const entry = useQuery({ queryKey: ["entry", id], queryFn: () => api.entry(id) });
  if (entry.isPending) return <div className="detail" aria-busy="true" />;
  if (entry.error) {
    const gone = entry.error instanceof ApiError && entry.error.status === 404;
    return (
      <div className="detail-empty" role="alert">
        <p>
          <strong>{gone ? "This entry isn't here" : "Couldn't load this entry"}</strong>
          {gone ? "It may have been deleted or moved. Pick another from your library." : friendlyError(entry.error)}
        </p>
      </div>
    );
  }
  return <Detail entry={entry.data} />;
}

function Detail({ entry }: { entry: EntryView }) {
  const scale = useRatingScale();
  const patch = useEntryPatch(entry.id);
  const [, navigate] = useLocation();
  const [historyOpen, setHistoryOpen] = useState(false);
  const historyBtn = useRef<HTMLButtonElement>(null);
  const type = entry.mediaTypeOverride ?? entry.work.mediaType;
  const nouns = engagementNouns(type);

  const engagements = useQuery({ queryKey: ["engagements", entry.id], queryFn: () => api.engagements(entry.id) });
  const changes = usePendingChanges();
  const sources = useSources();
  const engagementIds = new Set((engagements.data ?? []).map((g) => g.id));
  const pending = changesFor(changes.data?.items, entry.id, engagementIds);

  // "Book · Read twice · last finished 14 Sep 2026"
  const finished = (engagements.data ?? []).filter((g) => g.finishedAt && g.finishedAt.precision !== "unknown");
  const meta = [mediaTypeLabel(type)];
  if (entry.work.year) meta.push(String(entry.work.year));
  if (finished.length) {
    meta.push(`${nouns.past} ${TIMES[finished.length] ?? `${finished.length} times`}`);
    const last = finished.map((g) => g.finishedAt!).sort((a, b) => (a.value < b.value ? 1 : -1))[0]!;
    meta.push(`last finished ${formatPartialDate(last)}`);
  }

  return (
    <article className="detail" aria-labelledby="entry-title">
      <Link href="/" className="btn ghost back"><Icon name="back" /> Library</Link>
      <header className="det-head">
        <Cover url={entry.work.coverUrl} mediaType={type} draft={entry.draft} size="large" />
        <div style={{ minWidth: 0 }}>
          <h1 id="entry-title">
            {entry.work.title}
            {entry.draft && <span className="draft">Draft</span>}
          </h1>
          <p className="m">{meta.join(" · ")}</p>
          <div className="det-controls">
            <StarRating value={entry.rating} scale={scale} label="Your rating" onChange={(rating) => patch.mutate({ rating })} />
            <label>
              <span className="sr-only">Status</span>
              <select className="select" value={entry.status} onChange={(e) => patch.mutate({ status: e.target.value as EntryView["status"] })}>
                {STATUSES.map((s) => (
                  <option key={s} value={s}>{statusLabel(s, type)}</option>
                ))}
              </select>
            </label>
            <div className="det-tools">
              <button
                ref={historyBtn}
                type="button"
                className="btn ghost small"
                aria-expanded={historyOpen}
                aria-controls="history-drawer"
                onClick={() => setHistoryOpen((o) => !o)}
              >
                <Icon name="history" /> History
              </button>
            </div>
          </div>
          <Tags
            tags={entry.tags}
            onAdd={(t) => patch.edit((cur) => ({ tags: addTag(cur.tags, t) }))}
            onRemove={(t) => patch.edit((cur) => ({ tags: removeTag(cur.tags, t) }))}
          />
          {patch.error && <p className="error-text" role="alert">{friendlyError(patch.error)}</p>}
        </div>
      </header>

      {pending.length > 0 && (
        <div className="alert" role="status">
          <p>
            <b>{whoChanged(pending, sources.data)} changed this {mediaTypeLabel(type).toLowerCase()}.</b>{" "}
            {pending.length === 1 ? `On ${shortDate(pending[0]!.createdAt)}.` : `${pending.length} changes are waiting for you.`} Your rating,{" "}
            {nouns.box.toLowerCase()} and review here are unchanged.
          </p>
          <button type="button" className="btn" onClick={() => navigate(`/changes?entry=${entry.id}`)}>See what changed</button>
        </div>
      )}

      {entry.draft && <LinkToCatalogue entry={entry} />}

      <div className="det-grid">
        <EngagementsBox entry={entry} nouns={nouns} engagements={engagements.data} loading={engagements.isPending} />
        <CopyBox entry={entry} />
        <AttachmentsBox entry={entry} />
        <SourcesBox entry={entry} engagements={engagements.data ?? []} />
        <CustomFieldsBox entry={entry} type={type} />
        {entry.childSummary && <ChildrenBox entry={entry} type={type} />}
        <ReviewBox entry={entry} />
      </div>

      {historyOpen && (
        <HistoryDrawer
          entry={entry}
          onClose={() => {
            setHistoryOpen(false);
            historyBtn.current?.focus();
          }}
        />
      )}
    </article>
  );
}

function whoChanged(pending: { connectionId: string | null }[], sources: { id: string; name: string }[] | undefined): string {
  const ids = new Set(pending.map((p) => p.connectionId));
  if (ids.size === 1) {
    const name = sources?.find((s) => s.id === [...ids][0])?.name;
    if (name) return name;
  }
  return ids.size > 1 ? "Your sources" : "A source";
}

function Tags({ tags, onAdd, onRemove }: { tags: string[]; onAdd: (t: string) => void; onRemove: (t: string) => void }) {
  const [draft, setDraft] = useState("");
  function add() {
    if (draft.trim()) onAdd(draft);
    setDraft("");
  }
  return (
    <ul className="pills" aria-label="Tags" style={{ listStyle: "none" }}>
      {tags.map((t) => (
        <li key={t} className="pill">
          {t}
          <button type="button" aria-label={`Remove tag ${t}`} onClick={() => onRemove(t)}>
            <Icon name="x" />
          </button>
        </li>
      ))}
      <li>
        <label>
          <span className="sr-only">Add a tag</span>
          <input
            className="tag-input"
            placeholder="+ tag"
            value={draft}
            maxLength={100}
            onChange={(e) => setDraft(e.target.value)}
            onKeyDown={(e) => {
              if (e.key === "Enter" || e.key === ",") {
                e.preventDefault();
                add();
              }
            }}
            onBlur={add}
          />
        </label>
      </li>
    </ul>
  );
}