import { useCallback, useEffect, useRef, useState } from "react";
import type { UseFormRegisterReturn } from "react-hook-form";
import { Link } from "react-router";
import { t } from "@lingui/core/macro";
import { Plural, Trans } from "@lingui/react/macro";

import { API_URL, VALIDATION } from "../config/api.ts";
import type {
  CreateUrlDumpRequest,
  Dump,
  DumpUrlMatch,
  PlaylistMembership,
  RawDump,
  RawDumpUrlMatch,
  RawPlaylistMembership,
  UrlPreviewResponse,
} from "../model.ts";
import {
  deserializeDump,
  deserializeDumpUrlMatch,
  deserializePlaylistMembership,
} from "../model.ts";
import { useAuth } from "../hooks/useAuth.ts";
import { useWS } from "../hooks/useWS.ts";
import { dumpUrl, normalizeUrl } from "../utils/urls.ts";
import { relativeTime } from "../utils/relativeTime.ts";
import { titleFromFileName } from "../utils/format.ts";
import {
  clearDumpDraft,
  type DumpDraft,
  EMPTY_DUMP_DRAFT,
  loadDumpDraft,
  saveDumpDraft,
} from "../utils/dumpDraft.ts";
import { MAX_FILE_SIZE } from "../config/upload.ts";
import RichContentCard from "./RichContentCard.tsx";
import { MediaPlayer } from "./MediaPlayer.tsx";
import type { RichContent } from "../model.ts";
import { Modal } from "./Modal.tsx";
import type { TextEditorHandle } from "./TextEditor.tsx";
import { CategorySelect } from "./CategorySelect.tsx";
import { PlaylistMembershipPanel } from "./PlaylistMembershipPanel.tsx";
import {
  expectOk,
  FileField,
  FormError,
  FormProvider,
  RichTextField,
  SubmitButton,
  useApiForm,
  VisibilityToggle,
} from "./form/index.ts";

/**
 * Posting a dump walks three panels. The split is deliberate: categories and
 * visibility used to sit behind a disclosure, where they read as optional and
 * went untouched — they are neither, so "why & where" is a stop on the way to
 * posting rather than something to go looking for.
 */
type Step = "what" | "details" | "playlist";

/** Stable empty result, so rendering doesn't churn on a fresh array each pass. */
const NO_DUPLICATES: DumpUrlMatch[] = [];

const STEPS: { id: Step; label: () => string }[] = [
  { id: "what", label: () => t`Link or file` },
  { id: "details", label: () => t`Why & where` },
  { id: "playlist", label: () => t`Playlists` },
];

/** Where you are in the three panels — and, past the first, how far you got. */
function StepIndicator({ current }: { current: Step }) {
  const currentIndex = STEPS.findIndex((s) => s.id === current);

  return (
    <ol className="dump-steps">
      {STEPS.map((step, i) => {
        const state = i < currentIndex
          ? "done"
          : i === currentIndex
          ? "current"
          : "todo";
        return (
          <li
            key={step.id}
            className={`dump-step dump-step--${state}`}
            aria-current={state === "current" ? "step" : undefined}
          >
            <span className="dump-step-marker" aria-hidden="true">
              {state === "done" ? "✓" : i + 1}
            </span>
            <span className="dump-step-label">{step.label()}</span>
          </li>
        );
      })}
    </ol>
  );
}

type UrlPreview =
  | { status: "idle" }
  | { status: "loading" }
  | { status: "done"; reached: boolean; richContent: RichContent | null };

interface CreateValues {
  url: string;
  file: File | null;
  title: string;
  comment: string;
  isPublic: boolean;
}

/**
 * Whether the pointer is coarse — a touch device, where autofocusing the URL
 * input raises a keyboard that covers most of the modal before the user has
 * seen it.
 */
function prefersNoAutoFocus(): boolean {
  return globalThis.matchMedia?.("(pointer: coarse)").matches ?? false;
}

function LocalFilePreview({ file }: { file: File }) {
  const [src, setSrc] = useState<string | null>(null);

  useEffect(() => {
    const url = URL.createObjectURL(file);
    // Blob URL lifecycle requires setState in effect — no synchronous alternative.
    // eslint-disable-next-line react-hooks/set-state-in-effect
    setSrc(url);
    return () => {
      URL.revokeObjectURL(url);
    };
  }, [file]);

  if (!src) return null;
  const mime = file.type;
  if (mime.startsWith("image/")) {
    return <img src={src} alt={file.name} className="local-preview-image" />;
  }
  if (mime.startsWith("video/")) {
    return <MediaPlayer key={src} src={src} kind="video" mime={mime} />;
  }
  if (mime.startsWith("audio/")) {
    return <MediaPlayer key={src} src={src} kind="audio" mime={mime} />;
  }
  return null;
}

/**
 * Title row shared by both kinds of dump: the suggested title (scraped from the
 * page, or derived from the filename) sits there read-only until the ✎ is used,
 * which is enough to stop stray typing while keeping a correction one click
 * away. Once edited, a reset offers the suggestion back.
 */
function TitleField({
  registration,
  editing,
  onEdit,
  onReset,
  disabled,
}: {
  registration: UseFormRegisterReturn<"title">;
  editing: boolean;
  onEdit: () => void;
  onReset?: () => void;
  disabled: boolean;
}) {
  const inputRef = useRef<HTMLInputElement | null>(null);
  const { ref, ...titleReg } = registration;

  return (
    <div className="form-field">
      <label className="form-label" htmlFor="dc-title">
        <Trans>Title</Trans>
      </label>
      <div className="dump-create-title-row">
        <input
          id="dc-title"
          type="text"
          {...titleReg}
          ref={(el) => {
            ref(el);
            inputRef.current = el;
          }}
          disabled={disabled || !editing}
          maxLength={VALIDATION.DUMP_TITLE_MAX}
        />
        {!editing && (
          <button
            type="button"
            className="dump-create-title-edit-btn"
            onClick={() => {
              onEdit();
              setTimeout(() => inputRef.current?.focus(), 0);
            }}
            disabled={disabled}
            aria-label={t`Edit title`}
          >
            ✎
          </button>
        )}
        {editing && onReset && (
          <button
            type="button"
            className="dump-create-title-edit-btn"
            onClick={onReset}
            disabled={disabled}
            aria-label={t`Reset to the suggested title`}
            title={t`Reset to the suggested title`}
          >
            ↺
          </button>
        )}
      </div>
    </div>
  );
}

/** "Already dumped" hint — never blocking, since reposts are sometimes on purpose. */
function DuplicateNotice(
  { matches, onNavigate }: {
    matches: DumpUrlMatch[];
    onNavigate: () => void;
  },
) {
  const [first, ...rest] = matches;

  return (
    <div className="dump-duplicate" role="status">
      <span className="dump-duplicate-icon" aria-hidden="true">↩</span>
      <div className="dump-duplicate-body">
        <p className="dump-duplicate-lead">
          <Trans>
            Already dumped by {first.username} {relativeTime(first.createdAt)}
          </Trans>
        </p>
        <Link
          to={dumpUrl(first)}
          className="dump-duplicate-link"
          onClick={onNavigate}
        >
          {first.title}
        </Link>
        {rest.length > 0 && (
          <p className="dump-duplicate-more">
            <Plural
              value={rest.length}
              one="and # earlier dump"
              other="and # earlier dumps"
            />
          </p>
        )}
        <p className="dump-duplicate-hint">
          <Trans>You can post it anyway.</Trans>
        </p>
      </div>
    </div>
  );
}

interface DumpCreateModalProps {
  onClose: () => void;
  initialUrl?: string;
}

export function DumpCreateModal(
  { onClose, initialUrl = "" }: DumpCreateModalProps,
) {
  const { authFetch, authUpload } = useAuth();
  const { injectDump } = useWS();

  const [step, setStep] = useState<Step>("what");
  // Which way the next panel should come in from. Purely presentational.
  const [direction, setDirection] = useState<"forward" | "back">("forward");
  const [createdDump, setCreatedDump] = useState<Dump | null>(null);

  const goToStep = (next: Step, dir: "forward" | "back") => {
    setDirection(dir);
    setStep(next);
  };

  // Arriving with a URL (the Android share sheet) is a request to post *that*,
  // so an abandoned draft is dropped whole rather than half-merged: pairing
  // someone's old "why" with a link they just shared from another app would be
  // more confusing than starting them clean.
  const [restoredDraft] = useState<DumpDraft | null>(() =>
    initialUrl ? null : loadDumpDraft()
  );
  const draft = restoredDraft ?? EMPTY_DUMP_DRAFT;
  const [draftNoticeVisible, setDraftNoticeVisible] = useState(!!restoredDraft);

  // Composition state
  const [titleEditing, setTitleEditing] = useState(false);
  const [titleFromUser, setTitleFromUser] = useState(draft.titleFromUser);
  const [urlFetchState, setUrlFetchState] = useState<UrlPreview>({
    status: "idle",
  });
  // Tagged with the URL they describe, so a result never lingers over the next
  // link during the debounce (and so clearing them needs no effect).
  const [duplicateState, setDuplicateState] = useState<
    { url: string; matches: DumpUrlMatch[] }
  >({ url: "", matches: [] });
  const [uploadProgress, setUploadProgress] = useState<number | null>();
  const [confirmClose, setConfirmClose] = useState(false);
  const debounceRef = useRef<ReturnType<typeof setTimeout> | null>(null);
  const commentEditorRef = useRef<TextEditorHandle | null>(null);

  const form = useApiForm<CreateValues>({
    defaultValues: {
      url: initialUrl || draft.url,
      file: null,
      title: draft.title,
      comment: draft.comment,
      isPublic: draft.isPublic,
    },
  });
  const { register, setValue, watch, clearErrors, reset } = form;
  const submitting = form.formState.isSubmitting;
  const url = watch("url");
  const file = watch("file");
  const title = watch("title");
  const comment = watch("comment");
  const isPublic = watch("isPublic");

  // The dump's kind is whatever the user actually provided, so there is no mode
  // to pick: attaching a file makes it a file dump, typing a link makes it a
  // link dump, and clearing either offers both again.
  const mode: "url" | "file" = file ? "file" : "url";

  const [selectedCategoryIds, setSelectedCategoryIds] = useState<Set<string>>(
    () => new Set(draft.categoryIds),
  );
  const toggleCategory = (id: string) =>
    setSelectedCategoryIds((prev) => {
      const next = new Set(prev);
      if (next.has(id)) next.delete(id);
      else next.add(id);
      return next;
    });

  // Playlist step state
  const [memberships, setMemberships] = useState<PlaylistMembership[]>([]);
  const [playlistsLoading, setPlaylistsLoading] = useState(false);

  const selectFile = useCallback((f: File | null) => {
    setValue("file", f);
    if (f) {
      setValue("title", titleFromFileName(f.name));
      setTitleFromUser(false);
    }
    setTitleEditing(false);
  }, [setValue]);

  // Canonical form of `url`, used (rather than the raw input text) to decide
  // whether the preview actually needs to re-fetch — e.g. "example.com" and
  // "https://example.com" (set later by onBlur's normalizeUrl) canonicalize
  // to the same value, so they shouldn't trigger two separate fetches.
  let canonicalUrl: string | null;
  try {
    const u = new URL(normalizeUrl(url));
    canonicalUrl = (u.protocol === "http:" || u.protocol === "https:")
      ? u.toString()
      : null;
  } catch {
    canonicalUrl = null;
  }

  // Idle state is derived below from canonicalUrl rather than set here, so
  // this effect only ever needs to set loading/done (inside the timeout).
  const urlPreview: UrlPreview = canonicalUrl
    ? urlFetchState
    : { status: "idle" };

  const duplicates = canonicalUrl && duplicateState.url === canonicalUrl
    ? duplicateState.matches
    : NO_DUPLICATES;

  // Debounced preview + "already dumped?" lookup. Both answer questions about
  // the same link and settle at the same time, so they share one debounce.
  useEffect(() => {
    if (debounceRef.current) clearTimeout(debounceRef.current);
    if (!canonicalUrl) return;

    // Deferred to a microtask (rather than called directly) so the immediate
    // "loading" feedback doesn't fire synchronously within the effect body —
    // same timing for the user, just not in the same tick.
    queueMicrotask(() => setUrlFetchState({ status: "loading" }));

    debounceRef.current = setTimeout(() => {
      const encoded = encodeURIComponent(canonicalUrl);

      fetch(`${API_URL}/api/preview?url=${encoded}`)
        .then((res) => res.json())
        .then((body) => {
          const data = body.success
            ? body.data as UrlPreviewResponse
            : undefined;
          setUrlFetchState({
            status: "done",
            reached: data?.reached ?? false,
            richContent: data?.richContent ?? null,
          });
        })
        .catch(() => {
          setUrlFetchState({ status: "done", reached: false, richContent: null });
        });

      // Signed in, so that a private dump of the poster's own counts as a
      // duplicate for them and for nobody else.
      authFetch(`${API_URL}/api/dumps/by-url?url=${encoded}`)
        .then((res) => res.json())
        .then((body) => {
          setDuplicateState({
            url: canonicalUrl,
            matches: body.success
              ? (body.data as RawDumpUrlMatch[]).map(deserializeDumpUrlMatch)
              : [],
          });
        })
        .catch(() =>
          setDuplicateState({ url: canonicalUrl, matches: [] })
        );
    }, 600);

    return () => {
      if (debounceRef.current) clearTimeout(debounceRef.current);
    };
  }, [canonicalUrl, authFetch]);

  // Until the poster takes the field over, the title *is* the current page's
  // title — including when the new link suggests nothing, which is why this
  // writes an empty suggestion too rather than leaving the previous link's.
  const suggestedTitle = urlPreview.status === "done"
    ? urlPreview.richContent?.title ?? ""
    : "";
  useEffect(() => {
    if (mode !== "url" || titleFromUser) return;
    setValue("title", suggestedTitle);
  }, [mode, titleFromUser, suggestedTitle, setValue]);

  // Mirror the draft on every change so a dismissal — deliberate or not — never
  // costs more than the attached file, which cannot be stored.
  useEffect(() => {
    if (step === "playlist") return;
    saveDumpDraft({
      url,
      title,
      titleFromUser,
      comment,
      isPublic,
      categoryIds: [...selectedCategoryIds],
    });
  }, [
    step,
    url,
    title,
    titleFromUser,
    comment,
    isPublic,
    selectedCategoryIds,
  ]);

  const discardDraft = () => {
    clearDumpDraft();
    reset({
      url: "",
      file: null,
      title: "",
      comment: "",
      isPublic: true,
    });
    setSelectedCategoryIds(new Set());
    setTitleFromUser(false);
    setTitleEditing(false);
    setDraftNoticeVisible(false);
  };

  // Land the caret in the "why" box on arrival, so the second panel is
  // immediately typeable — except on touch, where it would raise a keyboard
  // over the categories this panel exists to show.
  useEffect(() => {
    if (step !== "details" || prefersNoAutoFocus()) return;
    commentEditorRef.current?.focus();
  }, [step]);

  // Only the attached file is unrecoverable, so it is the only thing worth
  // interrupting a dismissal for — the text comes back on its own.
  const handleBeforeClose = useCallback(() => {
    if (step === "playlist" || submitting || !file || confirmClose) return true;
    setConfirmClose(true);
    return false;
  }, [step, submitting, file, confirmClose]);

  /** Dismissal from inside the form (Cancel), guarded like Escape and the ✕. */
  const requestClose = () => {
    if (handleBeforeClose()) onClose();
  };

  // Paste handler
  useEffect(() => {
    const handler = (e: ClipboardEvent) => {
      // Fields own their paste: the comment editor uploads pasted images as
      // inline attachments, and the URL input has its own file handler below.
      // Without this guard, pasting an image into the description would flip
      // the whole modal over to a file dump.
      const tag = (e.target as HTMLElement).tagName;
      if (tag === "INPUT" || tag === "TEXTAREA") return;
      const pastedFile = e.clipboardData?.files[0];
      if (pastedFile) {
        setValue("url", "");
        selectFile(pastedFile);
        clearErrors("root");
        return;
      }
      const text = e.clipboardData?.getData("text") ?? "";
      try {
        const u = new URL(normalizeUrl(text));
        if (u.protocol === "http:" || u.protocol === "https:") {
          selectFile(null);
          setValue("url", u.toString());
          clearErrors("root");
        }
      } catch { /* not a URL */ }
    };
    globalThis.addEventListener("paste", handler);
    return () => globalThis.removeEventListener("paste", handler);
  }, [selectFile, setValue, clearErrors]);

  const [dragging, setDragging] = useState(false);

  // Dropping is accepted over the whole modal, not just the drop zone: once a
  // link is being typed the zone is hidden, and aiming at it was never the
  // point of dragging a file into a "new dump" dialog.
  const handleDrop = (e: React.DragEvent) => {
    e.preventDefault();
    setDragging(false);
    if (submitting) return;
    const dropped = e.dataTransfer.files[0];
    if (dropped) {
      setValue("url", "");
      selectFile(dropped);
      clearErrors("root");
    }
  };

  const onSubmit = form.submit(async (
    { url, file, title, comment, isPublic },
  ) => {
    const isPrivate = !isPublic;
    let res: Response;

    if (!file) {
      const normalizedUrl = normalizeUrl(url);
      if (!normalizedUrl) throw new Error(t`URL is required.`);
      setValue("url", normalizedUrl);
      const body: CreateUrlDumpRequest = {
        url: normalizedUrl,
        // Only when the poster typed it: otherwise the server would be pinned
        // to whatever the preview happened to scrape a moment ago.
        title: titleFromUser && title.trim() ? title.trim() : undefined,
        comment: comment.trim() || undefined,
        isPrivate,
        categoryIds: [...selectedCategoryIds],
      };
      res = await authFetch(`${API_URL}/api/dumps`, {
        method: "POST",
        body: JSON.stringify(body),
      });
    } else {
      if (!title.trim()) throw new Error(t`Title is required.`);
      if (file.size > MAX_FILE_SIZE) {
        throw new Error(t`File too large (max 50 MB).`);
      }
      const formData = new FormData();
      formData.append("file", file);
      if (comment.trim()) formData.append("comment", comment.trim());
      if (title.trim()) formData.append("title", title.trim());
      formData.append("isPrivate", String(isPrivate));
      formData.append("categoryIds", JSON.stringify([...selectedCategoryIds]));
      setUploadProgress(0);
      try {
        res = await authUpload(
          `${API_URL}/api/dumps`,
          formData,
          setUploadProgress,
        );
      } finally {
        setUploadProgress(undefined);
      }
    }

    const dump = deserializeDump(await expectOk<RawDump>(res));
    clearDumpDraft();
    injectDump(dump);
    setCreatedDump(dump);
    goToStep("playlist", "forward");
    setPlaylistsLoading(true);
    authFetch(`${API_URL}/api/playlists/by-dump/${dump.id}/memberships`)
      .then((r) => r.json())
      .then((body) => {
        if (body.success) {
          setMemberships(
            (body.data as RawPlaylistMembership[]).map(
              deserializePlaylistMembership,
            ),
          );
        }
      })
      .catch(() => {})
      .finally(() => setPlaylistsLoading(false));
  });

  const toggleMembership = async (membership: PlaylistMembership) => {
    if (!createdDump) return;
    const { playlist, hasDump } = membership;
    if (hasDump) {
      await authFetch(
        `${API_URL}/api/playlists/${playlist.id}/dumps/${createdDump.id}`,
        { method: "DELETE" },
      );
      setMemberships((prev) =>
        prev.map((m) =>
          m.playlist.id === playlist.id ? { ...m, hasDump: false } : m
        )
      );
    } else {
      await authFetch(
        `${API_URL}/api/playlists/${playlist.id}/dumps/${createdDump.id}`,
        { method: "POST" },
      );
      setMemberships((prev) =>
        prev.map((m) =>
          m.playlist.id === playlist.id ? { ...m, hasDump: true } : m
        )
      );
    }
  };

  const canProceed = !!file || !!canonicalUrl;

  // What the second panel's choices apply to, in one line.
  const recap = title.trim() || file?.name || normalizeUrl(url);
  const uploadPercentLabel = t`Uploading ${
    Math.round((uploadProgress ?? 0) * 100)
  }%`;

  // Enter in the link field advances rather than posts, so the panels behave
  // like a form the whole way through.
  const onFormSubmit = (e: React.FormEvent<HTMLFormElement>) => {
    if (step === "what") {
      e.preventDefault();
      if (canProceed) goToStep("details", "forward");
      return;
    }
    void onSubmit(e);
  };

  return (
    <Modal
      title={step === "playlist" ? t`Add to playlist` : t`New dump`}
      onClose={onClose}
      onBeforeClose={handleBeforeClose}
      wide
    >
      <div
        className={`dump-create${dragging ? " dump-create--drag" : ""}`}
        onDragOver={(e) => {
          e.preventDefault();
          if (!submitting && step !== "playlist") setDragging(true);
        }}
        onDragLeave={(e) => {
          if (!e.currentTarget.contains(e.relatedTarget as Node | null)) {
            setDragging(false);
          }
        }}
        onDrop={handleDrop}
      >
        {confirmClose && (
          <div className="dump-create-confirm" role="alert">
            <p>
              <Trans>
                Close without posting? The attached file won't be kept —
                everything you typed will.
              </Trans>
            </p>
            <div className="dump-create-confirm-actions">
              <button type="button" onClick={() => setConfirmClose(false)}>
                <Trans>Keep editing</Trans>
              </button>
              <button type="button" className="btn-danger" onClick={onClose}>
                <Trans>Close anyway</Trans>
              </button>
            </div>
          </div>
        )}

        {draftNoticeVisible && step === "what" && (
          <div className="dump-create-draft" role="status">
            <span>
              <Trans>Picked up where you left off.</Trans>
            </span>
            <button
              type="button"
              className="dump-create-draft-discard"
              onClick={discardDraft}
            >
              <Trans>Start fresh</Trans>
            </button>
          </div>
        )}

        <StepIndicator current={step} />

        {step === "playlist"
          ? (
            <div className="dump-panel dump-panel--forward">
              {createdDump && (
                <p className="dump-create-success">
                  <Trans>Dumped!</Trans>{" "}
                  <Link to={dumpUrl(createdDump)} onClick={onClose}>
                    <Trans>View dump →</Trans>
                  </Link>
                </p>
              )}

              <PlaylistMembershipPanel
                dumpId={createdDump?.id ?? ""}
                memberships={memberships}
                loading={playlistsLoading}
                onToggle={toggleMembership}
                onPlaylistCreated={(membership) =>
                  setMemberships((prev) => [membership, ...prev])}
              />

              <div className="form-actions">
                <div className="form-actions-right">
                  <button
                    type="button"
                    className="btn-primary"
                    onClick={onClose}
                  >
                    <Trans>Done</Trans>
                  </button>
                </div>
              </div>
            </div>
          )
          : (
            <FormProvider {...form}>
              <form onSubmit={onFormSubmit} className="form">
                <FormError title={t`Failed to post`} />

                {/* Keyed so each panel re-enters from the side it came from. */}
                <div
                  key={step}
                  className={`dump-panel dump-panel--${direction}`}
                >
                  {step === "what"
                    ? (
                      <>
                        {mode === "url" && (
                          <>
                            <div className="form-field">
                              <label className="form-label" htmlFor="dc-url">
                                <Trans>Link</Trans>
                              </label>
                              <input
                                id="dc-url"
                                type="url"
                                {...register("url")}
                                onBlur={(e) =>
                                  setValue("url", normalizeUrl(e.target.value))}
                                onPaste={(e) => {
                                  const pastedFile = e.clipboardData.files[0];
                                  if (pastedFile) {
                                    e.preventDefault();
                                    setValue("url", "");
                                    selectFile(pastedFile);
                                    clearErrors("root");
                                  }
                                }}
                                disabled={submitting}
                                placeholder={t`Paste a link…`}
                                autoFocus={!prefersNoAutoFocus()}
                              />
                            </div>

                            {urlPreview.status === "loading" && (
                              <p className="preview-loading">
                                <Trans>Fetching preview…</Trans>
                              </p>
                            )}

                            {urlPreview.status === "done" && (
                              <>
                                {urlPreview.richContent && (
                                  <RichContentCard
                                    richContent={urlPreview.richContent}
                                  />
                                )}
                                {!urlPreview.reached && (
                                  <p className="preview-note">
                                    <Trans>
                                      Couldn't load a preview for this link —
                                      check it, or post it as-is and refresh the
                                      preview later.
                                    </Trans>
                                  </p>
                                )}
                              </>
                            )}

                            {duplicates.length > 0 && (
                              <DuplicateNotice
                                matches={duplicates}
                                onNavigate={onClose}
                              />
                            )}

                            {urlPreview.status === "done" && (
                              <TitleField
                                registration={register("title")}
                                editing={titleEditing}
                                onEdit={() => {
                                  setTitleEditing(true);
                                  setTitleFromUser(true);
                                }}
                                onReset={titleFromUser && suggestedTitle
                                  ? () => {
                                    setTitleFromUser(false);
                                    setTitleEditing(false);
                                    setValue("title", suggestedTitle);
                                  }
                                  : undefined}
                                disabled={submitting}
                              />
                            )}
                          </>
                        )}

                        {/* Hidden only while a link is being written: an empty
                            panel offers both ways in at once, no mode to pick. */}
                        {!(mode === "url" && url.trim()) && (
                          <FileField<CreateValues>
                            name="file"
                            onValueChange={selectFile}
                            disabled={submitting}
                            hint={t`Drop a file here, or paste one`}
                          />
                        )}

                        {file && (
                          <>
                            <LocalFilePreview file={file} />
                            <TitleField
                              registration={register("title")}
                              editing={titleEditing}
                              onEdit={() => {
                                setTitleEditing(true);
                                setTitleFromUser(true);
                              }}
                              disabled={submitting}
                            />
                          </>
                        )}
                      </>
                    )
                    : (
                      <>
                        {/* The link itself is a panel back, so name the thing
                            these choices are about. */}
                        <p className="dump-panel-recap" title={recap}>
                          <span aria-hidden="true">
                            {mode === "url" ? "🔗" : "📎"}
                          </span>{" "}
                          {recap}
                        </p>

                        {uploadProgress !== undefined && (
                          <div
                            className={`dump-upload-progress${
                              typeof uploadProgress === "number"
                                ? ""
                                : " dump-upload-progress--indeterminate"
                            }`}
                            role="progressbar"
                            aria-valuemin={0}
                            aria-valuemax={100}
                            aria-valuenow={typeof uploadProgress === "number"
                              ? Math.round(uploadProgress * 100)
                              : undefined}
                          >
                            <div
                              className="dump-upload-progress-fill"
                              style={typeof uploadProgress === "number"
                                ? { width: `${uploadProgress * 100}%` }
                                : undefined}
                            />
                          </div>
                        )}

                        <RichTextField<CreateValues>
                          name="comment"
                          label={t`Why?`}
                          placeholder={t`What makes it worth it?`}
                          rows={3}
                          maxLength={VALIDATION.DUMP_COMMENT_MAX}
                          rules={{ maxLength: VALIDATION.DUMP_COMMENT_MAX }}
                          disabled={submitting}
                          editorRef={commentEditorRef}
                        />

                        <CategorySelect
                          selected={selectedCategoryIds}
                          onToggle={toggleCategory}
                          disabled={submitting}
                        />

                        <VisibilityToggle<CreateValues>
                          name="isPublic"
                          label={t`Who can see it`}
                          disabled={submitting}
                        />
                      </>
                    )}
                </div>

                <div className="form-actions">
                  {step === "details" && (
                    <button
                      type="button"
                      className="form-cancel"
                      onClick={() => goToStep("what", "back")}
                      disabled={submitting}
                    >
                      <Trans>← Back</Trans>
                    </button>
                  )}
                  <div className="form-actions-right">
                    {step === "what" && (
                      <button
                        type="button"
                        className="form-cancel"
                        onClick={requestClose}
                      >
                        <Trans>Cancel</Trans>
                      </button>
                    )}
                    <SubmitButton
                      disabled={step === "what" && !canProceed}
                      pendingLabel={mode === "url"
                        ? <Trans>Posting…</Trans>
                        : typeof uploadProgress === "number"
                        ? uploadPercentLabel
                        : <Trans>Uploading…</Trans>}
                    >
                      {step === "what"
                        ? <Trans>Next →</Trans>
                        : <Trans>Dump it</Trans>}
                    </SubmitButton>
                  </div>
                </div>
              </form>
            </FormProvider>
          )}
      </div>
    </Modal>
  );
}