import { Badge, Button, EmptyState, Field, Panel, TextInput } from "@ekklesia/ui";
import { type ChangeEvent, type ReactElement, useCallback, useMemo, useRef, useState } from "react";
import {
  createUploadQueue,
  type UploadFile,
  type UploadItem,
  type UploadQueue,
} from "../../browser/uploads.js";
import type { SignageApi } from "../api.js";
import { useAction, useResource } from "../hooks.js";
import type { ImageRecord, SettingsResponse } from "../types.js";
import { ConfirmButton, FailureNote, formatInstant, renderLoadable } from "./shared.js";

/**
 * The native image library and its upload queue.
 *
 * The upload behaviour is the part worth reading: an operator drops twenty slides and gets twenty
 * individually bounded requests, a few at a time. The page stays responsive because only a few are
 * in flight; one bad file fails alone; and the operator learns about a file that is too large or of
 * the wrong type before a byte is sent, while the server still checks both again.
 */
export function ImagesPanel({
  api,
  settings,
  canManage,
}: {
  readonly api: SignageApi;
  readonly settings: SettingsResponse;
  readonly canManage: boolean;
}): ReactElement {
  const images = useResource(
    () => api.get<{ images: readonly ImageRecord[] }>("images"),
    [],
    "images",
  );
  const [uploads, setUploads] = useState<readonly UploadItem[]>([]);
  const queueRef = useRef<UploadQueue | undefined>(undefined);
  const [renaming, setRenaming] = useState<{ id: string; value: string } | undefined>(undefined);
  const rename = useAction(() => {
    setRenaming(undefined);
    images.reload();
  });
  const remove = useAction(() => images.reload());

  const queue = useMemo(() => {
    const created = createUploadQueue({
      concurrency: settings.uploads.concurrency,
      maxBytes: settings.uploads.maxBytes,
      maxFiles: settings.uploads.batchMaxFiles,
      onChange: (items) => setUploads(items),
      upload: async (file) => {
        // One image per request, with the label in the query string so the body is exactly the
        // bytes. The server streams and counts them; nothing here buffers a second copy.
        const query = new URLSearchParams({ displayName: file.name, filename: file.name });
        await api.upload(`images?${query.toString()}`, file as unknown as Blob, file.type);
      },
    });
    queueRef.current = created;
    return created;
  }, [
    api,
    settings.uploads.batchMaxFiles,
    settings.uploads.concurrency,
    settings.uploads.maxBytes,
  ]);

  const onFiles = useCallback(
    (event: ChangeEvent<HTMLInputElement>) => {
      const files = Array.from(event.target.files ?? []) as unknown as UploadFile[];
      if (files.length === 0) {
        return;
      }
      queue.enqueue(files);
      void queue.drain().then(() => images.reload());
      event.target.value = "";
    },
    [images, queue],
  );

  const finished = uploads.filter(
    (item) => item.status !== "queued" && item.status !== "uploading",
  );

  return (
    <Panel
      actions={
        canManage ? (
          <label className="signage-upload-trigger">
            <span className="ek-button ek-button--primary">Add images</span>
            <input
              accept="image/png,image/jpeg,image/webp"
              className="signage-upload-input"
              data-testid="signage-upload-input"
              multiple
              onChange={onFiles}
              type="file"
            />
          </label>
        ) : undefined
      }
      description={`PNG, JPEG, and WebP. Up to ${Math.round(settings.uploads.maxBytes / (1024 * 1024))} MiB each, ${settings.uploads.batchMaxFiles} at a time.`}
      title="Images"
    >
      {uploads.length === 0 ? undefined : (
        <div className="signage-uploads" data-testid="signage-uploads">
          <ul className="ek-list">
            {uploads.map((item) => (
              <li className="ek-list__item signage-row" key={item.id}>
                <span className="signage-row__name">{item.name}</span>
                <Badge
                  tone={
                    item.status === "done"
                      ? "success"
                      : item.status === "failed" || item.status === "rejected"
                        ? "danger"
                        : "info"
                  }
                >
                  {item.status}
                </Badge>
                {item.message === undefined ? undefined : (
                  <span className="signage-uploads__message">{item.message}</span>
                )}
              </li>
            ))}
          </ul>
          {finished.length === 0 ? undefined : (
            <Button onClick={() => queue.clearFinished()}>Clear finished</Button>
          )}
        </div>
      )}

      {renderLoadable(
        images.state,
        (value) =>
          value.images.length === 0 ? (
            <EmptyState
              description="Add a PNG, JPEG, or WebP and it will be available to every timeline."
              title="No images yet"
            />
          ) : (
            <ul className="signage-image-grid" data-testid="signage-image-grid">
              {value.images.map((image) => {
                const thumbnail = image.renditions.find(
                  (rendition) => rendition.kind === "thumbnail",
                );
                return (
                  <li className="signage-image" key={image.id}>
                    {thumbnail === undefined ? (
                      <div className="signage-image__missing">No preview</div>
                    ) : (
                      <img
                        alt={image.displayName}
                        className="signage-image__thumbnail"
                        height={thumbnail.height}
                        src={thumbnail.url}
                        width={thumbnail.width}
                      />
                    )}
                    <div className="signage-image__meta">
                      {renaming?.id === image.id ? (
                        <Field label="Name">
                          {(control) => (
                            <TextInput
                              {...control}
                              onChange={(event) =>
                                setRenaming({ id: image.id, value: event.target.value })
                              }
                              value={renaming.value}
                            />
                          )}
                        </Field>
                      ) : (
                        <p className="signage-image__name">{image.displayName}</p>
                      )}
                      <p className="signage-image__detail">
                        {`${image.width}×${image.height} · ${formatInstant(image.createdAt, settings.timezone)}`}
                      </p>
                      {image.expiresAt === null ? undefined : (
                        <Badge className="signage-image__expiry" tone="warning">
                          {`Expires ${formatInstant(image.expiresAt, settings.timezone)}`}
                        </Badge>
                      )}
                    </div>
                    {canManage ? (
                      <div className="signage-image__actions">
                        {renaming?.id === image.id ? (
                          <>
                            <Button
                              disabled={rename.pending}
                              onClick={() =>
                                rename.run(() =>
                                  api.send("PATCH", `images/${image.id}`, {
                                    displayName: renaming.value,
                                  }),
                                )
                              }
                              variant="primary"
                            >
                              Save
                            </Button>
                            <Button onClick={() => setRenaming(undefined)}>Cancel</Button>
                          </>
                        ) : (
                          <Button
                            onClick={() => setRenaming({ id: image.id, value: image.displayName })}
                          >
                            Rename
                          </Button>
                        )}
                        <ConfirmButton
                          confirmLabel="Delete this image"
                          disabled={remove.pending}
                          label="Delete"
                          onConfirm={() =>
                            remove.run(() => api.send("DELETE", `images/${image.id}`))
                          }
                          testId={`signage-image-delete-${image.id}`}
                        />
                      </div>
                    ) : undefined}
                  </li>
                );
              })}
            </ul>
          ),
        { label: "Loading images…", onRetry: images.reload },
      )}
      <FailureNote failure={rename.failure ?? remove.failure} />
    </Panel>
  );
}