/*
 This file is part of GNU Anastasis
 (C) 2021-2022 Anastasis SARL

 GNU Anastasis is free software; you can redistribute it and/or modify it under the
 terms of the GNU Affero General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 GNU Anastasis is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License along with
 GNU Anastasis; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */
import { h, VNode } from "preact";
import { useRef, useState } from "preact/hooks";

const MAX_IMAGE_UPLOAD_SIZE = 1024 * 1024;

export interface FileTypeContent {
  content: string;
  type: string;
  name: string;
}

interface Props {
  label: string;
  onChange: (v: FileTypeContent | undefined) => void;
}
export function FileButton(props: Props): VNode {
  const fileInputRef = useRef<HTMLInputElement>(null);
  const [sizeError, setSizeError] = useState(false);
  return (
    <div>
      <button class="button" onClick={(e) => fileInputRef.current?.click()}>
        <span>{props.label}</span>
      </button>
      <input
        ref={fileInputRef}
        style={{ display: "none" }}
        type="file"
        onChange={(e) => {
          const f: FileList | null = e.currentTarget.files;
          if (!f || f.length != 1) {
            return props.onChange(undefined);
          }
          if (f[0].size > MAX_IMAGE_UPLOAD_SIZE) {
            setSizeError(true);
            return props.onChange(undefined);
          }
          setSizeError(false);
          return f[0].arrayBuffer().then((b) => {
            const content = new Uint8Array(b).reduce(
              (data, byte) => data + String.fromCharCode(byte),
              "",
            );
            return props.onChange({
              content,
              name: f[0].name,
              type: f[0].type,
            });
          });
        }}
      />
      {sizeError && (
        <p class="help is-danger">File should be smaller than 1 MB</p>
      )}
    </div>
  );
}