import React, { useCallback, useEffect, useMemo, useState } from 'react';
import { useNavigate } from 'react-router-dom';
import {
  Avatar,
  Box,
  Button,
  Icon,
  Icons,
  Input,
  MenuItem,
  Scroll,
  Spinner,
  Text,
  config,
} from 'folds';
import { Room } from 'matrix-js-sdk';
import { useAtomValue, useStore } from 'jotai';
import { useSetting } from '../../../state/hooks/settings';
import { settingsAtom } from '../../../state/settings';
import { Page, PageContent, PageHeader } from '../../../components/page';
import { useMatrixClient } from '../../../hooks/useMatrixClient';
import { useMediaAuthentication } from '../../../hooks/useMediaAuthentication';
import { useRoomNavigate } from '../../../hooks/useRoomNavigate';
import { mDirectAtom } from '../../../state/mDirectList';
import {
  roomIdToMsgDraftAtomFamily,
  roomIdToUploadItemsAtomFamily,
} from '../../../state/room/roomInputDrafts';
import { RoomAvatar, RoomIcon } from '../../../components/room-avatar';
import { mxcUrlToHttp } from '../../../utils/matrix';
import { filesToUploadItems } from '../../../utils/uploadItems';
import {
  clearSharedPayload,
  readSharedPayload,
  shareDraftText,
  SharePayload,
} from '../../../../swShare';
import { BlockType } from '../../../components/editor';
import { bytesToSize } from '../../../utils/common';
import { getHomePath } from '../../pathUtils';
import { useLocalRoomNames } from '../../../hooks/useRoomMeta';

type Shared = { payload: SharePayload; files: File[] };

/**
 * [Gitea #155] Landing page for the PWA share target: what was shared, pick
 * a room, and the files land on that room's composer upload board (text/url
 * as the draft) — the user still presses Send.
 */
export function Share() {
  const localNames = useLocalRoomNames();
  const mx = useMatrixClient();
  const navigate = useNavigate();
  const { navigateRoom } = useRoomNavigate();
  const directs = useAtomValue(mDirectAtom);
  const useAuthentication = useMediaAuthentication();
  const [shared, setShared] = useState<Shared | null | undefined>(undefined);
  const [query, setQuery] = useState('');
  const [busy, setBusy] = useState(false);
  const [stripImageMetadata] = useSetting(settingsAtom, 'stripImageMetadata');

  useEffect(() => {
    readSharedPayload()
      .then((s) => setShared(s ?? null))
      .catch(() => setShared(null));
  }, []);

  const rooms = useMemo(() => {
    const all = mx
      .getRooms()
      .filter((r) => r.getMyMembership() === 'join' && !r.isSpaceRoom())
      .sort((a, b) => (b.getLastActiveTimestamp() ?? 0) - (a.getLastActiveTimestamp() ?? 0));
    const q = query.trim().toLowerCase();
    return q
      ? all.filter((r) =>
          [r.name, localNames[r.roomId]].some((nm) => nm?.toLowerCase().includes(q)),
        )
      : all;
  }, [mx, query, localNames]);

  // Written straight into the room's draft atoms so its composer shows the
  // upload board + text as soon as it mounts.
  const store = useStore();
  const pick = useCallback(
    async (room: Room) => {
      if (!shared || busy) return;
      setBusy(true);
      try {
        if (shared.files.length) {
          store.set(roomIdToUploadItemsAtomFamily(room.roomId), {
            type: 'PUT',
            item: await filesToUploadItems(room, shared.files, stripImageMetadata),
          });
        }
        const text = shareDraftText(shared.payload);
        if (text) {
          store.set(roomIdToMsgDraftAtomFamily(room.roomId), [
            { type: BlockType.Paragraph, children: [{ text }] },
          ]);
        }
        await clearSharedPayload();
        navigateRoom(room.roomId);
      } finally {
        setBusy(false);
      }
    },
    [shared, busy, navigateRoom, store, stripImageMetadata],
  );

  return (
    <Page>
      <PageHeader>
        <Box grow="Yes" alignItems="Center" gap="200">
          <Icon size="400" src={Icons.Send} />
          <Text size="H3" truncate>
            Share to Lotus Chat
          </Text>
        </Box>
      </PageHeader>
      <Box grow="Yes" direction="Column">
        <Scroll hideTrack visibility="Hover">
          <PageContent>
            {shared === undefined && (
              <Box justifyContent="Center" style={{ padding: config.space.S500 }}>
                <Spinner size="400" />
              </Box>
            )}
            {shared === null && (
              <Box direction="Column" gap="300" alignItems="Start">
                <Text size="T300">
                  Nothing was shared, or it has already been placed in a room.
                </Text>
                <Button
                  size="300"
                  variant="Secondary"
                  fill="Soft"
                  radii="300"
                  onClick={() => navigate(getHomePath())}
                >
                  <Text size="B300">Go home</Text>
                </Button>
              </Box>
            )}
            {shared && (
              <Box direction="Column" gap="400">
                <Box direction="Column" gap="200">
                  <Text size="L400">Shared</Text>
                  {shared.files.map((f) => (
                    <Box key={f.name} alignItems="Center" gap="200">
                      <Icon
                        size="100"
                        src={f.type.startsWith('image/') ? Icons.Photo : Icons.File}
                      />
                      <Text size="T300" truncate>
                        {f.name}
                      </Text>
                      <Text size="T200" priority="300">
                        {bytesToSize(f.size)}
                      </Text>
                    </Box>
                  ))}
                  {shareDraftText(shared.payload) && (
                    <Text size="T300" style={{ whiteSpace: 'pre-wrap', wordBreak: 'break-word' }}>
                      {shareDraftText(shared.payload)}
                    </Text>
                  )}
                </Box>
                <Box direction="Column" gap="200">
                  <Text size="L400">Send to</Text>
                  <Input
                    size="400"
                    variant="Background"
                    radii="400"
                    placeholder="Search rooms"
                    value={query}
                    onChange={(evt) => setQuery(evt.currentTarget.value)}
                    autoFocus
                  />
                  <Box direction="Column" gap="100">
                    {rooms.slice(0, 60).map((room) => (
                      <ShareRoomRow
                        key={room.roomId}
                        room={room}
                        dm={directs.has(room.roomId)}
                        useAuthentication={useAuthentication}
                        disabled={busy}
                        onPick={pick}
                      />
                    ))}
                    {rooms.length === 0 && (
                      <Text size="T300" priority="300">
                        No rooms match.
                      </Text>
                    )}
                  </Box>
                </Box>
              </Box>
            )}
          </PageContent>
        </Scroll>
      </Box>
    </Page>
  );
}

function ShareRoomRow({
  room,
  dm,
  useAuthentication,
  disabled,
  onPick,
}: {
  room: Room;
  dm: boolean;
  useAuthentication: boolean;
  disabled: boolean;
  onPick: (room: Room) => void;
}) {
  const localNames = useLocalRoomNames();
  const mx = useMatrixClient();
  const avatarMxc = room.getMxcAvatarUrl();
  const avatarUrl = avatarMxc
    ? (mxcUrlToHttp(mx, avatarMxc, useAuthentication, 48, 48, 'crop') ?? undefined)
    : undefined;
  return (
    <MenuItem
      size="300"
      radii="300"
      variant="Background"
      disabled={disabled}
      onClick={() => onPick(room)}
      before={
        <Avatar size="200" radii="300">
          <RoomAvatar
            roomId={room.roomId}
            src={avatarUrl}
            alt={room.name}
            renderFallback={() => (
              <RoomIcon roomType={room.getType()} size="100" joinRule={room.getJoinRule()} filled />
            )}
          />
        </Avatar>
      }
    >
      <Box direction="Column">
        <Text size="T300" truncate>
          {localNames[room.roomId] ?? room.name}
        </Text>
        {dm && (
          <Text size="T200" priority="300" truncate>
            Direct Message
          </Text>
        )}
      </Box>
    </MenuItem>
  );
}