import React, { useCallback, useEffect, useState } from 'react';
import {
  Box,
  Button,
  Checkbox,
  color,
  config,
  Dialog,
  Header,
  Icon,
  IconButton,
  Icons,
  Input,
  Overlay,
  OverlayBackdrop,
  OverlayCenter,
  Spinner,
  Text,
} from 'folds';
import FocusTrap from 'focus-trap-react';
import { useAtomValue, useSetAtom, useStore } from 'jotai';
import { SequenceCard } from '../../../components/sequence-card';
import { SequenceCardStyle } from '../../room-settings/styles.css';
import { SettingTile } from '../../../components/setting-tile';
import { useRoom } from '../../../hooks/useRoom';
import { useMatrixClient } from '../../../hooks/useMatrixClient';
import { useModalStyle } from '../../../hooks/useModalStyle';
import { stopPropagation } from '../../../utils/keyboard';
import { toastQueueAtom } from '../../../state/toast';
import {
  cancelRedactJob,
  clearRedactJob,
  hydrateRedactJob,
  redactJobsAtom,
  runRedactJob,
} from '../../../state/redactOwnMessagesJob';
import { collectOwnEventIds } from '../../../utils/redactOwnMessages';

const TYPE_TO_CONFIRM_ABOVE = 50;

type ConfirmDialogProps = {
  onStart: (leaveAfter: boolean) => void;
  requestClose: () => void;
};

/**
 * Scan first (live count), then confirm with the number — typing the room name
 * for > 50 — and an optional "leave the room afterwards".
 */
function ConfirmDialog({ onStart, requestClose }: ConfirmDialogProps) {
  const mx = useMatrixClient();
  const room = useRoom();
  const modalStyle = useModalStyle(480);
  const [count, setCount] = useState<number | null>(null);
  const [scanError, setScanError] = useState<string>();
  const [typed, setTyped] = useState('');
  const [leaveAfter, setLeaveAfter] = useState(false);

  useEffect(() => {
    const ctrl = new AbortController();
    setCount(null);
    collectOwnEventIds(mx, room.roomId, mx.getSafeUserId(), (n) => setCount(n), ctrl.signal)
      .then((ids) => setCount(ids.length))
      .catch((e) => {
        if (!ctrl.signal.aborted) setScanError(e instanceof Error ? e.message : String(e));
      });
    return () => ctrl.abort();
  }, [mx, room.roomId]);

  const scanning = count === null && !scanError;
  const needsTyping = (count ?? 0) > TYPE_TO_CONFIRM_ABOVE;
  const roomName = room.name ?? room.roomId;
  const canStart =
    !scanning && !scanError && (count ?? 0) > 0 && (!needsTyping || typed.trim() === roomName);

  return (
    <Overlay open backdrop={<OverlayBackdrop />}>
      <OverlayCenter>
        <FocusTrap
          focusTrapOptions={{
            initialFocus: false,
            onDeactivate: requestClose,
            clickOutsideDeactivates: true,
            escapeDeactivates: stopPropagation,
          }}
        >
          <Dialog variant="Surface" style={modalStyle}>
            <Header
              style={{
                padding: `0 ${config.space.S200} 0 ${config.space.S400}`,
                borderBottomWidth: config.borderWidth.B300,
              }}
              variant="Surface"
              size="500"
            >
              <Box grow="Yes">
                <Text as="h2" size="H4">
                  Delete all your messages
                </Text>
              </Box>
              <IconButton size="300" onClick={requestClose} radii="300" aria-label="Close">
                <Icon src={Icons.Cross} />
              </IconButton>
            </Header>
            <Box style={{ padding: config.space.S400 }} direction="Column" gap="400">
              {scanning && (
                <Box alignItems="Center" gap="200">
                  <Spinner size="200" />
                  <Text>
                    Counting your messages in <b>{roomName}</b>…{' '}
                    {count ? `${Number(count).toLocaleString()} so far` : ''}
                  </Text>
                </Box>
              )}
              {scanError && (
                <Text style={{ color: color.Critical.Main }}>
                  Couldn&apos;t count your messages: {scanError}
                </Text>
              )}
              {!scanning && !scanError && (
                <>
                  <Text>
                    Redact <b>{(count ?? 0).toLocaleString()}</b> messages you sent in{' '}
                    <b>{roomName}</b>? This cannot be undone. Redactions are visible to others as
                    &ldquo;message deleted&rdquo;, and files you uploaded stay on the server until
                    an admin purges them.
                  </Text>
                  {needsTyping && (
                    <Box direction="Column" gap="100">
                      <Text size="L400">Type the room name to confirm</Text>
                      <Input
                        variant="Background"
                        size="400"
                        radii="300"
                        value={typed}
                        onChange={(e) => setTyped(e.currentTarget.value)}
                        placeholder={roomName}
                        aria-label="Room name confirmation"
                      />
                    </Box>
                  )}
                  <Box as="label" alignItems="Center" gap="200">
                    <Checkbox
                      variant="Critical"
                      checked={leaveAfter}
                      onClick={() => setLeaveAfter((v) => !v)}
                      aria-label="Leave the room afterwards"
                    />
                    <Text>Leave the room afterwards</Text>
                  </Box>
                </>
              )}
              <Box gap="200" justifyContent="End">
                <Button variant="Secondary" fill="Soft" onClick={requestClose}>
                  <Text size="B400">Cancel</Text>
                </Button>
                <Button variant="Critical" disabled={!canStart} onClick={() => onStart(leaveAfter)}>
                  <Text size="B400">Delete {count ? count.toLocaleString() : ''} messages</Text>
                </Button>
              </Box>
            </Box>
          </Dialog>
        </FocusTrap>
      </OverlayCenter>
    </Overlay>
  );
}

/**
 * [Gitea #169] Room Settings tile: "Your messages in this room" with a
 * Delete all… flow. The job runs outside React (closing settings is fine),
 * shows its progress here, persists so a reload can resume, and toasts when done.
 */
export function DeleteMyMessages() {
  const mx = useMatrixClient();
  const room = useRoom();
  const store = useStore();
  const setToast = useSetAtom(toastQueueAtom);
  const jobs = useAtomValue(redactJobsAtom);
  const job = jobs[room.roomId];
  const [confirm, setConfirm] = useState(false);

  // A reload mid-job: offer to resume.
  useEffect(() => {
    if (!jobs[room.roomId]) hydrateRedactJob(store, room.roomId);
  }, [store, room.roomId, jobs]);

  const start = useCallback(
    (leaveAfter: boolean, resume?: boolean) => {
      setConfirm(false);
      const resumeState = resume ? jobs[room.roomId] : undefined;
      const name = room.name ?? room.roomId;
      runRedactJob(
        store,
        mx,
        room.roomId,
        {
          leaveAfter,
          onDone: (s) =>
            setToast({
              id: `redact-done-${room.roomId}`,
              displayName: 'Lotus Chat',
              body: `Deleted ${s.redacted.toLocaleString()} of your messages in ${name}${s.skipped ? ` (${s.skipped} already gone)` : ''}.`,
              roomName: name,
              roomId: room.roomId,
            }),
        },
        resumeState,
      );
    },
    [store, mx, room, jobs, setToast],
  );

  const running = job && (job.phase === 'collecting' || job.phase === 'redacting');
  const total = job ? job.redacted + job.skipped + job.pending.length : 0;
  const done = job ? job.redacted + job.skipped : 0;

  let status: React.ReactNode = 'Redact everything you sent here — no moderator needed.';
  if (job?.phase === 'collecting') status = `Counting… ${job.found.toLocaleString()} found`;
  else if (job?.phase === 'redacting')
    status = `Deleting… ${done.toLocaleString()} / ${total.toLocaleString()}`;
  else if (job?.phase === 'error')
    status = `Stopped: ${job.error}. ${job.pending.length} left — you can resume.`;
  else if (job?.phase === 'cancelled' && job.pending.length > 0)
    status = `Cancelled with ${job.pending.length.toLocaleString()} left — you can resume.`;
  else if (job?.phase === 'done') status = `Deleted ${job.redacted.toLocaleString()} messages.`;

  const resumable = job && !running && job.pending.length > 0;

  return (
    <SequenceCard
      className={SequenceCardStyle}
      variant="SurfaceVariant"
      direction="Column"
      gap="400"
    >
      <SettingTile
        title="Your messages in this room"
        description={status}
        after={
          <Box gap="200">
            {running && (
              <Button
                size="300"
                variant="Secondary"
                fill="Soft"
                radii="300"
                onClick={() => cancelRedactJob(room.roomId)}
              >
                <Text size="B300">Cancel</Text>
              </Button>
            )}
            {resumable && (
              <>
                <Button
                  size="300"
                  variant="Critical"
                  fill="Soft"
                  radii="300"
                  onClick={() => start(job.leaveAfter, true)}
                >
                  <Text size="B300">Resume</Text>
                </Button>
                <Button
                  size="300"
                  variant="Secondary"
                  fill="None"
                  radii="300"
                  onClick={() => clearRedactJob(store, room.roomId)}
                >
                  <Text size="B300">Discard</Text>
                </Button>
              </>
            )}
            {!running && !resumable && (
              <Button
                size="300"
                variant="Critical"
                fill="Soft"
                radii="300"
                onClick={() => setConfirm(true)}
              >
                <Text size="B300">Delete all…</Text>
              </Button>
            )}
          </Box>
        }
      />
      {confirm && (
        <ConfirmDialog onStart={(leave) => start(leave)} requestClose={() => setConfirm(false)} />
      )}
    </SequenceCard>
  );
}