import type React from 'react';
import { useCallback, useEffect, useMemo, useState } from 'react';
import type { IUser } from '@growi/core';
import { GlobalCodeMirrorEditorKey } from '@growi/editor';
import { CodeMirrorEditorDiff } from '@growi/editor/dist/client/components/diff/CodeMirrorEditorDiff';
import { MergeViewer } from '@growi/editor/dist/client/components/diff/MergeViewer';
import { useCodeMirrorEditorIsolated } from '@growi/editor/dist/client/stores/codemirror-editor';
import { UserPicture } from '@growi/ui/dist/components';
import { format } from 'date-fns/format';
import { useTranslation } from 'next-i18next';
import { Modal, ModalBody, ModalFooter, ModalHeader } from 'reactstrap';

import { useCurrentUser } from '~/states/global';
import {
  useCurrentPageData,
  useRemoteRevisionBody,
  useRemoteRevisionLastUpdatedAt,
  useRemoteRevisionLastUpdateUser,
} from '~/states/page';
import {
  useConflictDiffModalActions,
  useConflictDiffModalStatus,
} from '~/states/ui/modal/conflict-diff';

import styles from './ConflictDiffModal.module.scss';

type IRevisionOnConflict = {
  revisionBody: string;
  createdAt: Date;
  user: IUser;
};

/**
 * ConflictDiffModalSubstance - Presentation component (heavy logic, rendered only when isOpen)
 */
type ConflictDiffModalSubstanceProps = {
  request: IRevisionOnConflict;
  latest: IRevisionOnConflict;
  isModalExpanded: boolean;
  setIsModalExpanded: React.Dispatch<React.SetStateAction<boolean>>;
};

const formatedDate = (date: Date): string => {
  return format(date, 'yyyy/MM/dd HH:mm:ss');
};

const ConflictDiffModalSubstance = (
  props: ConflictDiffModalSubstanceProps,
): React.JSX.Element => {
  const { request, latest, isModalExpanded, setIsModalExpanded } = props;

  const [resolvedRevision, setResolvedRevision] = useState<string>('');
  const [isRevisionselected, setIsRevisionSelected] = useState<boolean>(false);
  const [revisionSelectedToggler, setRevisionSelectedToggler] =
    useState<boolean>(false);

  const { t } = useTranslation();
  const conflictDiffModalStatus = useConflictDiffModalStatus();
  const { close: closeConflictDiffModal } = useConflictDiffModalActions();
  const { data: codeMirrorEditor } = useCodeMirrorEditorIsolated(
    GlobalCodeMirrorEditorKey.DIFF,
  );

  // Memoize formatted dates
  const requestFormattedDate = useMemo(
    () => formatedDate(request.createdAt),
    [request.createdAt],
  );
  const latestFormattedDate = useMemo(
    () => formatedDate(latest.createdAt),
    [latest.createdAt],
  );

  const selectRevisionHandler = useCallback(
    (selectedRevision: string) => {
      setResolvedRevision(selectedRevision);
      setRevisionSelectedToggler((prev) => !prev);

      if (!isRevisionselected) {
        setIsRevisionSelected(true);
      }
    },
    [isRevisionselected],
  );

  const resolveConflictHandler = useCallback(async () => {
    const newBody = codeMirrorEditor?.getDocString();
    if (newBody == null) {
      return;
    }

    await conflictDiffModalStatus?.onResolve?.(newBody);
  }, [codeMirrorEditor, conflictDiffModalStatus]);

  // biome-ignore lint/correctness/useExhaustiveDependencies: ignore
  useEffect(() => {
    codeMirrorEditor?.initDoc(resolvedRevision);
    // Enable selecting the same revision after editing by including revisionSelectedToggler in the dependency array of useEffect
  }, [codeMirrorEditor, resolvedRevision, revisionSelectedToggler]);

  const headerButtons = useMemo(
    () => (
      <div className="d-flex align-items-center">
        <button
          type="button"
          className="btn"
          onClick={() => setIsModalExpanded((prev) => !prev)}
        >
          <span className="material-symbols-outlined">
            {isModalExpanded ? 'close_fullscreen' : 'open_in_full'}
          </span>
        </button>
        <button
          type="button"
          className="btn"
          onClick={closeConflictDiffModal}
          aria-label="Close"
        >
          <span className="material-symbols-outlined">close</span>
        </button>
      </div>
    ),
    [closeConflictDiffModal, isModalExpanded, setIsModalExpanded],
  );

  return (
    <>
      <ModalHeader
        tag="h4"
        className="d-flex align-items-center"
        close={headerButtons}
      >
        <span className="material-symbols-outlined me-1">error</span>
        {t('modal_resolve_conflict.resolve_conflict')}
      </ModalHeader>

      <ModalBody className="mx-4 my-1">
        <div className="row">
          <div className="col-12 text-center mt-2 mb-4">
            <h3 className="fw-bold text-muted">
              {t('modal_resolve_conflict.resolve_conflict_message')}
            </h3>
          </div>

          <div className="col-6">
            <h4 className="fw-bold my-2 text-muted">
              {t('modal_resolve_conflict.requested_revision')}
            </h4>
            <div className="d-flex align-items-center my-3">
              <div>
                <UserPicture user={request.user} size="lg" noLink noTooltip />
              </div>
              <div className="ms-3 text-muted">
                <p className="my-0">updated by {request.user.username}</p>
                <p className="my-0">{requestFormattedDate}</p>
              </div>
            </div>
          </div>

          <div className="col-6">
            <h4 className="fw-bold my-2 text-muted">
              {t('modal_resolve_conflict.latest_revision')}
            </h4>
            <div className="d-flex align-items-center my-3">
              <div>
                <UserPicture user={latest.user} size="lg" noLink noTooltip />
              </div>
              <div className="ms-3 text-muted">
                <p className="my-0">updated by {latest.user.username}</p>
                <p className="my-0">{latestFormattedDate}</p>
              </div>
            </div>
          </div>

          <MergeViewer
            leftBody={request.revisionBody}
            rightBody={latest.revisionBody}
          />

          <div className="col-6">
            <div className="text-center my-4">
              <button
                type="button"
                className="btn btn-outline-primary"
                onClick={() => {
                  selectRevisionHandler(request.revisionBody);
                }}
              >
                <span className="material-symbols-outlined me-1">
                  arrow_circle_down
                </span>
                {t('modal_resolve_conflict.select_revision', {
                  revision: 'mine',
                })}
              </button>
            </div>
          </div>

          <div className="col-6">
            <div className="text-center my-4">
              <button
                type="button"
                className="btn btn-outline-primary"
                onClick={() => {
                  selectRevisionHandler(latest.revisionBody);
                }}
              >
                <span className="material-symbols-outlined me-1">
                  arrow_circle_down
                </span>
                {t('modal_resolve_conflict.select_revision', {
                  revision: 'theirs',
                })}
              </button>
            </div>
          </div>

          <div className="col-12">
            <div className="border border-dark">
              <h4 className="fw-bold my-2 mx-2 text-muted">
                {t('modal_resolve_conflict.selected_editable_revision')}
              </h4>
              <CodeMirrorEditorDiff />
            </div>
          </div>
        </div>
      </ModalBody>

      <ModalFooter>
        <button
          type="button"
          className="btn btn-outline-secondary"
          onClick={closeConflictDiffModal}
        >
          {t('Cancel')}
        </button>
        <button
          type="button"
          className="btn btn-primary ms-3"
          onClick={resolveConflictHandler}
          disabled={!isRevisionselected}
        >
          {t('modal_resolve_conflict.resolve_and_save')}
        </button>
      </ModalFooter>
    </>
  );
};

/**
 * ConflictDiffModal - Container component (lightweight, always rendered)
 */
export const ConflictDiffModal = (): React.JSX.Element => {
  const currentUser = useCurrentUser();
  const currentPage = useCurrentPageData();
  const conflictDiffModalStatus = useConflictDiffModalStatus();

  // state for latest page
  const remoteRevisionBody = useRemoteRevisionBody();
  const remoteRevisionLastUpdateUser = useRemoteRevisionLastUpdateUser();
  const remoteRevisionLastUpdatedAt = useRemoteRevisionLastUpdatedAt();

  const isRemotePageDataInappropriate =
    remoteRevisionBody == null || remoteRevisionLastUpdateUser == null;

  const [isModalExpanded, setIsModalExpanded] = useState<boolean>(false);

  // Check if all required data is available
  const isDataReady =
    conflictDiffModalStatus?.isOpened &&
    currentUser != null &&
    currentPage != null &&
    !isRemotePageDataInappropriate;

  // Prepare data for Substance
  const currentTime: Date = new Date();
  const request: IRevisionOnConflict | null = isDataReady
    ? {
        revisionBody: conflictDiffModalStatus.requestRevisionBody ?? '',
        createdAt: currentTime,
        user: currentUser,
      }
    : null;

  const latest: IRevisionOnConflict | null = isDataReady
    ? {
        revisionBody: remoteRevisionBody,
        createdAt: new Date(
          remoteRevisionLastUpdatedAt ?? currentTime.toString(),
        ),
        user: remoteRevisionLastUpdateUser,
      }
    : null;

  return (
    <Modal
      isOpen={conflictDiffModalStatus?.isOpened ?? false}
      className={`${styles['conflict-diff-modal']} ${isModalExpanded ? ' grw-modal-expanded' : ''}`}
      size="xl"
    >
      {isDataReady && request != null && latest != null && (
        <ConflictDiffModalSubstance
          request={request}
          latest={latest}
          isModalExpanded={isModalExpanded}
          setIsModalExpanded={setIsModalExpanded}
        />
      )}
    </Modal>
  );
};