'use client';

import axios from 'axios';
import clsx from 'clsx';
import { AnimatePresence } from 'framer-motion';
import fileDownload from 'js-file-download';
import { useCallback, useLayoutEffect, useMemo, useState } from 'react';
import { TabList, TabPanel, Tabs } from 'react-tabs';
import { toast } from 'react-toastify';

import AnimateFade from '@/components/AnimateFade';
import InfoError, { ErrorData } from '@/components/InfoError';
import Loader from '@/components/ui/Loader';
import TabLabel from '@/components/ui/TabLabel';
import TextURL from '@/components/ui/TextURL';
import { useAccessMode } from '@/context/AccessModeContext';
import { useAuth } from '@/context/AuthContext';
import { useLibrary } from '@/context/LibraryContext';
import { useBlockNavigation, useConceptNavigation } from '@/context/NavigationContext';
import { useRSForm } from '@/context/RSFormContext';
import { useConceptTheme } from '@/context/ThemeContext';
import DlgCloneLibraryItem from '@/dialogs/DlgCloneLibraryItem';
import DlgConstituentaTemplate from '@/dialogs/DlgConstituentaTemplate';
import DlgCreateCst from '@/dialogs/DlgCreateCst';
import DlgDeleteCst from '@/dialogs/DlgDeleteCst';
import DlgEditWordForms from '@/dialogs/DlgEditWordForms';
import DlgRenameCst from '@/dialogs/DlgRenameCst';
import DlgUploadRSForm from '@/dialogs/DlgUploadRSForm';
import useQueryStrings from '@/hooks/useQueryStrings';
import { UserAccessMode } from '@/models/miscellaneous';
import { CstType, IConstituenta, ICstCreateData, ICstRenameData, ICstUpdateData, TermForm } from '@/models/rsform';
import { generateAlias } from '@/models/rsformAPI';
import { EXTEOR_TRS_FILE, prefixes, TIMEOUT_UI_REFRESH } from '@/utils/constants';

import EditorConstituenta from './EditorConstituenta';
import EditorRSForm from './EditorRSForm';
import EditorRSList from './EditorRSList';
import EditorTermGraph from './EditorTermGraph';
import RSTabsMenu from './RSTabsMenu';

export enum RSTabID {
  CARD = 0,
  CST_LIST = 1,
  CST_EDIT = 2,
  TERM_GRAPH = 3
}

function RSTabs() {
  const router = useConceptNavigation();
  const query = useQueryStrings();
  const activeTab = (Number(query.get('tab')) ?? RSTabID.CARD) as RSTabID;
  const cstQuery = query.get('active');

  const {
    error,
    schema,
    loading,
    processing,
    isOwned,
    claim,
    download,
    isSubscribed,
    cstCreate,
    cstDelete,
    cstRename,
    subscribe,
    unsubscribe,
    cstUpdate,
    resetAliases
  } = useRSForm();
  const { destroyItem } = useLibrary();
  const { setNoFooter } = useConceptTheme();
  const { user } = useAuth();
  const { mode, setMode } = useAccessMode();

  const [isModified, setIsModified] = useState(false);
  useBlockNavigation(isModified);

  const isMutable = useMemo(() => {
    return (
      !loading &&
      !processing &&
      mode !== UserAccessMode.READER &&
      ((isOwned || (mode === UserAccessMode.ADMIN && user?.is_staff)) ?? false)
    );
  }, [user?.is_staff, mode, isOwned, loading, processing]);

  const [selected, setSelected] = useState<number[]>([]);
  const activeCst: IConstituenta | undefined = useMemo(() => {
    if (!schema || selected.length === 0) {
      return undefined;
    } else {
      return schema.items.find(cst => cst.id === selected.at(-1));
    }
  }, [schema, selected]);

  const [showUpload, setShowUpload] = useState(false);
  const [showClone, setShowClone] = useState(false);

  const [showDeleteCst, setShowDeleteCst] = useState(false);

  const [createInitialData, setCreateInitialData] = useState<ICstCreateData>();
  const [showCreateCst, setShowCreateCst] = useState(false);

  const [renameInitialData, setRenameInitialData] = useState<ICstRenameData>();
  const [showRenameCst, setShowRenameCst] = useState(false);

  const [showEditTerm, setShowEditTerm] = useState(false);

  const [insertCstID, setInsertCstID] = useState<number | undefined>(undefined);
  const [showTemplates, setShowTemplates] = useState(false);

  useLayoutEffect(() => {
    if (schema) {
      const oldTitle = document.title;
      document.title = schema.title;
      return () => {
        document.title = oldTitle;
      };
    }
  }, [schema, schema?.title]);

  useLayoutEffect(() => {
    setNoFooter(activeTab === RSTabID.CST_EDIT || activeTab === RSTabID.CST_LIST);
    setIsModified(false);
    if (activeTab === RSTabID.CST_EDIT) {
      const cstID = Number(cstQuery);
      if (cstID && schema && schema.items.find(cst => cst.id === cstID)) {
        setSelected([cstID]);
      } else if (schema && schema?.items.length > 0) {
        setSelected([schema.items[0].id]);
      } else {
        setSelected([]);
      }
    }
    return () => setNoFooter(false);
  }, [activeTab, cstQuery, setSelected, schema, setNoFooter, setIsModified]);

  useLayoutEffect(
    () =>
      setMode(prev => {
        if (prev === UserAccessMode.ADMIN) {
          return prev;
        } else if (isOwned) {
          return UserAccessMode.OWNER;
        } else {
          return UserAccessMode.READER;
        }
      }),
    [schema, setMode, isOwned]
  );

  const navigateTab = useCallback(
    (tab: RSTabID, activeID?: number) => {
      if (!schema) {
        return;
      }
      if (activeID) {
        if (tab === activeTab && tab !== RSTabID.CST_EDIT) {
          router.replace(`/rsforms/${schema.id}?tab=${tab}&active=${activeID}`);
        } else {
          router.push(`/rsforms/${schema.id}?tab=${tab}&active=${activeID}`);
        }
      } else if (tab !== activeTab && tab === RSTabID.CST_EDIT && schema.items.length > 0) {
        activeID = schema.items[0].id;
        router.replace(`/rsforms/${schema.id}?tab=${tab}&active=${activeID}`);
      } else {
        router.push(`/rsforms/${schema.id}?tab=${tab}`);
      }
    },
    [router, schema, activeTab]
  );

  function onSelectTab(index: number) {
    navigateTab(index, selected.length > 0 ? selected.at(-1) : undefined);
  }

  const handleCreateCst = useCallback(
    (data: ICstCreateData) => {
      if (!schema?.items) {
        return;
      }
      data.alias = data.alias || generateAlias(data.cst_type, schema);
      cstCreate(data, newCst => {
        toast.success(`Конституента добавлена: ${newCst.alias}`);
        navigateTab(activeTab, newCst.id);
        if (activeTab === RSTabID.CST_EDIT || activeTab === RSTabID.CST_LIST) {
          setTimeout(() => {
            const element = document.getElementById(`${prefixes.cst_list}${newCst.alias}`);
            if (element) {
              element.scrollIntoView({
                behavior: 'smooth',
                block: 'nearest',
                inline: 'nearest'
              });
            }
          }, TIMEOUT_UI_REFRESH);
        }
      });
    },
    [schema, cstCreate, navigateTab, activeTab]
  );

  const promptCreateCst = useCallback(
    (type: CstType | undefined, skipDialog: boolean, definition?: string) => {
      const data: ICstCreateData = {
        insert_after: activeCst?.id ?? null,
        cst_type: type ?? activeCst?.cst_type ?? CstType.BASE,
        alias: '',
        term_raw: '',
        definition_formal: definition ?? '',
        definition_raw: '',
        convention: '',
        term_forms: []
      };
      if (skipDialog) {
        handleCreateCst(data);
      } else {
        setCreateInitialData(data);
        setShowCreateCst(true);
      }
    },
    [handleCreateCst, activeCst]
  );

  const handleCloneCst = useCallback(() => {
    if (!activeCst) {
      return;
    }
    const data: ICstCreateData = {
      insert_after: activeCst.id,
      cst_type: activeCst.cst_type,
      alias: '',
      term_raw: activeCst.term_raw,
      definition_formal: activeCst.definition_formal,
      definition_raw: activeCst.definition_raw,
      convention: activeCst.convention,
      term_forms: activeCst.term_forms
    };
    handleCreateCst(data);
  }, [activeCst, handleCreateCst]);

  const handleRenameCst = useCallback(
    (data: ICstRenameData) => {
      cstRename(data, () => toast.success(`Переименование: ${renameInitialData!.alias} -> ${data.alias}`));
    },
    [cstRename, renameInitialData]
  );

  const promptRenameCst = useCallback(() => {
    if (!activeCst) {
      return;
    }
    const data: ICstRenameData = {
      id: activeCst.id,
      alias: activeCst.alias,
      cst_type: activeCst.cst_type
    };
    setRenameInitialData(data);
    setShowRenameCst(true);
  }, [activeCst]);

  const onReindex = useCallback(() => resetAliases(() => toast.success('Имена конституент обновлены')), [resetAliases]);

  const handleDeleteCst = useCallback(
    (deleted: number[]) => {
      if (!schema) {
        return;
      }
      const data = {
        items: deleted
      };

      const deletedNames = deleted.map(id => schema.items.find(cst => cst.id === id)?.alias).join(', ');
      const isEmpty = deleted.length === schema.items.length;
      const nextActive = isEmpty ? undefined : getNextActiveOnDelete(activeCst?.id, schema.items, deleted);

      cstDelete(data, () => {
        toast.success(`Конституенты удалены: ${deletedNames}`);
        if (isEmpty) {
          navigateTab(RSTabID.CST_LIST);
        } else if (activeTab === RSTabID.CST_EDIT) {
          navigateTab(activeTab, nextActive);
        } else {
          setSelected(nextActive ? [nextActive] : []);
          navigateTab(activeTab);
        }
      });
    },
    [cstDelete, schema, activeTab, activeCst, navigateTab]
  );

  const onOpenCst = useCallback(
    (cstID: number) => {
      setSelected([cstID]);
      navigateTab(RSTabID.CST_EDIT, cstID);
    },
    [navigateTab]
  );

  const onDestroySchema = useCallback(() => {
    if (!schema || !window.confirm('Вы уверены, что хотите удалить данную схему?')) {
      return;
    }
    destroyItem(schema.id, () => {
      toast.success('Схема удалена');
      router.push('/library');
    });
  }, [schema, destroyItem, router]);

  const onClaimSchema = useCallback(() => {
    if (!window.confirm('Вы уверены, что хотите стать владельцем данной схемы?')) {
      return;
    }
    claim(() => toast.success('Вы стали владельцем схемы'));
  }, [claim]);

  const onShareSchema = useCallback(() => {
    const url = window.location.href + '&share';
    navigator.clipboard
      .writeText(url)
      .then(() => toast.success(`Ссылка скопирована: ${url}`))
      .catch(console.error);
  }, []);

  const onShowTemplates = useCallback((selectedID?: number) => {
    setInsertCstID(selectedID);
    setShowTemplates(true);
  }, []);

  const onDownloadSchema = useCallback(() => {
    if (isModified) {
      if (!window.confirm('Присутствуют несохраненные изменения. Продолжить без их учета?')) {
        return;
      }
    }
    const fileName = (schema?.alias ?? 'Schema') + EXTEOR_TRS_FILE;
    download((data: Blob) => {
      try {
        fileDownload(data, fileName);
      } catch (error) {
        console.error(error);
      }
    });
  }, [schema?.alias, download, isModified]);

  const promptClone = useCallback(() => {
    if (isModified) {
      if (!window.confirm('Присутствуют несохраненные изменения. Продолжить без их учета?')) {
        return;
      }
    }
    setShowClone(true);
  }, [isModified]);

  const handleToggleSubscribe = useCallback(() => {
    if (isSubscribed) {
      unsubscribe(() => toast.success('Отслеживание отключено'));
    } else {
      subscribe(() => toast.success('Отслеживание включено'));
    }
  }, [isSubscribed, subscribe, unsubscribe]);

  const promptShowEditTerm = useCallback(() => {
    if (!activeCst) {
      return;
    }
    if (isModified) {
      if (!window.confirm('Присутствуют несохраненные изменения. Продолжить без их учета?')) {
        return;
      }
    }
    setShowEditTerm(true);
  }, [isModified, activeCst]);

  const handleSaveWordforms = useCallback(
    (forms: TermForm[]) => {
      if (!activeCst) {
        return;
      }
      const data: ICstUpdateData = {
        id: activeCst.id,
        term_forms: forms
      };
      cstUpdate(data, () => toast.success('Изменения сохранены'));
    },
    [cstUpdate, activeCst]
  );

  return (
    <>
      <AnimatePresence>
        {showUpload ? <DlgUploadRSForm hideWindow={() => setShowUpload(false)} /> : null}
        {showClone ? <DlgCloneLibraryItem base={schema!} hideWindow={() => setShowClone(false)} /> : null}
        {showCreateCst ? (
          <DlgCreateCst
            hideWindow={() => setShowCreateCst(false)}
            onCreate={handleCreateCst}
            schema={schema!}
            initial={createInitialData}
          />
        ) : null}
        {showRenameCst ? (
          <DlgRenameCst
            hideWindow={() => setShowRenameCst(false)}
            onRename={handleRenameCst}
            initial={renameInitialData!}
          />
        ) : null}
        {showDeleteCst ? (
          <DlgDeleteCst
            schema={schema!}
            hideWindow={() => setShowDeleteCst(false)}
            onDelete={handleDeleteCst}
            selected={selected}
          />
        ) : null}
        {showEditTerm ? (
          <DlgEditWordForms
            hideWindow={() => setShowEditTerm(false)}
            onSave={handleSaveWordforms}
            target={activeCst!}
          />
        ) : null}
        {showTemplates ? (
          <DlgConstituentaTemplate
            schema={schema!}
            hideWindow={() => setShowTemplates(false)}
            insertAfter={insertCstID}
            onCreate={handleCreateCst}
          />
        ) : null}
      </AnimatePresence>

      {loading ? <Loader /> : null}
      {error ? <ProcessError error={error} /> : null}
      {schema && !loading ? (
        <Tabs
          selectedIndex={activeTab}
          onSelect={onSelectTab}
          defaultFocus
          selectedTabClassName='clr-selected'
          className='flex flex-col min-w-[45rem]'
        >
          <TabList className={clsx('mx-auto', 'flex', 'border-b-2 border-x-2 divide-x-2')}>
            <RSTabsMenu
              isMutable={isMutable}
              onTemplates={onShowTemplates}
              onDownload={onDownloadSchema}
              onDestroy={onDestroySchema}
              onClaim={onClaimSchema}
              onShare={onShareSchema}
              onReindex={onReindex}
              showCloneDialog={promptClone}
              showUploadDialog={() => setShowUpload(true)}
            />
            <TabLabel label='Карточка' title={`Название схемы: ${schema.title ?? ''}`} />
            <TabLabel
              label='Содержание'
              title={`Конституент: ${schema.stats?.count_all ?? 0} | Ошибок: ${schema.stats?.count_errors ?? 0}`}
            />
            <TabLabel label='Редактор' />
            <TabLabel label='Граф термов' />
          </TabList>

          <AnimateFade>
            <TabPanel forceRender style={{ display: activeTab === RSTabID.CARD ? '' : 'none' }}>
              <EditorRSForm
                isMutable={isMutable}
                isModified={isModified}
                setIsModified={setIsModified}
                onToggleSubscribe={handleToggleSubscribe}
                onDownload={onDownloadSchema}
                onDestroy={onDestroySchema}
                onClaim={onClaimSchema}
                onShare={onShareSchema}
              />
            </TabPanel>

            <TabPanel forceRender style={{ display: activeTab === RSTabID.CST_LIST ? '' : 'none' }}>
              <EditorRSList
                selected={selected}
                setSelected={setSelected}
                isMutable={isMutable}
                onOpenEdit={onOpenCst}
                onClone={handleCloneCst}
                onCreate={type => promptCreateCst(type, type !== undefined)}
                onDelete={() => setShowDeleteCst(true)}
              />
            </TabPanel>

            <TabPanel forceRender style={{ display: activeTab === RSTabID.CST_EDIT ? '' : 'none' }}>
              <EditorConstituenta
                schema={schema}
                isMutable={isMutable}
                isModified={isModified}
                setIsModified={setIsModified}
                activeCst={activeCst}
                onOpenEdit={onOpenCst}
                onClone={handleCloneCst}
                onCreate={type => promptCreateCst(type, false)}
                onDelete={() => setShowDeleteCst(true)}
                onRename={promptRenameCst}
                onEditTerm={promptShowEditTerm}
              />
            </TabPanel>

            <TabPanel style={{ display: activeTab === RSTabID.TERM_GRAPH ? '' : 'none' }}>
              <EditorTermGraph
                schema={schema}
                selected={selected}
                setSelected={setSelected}
                isMutable={isMutable}
                onOpenEdit={onOpenCst}
                onCreate={(type, definition) => promptCreateCst(type, false, definition)}
                onDelete={() => setShowDeleteCst(true)}
              />
            </TabPanel>
          </AnimateFade>
        </Tabs>
      ) : null}
    </>
  );
}

export default RSTabs;

// ====== Internals =========
function ProcessError({ error }: { error: ErrorData }): React.ReactElement {
  if (axios.isAxiosError(error) && error.response && error.response.status === 404) {
    return (
      <div className='p-2 text-center'>
        <p>Схема с указанным идентификатором отсутствует на портале.</p>
        <TextURL text='Перейти в Библиотеку' href='/library' />
      </div>
    );
  } else {
    return <InfoError error={error} />;
  }
}

function getNextActiveOnDelete(
  activeID: number | undefined,
  items: IConstituenta[],
  deleted: number[]
): number | undefined {
  if (items.length === deleted.length) {
    return undefined;
  }

  let activeIndex = items.findIndex(cst => cst.id === activeID);
  if (activeIndex === -1) {
    return undefined;
  }

  while (activeIndex < items.length && deleted.find(id => id === items[activeIndex].id)) {
    ++activeIndex;
  }
  if (activeIndex >= items.length) {
    activeIndex = items.length - 1;
    while (activeIndex >= 0 && deleted.find(id => id === items[activeIndex].id)) {
      --activeIndex;
    }
  }
  return items[activeIndex].id;
}