import { useCallback } from 'react';
import { useMutation, useQueryClient } from '@tanstack/react-query';
import axios, { AxiosError } from 'axios';
import { OntimeRundown, OntimeRundownEntry, SupportedEvent } from 'ontime-types';

import { RUNDOWN_TABLE, RUNDOWN_TABLE_KEY } from '../api/apiConstants';
import {
  ReorderEntry,
  requestApplyDelay,
  requestDelete,
  requestDeleteAll,
  requestPostEvent,
  requestPutEvent,
  requestReorderEvent,
} from '../api/eventsApi';
import { useLocalEvent } from '../stores/localEvent';
import { useEmitLog } from '../stores/logger';

/**
 * @description Set of utilities for events
 */
export const useEventAction = () => {
  const queryClient = useQueryClient();
  const { emitError } = useEmitLog();
  const { eventSettings } = useLocalEvent();
  const defaultPublic = eventSettings.defaultPublic;
  const startTimeIsLastEnd = eventSettings.startTimeIsLastEnd;

  /**
   * Calls mutation to add new event
   * @private
   */
  const _addEventMutation = useMutation(requestPostEvent, {
    // Mutation finished, failed or successful
    // Fetch anyway, just to be sure
    onSettled: () => {
      queryClient.invalidateQueries(RUNDOWN_TABLE);
    },
    networkMode: 'always',
  });

  type BaseOptions = {
    after?: string;
  };

  type EventOptions = BaseOptions & {
    defaultPublic?: boolean;
    lastEventId?: string;
    startTimeIsLastEnd?: boolean;
  };

  /**
   * Adds an event to rundown
   */
  const addEvent = useCallback(
    async (event: Partial<OntimeRundownEntry>, options?: EventOptions) => {
      const newEvent: Partial<OntimeRundownEntry> = { ...event };

      // ************* CHECK OPTIONS specific to events
      if (newEvent.type === SupportedEvent.Event) {
        const applicationOptions = {
          defaultPublic: options?.defaultPublic ?? defaultPublic,
          startTimeIsLastEnd: options?.startTimeIsLastEnd ?? startTimeIsLastEnd,
          lastEventId: options?.lastEventId,
          after: options?.after,
        };

        // hard coding duration value to be as expected for now
        // this until timeOptions gets implemented
        if (typeof newEvent?.timeStart !== 'undefined' && typeof newEvent.timeEnd !== 'undefined') {
          newEvent.duration = Math.max(0, newEvent?.timeEnd - newEvent?.timeStart) || 0;
        }

        if (applicationOptions.startTimeIsLastEnd && applicationOptions?.lastEventId) {
          const rundown = queryClient.getQueryData(RUNDOWN_TABLE) as OntimeRundown;
          const previousEvent = rundown.find((event) => event.id === applicationOptions.lastEventId);
          if (typeof previousEvent !== 'undefined' && previousEvent.type === 'event') {
            newEvent.timeStart = previousEvent.timeEnd;
          }
        }

        if (applicationOptions.defaultPublic) {
          newEvent.isPublic = true;
        }
      }

      // handle adding options that concern all event type
      if (options?.after) {
        newEvent.after = options.after;
      }

      try {
        // @ts-expect-error -- we know that the object is well formed now
        await _addEventMutation.mutateAsync(newEvent);
      } catch (error) {
        if (!axios.isAxiosError(error)) {
          emitError(`Error fetching data: ${(error as AxiosError).message}`);
        } else {
          emitError(`Error fetching data: ${error}`);
        }
      }
    },
    [_addEventMutation, defaultPublic, emitError, queryClient, startTimeIsLastEnd],
  );

  /**
   * Calls mutation to update existing event
   * @private
   */
  const _updateEventMutation = useMutation(requestPutEvent, {
    // we optimistically update here
    onMutate: async (newEvent) => {
      // cancel ongoing queries
      await queryClient.cancelQueries([RUNDOWN_TABLE_KEY, newEvent.id]);

      // Snapshot the previous value
      const previousEvent = queryClient.getQueryData([RUNDOWN_TABLE_KEY, newEvent.id]);

      // optimistically update object
      queryClient.setQueryData([RUNDOWN_TABLE_KEY, newEvent.id], newEvent);

      // Return a context with the previous and new events
      return { previousEvent, newEvent };
    },

    // Mutation fails, rollback undoes optimist update
    onError: (_error, _newEvent, context) => {
      queryClient.setQueryData([RUNDOWN_TABLE_KEY, context?.newEvent.id], context?.previousEvent);
    },
    // Mutation finished, failed or successful
    // Fetch anyway, just to be sure
    onSettled: async () => {
      await queryClient.invalidateQueries([RUNDOWN_TABLE_KEY]);
    },
    networkMode: 'always',
  });

  /**
   * Updates existing event
   */
  const updateEvent = useCallback(
    async (event: Partial<OntimeRundownEntry>) => {
      try {
        await _updateEventMutation.mutateAsync(event);
      } catch (error) {
        if (!axios.isAxiosError(error)) {
          emitError(`Error updating event: ${(error as AxiosError).message}`);
        } else {
          emitError(`Error updating event: ${error}`);
        }
      }
    },
    [_updateEventMutation, emitError],
  );

  /**
   * Calls mutation to delete an event
   * @private
   */
  const _deleteEventMutation = useMutation(requestDelete, {
    // we optimistically update here
    onMutate: async (eventId) => {
      // cancel ongoing queries
      await queryClient.cancelQueries([RUNDOWN_TABLE_KEY, eventId]);

      // Snapshot the previous value
      const previousEvents = queryClient.getQueryData(RUNDOWN_TABLE);

      const filtered = [...(previousEvents as OntimeRundown)].filter((e) => e.id !== eventId);

      // optimistically update object
      queryClient.setQueryData(RUNDOWN_TABLE, filtered);

      // Return a context with the previous and new events
      return { previousEvents };
    },

    // Mutation fails, rollback undoes optimist update
    onError: (_error, _eventId, context) => {
      queryClient.setQueryData(RUNDOWN_TABLE, context?.previousEvents);
    },
    // Mutation finished, failed or successful
    // Fetch anyway, just to be sure
    onSettled: () => {
      queryClient.invalidateQueries(RUNDOWN_TABLE);
    },
    networkMode: 'always',
  });

  /**
   * Deletes an event form the list
   */
  const deleteEvent = useCallback(
    async (eventId: string) => {
      try {
        await _deleteEventMutation.mutateAsync(eventId);
      } catch (error) {
        if (!axios.isAxiosError(error)) {
          emitError(`Error deleting event: ${(error as AxiosError).message}`);
        } else {
          emitError(`Error deleting event: ${error}`);
        }
      }
    },
    [_deleteEventMutation, emitError],
  );

  /**
   * Calls mutation to delete all events
   * @private
   */
  const _deleteAllEventsMutation = useMutation(requestDeleteAll, {
    // we optimistically update here
    onMutate: async () => {
      // cancel ongoing queries
      await queryClient.cancelQueries(RUNDOWN_TABLE, { exact: true });

      // Snapshot the previous value
      const previousEvents = queryClient.getQueryData(RUNDOWN_TABLE);

      // optimistically update object
      queryClient.setQueryData(RUNDOWN_TABLE, []);

      // Return a context with the previous and new events
      return { previousEvents };
    },

    // Mutation fails, rollback undos optimist update
    onError: (_error, _eventId, context) => {
      queryClient.setQueryData(RUNDOWN_TABLE, context?.previousEvents);
    },
    // Mutation finished, failed or successful
    // Fetch anyway, just to be sure
    onSettled: () => {
      queryClient.invalidateQueries(RUNDOWN_TABLE);
    },
    networkMode: 'always',
  });

  /**
   * Deletes all events from list
   */
  const deleteAllEvents = useCallback(async () => {
    try {
      await _deleteAllEventsMutation.mutateAsync();
    } catch (error) {
      if (!axios.isAxiosError(error)) {
        emitError(`Error deleting events: ${(error as AxiosError).message}`);
      } else {
        emitError(`Error deleting events: ${error}`);
      }
    }
  }, [_deleteAllEventsMutation, emitError]);

  /**
   * Calls mutation to apply a delay
   * @private
   */
  const _applyDelayMutation = useMutation(requestApplyDelay, {
    // Mutation finished, failed or successful
    onSettled: () => {
      queryClient.invalidateQueries(RUNDOWN_TABLE);
    },
    networkMode: 'always',
  });

  /**
   * Applies a given delay block
   */
  const applyDelay = useCallback(
    async (delayEventId: string) => {
      try {
        await _applyDelayMutation.mutateAsync(delayEventId);
      } catch (error) {
        if (!axios.isAxiosError(error)) {
          emitError(`Error applying delay: ${(error as AxiosError).message}`);
        } else {
          emitError(`Error applying delay: ${error}`);
        }
      }
    },
    [_applyDelayMutation, emitError],
  );

  /**
   * Calls mutation to reorder an event
   * @private
   */
  const _reorderEventMutation = useMutation(requestReorderEvent, {
    // we optimistically update here
    onMutate: async (data) => {
      // cancel ongoing queries
      await queryClient.cancelQueries(RUNDOWN_TABLE, { exact: true });

      // Snapshot the previous value
      const previousEvents = queryClient.getQueryData(RUNDOWN_TABLE);

      const e = [...(previousEvents as OntimeRundown)];
      const [reorderedItem] = e.splice(data.from, 1);
      e.splice(data.to, 0, reorderedItem);

      // optimistically update object
      queryClient.setQueryData(RUNDOWN_TABLE, e);

      // Return a context with the previous and new events
      return { previousEvents };
    },

    // Mutation fails, rollback undoes optimist update
    onError: (_error, _eventId, context) => {
      queryClient.setQueryData(RUNDOWN_TABLE, context?.previousEvents);
    },
    // Mutation finished, failed or successful
    // Fetch anyway, just to be sure
    onSettled: () => {
      queryClient.invalidateQueries(RUNDOWN_TABLE);
    },
    networkMode: 'always',
  });

  /**
   * Reorders a given event
   */
  const reorderEvent = useCallback(
    async (eventId: string, from: number, to: number) => {
      try {
        const reorderObject: ReorderEntry = {
          eventId: eventId,
          from: from,
          to: to,
        };
        await _reorderEventMutation.mutateAsync(reorderObject);
      } catch (error) {
        if (!axios.isAxiosError(error)) {
          emitError(`Error re-ordering event: ${(error as AxiosError).message}`);
        } else {
          emitError(`Error re-ordering event: ${error}`);
        }
      }
    },
    [_reorderEventMutation, emitError],
  );

  return { addEvent, updateEvent, deleteEvent, deleteAllEvents, applyDelay, reorderEvent };
};