import React, { useEffect, useState } from "react";

import { useRouter } from "next/router";

import { mutate } from "swr";

// react-beautiful-dnd
import { DragDropContext, DropResult } from "react-beautiful-dnd";
// services
import issuesService from "services/issues.service";
// hooks
import useCalendarIssuesView from "hooks/use-calendar-issues-view";
// components
import { SingleCalendarDate, CalendarHeader } from "components/core";
// ui
import { Spinner } from "components/ui";
// helpers
import { renderDateFormat } from "helpers/date-time.helper";
import {
  startOfWeek,
  lastDayOfWeek,
  eachDayOfInterval,
  weekDayInterval,
  formatDate,
} from "helpers/calendar.helper";
// types
import { ICalendarRange, ICurrentUserResponse, IIssue, UserAuth } from "types";
// fetch-keys
import {
  CYCLE_ISSUES_WITH_PARAMS,
  MODULE_ISSUES_WITH_PARAMS,
  PROJECT_ISSUES_LIST_WITH_PARAMS,
  VIEW_ISSUES,
} from "constants/fetch-keys";

type Props = {
  handleEditIssue: (issue: IIssue) => void;
  handleDeleteIssue: (issue: IIssue) => void;
  addIssueToDate: (date: string) => void;
  isCompleted: boolean;
  user: ICurrentUserResponse | undefined;
  userAuth: UserAuth;
};

export const CalendarView: React.FC<Props> = ({
  handleEditIssue,
  handleDeleteIssue,
  addIssueToDate,
  isCompleted = false,
  user,
  userAuth,
}) => {
  const [showWeekEnds, setShowWeekEnds] = useState(false);
  const [currentDate, setCurrentDate] = useState(new Date());
  const [isMonthlyView, setIsMonthlyView] = useState(true);

  const [calendarDates, setCalendarDates] = useState<ICalendarRange>({
    startDate: startOfWeek(currentDate),
    endDate: lastDayOfWeek(currentDate),
  });

  const router = useRouter();
  const { workspaceSlug, projectId, cycleId, moduleId, viewId } = router.query;

  const { calendarIssues, params, setCalendarDateRange } = useCalendarIssuesView();

  const totalDate = eachDayOfInterval({
    start: calendarDates.startDate,
    end: calendarDates.endDate,
  });

  const onlyWeekDays = weekDayInterval({
    start: calendarDates.startDate,
    end: calendarDates.endDate,
  });

  const currentViewDays = showWeekEnds ? totalDate : onlyWeekDays;

  const currentViewDaysData = currentViewDays.map((date: Date) => {
    const filterIssue =
      calendarIssues.length > 0
        ? calendarIssues.filter(
            (issue) =>
              issue.target_date && renderDateFormat(issue.target_date) === renderDateFormat(date)
          )
        : [];
    return {
      date: renderDateFormat(date),
      issues: filterIssue,
    };
  });

  const weeks = ((date: Date[]) => {
    const weeks = [];
    if (showWeekEnds) {
      for (let day = 0; day <= 6; day++) {
        weeks.push(date[day]);
      }
    } else {
      for (let day = 0; day <= 4; day++) {
        weeks.push(date[day]);
      }
    }

    return weeks;
  })(currentViewDays);

  const onDragEnd = (result: DropResult) => {
    const { source, destination, draggableId } = result;

    if (!destination || !workspaceSlug || !projectId) return;

    if (source.droppableId === destination.droppableId) return;

    const fetchKey = cycleId
      ? CYCLE_ISSUES_WITH_PARAMS(cycleId.toString(), params)
      : moduleId
      ? MODULE_ISSUES_WITH_PARAMS(moduleId.toString(), params)
      : viewId
      ? VIEW_ISSUES(viewId.toString(), params)
      : PROJECT_ISSUES_LIST_WITH_PARAMS(projectId.toString(), params);

    mutate<IIssue[]>(
      fetchKey,
      (prevData) =>
        (prevData ?? []).map((p) => {
          if (p.id === draggableId)
            return {
              ...p,
              target_date: destination.droppableId,
            };

          return p;
        }),
      false
    );

    issuesService
      .patchIssue(
        workspaceSlug as string,
        projectId as string,
        draggableId,
        {
          target_date: destination?.droppableId,
        },
        user
      )
      .then(() => mutate(fetchKey));
  };

  const changeDateRange = (startDate: Date, endDate: Date) => {
    setCalendarDates({
      startDate,
      endDate,
    });

    setCalendarDateRange(
      `${renderDateFormat(startDate)};after,${renderDateFormat(endDate)};before`
    );
  };

  useEffect(() => {
    setCalendarDateRange(
      `${renderDateFormat(startOfWeek(currentDate))};after,${renderDateFormat(
        lastDayOfWeek(currentDate)
      )};before`
    );
  }, [currentDate]);

  const isNotAllowed = userAuth.isGuest || userAuth.isViewer || isCompleted;

  return calendarIssues ? (
    <div className="h-full overflow-y-auto">
      <DragDropContext onDragEnd={onDragEnd}>
        <div className="h-full rounded-lg p-8 text-brand-secondary">
          <CalendarHeader
            isMonthlyView={isMonthlyView}
            setIsMonthlyView={setIsMonthlyView}
            showWeekEnds={showWeekEnds}
            setShowWeekEnds={setShowWeekEnds}
            currentDate={currentDate}
            setCurrentDate={setCurrentDate}
            changeDateRange={changeDateRange}
          />

          <div
            className={`grid auto-rows-[minmax(36px,1fr)] rounded-lg ${
              showWeekEnds ? "grid-cols-7" : "grid-cols-5"
            }`}
          >
            {weeks.map((date, index) => (
              <div
                key={index}
                className={`flex  items-center justify-start gap-2 border-brand-base bg-brand-surface-1 p-1.5 text-base font-medium text-brand-secondary ${
                  !isMonthlyView
                    ? showWeekEnds
                      ? (index + 1) % 7 === 0
                        ? ""
                        : "border-r"
                      : (index + 1) % 5 === 0
                      ? ""
                      : "border-r"
                    : ""
                }`}
              >
                <span>
                  {isMonthlyView
                    ? formatDate(date, "eee").substring(0, 3)
                    : formatDate(date, "eee")}
                </span>
                {!isMonthlyView && <span>{formatDate(date, "d")}</span>}
              </div>
            ))}
          </div>

          <div
            className={`grid h-full ${isMonthlyView ? "auto-rows-min" : ""} ${
              showWeekEnds ? "grid-cols-7" : "grid-cols-5"
            } `}
          >
            {currentViewDaysData.map((date, index) => (
              <SingleCalendarDate
                index={index}
                date={date}
                handleEditIssue={handleEditIssue}
                handleDeleteIssue={handleDeleteIssue}
                addIssueToDate={addIssueToDate}
                isMonthlyView={isMonthlyView}
                showWeekEnds={showWeekEnds}
                user={user}
                isNotAllowed={isNotAllowed}
              />
            ))}
          </div>
        </div>
      </DragDropContext>
    </div>
  ) : (
    <div className="flex h-full w-full items-center justify-center">
      <Spinner />
    </div>
  );
};
