import dayjs from "@calcom/dayjs";
import { useTimePreferences } from "@calcom/features/bookings/lib/timePreferences";
import { TimezoneSelect } from "@calcom/web/modules/timezone/components/TimezoneSelect";
import { useLocale } from "@calcom/lib/hooks/useLocale";
import { DatePicker, SettingsToggle } from "@calcom/ui/components/form";
import { DatePickerWithRange as DateRangePicker } from "@calcom/ui/components/form/date-range-picker/DateRangePicker";
import { Button } from "@coss/ui/components/button";
import {
  Dialog,
  DialogClose,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogPanel,
  DialogPopup,
  DialogTitle,
} from "@coss/ui/components/dialog";
import { Label } from "@coss/ui/components/label";
import { useIsMobile } from "@coss/ui/hooks/use-mobile";
import { useState } from "react";
import type { UseFormSetValue } from "react-hook-form";
import type { FormValues } from "~/settings/my-account/general-view";

interface TravelScheduleModalProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  setValue: UseFormSetValue<FormValues>;
  existingSchedules: FormValues["travelSchedules"];
}

const TravelScheduleModal = ({
  open,
  onOpenChange,
  setValue,
  existingSchedules,
}: TravelScheduleModalProps) => {
  const { t } = useLocale();
  const { timezone: preferredTimezone } = useTimePreferences();
  const isMobile = useIsMobile();

  const [startDate, setStartDate] = useState<Date>(new Date());
  const [endDate, setEndDate] = useState<Date | undefined>(new Date());

  const [selectedTimeZone, setSelectedTimeZone] = useState(preferredTimezone);
  const [isNoEndDate, setIsNoEndDate] = useState(false);
  const [isDateRangeOpen, setIsDateRangeOpen] = useState(false);
  const [errorMessage, setErrorMessage] = useState("");

  const isOverlapping = (newSchedule: { startDate: Date; endDate?: Date }) => {
    const newStart = dayjs(newSchedule.startDate);
    const newEnd = newSchedule.endDate ? dayjs(newSchedule.endDate) : null;

    for (const schedule of existingSchedules) {
      const start = dayjs(schedule.startDate);
      const end = schedule.endDate ? dayjs(schedule.endDate) : null;

      if (!newEnd) {
        // if the start date is after or on the existing schedule's start date and before the existing schedule's end date (if it has one)
        if (newStart.isSame(start) || newStart.isAfter(start)) {
          if (!end || newStart.isSame(end) || newStart.isBefore(end)) return true;
        }
      } else {
        // For schedules with an end date, check for any overlap
        if (newStart.isSame(end) || newStart.isBefore(end) || end === null) {
          if (newEnd.isSame(start) || newEnd.isAfter(start)) {
            return true;
          }
        }
      }
    }
  };

  const resetValues = () => {
    setStartDate(new Date());
    setEndDate(new Date());
    setSelectedTimeZone(preferredTimezone);
    setIsNoEndDate(false);
    setIsDateRangeOpen(false);
  };

  const createNewSchedule = () => {
    const newSchedule = {
      startDate,
      endDate,
      timeZone: selectedTimeZone,
    };

    if (!isOverlapping(newSchedule)) {
      setValue("travelSchedules", existingSchedules.concat(newSchedule), { shouldDirty: true });
      onOpenChange(false);
      resetValues();
    } else {
      setErrorMessage(t("overlaps_with_existing_schedule"));
    }
  };

  return (
    <Dialog
      open={open}
      disablePointerDismissal={isDateRangeOpen}
      onOpenChange={(nextOpen) => {
        onOpenChange(nextOpen);
        if (!nextOpen) {
          setIsDateRangeOpen(false);
        }
      }}>
      <DialogPopup>
        <DialogHeader>
          <DialogTitle>{t("travel_schedule")}</DialogTitle>
          <DialogDescription>{t("travel_schedule_description")}</DialogDescription>
        </DialogHeader>
        <DialogPanel>
          <div>
            {!isNoEndDate ? (
              <>
                <Label className="mt-2">{t("time_range")}</Label>
                <DateRangePicker
                  dates={{
                    startDate,
                    endDate,
                  }}
                  popoverModal={isMobile}
                  onPopoverOpenChange={setIsDateRangeOpen}
                  onDatesChange={({ startDate: newStartDate, endDate: newEndDate }) => {
                    // If newStartDate does become undefined - we resort back to to-todays date
                    setStartDate(newStartDate ?? new Date());
                    setEndDate(newEndDate);
                    setErrorMessage("");
                  }}
                />
              </>
            ) : (
              <>
                <Label className="mt-2">{t("date")}</Label>
                <DatePicker
                  minDate={new Date()}
                  date={startDate}
                  className="w-56"
                  onDatesChange={(newDate) => {
                    setStartDate(newDate);
                    setErrorMessage("");
                  }}
                />
              </>
            )}
            <div className="text-error mt-1 text-sm">{errorMessage}</div>

            <div className="mt-3">
              <SettingsToggle
                labelClassName="mt-1 font-normal"
                title={t("schedule_tz_without_end_date")}
                checked={isNoEndDate}
                onCheckedChange={(checked) => {
                  setEndDate(!checked ? startDate : undefined);
                  setIsNoEndDate(checked);
                  if (checked) {
                    setIsDateRangeOpen(false);
                  }
                  setErrorMessage("");
                }}
              />
            </div>

            <Label className="mt-6">{t("timezone")}</Label>
            <TimezoneSelect
              id="timeZone"
              value={selectedTimeZone}
              onChange={({ value }) => setSelectedTimeZone(value)}
              menuPortalTarget={typeof document === "undefined" ? undefined : document.body}
              menuPlacement={isMobile ? "top" : "auto"}
              styles={{ menuPortal: (base) => Object.assign({}, base, { zIndex: 9999 }) }}
              className="mb-11 mt-2 w-full rounded-md text-sm"
            />
          </div>
        </DialogPanel>
        <DialogFooter>
          <DialogClose render={<Button variant="ghost" />}>{t("cancel")}</DialogClose>
          <Button
            disabled={isNoEndDate ? !startDate : !startDate || !endDate}
            onClick={() => {
              createNewSchedule();
            }}>
            {t("add")}
          </Button>
        </DialogFooter>
      </DialogPopup>
    </Dialog>
  );
};

export default TravelScheduleModal;