import { Instance, DayElement } from "types/instance";

type InstancePlusWeeks = Instance & {
  weekStartDay: Date;
  weekEndDay: Date;
};

function weekSelectPlugin() {
  return function(fp: InstancePlusWeeks) {
    function onDayHover(event: MouseEvent) {
      const day = event.target as DayElement;
      if (!day.classList.contains("flatpickr-day")) return;

      const days = fp.days.childNodes;
      const dayIndex = day.$i;

      const dayIndSeven = dayIndex / 7;
      const weekStartDay = (days[7 * Math.floor(dayIndSeven)] as DayElement)
        .dateObj;
      const weekEndDay = (days[
        7 * Math.ceil(dayIndSeven + 0.01) - 1
      ] as DayElement).dateObj;

      for (let i = days.length; i--; ) {
        const day = days[i] as DayElement;
        const date = day.dateObj;
        if (date > weekEndDay || date < weekStartDay)
          day.classList.remove("inRange");
        else day.classList.add("inRange");
      }
    }

    function highlightWeek() {
      if (fp.selectedDateElem) {
        fp.weekStartDay = (fp.days.childNodes[
          7 * Math.floor(fp.selectedDateElem.$i / 7)
        ] as DayElement).dateObj;
        fp.weekEndDay = (fp.days.childNodes[
          7 * Math.ceil(fp.selectedDateElem.$i / 7 + 0.01) - 1
        ] as DayElement).dateObj;
      }
      const days = fp.days.childNodes;
      for (let i = days.length; i--; ) {
        const date = (days[i] as DayElement).dateObj;
        if (date >= fp.weekStartDay && date <= fp.weekEndDay)
          (days[i] as DayElement).classList.add("week", "selected");
      }
    }

    function clearHover() {
      const days = fp.days.childNodes;
      for (let i = days.length; i--; )
        (days[i] as Element).classList.remove("inRange");
    }

    function onReady() {
      if (fp.daysContainer !== undefined)
        fp.daysContainer.addEventListener("mouseover", onDayHover);
    }

    function onDestroy() {
      if (fp.daysContainer !== undefined)
        fp.daysContainer.removeEventListener("mouseover", onDayHover);
    }

    return {
      onValueUpdate: highlightWeek,
      onMonthChange: highlightWeek,
      onYearChange: highlightWeek,
      onClose: clearHover,
      onParseConfig: function() {
        fp.config.mode = "single";
        fp.config.enableTime = false;
        fp.config.dateFormat = "\\W\\e\\e\\k #W, Y";
        fp.config.altFormat = "\\W\\e\\e\\k #W, Y";
      },
      onReady: [onReady, highlightWeek],
      onDestroy,
    };
  };
}

export default weekSelectPlugin;