import { useEffect, useRef } from "react";
import dayjs from "dayjs";
import customParseFormat from "dayjs/plugin/customParseFormat";
import "./style/DatePicker.css";
dayjs.extend(customParseFormat);

/**
 * Custom DatePicker by Benoît M
 * @component react
 * @param {Object} getDate props, function returning value to the parent elt 
 * @returns {JsxElement} 
 */

const DatePickerCustom = (props) => {

  useEffect(() => {
    createTable();
    hydrateMonthScroller();
    hydrateYearScroller();
    eventOnDays();
    switchDisplayDays();
    displayCurrentDate(currentDate);
    // eslint-disable-next-line
  }, []);


  const inputRef = useRef("");
  const tableref = useRef("");
  const datepicker = useRef("");





  const monthRef = useRef(null);
  const yearRef = useRef(null);



  const { getDate } = props;

  const displayCurrentDate = (b) => {
    inputRef.current.value = b;
    if(!getDate){
      return
    }
    getDate(b);
  };

  let date = dayjs();
  let months = [
    "January",
    "February",
    "March",
    "April",
    "May",
    "June",
    "July",
    "August",
    "September",
    "October",
    "November",
    "December",
  ];
  let currentDate = date.format("DD/MM/YYYY");
  let showDatePicker = datepicker.current;
  let swipeDate;
  let currentMonth = date.format("MM");
  let currentYear = date.format("YYYY");

  /*
  Create Table
  */
  const createTable = () => {
    let table = tableref.current;
    let b = dayjs().format("DD/MM/YYYY");

    for (let i = 0; i < 6; i++) {
      // 5 lines
      let row = table.insertRow();

      for (let t = 0; t < 7; t++) {
        // 7 columns
        let cell = row.insertCell();
        let btn = document.createElement("button");
        btn.classList.add("choosingDay");
        cell.appendChild(btn);
      }
    }

    switchDisplayDays(table, b);
  };

  /*
  Hydrate scrollers selectMonth
  */

  const hydrateMonthScroller = () => {
    let selectMonth = monthRef.current;
    let defaultMonthOption = document.createElement("option");
    defaultMonthOption.value = date.format("MM");
    defaultMonthOption.innerHTML = date.format("MMMM");
    selectMonth.appendChild(defaultMonthOption);

    for (const [index, w] of months.entries()) {
      let createOption = document.createElement("option");
      createOption.innerHTML = w;
      selectMonth.appendChild(createOption);
      createOption.setAttribute("value", index + 1);
      createOption.classList.add("monthOption");
    }
  };

  /*
  Hydrate scrollers selectYear
  */
  const hydrateYearScroller = () => {
    let selectYear = yearRef.current;
    let defaultYearOption = document.createElement("option");
    defaultYearOption.value = date.format("YYYY");
    defaultYearOption.innerHTML = date.format("YYYY");
    selectYear.appendChild(defaultYearOption);

    let startDate = 1949;
    let endDate = 2049;
    while (startDate < endDate) {
      startDate++;
      let createOption = document.createElement("option");
      createOption.innerHTML = startDate;
      createOption.value = startDate;
      createOption.classList.add("yearOption");
      selectYear.appendChild(createOption);
    }
  };

  /*
  Toggle calendar appearance
  */

  const toggleDateOpen = (e) => {
    switchDisplayDays(e, date);
    let showDatePicker = datepicker.current;
    showDatePicker.classList.toggle("dateHided");
    document.addEventListener("click", function (event) {
      if (!event.target.closest(".inputpicker")) {
        // IF le closest qui remonte au parent n'a pas la classe dateofbirth, alors on est pas dessus
        showDatePicker.classList.add("dateHided");
      }
    });
  };

  /*
  CurrentDate into input
  */

  const homeDate = (event, e, b) => {
    event.preventDefault();
    swipeDate = dayjs().format("DD/MM/YYYY");

    b = dayjs().format("DD/MM/YYYY");
    displayCurrentDate(b);
    let monthsOption = tableref.current.querySelectorAll(".monthOption");
    let yearsOption = tableref.current.querySelectorAll(".yearOption");
    monthRef.current.value = currentMonth;
    yearRef.current.value = currentYear;
    updateMonth(swipeDate, monthsOption); // input select follows the current month selected
    updateYear(swipeDate, yearsOption);

    switchDisplayDays(e, b);
  };

  /*
  Playing with btn months
  */

  const updateNextMonth = (e, b) => {
    e.preventDefault();
    let currentdayjs = inputRef.current.value;
    let nextMonthTimeStamp = dayjs(currentdayjs, "DD/MM/YYY").toDate();
    swipeDate = dayjs(nextMonthTimeStamp).add(1, "month");
    let year = dayjs(swipeDate).format("YYYY"); // return string, we need int
    year = parseInt(year) + 100; // dayjs begins at 1900
    yearRef.current.value = year;
    let sanitizedMonth = dayjs(swipeDate).format("MM"); // return string, we need int
    monthRef.current.value = parseInt(sanitizedMonth);
    b = swipeDate.format("DD/" + sanitizedMonth + "/" + year);

    let monthsOption = tableref.current.querySelectorAll(".monthOption");
    let yearsOption = tableref.current.querySelectorAll(".yearOption");

    updateMonth(b, monthsOption); // input select follows the current month selected
    updateYear(b, yearsOption);
    displayCurrentDate(b);
    switchDisplayDays(e, b);
  };

  const updatePreviousMonth = (e, b) => {
    e.preventDefault();
    let currentdayjs = inputRef.current.value;

    let previousMonthTimeStamp = dayjs(currentdayjs, "DD/MM/YYYY").toDate();
    swipeDate = dayjs(previousMonthTimeStamp).subtract(1, "month");
    let year = dayjs(swipeDate).format("YYYY");
    yearRef.current.value = parseInt(year);
    let sanitizedMonth = swipeDate.format("MM");
    monthRef.current.value = parseInt(sanitizedMonth);
    b = swipeDate.format("DD/" + sanitizedMonth + "/" + year);
    let monthsOption = tableref.current.querySelectorAll(".monthOption");
    let yearsOption = tableref.current.querySelectorAll(".yearOption");
    updateMonth(b, monthsOption);
    updateYear(b, yearsOption);
    displayCurrentDate(b);
    switchDisplayDays(e, b);
  };

  /*
  Event on scrollers 
  */

  const changeMonth = (e, b) => {
    let previousTimeStamp = dayjs(b, "DD/MM/YYYY").toDate(); // Converting string to date
    swipeDate = dayjs(previousTimeStamp);
    let year = yearRef.current.value;
    let month = monthRef.current.value;

    let sanitizedMonth = month.padStart(2, "0");
    b = swipeDate.format("DD/" + sanitizedMonth + "/" + year);
    displayCurrentDate(b);
    switchDisplayDays(e, b);
  };

  const changeYear = (e, b) => {
    let previousTimeStamp = dayjs(b, "DD/MM/YYYY").toDate();
    swipeDate = dayjs(previousTimeStamp);
    let sanitizedYear = e.padStart(2, "0"); // adding 0 when number < 10
    let month = monthRef.current.value;
    let sanitizedMonth = month.padStart(2, "0");
    b = swipeDate.format("DD/" + sanitizedMonth + "/" + sanitizedYear);
    displayCurrentDate(b);
    switchDisplayDays(e, b);
  };

  /*
  Event on days
  */

  const eventOnDays = (e, b) => {
    let btnDayValueFill;
    let btnDays = tableref.current.querySelectorAll(".choosingDay");

    for (let i = 0; i < btnDays.length; i++) {
      // eslint-disable-next-line no-loop-func
      btnDays[i].addEventListener("click", function (e) {
        e.preventDefault();
        let btnDayValue = btnDays[i].innerHTML;
        let monthChoosed = monthRef.current.value;
        let sanitizedMonth = monthChoosed.padStart(2, "0");
        let yearChoosed = yearRef.current.value;
        btnDayValueFill = btnDayValue.padStart(2, "0");
        e = date.format(
          btnDayValueFill + "/" + sanitizedMonth + "/" + yearChoosed
        );
        toggleDateOpen(showDatePicker);
        displayCurrentDate(e);
      });
    }
  };

  /*
  Update current month index
  */

  function updateMonth(date, elts) {
    let previousTimeStamp = dayjs(date, "DD/MM/YYYY").toDate();
    swipeDate = dayjs(previousTimeStamp);
    let monthIndex = swipeDate.format("M");
    for (let i = 0; i < elts.length; i++) {
      if (elts[i].value === monthIndex) {
        elts[i].setAttribute("selected", "true");
      } else {
        elts[i].removeAttribute("selected", "true");
      }
    }
  }

  /*
  Update current year index
  */

  function updateYear(date, elts) {
    let previousTimeStamp = dayjs(date, "DD/MM/YYYY").toDate();
    swipeDate = dayjs(previousTimeStamp);

    let yearIndex = swipeDate.format("YYYY");
    for (let i = 0; i < elts.length; i++) {
      if (elts[i].value === yearIndex) {
        elts[i].setAttribute("selected", "true");
      } else {
        elts[i].removeAttribute("selected", "true");
      }
    }
  }

  /*
  Update current display
  */
  const switchDisplayDays = (e, b) => {
    let lastMonthDate = [];
    let nextMonthDate = [];
    let previousMonthTimeStamp = dayjs(b, "DD/MM/YYYY").toDate(); // b is date passed and works with everything because daysInMonth gives a date format
    let previousMonthSanitize = dayjs(previousMonthTimeStamp)
      .subtract(1, "month")
      .format("DD/MM/YYYY"); // INDEX last day of last month
    let lastDayPreviousMonthNumber = dayjs(previousMonthSanitize, "DD/MM/YYYY")
      .endOf("month")
      .format("DD"); // INT
    let currentMonthTimeStamp = dayjs(b, "DD/MM/YYYY").toDate();
    let firstDay = dayjs(currentMonthTimeStamp).startOf("month").format("d");

    let firstDayNumber = dayjs(currentMonthTimeStamp)
      .startOf("month")
      .format("DD"); // number of current day
    let lastDayNumber = dayjs(currentMonthTimeStamp)
      .endOf("month")
      .format("DD"); // number date of the day

    // If month began at THURSDAY, then the first day of the month has to begin on the index of THURSDAY
    // We fill days until then end, if the last one is SUNDAY, then we have to finish on the index of SUNDAY
    // Then we fill the index of the previous and next month
    let dayz = tableref.current.querySelectorAll(".day-value");
    let btns = tableref.current.querySelectorAll(".choosingDay");

    for (let i = 0; i < btns.length; i++) {
      btns[i].classList.remove("beforeFirstDay");
      btns[i].classList.remove("lastDayOfCurrentMonth");
      btns[i].classList.remove("afterLastDayOfCurrentMonth");
      btns[i].classList.remove("afterFirstDay");
    }
    let firstDayFound = 0;
    let daytobegin;

    // eslint-disable-next-line
    let daytoend;

    for (let i = 0; i < 7; i++) {
      if (firstDay === dayz[i].getAttribute("datavalue")) {
        btns[i].innerHTML = firstDayNumber;
        firstDayFound = i; // Found the day of the first week from current month
      }
    }

    btns.forEach((element, index) => {
      if (index === firstDayFound) {
        element.innerHTML = parseInt(firstDayNumber);
        element.classList.add("firstDay");
        daytobegin = index;
      } else if (index < firstDayFound) {
        lastMonthDate.push(lastDayPreviousMonthNumber - index);
        lastMonthDate.sort();
        element.classList.add("beforeFirstDay");
      } else if (index > firstDayFound) {
        if (parseInt(daytobegin) > parseInt(lastDayNumber)) {
          element.classList.add("afterLastDayOfCurrentMonth");
          element.innerHTML = parseInt(daytobegin) - parseInt(lastDayNumber);
        } else {
          nextMonthDate.push(parseInt(index) - parseInt(firstDayFound) + 1);
          element.classList.add("afterFirstDay");
        }
      }
    });

    let beforeDays = tableref.current.querySelectorAll(".beforeFirstDay");
    let afterDays = tableref.current.querySelectorAll(".afterFirstDay");

    lastMonthDate.forEach((lastDates, index) => {
      beforeDays[index].innerHTML = lastDates;
    });

    nextMonthDate.forEach((afterDates, index) => {
      if (parseInt(afterDates) === parseInt(lastDayNumber)) {
        afterDays[index].classList.add("lastDayOfCurrentMonth");
        afterDays[index].innerHTML = afterDates;
        daytoend = afterDates;
      } else if (parseInt(afterDates) < parseInt(lastDayNumber)) {
        afterDays[index].innerHTML = afterDates;
      } else {
        afterDays[index].classList.add("afterLastDayOfCurrentMonth");
      }
    });

    let afterLastDays = tableref.current.querySelectorAll(
      ".afterLastDayOfCurrentMonth"
    );

    for (let i = 0; i < afterLastDays.length; i++) {
      afterLastDays[i].innerHTML = i + 1;
    }
  };

  if(!props.getDate){
  console.error('Vous devez ajouter un état a votre composant')
  }

  return (
    <>
      
      <div className="inputpicker">

        <label className='custom-date-picker-label' htmlFor={props.className}>{props.label ? props.label : null}</label>
        <input
          typeof="text"
          className="displayDate"
          ref={inputRef}
          defaultValue={currentDate}
          onClick={(e) => toggleDateOpen(e.target.value, currentDate)}
          name={props.className}
          id={props.className}
        ></input> <br/>
                {!props.getDate && ('Vous devez ajouter un état "getDate" en props de votre composant' )}

        <div id="datepicker" ref={datepicker} className="dateHided">
          <div className="first-row btns-spec">
            <button
              className="previousMonth btnUtils"
              onClick={(e) => updatePreviousMonth(e)}
            >
              {" "}
              &lt;{" "}
            </button>
            <button
              className="homeDay btnUtils"
              onClick={(e) => homeDate(e, e.target.value, currentDate)}
            >
              <i className="fa fa-home"></i>
            </button>
            <select
              className="selectMonth btnUtils"
              ref={monthRef}
              defaultValue={currentMonth}
              onChange={(e) => changeMonth(e.target.value, currentDate)}
            ></select>
            <select
              className="selectYear btnUtils"
              ref={yearRef}
              defaultValue={currentYear}
              onChange={(e) => changeYear(e.target.value, currentDate)}
            ></select>
            <button
              className="nextMonth btnUtils"
              onClick={(e) => updateNextMonth(e)}
            >
              {" "}
              &gt;{" "}
            </button>
          </div>
          <div className="second-row">
            <table ref={tableref}>
              <tbody>
                <tr className="days-label">
                  <th className="day-value" datavalue="0">
                    Sun
                  </th>
                  <th className="day-value" datavalue="1">
                    Mon
                  </th>
                  <th className="day-value" datavalue="2">
                    Tues
                  </th>
                  <th className="day-value" datavalue="3">
                    Wed
                  </th>
                  <th className="day-value" datavalue="4">
                    Thur
                  </th>
                  <th className="day-value" datavalue="5">
                    Fri
                  </th>
                  <th className="day-value" datavalue="6">
                    Sat
                  </th>
                </tr>
                <tr className="days-btn"></tr>
              </tbody>
            </table>
          </div>
        </div>
      </div>
      

    </>
  );
};

export default DatePickerCustom;