/*
    provide utilities for converting between Date objects and formatted date/time strings, 
    allowing for flexible handling of date and time data within React applications.
*/


interface DateTimeFormat {
    date: string;
    time: string;
}

export const useDateTimeConverter = () => {

    // Function to convert a Date object to a date and time string
    const dateToString = (date: Date | null, format: DateTimeFormat): string => {
        if (!date) return '';
        const dateString = formatDate(date, format.date);
        const timeString = formatTime(date, format.time);
        return `${dateString} ${timeString}`;
    };

    // Function to convert a date and time string to a Date object
    const stringToDate = (dateTimeString: string, format: DateTimeFormat): Date | null => {
        if (!dateTimeString) return null;
        const [dateString, timeString] = dateTimeString.split(' ');
        const date = parseDate(dateString, format.date);
        const time = parseTime(timeString, format.time);
        if (date && time) {
            return new Date(date.getFullYear(), date.getMonth(), date.getDate(), time.getHours(), time.getMinutes(), time.getSeconds());
        }
        return null;
    };

    // Function to format the date portion of a Date object
    const formatDate = (date: Date, format: string): string => {
        if (!date) return '';
        const year = date.getFullYear();
        const month = (date.getMonth() + 1).toString().padStart(2, '0');
        const day = date.getDate().toString().padStart(2, '0');
        return format.replace('YYYY', year.toString()).replace('MM', month).replace('DD', day);
    };

    // Function to format the time portion of a Date object
    const formatTime = (date: Date, format: string): string => {
        if (!date) return '';
        const hours = date.getHours().toString().padStart(2, '0');
        const minutes = date.getMinutes().toString().padStart(2, '0');
        const seconds = date.getSeconds().toString().padStart(2, '0');
        return format.replace('HH', hours).replace('mm', minutes).replace('ss', seconds);
    };

    // Function to parse the time string and construct a Date object
    const parseTime = (timeString: string, format: string): Date | null => {
        if (!timeString) return null;
        const hoursIndex = format.indexOf('HH');
        const minutesIndex = format.indexOf('mm');
        const secondsIndex = format.indexOf('ss');

        // Ensure all required components are present in the format
        if (hoursIndex === -1 || minutesIndex === -1 || secondsIndex === -1) {
            return null;
        }

        const hours = parseInt(timeString.substr(hoursIndex, 2), 10);
        const minutes = parseInt(timeString.substr(minutesIndex, 2), 10);
        const seconds = parseInt(timeString.substr(secondsIndex, 2), 10);

        // Ensure parsed components are valid
        if (isNaN(hours) || isNaN(minutes) || isNaN(seconds)) {
            return null;
        }

        // Construct a Date object with January 1, 1900
        return new Date(0, 0, 0, hours, minutes, seconds);
    };

    // Function to parse the date string and construct a Date object
    const parseDate = (dateString: string, format: string): Date | null => {
        if (!dateString) return null;
        const yearIndex = format.indexOf('YYYY');
        const monthIndex = format.indexOf('MM');
        const dayIndex = format.indexOf('DD');

        // Ensure all required components are present in the format
        if (yearIndex === -1 || monthIndex === -1 || dayIndex === -1) {
            return null;
        }

        const year = parseInt(dateString.substr(yearIndex, 4), 10);
        const month = parseInt(dateString.substr(monthIndex, 2), 10) - 1;
        const day = parseInt(dateString.substr(dayIndex, 2), 10);

        // Ensure parsed components are valid
        if (isNaN(year) || isNaN(month) || isNaN(day)) {
            return null;
        }

        // Construct a Date object
        return new Date(year, month, day);
    };

    // Return the functions to use in a component
    return {
        stringToDate,
        dateToString,
        formatTime,
        formatDate,
        parseTime,
        parseDate,
    };
}