import axios, { AxiosResponseTransformer } from 'axios';

const dateISO = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:[.,]\d+)?(?:[+-]\d{2}:\d{2}|Z)?$/i;
const dateISOMilliseconds = /[.,](\d+)/i;
const dateNet = /\/Date\((-?\d+)(?:-\d+)?\)\//i;

function dateFromString(date: string) {
    if (dateISO.test(date)) {
        const ms = dateISOMilliseconds.exec(date);
        const fixedValue = date.replace(dateISOMilliseconds, '');
        const result = new Date(fixedValue);

        if (ms !== null) {
            let millisecond = parseInt(ms[1].substring(0, 3), 10);
            millisecond = isNaN(millisecond) ? 0 : millisecond;
            result.setMilliseconds(millisecond);
        }

        return result;
    }

    const parsedDate = dateNet.exec(date);
    if (parsedDate !== null) {
        return new Date(parseInt(parsedDate[1], 10));
    }

    return date;
}

function transformDates(obj: any): any {
    if (typeof obj === 'string') {
        return dateFromString(obj);
    }

    if (obj === null || typeof obj !== 'object' || obj instanceof Blob) {
        return obj;
    }

    if (Array.isArray(obj)) {
        return obj.map(transformDates);
    }

    const keys = Object.keys(obj);
    if (!keys.length) {
        return obj;
    }

    return keys.reduce(
        (result, key) => {
            result[key] = transformDates(result[key]);
            return result;
        },
        { ...obj }
    );
}

export const initAjaxHandlersParseDates = () => {
    const transformer: AxiosResponseTransformer = data => transformDates(data);

    if (axios.defaults.transformResponse === undefined) {
        axios.defaults.transformResponse = [transformer];
    } else if (Array.isArray(axios.defaults.transformResponse)) {
        axios.defaults.transformResponse.push(transformer);
    } else {
        axios.defaults.transformResponse = [axios.defaults.transformResponse, transformer];
    }
};