// @flow strict

import * as React from 'react';

import * as COLORS from '../../styles/variables/_color';
import classify from '../../utils/classify';
import {BodyLargeBold} from '../Text';

import css from './ProgressDonut.module.css';


const STROKE_WIDTH = 8;
const MIN_PERCENTAGE = 0;
const DIVISOR_TWO = 2;
const MAX_PERCENTAGE = 100;
const SUCCESS_THRESHOLD = 80;
const LARGE_DONUT_SIZE = 72;
const INFO_THRESHOLD = 50;
const WARNING_THRESHOLD = 30;

type ClassNames = $ReadOnly<{
  wrapper?: string,
}>;

export type ProgressDonutProps = {
  classNames?: ClassNames,
  color?: $Keys<typeof COLORS>,
  percentage: number,
};

const getProgressDonutColor = (percentage: number): string => {
  if (percentage >= SUCCESS_THRESHOLD) {
    return COLORS.colorSuccess;
  } else if (percentage >= INFO_THRESHOLD && percentage < SUCCESS_THRESHOLD) {
    return COLORS.colorInformation;
  } else if (percentage >= WARNING_THRESHOLD && percentage < INFO_THRESHOLD) {
    return COLORS.colorWarning;
  } else {
    return COLORS.colorDanger;
  }
};

export const ProgressDonut: React$AbstractComponent<
  ProgressDonutProps,
  HTMLDivElement,
> = React.forwardRef<ProgressDonutProps, HTMLDivElement>(
  ({classNames, percentage = 0, color = ''}: ProgressDonutProps, ref) => {
    const donutPercentage = React.useMemo(
      () => Math.min(Math.max(percentage, MIN_PERCENTAGE), MAX_PERCENTAGE),
      [percentage],
    );
    const donutColor = React.useMemo(
      () => getProgressDonutColor(donutPercentage),
      [donutPercentage],
    );

    const radius = React.useMemo(
      () => (LARGE_DONUT_SIZE - STROKE_WIDTH) / DIVISOR_TWO,
      [LARGE_DONUT_SIZE],
    );
    const circumference = React.useMemo(
      () => DIVISOR_TWO * Math.PI * radius,
      [radius],
    );
    const offset = React.useMemo(
      () => circumference - (donutPercentage / MAX_PERCENTAGE) * circumference,
      [circumference, donutPercentage],
    );

    return (
      <div
        ref={ref}
        data-testid="ProgressDonut"
        className={classify(css.wrapper, classNames?.wrapper)}
      >
        <div className={css.donutChart}>
          <svg
            width={LARGE_DONUT_SIZE}
            height={LARGE_DONUT_SIZE}
            viewBox={`0 0 ${LARGE_DONUT_SIZE} ${LARGE_DONUT_SIZE}`}
            className={css.donutChartSvg}
          >
            <circle
              className={css.donutChartBackground}
              cx={LARGE_DONUT_SIZE / DIVISOR_TWO}
              cy={LARGE_DONUT_SIZE / DIVISOR_TWO}
              r={radius}
              strokeWidth={STROKE_WIDTH}
            />
            <circle
              className={css.donutChartForeground}
              cx={LARGE_DONUT_SIZE / DIVISOR_TWO}
              cy={LARGE_DONUT_SIZE / DIVISOR_TWO}
              r={radius}
              strokeWidth={STROKE_WIDTH}
              strokeDasharray={circumference}
              strokeDashoffset={
                donutPercentage === MIN_PERCENTAGE ? circumference : offset
              }
              stroke={COLORS[color] || donutColor}
              strokeLinecap="round"
            />
          </svg>
          <BodyLargeBold className={css.donutChartPercentage}>
            {`${donutPercentage}%`}
          </BodyLargeBold>
        </div>
      </div>
    );
  },
);