import { AxisBottom, AxisLeft } from "@visx/axis";
import { bottomTickLabelProps } from "@visx/axis/lib/axis/AxisBottom";
import { leftTickLabelProps } from "@visx/axis/lib/axis/AxisLeft";
import { GridColumns, GridRows } from "@visx/grid";
import { Group } from "@visx/group";
import { LegendOrdinal } from "@visx/legend";
import { scaleBand, scaleLinear, scaleOrdinal } from "@visx/scale";
import { Bar, BarGroup, BarGroupHorizontal } from "@visx/shape";
import { BarGroupBar as BarGroupBarType } from "@visx/shape/lib/types";
import { Text } from "@visx/text";
import React, { useState } from "react";
import { Color } from "utils/Color";

import styles from "./GroupedBarGraph.module.css";

interface GroupedBarGraphProps {
  data: GroupedBarGraphData[];
  /** Colours of bars in each group. */
  barColors: string[];
  /** Object mapping from the possible colours of bars in each group (barColors) to the colour of the bar when hovered. */
  barHoverColorsMap: Record<string, string>;
  /** Width of the entire graph, in pixels. */
  width: number;
  /** Height of the entire graph, in pixels. */
  height: number;
  /** Distance between the edge of the graph and the area where the bars are drawn, in pixels. */
  margin: {
    top: number;
    bottom: number;
    left: number;
    right: number;
  };
  className?: string;
  /** Font size of the category axis tick labels, in pixels. Default is 16px. */
  categoryTickLabelSize?: number;
  /** Font size of the value axis tick labels, in pixels. Default is 16px. */
  valueTickLabelSize?: number;
  /** Font size of the value that appears when hovering over a bar, in pixels. */
  hoverLabelSize?: number;
  /** Label text for the category axis. */
  categoryAxisLabel?: string;
  /** Font size of the label for the cateogry axis, in pixels. */
  categoryAxisLabelSize?: number;
  /** Controls the distance between the category axis label and the category axis. */
  categoryAxisLabelOffset?: number;
  /** Label text for the value axis. */
  valueAxisLabel?: string;
  /** Font size of the label for the value axis, in pixels. */
  valueAxisLabelSize?: number;
  /** Controls the distance between the value axis label and the value axis. */
  valueAxisLabelOffset?: number;
  legendProps?: LegendProps;
}

// Best format for props
interface GroupedBarGraphData {
  category: string;
  values: {
    [key: string]: number;
  };
}

// Best format for visx
interface BarGroupData {
  category: string;
  [key: string]: string | number;
}

interface LegendProps {
  /** Position of the legend, relative to the graph. */
  position?: "top" | "right";
  /** Font size of the labels in the legend, in pixels. Default is 16px. */
  itemLabelSize?: number;
  /** Gap between items in the legend, in pixels. */
  itemGap?: number;
  /** Distance between the legend and other adjacent elements, in pixels. */
  margin?: {
    top?: number;
    bottom?: number;
    left?: number;
    right?: number;
  };
}

// BAR_PADDING must be in the range [0, 1)
const BAR_PADDING = 0.2;
const BAR_TEXT_PADDING = 12;

const DEFAULT_LABEL_SIZE = 16;
const DEFAULT_LEGEND_GAP = 16;

export function GroupedBarGraphVertical(props: GroupedBarGraphProps) {
  const {
    data: propsData,
    barColors,
    barHoverColorsMap,
    width,
    height,
    margin,
    className,
    categoryTickLabelSize = DEFAULT_LABEL_SIZE,
    valueTickLabelSize = DEFAULT_LABEL_SIZE,
    hoverLabelSize,
    categoryAxisLabel,
    categoryAxisLabelSize = DEFAULT_LABEL_SIZE,
    categoryAxisLabelOffset = 0,
    valueAxisLabel,
    valueAxisLabelSize = DEFAULT_LABEL_SIZE,
    valueAxisLabelOffset = 0,
    legendProps,
  } = props;

  const {
    position: legendPosition = "right",
    itemLabelSize: legendLabelSize = DEFAULT_LABEL_SIZE,
    itemGap: legendItemGap = DEFAULT_LEGEND_GAP,
    margin: legendMargin = {},
  } = legendProps ?? {};

  const data: BarGroupData[] = propsData.map((datum: GroupedBarGraphData) => {
    return { category: datum.category, ...datum.values };
  });

  const keys = Object.keys(propsData[0].values);
  propsData.forEach((d: GroupedBarGraphData) => {
    const currentKeys = Object.keys(d.values);
    if (
      keys.length != currentKeys.length ||
      !keys.every((key: string) => currentKeys.includes(key))
    ) {
      throw new Error(
        "Every category in a GroupedBarGraph must have the same keys. Check the data prop"
      );
    }
  });

  const allValues = propsData
    .map((d: GroupedBarGraphData) => Object.values(d.values))
    .flat();

  const categoryMax = width - margin.left - margin.right;
  const valueMax = height - margin.top - margin.bottom;

  const getCategory = (d: BarGroupData) => d.category;

  const categoryScale = scaleBand({
    domain: data.map(getCategory),
    padding: BAR_PADDING,
  });

  const keyScale = scaleBand({
    domain: keys,
  });

  const valueScale = scaleLinear<number>({
    domain: [0, Math.max(...allValues)],
  });

  const colorScale = scaleOrdinal<string, string>({
    domain: keys,
    range: barColors,
  });

  categoryScale.rangeRound([0, categoryMax]);
  keyScale.rangeRound([0, categoryScale.bandwidth()]);
  valueScale.rangeRound([valueMax, 0]);

  return (
    <div
      className={className ? `${className} ${styles.wrapper}` : styles.wrapper}
      style={{
        flexDirection: legendPosition === "right" ? "row" : "column-reverse",
      }}
    >
      <svg width={width} height={height}>
        <defs>
          {Object.keys(barHoverColorsMap).map((color: string) => {
            // remove brackets from colour name to make ids work
            const colorId = removeBrackets(color);
            return (
              <filter key={`glow-${color}`} id={`glow-${colorId}`}>
                <feDropShadow
                  dx="0"
                  dy="0"
                  stdDeviation="4"
                  floodColor={barHoverColorsMap[color]}
                />
              </filter>
            );
          })}
        </defs>
        <Group top={margin.top} left={margin.left}>
          <Group>
            {data.map((d, idx) => {
              const barName = `${getCategory(d)}-${idx}`;
              const barWidth = categoryScale.bandwidth();
              const backgroundBarWidth = barWidth / (1 - BAR_PADDING);
              return idx % 2 === 0 ? (
                <Bar
                  className={styles.barBackground}
                  key={`bar-${barName}-background`}
                  x={
                    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
                    categoryScale(getCategory(d))! -
                    (backgroundBarWidth - barWidth) / 2
                  }
                  y={0}
                  width={backgroundBarWidth}
                  height={valueMax}
                />
              ) : null;
            })}
          </Group>
          <GridRows
            scale={valueScale}
            width={categoryMax}
            numTicks={5}
            stroke={Color.label}
            strokeWidth={4}
            strokeDasharray="10"
            strokeLinecap="round"
          />
          <BarGroup
            data={data}
            keys={keys}
            height={valueMax}
            x0={getCategory}
            x0Scale={categoryScale}
            x1Scale={keyScale}
            yScale={valueScale}
            color={colorScale}
          >
            {(barGroups) =>
              barGroups.map((barGroup) => (
                <Group
                  key={`bar-group-${barGroup.x0}-${barGroup.index}`}
                  left={barGroup.x0}
                >
                  {barGroup.bars.map((bar) => (
                    <HoverableBar
                      key={`bar-group-bar-${barGroup.x0}-${barGroup.index}-${bar.key}-${bar.index}`}
                      bar={bar}
                      valueMax={valueMax}
                      hoverFillColor={barHoverColorsMap[bar.color]}
                      hoverLabelSize={hoverLabelSize}
                    />
                  ))}
                </Group>
              ))
            }
          </BarGroup>
        </Group>
        <AxisBottom
          scale={categoryScale}
          top={valueMax + margin.top}
          left={margin.left}
          hideAxisLine
          hideTicks
          tickLabelProps={() => {
            return {
              ...bottomTickLabelProps(),
              className: styles.tickLabel,
              dy: "-0.25rem",
              fontSize: `${categoryTickLabelSize / 16}rem`,
              width: categoryScale.bandwidth(),
              verticalAnchor: "start",
            };
          }}
          label={categoryAxisLabel}
          labelClassName={styles.axisLabel}
          labelOffset={categoryAxisLabelOffset}
          labelProps={{
            fontSize: `${categoryAxisLabelSize / 16}rem`,
          }}
        />
        <AxisLeft
          scale={valueScale}
          top={margin.top}
          left={margin.left}
          hideAxisLine
          hideTicks
          numTicks={5}
          tickLabelProps={() => {
            return {
              ...leftTickLabelProps(),
              className: styles.tickLabel,
              dx: "-0.5rem",
              dy: "0.25rem",
              fontSize: `${valueTickLabelSize / 16}rem`,
            };
          }}
          label={valueAxisLabel}
          labelClassName={styles.axisLabel}
          labelOffset={valueAxisLabelOffset}
          labelProps={{
            fontSize: `${valueAxisLabelSize / 16}rem`,
          }}
        />
      </svg>
      <LegendOrdinal
        className={styles.legend}
        style={{
          marginTop: legendMargin.top,
          marginRight: legendMargin.right,
          marginBottom: legendMargin.bottom,
          marginLeft: legendMargin.left,
          fontSize: legendLabelSize,
        }}
        scale={colorScale}
        direction={legendPosition === "right" ? "column" : "row"}
        itemMargin={
          legendPosition === "right"
            ? `calc(${legendItemGap / 2}rem / 16) 0 calc(${
                legendItemGap / 2
              }rem / 16) 0`
            : `0 calc(${legendItemGap / 2}rem / 16) 0 calc(${
                legendItemGap / 2
              }rem / 16)`
        }
      />
    </div>
  );
}

export function GroupedBarGraphHorizontal(props: GroupedBarGraphProps) {
  const {
    data: propsData,
    barColors,
    barHoverColorsMap,
    width,
    height,
    margin,
    className,
    categoryTickLabelSize = DEFAULT_LABEL_SIZE,
    valueTickLabelSize = DEFAULT_LABEL_SIZE,
    hoverLabelSize,
    categoryAxisLabel,
    categoryAxisLabelSize = DEFAULT_LABEL_SIZE,
    categoryAxisLabelOffset = 0,
    valueAxisLabel,
    valueAxisLabelSize = DEFAULT_LABEL_SIZE,
    valueAxisLabelOffset = 0,
    legendProps,
  } = props;

  const {
    position: legendPosition = "top",
    itemLabelSize: legendLabelSize = DEFAULT_LABEL_SIZE,
    itemGap: legendItemGap = DEFAULT_LEGEND_GAP,
    margin: legendMargin = {},
  } = legendProps ?? {};

  const data: BarGroupData[] = propsData.map((datum: GroupedBarGraphData) => {
    return { category: datum.category, ...datum.values };
  });

  const keys = Object.keys(propsData[0].values);
  propsData.forEach((d: GroupedBarGraphData) => {
    const currentKeys = Object.keys(d.values);
    if (
      keys.length != currentKeys.length ||
      !keys.every((key: string) => currentKeys.includes(key))
    ) {
      throw new Error(
        "Every category in a GroupedBarGraph must have the same keys. Check the data prop"
      );
    }
  });

  const allValues = propsData
    .map((d: GroupedBarGraphData) => Object.values(d.values))
    .flat();

  const categoryMax = height - margin.top - margin.bottom;
  const valueMax = width - margin.left - margin.right;

  const getCategory = (d: BarGroupData) => d.category;

  const categoryScale = scaleBand({
    domain: data.map(getCategory),
    padding: BAR_PADDING,
  });

  const keyScale = scaleBand({
    domain: keys,
  });

  const valueScale = scaleLinear<number>({
    domain: [Math.max(...allValues), 0],
  });

  const colorScale = scaleOrdinal<string, string>({
    domain: keys,
    range: barColors,
  });

  categoryScale.rangeRound([0, categoryMax]);
  keyScale.rangeRound([0, categoryScale.bandwidth()]);
  valueScale.rangeRound([valueMax, 0]);

  return (
    <div
      className={className ? `${className} ${styles.wrapper}` : styles.wrapper}
      style={{
        flexDirection: legendPosition === "right" ? "row" : "column-reverse",
      }}
    >
      <svg width={width} height={height}>
        <defs>
          {Object.keys(barHoverColorsMap).map((color: string) => {
            // remove brackets from colour name to make ids work
            const colorId = removeBrackets(color);
            return (
              <filter key={`glow-${color}`} id={`glow-${colorId}`}>
                <feDropShadow
                  dx="0"
                  dy="0"
                  stdDeviation="4"
                  floodColor={barHoverColorsMap[color]}
                />
              </filter>
            );
          })}
        </defs>
        <Group top={margin.top} left={margin.left}>
          <Group>
            {data.map((d, idx) => {
              const barName = `${getCategory(d)}-${idx}`;
              const barWidth = categoryScale.bandwidth();
              const backgroundBarWidth = barWidth / (1 - BAR_PADDING);
              return idx % 2 === 0 ? (
                <Bar
                  className={styles.barBackground}
                  key={`bar-${barName}-background`}
                  x={0}
                  y={
                    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
                    categoryScale(getCategory(d))! -
                    (backgroundBarWidth - barWidth) / 2
                  }
                  width={valueMax}
                  height={backgroundBarWidth}
                />
              ) : null;
            })}
          </Group>
          <GridColumns
            scale={valueScale}
            height={categoryMax}
            numTicks={5}
            stroke={Color.label}
            strokeWidth={4}
            strokeDasharray="10"
            strokeLinecap="round"
          />
          <BarGroupHorizontal
            data={data}
            keys={keys}
            width={valueMax}
            y0={getCategory}
            y0Scale={categoryScale}
            y1Scale={keyScale}
            xScale={valueScale}
            color={colorScale}
          >
            {(barGroups) =>
              barGroups.map((barGroup) => (
                <Group
                  key={`bar-group-${barGroup.y0}-${barGroup.index}`}
                  top={barGroup.y0}
                >
                  {barGroup.bars.map((bar) => (
                    <HoverableBar
                      key={`bar-group-bar-${barGroup.y0}-${barGroup.index}-${bar.key}-${bar.index}`}
                      bar={bar}
                      valueMax={valueMax}
                      hoverFillColor={barHoverColorsMap[bar.color]}
                      hoverLabelSize={hoverLabelSize}
                      isHorizontal
                    />
                  ))}
                </Group>
              ))
            }
          </BarGroupHorizontal>
        </Group>
        <AxisLeft
          scale={categoryScale}
          top={margin.top}
          left={margin.left}
          hideAxisLine
          hideTicks
          tickLabelProps={() => {
            return {
              ...leftTickLabelProps(),
              className: styles.tickLabel,
              dx: "-0.5rem",
              dy: "0.25rem",
              fontSize: `${valueTickLabelSize / 16}rem`,
              height: categoryScale.bandwidth(),
            };
          }}
          label={categoryAxisLabel}
          labelClassName={styles.axisLabel}
          labelOffset={categoryAxisLabelOffset}
          labelProps={{
            fontSize: `${categoryAxisLabelSize / 16}rem`,
          }}
        />
        <AxisBottom
          scale={valueScale}
          top={categoryMax + margin.top}
          left={margin.left}
          hideAxisLine
          hideTicks
          numTicks={5}
          tickLabelProps={() => {
            return {
              ...bottomTickLabelProps(),
              className: styles.tickLabel,
              dy: "-0.25rem",
              fontSize: `${categoryTickLabelSize / 16}rem`,
              verticalAnchor: "start",
            };
          }}
          label={valueAxisLabel}
          labelClassName={styles.axisLabel}
          labelOffset={valueAxisLabelOffset}
          labelProps={{
            fontSize: `${valueAxisLabelSize / 16}rem`,
          }}
        />
      </svg>
      <LegendOrdinal
        className={styles.legend}
        style={{
          marginTop: legendMargin.top,
          marginRight: legendMargin.right,
          marginBottom: legendMargin.bottom,
          marginLeft: legendMargin.left,
          fontSize: legendLabelSize,
        }}
        scale={colorScale}
        direction={legendPosition === "right" ? "column" : "row"}
        itemMargin={
          legendPosition === "right"
            ? `calc(${legendItemGap / 2}rem / 16) 0 calc(${
                legendItemGap / 2
              }rem / 16) 0`
            : `0 calc(${legendItemGap / 2}rem / 16) 0 calc(${
                legendItemGap / 2
              }rem / 16)`
        }
      />
    </div>
  );
}

interface HoverableBarProps {
  bar: BarGroupBarType<string>;
  valueMax: number;
  hoverFillColor?: string;
  hoverLabelSize?: number;
  isHorizontal?: boolean;
}

function HoverableBar(props: HoverableBarProps) {
  const {
    bar,
    valueMax,
    hoverLabelSize,
    hoverFillColor,
    isHorizontal = false,
  } = props;

  const [isHovered, setIsHovered] = useState(false);

  const colorId = removeBrackets(bar.color);

  return (
    <Group
      className={styles.singleBar}
      onMouseEnter={() => {
        setIsHovered(true);
      }}
      onMouseLeave={() => {
        setIsHovered(false);
      }}
    >
      <Bar
        x={bar.x}
        y={bar.y}
        width={bar.width}
        height={bar.height}
        fill={isHovered && hoverFillColor ? hoverFillColor : bar.color}
        // apply the glow effect when the bar is hovered
        filter={isHovered ? `url(#glow-${colorId})` : undefined}
      />
      <Text
        className={styles.barText}
        x={isHorizontal ? bar.width - BAR_TEXT_PADDING : bar.x + bar.width / 2}
        y={
          isHorizontal
            ? bar.y + bar.height / 2
            : valueMax - bar.height + BAR_TEXT_PADDING
        }
        fontSize={
          hoverLabelSize ?? (isHorizontal ? bar.height : bar.width) * 0.5
        }
        textAnchor={isHorizontal ? "end" : "middle"}
        verticalAnchor={isHorizontal ? "middle" : "start"}
      >
        {bar.value}
      </Text>
    </Group>
  );
}

function removeBrackets(str: string) {
  return str.replace(/\(|\)/g, "");
}