import {max, min} from 'd3-array';
import {interpolateNumber} from 'd3-interpolate';
import {BaseType, select, Selection} from 'd3-selection';
import 'd3-transition';
import {
  D3ZoomEvent,
  zoom,
  ZoomBehavior,
  ZoomedElementBaseType,
  zoomTransform,
} from 'd3-zoom';
import {saveAs} from 'file-saver';
import {useEffect, useMemo, useRef} from 'react';
import {IntlShape, useIntl} from 'react-intl';
import {
  ChartHandle,
  ChartInfo,
  CircleRenderer,
  createChart,
  DetailedRenderer,
  FancyChart,
  HourglassChart,
  IndiInfo,
  JsonGedcomData,
  RelativesChart,
  ChartColors as TopolaChartColors,
} from 'topola';
import {ChartColors, Ids, PlaceDisplay, Sex} from './sidepanel/config/config';
import {Media} from './util/media';
import {DEFAULT_PLACE_DISPLAY_COUNT, shortenPlace} from './util/place_util';
import {usePrevious} from './util/previous-hook';

/** How much to zoom when using the +/- buttons. */
const ZOOM_FACTOR = 1.3;

/**
 * Called when the view is dragged with the mouse.
 *
 * @param size the size of the chart
 */
function zoomed(
  size: [number, number],
  event: D3ZoomEvent<ZoomedElementBaseType, unknown>,
) {
  const parent = select('#svgContainer').node() as Element;

  const scale = event.transform.k;
  const offsetX = max([0, (parent.clientWidth - size[0] * scale) / 2]);
  const offsetY = max([0, (parent.clientHeight - size[1] * scale) / 2]);
  select('#chartSvg')
    .attr('width', size[0] * scale)
    .attr('height', size[1] * scale)
    .attr('transform', `translate(${offsetX}, ${offsetY})`);
  select('#chart').attr('transform', `scale(${scale})`);

  parent.scrollLeft = -event.transform.x;
  parent.scrollTop = -event.transform.y;
}

/** Called when the scrollbars are used. */
function scrolled() {
  const parent = select('#svgContainer').node() as Element;
  const x = parent.scrollLeft + parent.clientWidth / 2;
  const y = parent.scrollTop + parent.clientHeight / 2;
  const scale = zoomTransform(parent).k;
  select(parent).call(zoom().translateTo, x / scale, y / scale);
}

/** Loads blob as data URL. */
function loadAsDataUrl(blob: Blob): Promise<string> {
  const reader = new FileReader();
  reader.readAsDataURL(blob);
  return new Promise<string>((resolve, _reject) => {
    reader.onload = (e) => resolve((e.target as FileReader).result as string);
  });
}

async function inlineImage(image: SVGImageElement) {
  const href = image.href.baseVal;
  if (!href) {
    return;
  }
  try {
    const response = await fetch(href);
    const blob = await response.blob();
    const dataUrl = await loadAsDataUrl(blob);
    image.href.baseVal = dataUrl;
  } catch (e) {
    console.warn('Failed to load image:', e);
  }
}

/**
 * Fetches all images in the SVG and replaces them with inlined images as data
 * URLs. Images are replaced in place. The replacement is done, the returned
 * promise is resolved.
 */
async function inlineImages(svg: Element): Promise<void> {
  const images = Array.from(svg.getElementsByTagName('image'));
  await Promise.all(images.map(inlineImage));
}

/** Loads a blob into an image object. */
function loadImage(blob: Blob): Promise<HTMLImageElement> {
  const image = new Image();
  image.src = URL.createObjectURL(blob);
  return new Promise<HTMLImageElement>((resolve, _reject) => {
    image.addEventListener('load', () => resolve(image));
  });
}

/** Draw image on a new canvas and return the canvas. */
function drawImageOnCanvas(image: HTMLImageElement) {
  const canvas = document.createElement('canvas');
  // Scale image for better quality.
  canvas.width = image.width * 2;
  canvas.height = image.height * 2;

  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  const ctx = canvas.getContext('2d')!;
  const oldFill = ctx.fillStyle;
  ctx.fillStyle = 'white';
  ctx.fillRect(0, 0, canvas.width, canvas.height);
  ctx.fillStyle = oldFill;

  ctx.drawImage(image, 0, 0, canvas.width, canvas.height);
  return canvas;
}

function canvasToBlob(canvas: HTMLCanvasElement, type: string) {
  return new Promise<Blob>((resolve, reject) => {
    canvas.toBlob((blob) => {
      if (blob) {
        resolve(blob);
      } else {
        reject();
      }
    }, type);
  });
}

/** Return a copy of the SVG chart but without scaling and positioning. */
function getStrippedSvg() {
  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  const svg = document.getElementById('chartSvg')!.cloneNode(true) as Element;

  svg.removeAttribute('transform');
  const parent = select('#svgContainer').node() as Element;
  const scale = zoomTransform(parent).k;
  svg.setAttribute('width', String(Number(svg.getAttribute('width')) / scale));
  svg.setAttribute(
    'height',
    String(Number(svg.getAttribute('height')) / scale),
  );
  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  svg.querySelector('#chart')!.removeAttribute('transform');

  return svg;
}

function getSvgDimensions() {
  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  const svg = document.getElementById('chartSvg')!;
  return {
    width: Number(svg.getAttribute('width')),
    height: Number(svg.getAttribute('height')),
  };
}

function getSvgContents() {
  return new XMLSerializer().serializeToString(getStrippedSvg());
}

async function getSvgContentsWithInlinedImages() {
  const svg = getStrippedSvg();

  // Set white background because the default background of the SVG
  // is transparent, which causes issues when printing or exporting to PDF.
  const svgNs = 'http://www.w3.org/2000/svg';
  const rect = document.createElementNS(svgNs, 'rect');
  rect.setAttribute('x', '0');
  rect.setAttribute('y', '0');
  rect.setAttribute('width', '100%');
  rect.setAttribute('height', '100%');
  rect.setAttribute('fill', 'white');
  svg.prepend(rect);

  await inlineImages(svg);
  return new XMLSerializer().serializeToString(svg);
}

/** Shows the print dialog to print the currently displayed chart. */
export function printChart() {
  const printWindow = document.createElement('iframe');
  printWindow.style.position = 'absolute';
  printWindow.style.top = '-1000px';
  printWindow.style.left = '-1000px';
  printWindow.onload = () => {
    printWindow.contentDocument?.open();
    printWindow.contentDocument?.write(getSvgContents());
    printWindow.contentDocument?.close();
    // Doesn't work on Firefox without the setTimeout.
    setTimeout(() => {
      printWindow.contentWindow?.focus();
      printWindow.contentWindow?.print();
      printWindow.parentNode?.removeChild(printWindow);
    }, 500);
  };
  document.body.appendChild(printWindow);
}

export async function downloadSvg() {
  const contents = await getSvgContentsWithInlinedImages();
  const blob = new Blob([contents], {type: 'image/svg+xml'});
  saveAs(blob, 'topola.svg');
}

async function drawOnCanvas(): Promise<HTMLCanvasElement> {
  const contents = await getSvgContentsWithInlinedImages();
  const blob = new Blob([contents], {type: 'image/svg+xml'});
  return drawImageOnCanvas(await loadImage(blob));
}

export async function downloadPng() {
  const canvas = await drawOnCanvas();
  const blob = await canvasToBlob(canvas, 'image/png');
  saveAs(blob, 'topola.png');
}

export async function downloadPdf() {
  // Lazy load jspdf.
  const {default: jspdf} = await import('jspdf');

  const {width, height} = getSvgDimensions();
  const doc = new jspdf({
    orientation: width > height ? 'l' : 'p',
    unit: 'pt',
    format: [width, height],
  });
  const contents = await getSvgContentsWithInlinedImages();
  await doc.addSvgAsImage(contents, 0, 0, width, height);
  doc.save('topola.pdf');
}

/** Supported chart types. */
export enum ChartType {
  Hourglass,
  Relatives,
  Donatso,
  Fancy,
}

const chartColors = new Map<ChartColors, TopolaChartColors>([
  [ChartColors.NO_COLOR, TopolaChartColors.NO_COLOR],
  [ChartColors.COLOR_BY_GENERATION, TopolaChartColors.COLOR_BY_GENERATION],
  [ChartColors.COLOR_BY_SEX, TopolaChartColors.COLOR_BY_SEX],
]);

function getChartType(chartType: ChartType) {
  switch (chartType) {
    case ChartType.Hourglass:
      return HourglassChart;
    case ChartType.Relatives:
      return RelativesChart;
    case ChartType.Fancy:
      return FancyChart;
    default:
      // Fall back to hourglass chart.
      return HourglassChart;
  }
}

function getRendererType(chartType: ChartType) {
  switch (chartType) {
    case ChartType.Fancy:
      return CircleRenderer;
    default:
      // Use DetailedRenderer by default.
      return DetailedRenderer;
  }
}

/** Returns the element’s usable width and height by subtracting the assumed scrollbar size. */
function getScrollbarAwareSize(
  element: Element,
  scrollbarSize = 20,
): [number, number] {
  const htmlElement = element as HTMLElement;
  return [
    htmlElement.clientWidth - scrollbarSize,
    htmlElement.clientHeight - scrollbarSize,
  ];
}

/**
 * Calculates the allowed zoom scale range.
 * Sets the minimum scale so the chart cannot zoom out beyond full visibility,
 * and fixes the maximum scale at 2.
 */
function calculateScaleExtent(
  parent: Element,
  scale: number,
  chartInfo: ChartInfo,
): [number, number] {
  const [availWidth, availHeight] = getScrollbarAwareSize(parent);

  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  const zoomOutFactor = min([
    1,
    scale,
    availWidth / chartInfo.size[0],
    availHeight / chartInfo.size[1],
  ])!;

  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  return [max([0.1, zoomOutFactor])!, 2];
}

export interface ChartProps {
  data: JsonGedcomData;
  selection: IndiInfo;
  chartType: ChartType;
  onSelection: (indiInfo: IndiInfo) => void;
  onDetailSelection: (indiInfo: IndiInfo) => void;
  freezeAnimation?: boolean;
  colors?: ChartColors;
  hideIds?: Ids;
  hideSex?: Sex;
  placeDisplay?: PlaceDisplay;
  placeCount?: number;
  /** Called once after the initial D3 layout and SVG render completes. */
  onFirstRender?: () => void;
}

class ChartWrapper {
  private chart?: ChartHandle;
  /** Animation is in progress. */
  private animating = false;
  /** Rendering is required after the current animation finishes. */
  private rerenderRequired = false;
  /** The d3 zoom behavior object. */
  private zoomBehavior?: ZoomBehavior<Element, unknown>;
  /** Props that will be used for rerendering. */
  private rerenderProps?: ChartProps;
  private rerenderResetPosition?: boolean;

  zoom(factor: number) {
    const parent = select('#svgContainer') as Selection<
      Element,
      unknown,
      BaseType,
      unknown
    >;
    this.zoomBehavior?.scaleBy(parent, factor);
  }

  /**
   * Renders the chart or performs a transition animation to a new state.
   * If indiInfo is not given, it means that it is the initial render and no
   * animation is performed.
   */
  renderChart(
    props: ChartProps,
    intl: IntlShape,
    args: {initialRender: boolean; resetPosition: boolean} = {
      initialRender: false,
      resetPosition: false,
    },
  ) {
    // Nothing changed — the SVG is already correct. Skip re-render.
    // This prevents repeated full D3 layout passes (500ms+ each) that happen
    // when React re-renders for unrelated state changes.
    if (!args.initialRender && !args.resetPosition) {
      return;
    }

    // Wait for animation to finish if animation is in progress.
    if (!args.initialRender && this.animating) {
      this.rerenderRequired = true;
      this.rerenderProps = props;
      this.rerenderResetPosition = args.resetPosition;
      return;
    }

    // Freeze changing selection after initial rendering.
    if (!args.initialRender && props.freezeAnimation) {
      return;
    }

    if (args.initialRender || !this.chart) {
      (select('#chart').node() as HTMLElement).innerHTML = '';
      this.chart = createChart({
        json: props.data,
        chartType: getChartType(props.chartType),
        renderer: getRendererType(props.chartType),
        svgSelector: '#chart',
        indiCallback: (info) => {
          // ths is called when an individual is selected in the chart
          if (info.modifiers?.shiftKey) {
            // If the shift key is pressed, we just update the details tab without changing the selection in the chart.
            // This allows users to quickly view details of multiple individuals without losing their place in the chart.
            props.onDetailSelection(info);
          } else {
            // If the shift key is not pressed, we update the selection in the chart as usual.
            props.onSelection(info);
          }
        },
        colors:
          props.colors !== undefined
            ? chartColors.get(props.colors)
            : undefined,
        animate: true,
        updateSvgSize: false,
        locale: intl.locale,
      });
    } else {
      this.chart.setData(props.data);
    }
    const chartInfo = this.chart.render({
      startIndi: props.selection.id,
      baseGeneration: props.selection.generation,
    });
    const svg = select('#chartSvg');
    const parent = select('#svgContainer').node() as Element;
    const scale = zoomTransform(parent).k;
    const extent: [number, number] = calculateScaleExtent(
      parent,
      scale,
      chartInfo,
    );

    this.zoomBehavior = zoom()
      .scaleExtent(extent)
      .translateExtent([[0, 0], chartInfo.size])
      .on('zoom', (event) => zoomed(chartInfo.size, event));

    select(parent).on('scroll', scrolled).call(this.zoomBehavior);

    const scrollTopTween = (scrollTop: number) => {
      return () => {
        const i = interpolateNumber(parent.scrollTop, scrollTop);
        return (t: number) => {
          parent.scrollTop = i(t);
        };
      };
    };
    const scrollLeftTween = (scrollLeft: number) => {
      return () => {
        const i = interpolateNumber(parent.scrollLeft, scrollLeft);
        return (t: number) => {
          parent.scrollLeft = i(t);
        };
      };
    };

    const dx = parent.clientWidth / 2 - chartInfo.origin[0] * scale;
    const dy = parent.clientHeight / 2 - chartInfo.origin[1] * scale;
    const offsetX = max([
      0,
      (parent.clientWidth - chartInfo.size[0] * scale) / 2,
    ]);
    const offsetY = max([
      0,
      (parent.clientHeight - chartInfo.size[1] * scale) / 2,
    ]);
    const svgTransition = svg.transition().delay(200).duration(500);
    const transition = args.initialRender ? svg : svgTransition;
    transition.attr('transform', `translate(${offsetX}, ${offsetY})`);
    transition.attr('width', chartInfo.size[0] * scale);
    transition.attr('height', chartInfo.size[1] * scale);
    if (args.resetPosition) {
      if (args.initialRender) {
        parent.scrollLeft = -dx;
        parent.scrollTop = -dy;
      } else {
        svgTransition
          .tween('scrollLeft', scrollLeftTween(-dx))
          .tween('scrollTop', scrollTopTween(-dy));
      }
    }

    // After the animation is finished, rerender the chart if required.
    this.animating = true;
    chartInfo.animationPromise.then(() => {
      this.animating = false;
      if (this.rerenderRequired) {
        this.rerenderRequired = false;
        // Use `this.rerenderProps` instead of the props in scope because
        // the props may have been updated in the meantime.
        if (this.rerenderProps) {
          this.renderChart(this.rerenderProps, intl, {
            initialRender: false,
            resetPosition: !!this.rerenderResetPosition,
          });
        } else {
          console.error(
            'Rerender required after animation, but rerenderProps was not set.',
          );
        }
      }
    });
  }
}

export function Chart(props: ChartProps) {
  const chartWrapper = useRef(new ChartWrapper());
  const prevProps = usePrevious(props);
  const intl = useIntl();

  const placeDisplay = props.placeDisplay ?? PlaceDisplay.FULL;
  const placeCount = props.placeCount ?? DEFAULT_PLACE_DISPLAY_COUNT;

  const processedData = useMemo(() => {
    if (placeDisplay === PlaceDisplay.FULL) {
      return props.data;
    }
    return {
      ...props.data,
      indis: props.data.indis.map((indi) => ({
        ...indi,
        birth: indi.birth
          ? {
              ...indi.birth,
              place: shortenPlace(indi.birth.place, placeDisplay, placeCount),
            }
          : undefined,
        death: indi.death
          ? {
              ...indi.death,
              place: shortenPlace(indi.death.place, placeDisplay, placeCount),
            }
          : undefined,
      })),
      fams: props.data.fams.map((fam) => ({
        ...fam,
        marriage: fam.marriage
          ? {
              ...fam.marriage,
              place: shortenPlace(fam.marriage.place, placeDisplay, placeCount),
            }
          : undefined,
      })),
    };
  }, [props.data, placeDisplay, placeCount]);

  useEffect(() => {
    const propsWithProcessedData: ChartProps = {...props, data: processedData};
    if (prevProps) {
      const initialRender =
        props.chartType !== prevProps?.chartType ||
        props.colors !== prevProps?.colors ||
        props.hideIds !== prevProps?.hideIds ||
        props.hideSex !== prevProps?.hideSex ||
        props.placeDisplay !== prevProps?.placeDisplay ||
        props.placeCount !== prevProps?.placeCount;
      const resetPosition =
        props.chartType !== prevProps?.chartType ||
        props.data !== prevProps.data ||
        // This does not work as the objects are always different instances.
        //props.selection !== prevProps.selection;
        // Therefore, compare id and generation instead.
        props.selection.id !== prevProps.selection.id ||
        props.selection.generation !== prevProps.selection.generation;
      chartWrapper.current.renderChart(propsWithProcessedData, intl, {
        initialRender,
        resetPosition,
      });
    } else {
      chartWrapper.current.renderChart(propsWithProcessedData, intl, {
        initialRender: true,
        resetPosition: true,
      });
      // Clear the loading pill now that the chart SVG is in the DOM.
      // This fires before the D3 fade-in animation completes (~400ms), which
      // is intentional: the chart is visible and interactive at this point,
      // and keeping the pill visible during the animation would create a
      // confusing overlap.
      props.onFirstRender?.();
    }
  });

  return (
    <div id="svgContainer">
      <Media greaterThanOrEqual="large" className="zoom">
        <button
          className="zoom-in"
          onClick={() => chartWrapper.current.zoom(ZOOM_FACTOR)}
        >
          +
        </button>
        <button
          className="zoom-out"
          onClick={() => chartWrapper.current.zoom(1 / ZOOM_FACTOR)}
        >
          −
        </button>
      </Media>
      <svg id="chartSvg">
        <g id="chart" data-testid="chart" />
      </svg>
    </div>
  );
}