---

import { Observable } from 'rxjs';

import {
  CustomPriceAxisPaneView,
  CustomPriceAxisView,
  CustomTimeAxisPaneView,
  CustomTimeAxisView,
} from '@core/Drawings/axis';
import { SeriesDrawingBase } from '@core/Drawings/common';
import {
  clamp,
  clampPointToContainer as clampPointToContainerInElement,
  getAnchorFromPoint,
  getContainerSize as getElementContainerSize,
  getPriceDelta as getPriceDeltaFromCoordinates,
  getPriceFromYCoordinate,
  getTimeFromXCoordinate,
  getXCoordinateFromTime,
  getYCoordinateFromPrice,
  isNearPoint,
  isPointInBounds,
  normalizeBounds,
  shiftTimeByPixels,
} from '@core/Drawings/helpers';
import { updateViews } from '@core/Drawings/utils';

import { getThemeStore } from '@src/theme';
import { Defaults } from '@src/types/defaults';
import { formatPrice } from '@src/utils';
import { formatDate } from '@src/utils/formatter';

import { RectanglePaneView } from './paneView';
import {
  createDefaultSettings,
  getRectangleSettingsTabs,
  RectangleSettings,
  RectangleStyle,
  RectangleTextStyle,
} from './settings';

import type { DrawingInteraction, ISeriesDrawing } from '@core/Drawings/common';
import type { AxisLabel, AxisSegment, Point, SeriesApi } from '@core/Drawings/types';
import type { ChartOptionsModel, SettingsTab } from '@src/types';
import type { IChartApi, IPrimitivePaneView, PrimitiveHoveredItem, Time, UTCTimestamp } from 'lightweight-charts';

type RectangleMode = 'idle' | 'drawing' | 'ready' | 'dragging';
type RectangleHandle = 'body' | 'nw' | 'n' | 'ne' | 'e' | 'se' | 's' | 'sw' | 'w' | null;
type RectangleHandleKey = Exclude<RectangleHandle, 'body' | null>;
type TimeLabelKind = 'left' | 'right';
type PriceLabelKind = 'top' | 'bottom';

interface RectangleParams {
  container: HTMLElement;
  interaction: DrawingInteraction;
  formatObservable?: Observable<ChartOptionsModel>;
  removeSelf?: () => void;
  openSettings?: () => void;
}

interface RectangleState {
  hidden: boolean;
  mode: RectangleMode;
  startTime: Time | null;
  endTime: Time | null;
  startPrice: number | null;
  endPrice: number | null;
  settings: RectangleSettings;
}

interface RectangleGeometry {
  left: number;
  right: number;
  top: number;
  bottom: number;
  width: number;
  height: number;
  handles: Record<RectangleHandleKey, Point>;
}

export interface RectangleRenderData extends RectangleGeometry, RectangleStyle, RectangleTextStyle {
  showFill: boolean;
  showHandles: boolean;
}

const HANDLE_HIT_TOLERANCE = 8;
const BODY_HIT_TOLERANCE = 6;
const MIN_RECTANGLE_SIZE = 6;

export class Rectangle extends SeriesDrawingBase<RectangleSettings> implements ISeriesDrawing {
  private removeSelf?: () => void;
  private openSettings?: () => void;

  protected settings: RectangleSettings = createDefaultSettings();

  protected mode: RectangleMode = 'idle';

  private startTime: Time | null = null;
  private endTime: Time | null = null;
  private startPrice: number | null = null;
  private endPrice: number | null = null;

  private activeDragTarget: RectangleHandle = null;
  private dragPointerId: number | null = null;
  private dragStartPoint: Point | null = null;
  private dragStateSnapshot: RectangleState | null = null;
  private dragGeometrySnapshot: RectangleGeometry | null = null;

  private displayFormat: ChartOptionsModel = {
    dateFormat: Defaults.dateFormat,
    timeFormat: Defaults.timeFormat,
    showTime: Defaults.showTime,
  };

  private readonly paneView: RectanglePaneView;
  private readonly timeAxisPaneView: CustomTimeAxisPaneView;
  private readonly priceAxisPaneView: CustomPriceAxisPaneView;
  private readonly leftTimeAxisView: CustomTimeAxisView;
  private readonly rightTimeAxisView: CustomTimeAxisView;
  private readonly topPriceAxisView: CustomPriceAxisView;
  private readonly bottomPriceAxisView: CustomPriceAxisView;

  constructor(
    chart: IChartApi,
    series: SeriesApi,
    { container, interaction, formatObservable, removeSelf, openSettings }: RectangleParams,
  ) {
    super({ chart, series, container, interaction });

    this.removeSelf = removeSelf;
    this.openSettings = openSettings;

    this.paneView = new RectanglePaneView(this);

    this.timeAxisPaneView = new CustomTimeAxisPaneView({
      getAxisSegments: () => this.getTimeAxisSegments(),
    });

    this.priceAxisPaneView = new CustomPriceAxisPaneView({
      getAxisSegments: () => this.getPriceAxisSegments(),
    });

    this.leftTimeAxisView = new CustomTimeAxisView({
      getAxisLabel: (kind) => this.getTimeAxisLabel(kind),
      labelKind: 'left',
    });

    this.rightTimeAxisView = new CustomTimeAxisView({
      getAxisLabel: (kind) => this.getTimeAxisLabel(kind),
      labelKind: 'right',
    });

    this.topPriceAxisView = new CustomPriceAxisView({
      getAxisLabel: (kind) => this.getPriceAxisLabel(kind),
      labelKind: 'top',
    });

    this.bottomPriceAxisView = new CustomPriceAxisView({
      getAxisLabel: (kind) => this.getPriceAxisLabel(kind),
      labelKind: 'bottom',
    });

    if (formatObservable) {
      this.subscriptions.add(
        formatObservable.subscribe((format) => {
          this.displayFormat = format;
          this.render();
        }),
      );
    }

    this.series.attachPrimitive(this);
  }

  public isCreationPending(): boolean {
    return this.mode === 'idle' || this.mode === 'drawing';
  }

  public getState(): RectangleState {
    return {
      hidden: this.hidden,
      mode: this.mode,
      startTime: this.startTime,
      endTime: this.endTime,
      startPrice: this.startPrice,
      endPrice: this.endPrice,
      settings: { ...this.settings },
    };
  }

  public setState(state: unknown): void {
    const nextState = state as Partial<RectangleState>;

    if ('hidden' in nextState && typeof nextState.hidden === 'boolean') {
      this.hidden = nextState.hidden;
    }

    if ('mode' in nextState && nextState.mode) {
      this.mode = nextState.mode;
    }

    if ('startTime' in nextState) {
      this.startTime = nextState.startTime ?? null;
    }

    if ('endTime' in nextState) {
      this.endTime = nextState.endTime ?? null;
    }

    if ('startPrice' in nextState) {
      this.startPrice = nextState.startPrice ?? null;
    }

    if ('endPrice' in nextState) {
      this.endPrice = nextState.endPrice ?? null;
    }

    if ('settings' in nextState && nextState.settings) {
      this.settings = {
        ...createDefaultSettings(),
        ...nextState.settings,
      };
    }

    this.render();
  }

  public getSettingsTabs(): SettingsTab[] {
    return getRectangleSettingsTabs(this.settings);
  }

  public updateAllViews(): void {
    updateViews([
      this.paneView,
      this.timeAxisPaneView,
      this.priceAxisPaneView,
      this.leftTimeAxisView,
      this.rightTimeAxisView,
      this.topPriceAxisView,
      this.bottomPriceAxisView,
    ]);
  }

  public paneViews(): readonly IPrimitivePaneView[] {
    return [this.paneView];
  }

  public timeAxisPaneViews(): readonly IPrimitivePaneView[] {
    return [this.timeAxisPaneView];
  }

  public priceAxisPaneViews(): readonly IPrimitivePaneView[] {
    return [this.priceAxisPaneView];
  }

  public timeAxisViews() {
    return [this.leftTimeAxisView, this.rightTimeAxisView];
  }

  public priceAxisViews() {
    return [this.topPriceAxisView, this.bottomPriceAxisView];
  }

  public getRenderData(): RectangleRenderData | null {
    if (this.hidden) {
      return null;
    }

    const geometry = this.getGeometry();

    if (!geometry) {
      return null;
    }

    return {
      ...geometry,
      showFill: true,
      showHandles: this.shouldShowHandles(),
      ...this.settings,
    };
  }

  protected getHoveredItem(x: number, y: number): PrimitiveHoveredItem | null {
    if (this.hidden || this.mode === 'idle' || this.mode === 'drawing') {
      return null;
    }

    const point = { x, y };

    if (!this.isSelected()) {
      if (!this.containsPoint(point)) {
        return null;
      }

      return {
        cursorStyle: 'pointer',
        externalId: 'rectangle-position',
        zOrder: 'top',
      };
    }

    const handleTarget = this.getHandleTarget(point);

    if (handleTarget) {
      return {
        cursorStyle: this.getCursorStyle(handleTarget),
        externalId: 'rectangle-position',
        zOrder: 'top',
      };
    }

    if (!this.containsPoint(point)) {
      return null;
    }

    return {
      cursorStyle: 'grab',
      externalId: 'rectangle-position',
      zOrder: 'top',
    };
  }

  protected getTimeAxisSegments(): AxisSegment[] {
    if (!this.isSelected() && !this.isCreationPending()) {
      return [];
    }

    const bounds = this.getTimeBounds();

    if (!bounds) {
      return [];
    }

    const { colors } = getThemeStore();

    return [
      {
        from: bounds.left,
        to: bounds.right,
        color: colors.axisMarkerAreaFill,
      },
    ];
  }

  protected getPriceAxisSegments(): AxisSegment[] {
    if (!this.isSelected() && !this.isCreationPending()) {
      return [];
    }

    const bounds = this.getPriceBounds();

    if (!bounds) {
      return [];
    }

    const { colors } = getThemeStore();

    return [
      {
        from: bounds.top,
        to: bounds.bottom,
        color: colors.axisMarkerAreaFill,
      },
    ];
  }

  protected getTimeAxisLabel(kind: string): AxisLabel | null {
    if ((!this.isSelected() && !this.isCreationPending()) || (kind !== 'left' && kind !== 'right')) {
      return null;
    }

    const labelKind = kind as TimeLabelKind;
    const coordinate = this.getTimeCoordinate(labelKind);
    const text = this.getTimeText(labelKind);

    if (coordinate === null || !text) {
      return null;
    }

    const { colors } = getThemeStore();

    return {
      coordinate,
      text,
      textColor: colors.chartPriceLineText,
      backgroundColor: colors.axisMarkerLabelFill,
    };
  }

  protected getPriceAxisLabel(kind: string): AxisLabel | null {
    if ((!this.isSelected() && !this.isCreationPending()) || (kind !== 'top' && kind !== 'bottom')) {
      return null;
    }

    const labelKind = kind as PriceLabelKind;
    const coordinate = this.getPriceCoordinate(labelKind);
    const text = this.getPriceText(labelKind);

    if (coordinate === null || !text) {
      return null;
    }

    const { colors } = getThemeStore();

    return {
      coordinate,
      text,
      textColor: colors.chartPriceLineText,
      backgroundColor: colors.axisMarkerLabelFill,
    };
  }

  protected handleDoubleClick = (event: MouseEvent): void => {
    if (this.hidden || this.mode !== 'ready') {
      return;
    }

    const rect = this.container.getBoundingClientRect();
    const point = {
      x: event.clientX - rect.left,
      y: event.clientY - rect.top,
    };

    if (!this.containsPoint(point) && !this.getHandleTarget(point)) {
      return;
    }

    event.preventDefault();
    event.stopPropagation();

    this.openSettings?.();
  };

  protected handlePointerDown = (event: PointerEvent): void => {
    if (this.hidden || event.button !== 0) {
      return;
    }

    const point = this.getEventPoint(event);

    if (this.mode === 'idle') {
      event.preventDefault();
      event.stopPropagation();

      this.startDrawing(point);
      return;
    }

    if (this.mode === 'drawing') {
      event.preventDefault();
      event.stopPropagation();

      this.updateDrawing(point);
      this.finishDrawing();
      return;
    }

    if (this.mode !== 'ready') {
      return;
    }

    if (!this.isSelected()) {
      if (!this.containsPoint(point)) {
        return;
      }

      event.preventDefault();
      event.stopPropagation();

      this.select();
      return;
    }

    const dragTarget = this.getDragTarget(point);

    if (!dragTarget) {
      this.deselect();
      return;
    }

    event.preventDefault();
    event.stopPropagation();

    this.startDragging(point, event.pointerId, dragTarget);
  };

  protected handlePointerMove = (event: PointerEvent): void => {
    const point = this.getEventPoint(event);

    if (this.mode === 'drawing') {
      this.updateDrawing(point);
      return;
    }

    if (this.mode !== 'dragging' || this.dragPointerId !== event.pointerId) {
      return;
    }

    event.preventDefault();

    if (this.activeDragTarget === 'body') {
      this.moveWhole(point);
      this.render();
      return;
    }

    this.resizeRectangle(point);
    this.render();
  };

  protected handlePointerUp = (event: PointerEvent): void => {
    if (this.mode !== 'dragging' || this.dragPointerId !== event.pointerId) {
      return;
    }

    this.finishDragging();
  };

  private startDrawing(point: Point): void {
    const anchor = this.createAnchor(point);

    if (!anchor) {
      return;
    }

    this.startTime = anchor.time;
    this.endTime = anchor.time;
    this.startPrice = anchor.price;
    this.endPrice = anchor.price;
    this.mode = 'drawing';

    this.render();
  }

  private updateDrawing(point: Point): void {
    const clampedPoint = this.clampPointToContainer(point);
    const anchor = this.createAnchor(clampedPoint);

    if (!anchor) {
      return;
    }

    this.endTime = anchor.time;
    this.endPrice = anchor.price;

    this.render();
  }

  private finishDrawing(): void {
    const geometry = this.getGeometry();

    if (!geometry || geometry.width < MIN_RECTANGLE_SIZE || geometry.height < MIN_RECTANGLE_SIZE) {
      if (this.removeSelf) {
        this.removeSelf();
        return;
      }

      this.resetToIdle();
      return;
    }

    this.mode = 'ready';
    this.resolveReady?.();

    this.render();
  }

  private startDragging(point: Point, pointerId: number, dragTarget: Exclude<RectangleHandle, null>): void {
    this.mode = 'dragging';

    this.activeDragTarget = dragTarget;
    this.dragPointerId = pointerId;
    this.dragStartPoint = point;
    this.dragStateSnapshot = this.getState();
    this.dragGeometrySnapshot = this.getGeometry();

    this.render();
  }

  private finishDragging(): void {
    this.mode = 'ready';
    this.resolveReady?.();

    this.clearInteractionState();
    this.render();
  }

  private clearInteractionState(): void {
    this.activeDragTarget = null;
    this.dragPointerId = null;
    this.dragStartPoint = null;
    this.dragStateSnapshot = null;
    this.dragGeometrySnapshot = null;
  }

  private resetToIdle(): void {
    this.hidden = false;
    this.mode = 'idle';

    this.startTime = null;
    this.endTime = null;
    this.startPrice = null;
    this.endPrice = null;

    this.clearInteractionState();
    this.render();
  }

  private getDragTarget(point: Point): Exclude<RectangleHandle, null> | null {
    const handleTarget = this.getHandleTarget(point);

    if (handleTarget) {
      return handleTarget;
    }

    if (this.containsPoint(point)) {
      return 'body';
    }

    return null;
  }

  private moveWhole(point: Point): void {
    const snapshot = this.dragStateSnapshot;
    const geometry = this.dragGeometrySnapshot;

    if (!snapshot || !geometry || !this.dragStartPoint) {
      return;
    }

    if (
      snapshot.startTime === null ||
      snapshot.endTime === null ||
      snapshot.startPrice === null ||
      snapshot.endPrice === null
    ) {
      return;
    }

    const containerSize = this.getContainerSize();

    const rawOffsetX = point.x - this.dragStartPoint.x;
    const rawOffsetY = point.y - this.dragStartPoint.y;

    const minOffsetX = -geometry.left;
    const maxOffsetX = containerSize.width - geometry.right;
    const clampedOffsetX = clamp(rawOffsetX, minOffsetX, maxOffsetX);

    const minOffsetY = -geometry.top;
    const maxOffsetY = containerSize.height - geometry.bottom;
    const clampedOffsetY = clamp(rawOffsetY, minOffsetY, maxOffsetY);

    const nextStartTime = this.shiftTime(snapshot.startTime, clampedOffsetX);
    const nextEndTime = this.shiftTime(snapshot.endTime, clampedOffsetX);

    if (nextStartTime === null || nextEndTime === null) {
      return;
    }

    const priceOffset = this.getPriceDelta(this.dragStartPoint.y, this.dragStartPoint.y + clampedOffsetY);

    this.startTime = nextStartTime;
    this.endTime = nextEndTime;
    this.startPrice = snapshot.startPrice + priceOffset;
    this.endPrice = snapshot.endPrice + priceOffset;
  }

  private resizeRectangle(point: Point): void {
    const geometry = this.dragGeometrySnapshot;

    if (!geometry || !this.activeDragTarget || this.activeDragTarget === 'body') {
      return;
    }

    const clampedPoint = this.clampPointToContainer(point);

    let { left } = geometry;
    let { right } = geometry;
    let { top } = geometry;
    let { bottom } = geometry;

    switch (this.activeDragTarget) {
      case 'nw':
        left = clampedPoint.x;
        top = clampedPoint.y;
        break;
      case 'n':
        top = clampedPoint.y;
        break;
      case 'ne':
        right = clampedPoint.x;
        top = clampedPoint.y;
        break;
      case 'e':
        right = clampedPoint.x;
        break;
      case 'se':
        right = clampedPoint.x;
        bottom = clampedPoint.y;
        break;
      case 's':
        bottom = clampedPoint.y;
        break;
      case 'sw':
        left = clampedPoint.x;
        bottom = clampedPoint.y;
        break;
      case 'w':
        left = clampedPoint.x;
        break;
      default:
        return;
    }

    this.setRectangleBounds(left, right, top, bottom);
  }

  private setRectangleBounds(left: number, right: number, top: number, bottom: number): boolean {
    const bounds = normalizeBounds(left, right, top, bottom, this.container);

    const startTime = getTimeFromXCoordinate(this.chart, bounds.left);
    const endTime = getTimeFromXCoordinate(this.chart, bounds.right);
    const startPrice = getPriceFromYCoordinate(this.series, bounds.top);
    const endPrice = getPriceFromYCoordinate(this.series, bounds.bottom);

    if (startTime === null || endTime === null || startPrice === null || endPrice === null) {
      return false;
    }

    this.startTime = startTime;
    this.endTime = endTime;
    this.startPrice = startPrice;
    this.endPrice = endPrice;

    return true;
  }

  private createAnchor(point: Point): { time: Time; price: number } | null {
    return getAnchorFromPoint(this.chart, this.series, point);
  }

  protected getGeometry(): RectangleGeometry | null {
    if (this.startTime === null || this.endTime === null || this.startPrice === null || this.endPrice === null) {
      return null;
    }

    const startX = getXCoordinateFromTime(this.chart, this.startTime, this.series);
    const endX = getXCoordinateFromTime(this.chart, this.endTime, this.series);
    const startY = getYCoordinateFromPrice(this.series, this.startPrice);
    const endY = getYCoordinateFromPrice(this.series, this.endPrice);

    if (startX === null || endX === null || startY === null || endY === null) {
      return null;
    }

    const left = Math.round(Math.min(Number(startX), Number(endX)));
    const right = Math.round(Math.max(Number(startX), Number(endX)));
    const top = Math.round(Math.min(Number(startY), Number(endY)));
    const bottom = Math.round(Math.max(Number(startY), Number(endY)));

    const centerX = (left + right) / 2;
    const centerY = (top + bottom) / 2;

    return {
      left,
      right,
      top,
      bottom,
      width: right - left,
      height: bottom - top,
      handles: {
        nw: { x: left, y: top },
        n: { x: centerX, y: top },
        ne: { x: right, y: top },
        e: { x: right, y: centerY },
        se: { x: right, y: bottom },
        s: { x: centerX, y: bottom },
        sw: { x: left, y: bottom },
        w: { x: left, y: centerY },
      },
    };
  }

  private getTimeBounds(): { left: number; right: number } | null {
    const geometry = this.getGeometry();

    if (!geometry) {
      return null;
    }

    return {
      left: geometry.left,
      right: geometry.right,
    };
  }

  private getPriceBounds(): { top: number; bottom: number } | null {
    const geometry = this.getGeometry();

    if (!geometry) {
      return null;
    }

    return {
      top: geometry.top,
      bottom: geometry.bottom,
    };
  }

  private getTimeCoordinate(kind: TimeLabelKind): number | null {
    const geometry = this.getGeometry();

    if (!geometry) {
      return null;
    }

    return kind === 'left' ? geometry.left : geometry.right;
  }

  private getPriceCoordinate(kind: PriceLabelKind): number | null {
    const geometry = this.getGeometry();

    if (!geometry) {
      return null;
    }

    return kind === 'top' ? geometry.top : geometry.bottom;
  }

  private getTimeText(kind: TimeLabelKind): string {
    const time = this.getTimeValueForLabel(kind);

    if (typeof time !== 'number') {
      return '';
    }

    return formatDate(
      time as UTCTimestamp,
      this.displayFormat.dateFormat,
      this.displayFormat.timeFormat,
      this.displayFormat.showTime,
    );
  }

  private getPriceText(kind: PriceLabelKind): string {
    const price = this.getPriceValueForLabel(kind);

    if (price === null) {
      return '';
    }

    return formatPrice(price) ?? '';
  }

  private getTimeValueForLabel(kind: TimeLabelKind): Time | null {
    if (this.startTime === null || this.endTime === null) {
      return null;
    }

    const startX = getXCoordinateFromTime(this.chart, this.startTime, this.series);
    const endX = getXCoordinateFromTime(this.chart, this.endTime, this.series);

    if (startX === null || endX === null) {
      return kind === 'left' ? this.startTime : this.endTime;
    }

    const startIsLeft = Number(startX) <= Number(endX);

    if (kind === 'left') {
      return startIsLeft ? this.startTime : this.endTime;
    }

    return startIsLeft ? this.endTime : this.startTime;
  }

  private getPriceValueForLabel(kind: PriceLabelKind): number | null {
    if (this.startPrice === null || this.endPrice === null) {
      return null;
    }

    const startY = getYCoordinateFromPrice(this.series, this.startPrice);
    const endY = getYCoordinateFromPrice(this.series, this.endPrice);

    if (startY === null || endY === null) {
      return kind === 'top' ? Math.max(this.startPrice, this.endPrice) : Math.min(this.startPrice, this.endPrice);
    }

    const startIsTop = Number(startY) <= Number(endY);

    if (kind === 'top') {
      return startIsTop ? this.startPrice : this.endPrice;
    }

    return startIsTop ? this.endPrice : this.startPrice;
  }

  private getHandleTarget(point: Point): RectangleHandleKey | null {
    const geometry = this.getGeometry();

    if (!geometry) {
      return null;
    }

    const handleOrder: RectangleHandleKey[] = ['nw', 'n', 'ne', 'e', 'se', 's', 'sw', 'w'];

    for (const handleName of handleOrder) {
      const handle = geometry.handles[handleName];

      if (isNearPoint(point, handle.x, handle.y, HANDLE_HIT_TOLERANCE)) {
        return handleName;
      }
    }

    return null;
  }

  private containsPoint(point: Point): boolean {
    const geometry = this.getGeometry();

    if (!geometry) {
      return false;
    }

    return isPointInBounds(point, geometry, BODY_HIT_TOLERANCE);
  }

  private getCursorStyle(handle: Exclude<RectangleHandle, null>): PrimitiveHoveredItem['cursorStyle'] {
    switch (handle) {
      case 'nw':
      case 'se':
        return 'nwse-resize';
      case 'ne':
      case 'sw':
        return 'nesw-resize';
      case 'n':
      case 's':
        return 'ns-resize';
      case 'e':
      case 'w':
        return 'ew-resize';
      case 'body':
        return 'grab';
      default:
        return 'default';
    }
  }

  private shiftTime(time: Time, offsetX: number): Time | null {
    return shiftTimeByPixels(this.chart, time, offsetX, this.series);
  }

  private getPriceDelta(fromY: number, toY: number): number {
    return getPriceDeltaFromCoordinates(this.series, fromY, toY);
  }

  private getContainerSize(): { width: number; height: number } {
    return getElementContainerSize(this.container);
  }

  private clampPointToContainer(point: Point): Point {
    return clampPointToContainerInElement(point, this.container);
  }
}