---

export type DrawingHitArea = 'handle' | 'body';


import {
  AutoscaleInfo,
  CrosshairMode,
  IChartApi,
  IPrimitivePaneView,
  ISeriesApi,
  ISeriesPrimitive,
  ISeriesPrimitiveAxisView,
  Logical,
  PrimitiveHoveredItem,
  SeriesAttachedParameter,
  SeriesOptionsMap,
  SeriesType,
  Time,
} from 'lightweight-charts';
import { Observable, Subject, Subscription } from 'rxjs';

import { getPointerPoint as getPointerPointFromEvent } from '@core/Drawings/helpers';
import { AxisLabel, AxisSegment, DrawingHitArea, Point, SeriesApi } from '@core/Drawings/types';

import { SettingsTab, SettingsValues } from '@src/types';

export interface DrawingInteraction {
  selected$: Observable<boolean>;
  locked$: Observable<boolean>;

  isSelected(): boolean;
  isLocked(): boolean;

  select(): void;
  deselect(): void;
}

export interface ISeriesDrawing extends ISeriesPrimitive<Time> {
  show(): void;
  hide(): void;
  rebind(series: ISeriesApi<SeriesType>): void;
  destroy(): void;

  waitTillReady(): Promise<void>;
  isCreationPending(): boolean;
  shouldShowInObjectTree(): boolean;

  getState(): unknown;
  setState(state: unknown): void;

  getSettings(): SettingsValues;
  getSettingsTabs(): SettingsTab[];
  updateSettings(settings: SettingsValues): void;

  subscribeSettings(callback: (settings: SettingsValues) => void): Subscription;

  getHitArea(event: PointerEvent): DrawingHitArea | null;
  handlePointerDownEvent(event: PointerEvent): void;

  getRenderData(): unknown;
}

interface SeriesDrawingBaseParams {
  container: HTMLElement;
  chart: IChartApi;
  series: SeriesApi;
  interaction: DrawingInteraction;
}

export abstract class SeriesDrawingBase<TSettings extends SettingsValues = SettingsValues> implements ISeriesDrawing {
  protected hidden = false;
  protected chart: IChartApi;
  protected series: SeriesApi;
  protected subscriptions = new Subscription();
  protected abstract mode: unknown; // todo: хочется иметь единый mode
  protected abstract settings: TSettings;
  protected readonly container: HTMLElement;
  protected isBound = false;

  private readonly interaction: DrawingInteraction;
  private readonly settingsSubject = new Subject<SettingsValues>();
  private isInteractionBound = false;

  protected readyPromise: Promise<void> | null = null;
  protected resolveReady: (() => void) | null = null;
  protected requestUpdate: (() => void) | null = null;

  constructor({ chart, series, container, interaction }: SeriesDrawingBaseParams) {
    this.chart = chart;
    this.series = series;
    this.container = container;
    this.interaction = interaction;
  }

  public subscribeSettings(callback: (settings: SettingsValues) => void): Subscription {
    callback(this.getSettings());

    return this.settingsSubject.subscribe(callback);
  }

  public show(): void {
    this.hidden = false;
    this.render();
  }

  public hide(): void {
    this.hidden = true;
    this.showCrosshair();
    this.render();
  }

  public rebind(series: SeriesApi): void {
    if (this.series === series) {
      return;
    }

    this.showCrosshair();
    this.unbindEvents();
    this.series.detachPrimitive(this as unknown as ISeriesPrimitive<Time>);

    this.series = series;
    this.requestUpdate = null;

    this.series.attachPrimitive(this as unknown as ISeriesPrimitive<Time>);
    this.render();
  }

  public destroy(): void {
    this.showCrosshair();
    this.unbindEvents();
    this.subscriptions.unsubscribe();
    this.settingsSubject.complete();
    this.series.detachPrimitive(this as unknown as ISeriesPrimitive<Time>);
    this.requestUpdate = null;
    this.resolveReady?.();
  }

  public waitTillReady(): Promise<void> {
    if (this.mode === 'ready') {
      return Promise.resolve();
    }

    if (!this.readyPromise) {
      this.readyPromise = new Promise((resolve) => {
        this.resolveReady = resolve;
      });
    }

    return this.readyPromise;
  }

  public shouldShowInObjectTree(): boolean {
    return this.mode !== 'idle';
  }

  public getSettings(): SettingsValues {
    return { ...this.settings };
  }

  public updateSettings(settings: SettingsValues): void {
    this.settings = {
      ...this.settings,
      ...settings,
    };

    this.settingsSubject.next(this.getSettings());
    this.render();
  }

  public attached(param: SeriesAttachedParameter<Time, keyof SeriesOptionsMap>): void {
    this.requestUpdate = param.requestUpdate;
    this.bindInteraction();
    this.bindEvents();
  }

  public detached(): void {
    this.showCrosshair();
    this.unbindEvents();
    this.requestUpdate = null;
  }

  public autoscaleInfo(_start: Logical, _end: Logical): AutoscaleInfo | null {
    return null;
  }

  public hitTest(x: number, y: number): PrimitiveHoveredItem | null {
    const hoveredItem = this.getHoveredItem(x, y);

    if (!hoveredItem || !this.isLocked()) {
      return hoveredItem;
    }

    return {
      ...hoveredItem,
      cursorStyle: 'pointer',
    };
  }

  public getHitArea(event: PointerEvent): DrawingHitArea | null {
    if (!this.isPointerInside(event)) {
      return null;
    }

    const point = this.getEventPoint(event);

    if (!this.getHoveredItem(point.x, point.y)) {
      return null;
    }

    if (!this.isLocked() && this.isSelected() && this.isHandle(point)) {
      return 'handle';
    }

    return 'body';
  }

  public abstract getRenderData(): unknown; // todo: make proper type
  public abstract getState(): unknown;
  public abstract getSettingsTabs(): SettingsTab[];
  public abstract isCreationPending(): boolean;
  public abstract setState(state: unknown): void;
  public abstract updateAllViews(): void;
  public abstract paneViews(): readonly IPrimitivePaneView[];
  public abstract priceAxisPaneViews(): readonly IPrimitivePaneView[];
  public abstract priceAxisViews(): readonly ISeriesPrimitiveAxisView[];
  public abstract timeAxisPaneViews(): readonly IPrimitivePaneView[];
  public abstract timeAxisViews(): readonly ISeriesPrimitiveAxisView[];

  protected isSelected(): boolean {
    return this.interaction.isSelected();
  }

  protected isLocked(): boolean {
    return this.interaction.isLocked();
  }

  protected select(): void {
    this.interaction.select();
  }

  protected deselect(): void {
    this.interaction.deselect();
  }

  protected shouldShowHandles(): boolean {
    return !this.isLocked() && (this.isSelected() || this.isCreationPending());
  }

  protected render(): void {
    this.updateAllViews();
    this.requestUpdate?.();
  }

  protected hideCrosshair(): void {
    this.chart.applyOptions({
      crosshair: {
        mode: CrosshairMode.Hidden,
      },
    });
  }

  protected showCrosshair(): void {
    this.chart.applyOptions({
      crosshair: {
        mode: CrosshairMode.Normal,
      },
    });
  }

  protected getEventPoint(event: PointerEvent): Point {
    return getPointerPointFromEvent(this.container, event);
  }

  protected bindEvents(): void {
    if (this.isBound) {
      return;
    }

    this.isBound = true;

    this.container.addEventListener('dblclick', this.handleDoubleClick);
    this.container.addEventListener('contextmenu', this.handleContextMenu);

    window.addEventListener('pointermove', this.handlePointerMove);
    window.addEventListener('pointerup', this.handlePointerUp);
    window.addEventListener('pointercancel', this.handlePointerUp);
  }

  protected unbindEvents(): void {
    if (!this.isBound) {
      return;
    }

    this.isBound = false;

    this.container.removeEventListener('dblclick', this.handleDoubleClick);
    this.container.removeEventListener('contextmenu', this.handleContextMenu);

    window.removeEventListener('pointermove', this.handlePointerMove);
    window.removeEventListener('pointerup', this.handlePointerUp);
    window.removeEventListener('pointercancel', this.handlePointerUp);
  }

  // todo: хочется общую реализацию для каждой кнопки
  protected handleContextMenu(event: MouseEvent): void {}
  protected handleDoubleClick(event: MouseEvent): void {}
  protected handlePointerDown(event: PointerEvent): void {}
  protected handlePointerMove(event: PointerEvent): void {}
  protected handlePointerUp(event: PointerEvent): void {}

  protected isHandle(point: Point): boolean {
    return false;
  }

  protected abstract getHoveredItem(x: number, y: number): PrimitiveHoveredItem | null;
  protected abstract getGeometry(): unknown; // todo: make proper type
  protected abstract getTimeAxisSegments(): AxisSegment[];
  protected abstract getPriceAxisSegments(): AxisSegment[];
  protected abstract getTimeAxisLabel(kind: string): AxisLabel | null;
  protected abstract getPriceAxisLabel(kind: string): AxisLabel | null;

  private bindInteraction(): void {
    if (this.isInteractionBound) {
      return;
    }

    this.isInteractionBound = true;

    this.subscriptions.add(
      this.interaction.selected$.subscribe(() => {
        this.render();
      }),
    );

    this.subscriptions.add(
      this.interaction.locked$.subscribe((isLocked) => {
        if (isLocked) {
          this.showCrosshair();
        }

        this.render();
      }),
    );
  }

  public handlePointerDownEvent = (event: PointerEvent): void => {
    if (!this.isPointerInside(event)) {
      return;
    }

    if (!this.isLocked() || this.isCreationPending() || event.button !== 0) {
      this.handlePointerDown(event);

      return;
    }

    const point = this.getEventPoint(event);
    const isDrawingHit = this.getHoveredItem(point.x, point.y) !== null;

    if (isDrawingHit) {
      this.select();

      return;
    }

    if (this.isSelected()) {
      this.deselect();
    }
  };

  private isPointerInside(event: PointerEvent): boolean {
    return event.target instanceof Node && this.container.contains(event.target);
  }
}


private handlePointerDown = (event: PointerEvent): void => {
  this.selectedDrawingSnapshot = null;

  queueMicrotask(() => {
    const drawing = this.selectedDrawing$.value;

    if (!drawing || drawing.isCreationPending()) {
      return;
    }

    this.selectedDrawingSnapshot = this.createDrawingSnapshot(drawing);
  });

  if (event.button === 0) {
    const pendingDrawing = this.drawings$.value.find((drawing) => drawing.isCreationPending());
    const drawing = pendingDrawing ?? this.getPointerDownDrawing(event) ?? this.selectedDrawing$.value;

    drawing?.getLwcDrawing().handlePointerDownEvent(event);
  }

  this.DOM.refreshEntities();
};

private getPointerDownDrawing(event: PointerEvent): Drawing | null {
  const selectedDrawing = this.selectedDrawing$.value;

  let candidate: Drawing | null = null;
  let candidatePriority = -1;

  this.drawings$.value.forEach((drawing) => {
    const area = drawing.getLwcDrawing().getHitArea(event);

    if (!area) {
      return;
    }

    const priority = area === 'handle' ? 2 : drawing === selectedDrawing ? 1 : 0;

    if (
      candidate &&
      (priority < candidatePriority || (priority === candidatePriority && drawing.zIndex <= candidate.zIndex))
    ) {
      return;
    }

    candidate = drawing;
    candidatePriority = priority;
  });

  return candidate;
}



protected isHandle(point: Point): boolean {
  return this.getPointTarget(point) !== null;
}


protected isHandle(point: Point): boolean {
  const target = this.getDragTarget(point);

  return target !== null && target !== 'body';
}


protected isHandle(point: Point): boolean {
  return this.getPointIndexAt(point) !== null;
}

protected isHandle(point: Point): boolean {
  const data = this.getRenderData();

  return data !== null && isNearPoint(point, data.handle.x, data.handle.y, HANDLE_HIT_TOLERANCE);
}