---

import type { Anchor, Bounds, ContainerSize, Point, SeriesApi } from './types';

import type { Coordinate, IChartApi, Logical, Time } from 'lightweight-charts';

interface SeriesTimeItem {
  time: Time;
}

interface TimePoint {
  time: number;
  logical: number;
}

export function getPriceFromYCoordinate(series: SeriesApi, yCoordinate: number): number | null {
  return series.coordinateToPrice(yCoordinate as Coordinate);
}

export function getYCoordinateFromPrice(series: SeriesApi, price: number): Coordinate | null {
  return series.priceToCoordinate(price);
}

export function getTimeFromXCoordinate(chart: IChartApi, xCoordinate: number): Time | null {
  return chart.timeScale().coordinateToTime(xCoordinate as Coordinate) ?? null;
}

export function getXCoordinateFromTime(chart: IChartApi, time: Time, series?: SeriesApi): Coordinate | null {
  const coordinate = chart.timeScale().timeToCoordinate(time);

  if (isValidCoordinate(coordinate)) {
    return coordinate;
  }

  if (!series) {
    return null;
  }

  const logical = getNearestLogicalFromTime(series, time);

  if (logical === null) {
    return null;
  }

  const projectedCoordinate = chart.timeScale().logicalToCoordinate(logical as Logical);

  if (!isValidCoordinate(projectedCoordinate)) {
    return null;
  }

  return projectedCoordinate;
}

export function clamp(value: number, min: number, max: number): number {
  return Math.max(min, Math.min(value, max));
}

export function getContainerSize(container: HTMLElement): ContainerSize {
  const rect = container.getBoundingClientRect();

  return {
    width: rect.width,
    height: rect.height,
  };
}

export function clampPointToContainer(point: Point, container: HTMLElement): Point {
  const { width, height } = getContainerSize(container);

  return {
    x: clamp(point.x, 0, width),
    y: clamp(point.y, 0, height),
  };
}

export function getPointerPoint(container: HTMLElement, event: PointerEvent): Point {
  const rect = container.getBoundingClientRect();

  return clampPointToContainer(
    {
      x: event.clientX - rect.left,
      y: event.clientY - rect.top,
    },
    container,
  );
}

export function isNearPoint(point: Point, x: number, y: number, tolerance: number): boolean {
  return Math.abs(point.x - x) <= tolerance && Math.abs(point.y - y) <= tolerance;
}

export function isPointInBounds(point: Point, bounds: Bounds, tolerance = 0): boolean {
  return (
    point.x >= bounds.left - tolerance &&
    point.x <= bounds.right + tolerance &&
    point.y >= bounds.top - tolerance &&
    point.y <= bounds.bottom + tolerance
  );
}

export function normalizeBounds(
  left: number,
  right: number,
  top: number,
  bottom: number,
  container: HTMLElement,
): Bounds {
  const { width, height } = getContainerSize(container);

  return {
    left: clamp(Math.min(left, right), 0, width),
    right: clamp(Math.max(left, right), 0, width),
    top: clamp(Math.min(top, bottom), 0, height),
    bottom: clamp(Math.max(top, bottom), 0, height),
  };
}

export function shiftTimeByPixels(chart: IChartApi, time: Time, offsetX: number): Time | null {
  const coordinate = chart.timeScale().timeToCoordinate(time);

  if (!isValidCoordinate(coordinate)) {
    return null;
  }

  return getTimeFromXCoordinate(chart, Number(coordinate) + offsetX);
}

export function getPriceDelta(series: SeriesApi, fromY: number, toY: number): number {
  const fromPrice = getPriceFromYCoordinate(series, fromY);
  const toPrice = getPriceFromYCoordinate(series, toY);

  if (fromPrice === null || toPrice === null) {
    return 0;
  }

  return toPrice - fromPrice;
}

export function getPriceRangeInContainer(
  series: SeriesApi,
  container: HTMLElement,
): { min: number; max: number } | null {
  const { height } = getContainerSize(container);

  if (!height) {
    return null;
  }

  const topPrice = getPriceFromYCoordinate(series, 0);
  const bottomPrice = getPriceFromYCoordinate(series, height);

  if (topPrice === null || bottomPrice === null) {
    return null;
  }

  return {
    min: Math.min(topPrice, bottomPrice),
    max: Math.max(topPrice, bottomPrice),
  };
}

export function getAnchorFromPoint(chart: IChartApi, series: SeriesApi, point: Point): Anchor | null {
  const time = getTimeFromXCoordinate(chart, point.x);
  const price = getPriceFromYCoordinate(series, point.y);

  if (time === null || price === null) {
    return null;
  }

  return {
    time,
    price,
  };
}

function getNearestLogicalFromTime(series: SeriesApi, time: Time): number | null {
  const targetTime = getNumericTime(time);

  if (targetTime === null) {
    return null;
  }

  const points = getSeriesTimePoints(series);

  if (!points.length) {
    return null;
  }

  const lastIndex = points.length - 1;

  if (targetTime <= points[0].time) {
    return points[0].logical;
  }

  if (targetTime >= points[lastIndex].time) {
    return points[lastIndex].logical;
  }

  let left = 0;
  let right = lastIndex;

  while (left <= right) {
    const middleIndex = Math.floor((left + right) / 2);
    const middleTime = points[middleIndex].time;

    if (middleTime === targetTime) {
      return points[middleIndex].logical;
    }

    if (middleTime < targetTime) {
      left = middleIndex + 1;
    } else {
      right = middleIndex - 1;
    }
  }

  // Если точного времени нет на текущем таймфрейме, left и right становятся соседними свечами вокруг targetTime
  // Для отображения дровинга берём ближайшую существующую свечу, но исходный state дровинга не меняем
  const previousPoint = points[right] ?? null;
  const nextPoint = points[left] ?? null;

  return getNearestLogicalByTime(targetTime, previousPoint, nextPoint);
}

function getNearestLogicalByTime(
  targetTime: number,
  previousPoint: TimePoint | null,
  nextPoint: TimePoint | null,
): number | null {
  if (!previousPoint && !nextPoint) {
    return null;
  }

  if (!previousPoint) {
    return nextPoint?.logical ?? null;
  }

  if (!nextPoint) {
    return previousPoint.logical;
  }

  const previousDistance = Math.abs(targetTime - previousPoint.time);
  const nextDistance = Math.abs(nextPoint.time - targetTime);

  return nextDistance < previousDistance ? nextPoint.logical : previousPoint.logical;
}

function getSeriesTimePoints(series: SeriesApi): TimePoint[] {
  const data = series.data() as readonly SeriesTimeItem[];

  return data.reduce<TimePoint[]>((points, item, logical) => {
    const time = getNumericTime(item.time);

    if (time === null) {
      return points;
    }

    points.push({
      time,
      logical,
    });

    return points;
  }, []);
}

function getNumericTime(time: Time): number | null {
  if (typeof time !== 'number') {
    return null;
  }

  return Number.isFinite(time) ? time : null;
}

function isValidCoordinate(coordinate: Coordinate | null): coordinate is Coordinate {
  return coordinate !== null && Number.isFinite(Number(coordinate));
}