// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import * as Host from '../../../core/host/host.js';
import type * as LitHtml from '../../../ui/lit-html/lit-html.js';
import * as i18n from '../../../core/i18n/i18n.js';

import type {Event, Marker, Timebox, WebVitalsTimeline} from './WebVitalsTimeline.js';
import {assertInstanceOf, LONG_TASK_THRESHOLD, MarkerType} from './WebVitalsTimeline.js';

type GetMarkerTypeCallback = (event: Event) => MarkerType;
type GetMarkerOverlayCallback = (marker: Marker) => LitHtml.TemplateResult;
type GetTimeboxOverlayCallback = (marker: Timebox) => LitHtml.TemplateResult;

abstract class WebVitalsLane {
  protected context: CanvasRenderingContext2D;
  protected timeline: WebVitalsTimeline;
  protected theme: {[key: string]: string};

  constructor(timeline: WebVitalsTimeline) {
    this.timeline = timeline;
    this.context = timeline.getContext();

    const styles = getComputedStyle(document.documentElement);
    this.theme = {
      good: styles.getPropertyValue('--lighthouse-green'),
      medium: styles.getPropertyValue('--lighthouse-orange'),
      bad: styles.getPropertyValue('--lighthouse-red'),
      frame: styles.getPropertyValue('--color-primary'),
      textPrimary: styles.getPropertyValue('--color-text-primary'),
      textSecondary: styles.getPropertyValue('--color-text-secondary'),
      background: styles.getPropertyValue('--color-background'),
      background50: styles.getPropertyValue('--color-background-opacity-50'),
      timeboxColor: styles.getPropertyValue('--color-primary-variant'),
    };
  }

  abstract handlePointerMove(x: number|null): void;
  abstract handleClick(x: number|null): void;

  protected tX(x: number): number {
    return this.timeline.tX(x);
  }

  protected tD(x: number): number {
    return this.timeline.tD(x);
  }

  protected renderLaneLabel(label: string): void {
    const upperCaseLabel = label.toLocaleUpperCase();
    this.context.save();

    this.context.font = '9px ' + Host.Platform.fontFamily();
    const text = this.context.measureText(upperCaseLabel);
    const height = text.actualBoundingBoxAscent - text.actualBoundingBoxDescent;
    this.context.fillStyle = this.theme.background50;
    this.context.fillRect(0, 1, text.width + 12, height + 6);
    this.context.fillStyle = this.theme.textSecondary;
    this.context.fillText(upperCaseLabel, 6, height + 4);
    this.context.restore();
  }

  render(): void {
  }
}

export class WebVitalsEventLane extends WebVitalsLane {
  #markers: readonly Marker[] = [];
  #selectedMarker: Marker|null = null;
  #hoverMarker: Marker|null = null;
  #labelMetrics: TextMetrics;
  #label: string;
  #getMarkerType: GetMarkerTypeCallback;
  #getMarkerOverlay?: GetMarkerOverlayCallback;

  constructor(
      timeline: WebVitalsTimeline, label: string, getMarkerType: GetMarkerTypeCallback,
      getMarkerOverlay?: GetMarkerOverlayCallback) {
    super(timeline);
    this.context = timeline.getContext();
    this.#label = label;
    this.#getMarkerType = getMarkerType;
    this.#getMarkerOverlay = getMarkerOverlay;
    this.#labelMetrics = this.#measureLabel(this.#label);
  }

  handlePointerMove(x: number|null): void {
    const prevHoverMarker = this.#hoverMarker;
    if (x === null) {
      this.#hoverMarker = null;
    } else {
      this.#hoverMarker = this.#markers.find(m => {
        const tX = this.tX(m.timestamp);
        return tX - 5 <= x && x <= tX + m.widthIncludingLabel;
      }) ||
          null;
    }

    if (prevHoverMarker !== this.#hoverMarker) {
      if (this.#hoverMarker && this.#getMarkerOverlay) {
        this.timeline.showOverlay(this.#getMarkerOverlay(this.#hoverMarker));
      } else {
        this.timeline.hideOverlay();
      }
    }
  }

  handleClick(_: number|null): void {
    this.#selectedMarker = this.#hoverMarker;
  }

  setEvents(markers: readonly Event[]): void {
    this.#hoverMarker = null;
    this.#selectedMarker = null;
    this.#markers = markers.map(e => this.#getMarker(e));
  }

  #measureLabel(label: string): TextMetrics {
    this.context.save();
    this.context.font = '11px ' + Host.Platform.fontFamily();
    const textMetrics = this.context.measureText(label);
    this.context.restore();
    return textMetrics;
  }

  #measureTimestamp(timestamp: string): TextMetrics {
    this.context.save();
    this.context.font = '11px ' + Host.Platform.fontFamily();
    const textMetrics = this.context.measureText(timestamp);
    this.context.restore();
    return textMetrics;
  }

  #getMarker(event: Event): Marker {
    const markerType = this.#getMarkerType(event);
    const timestamp = this.timeline.getTimeSinceLastMainFrameNavigation(event.timestamp);
    const timestampLabel = i18n.TimeUtilities.preciseMillisToString(timestamp, 1);
    const timestampMetrics = this.#measureTimestamp(timestampLabel);
    const widthIncludingLabel = 10 + 5 + this.#labelMetrics.width + 5;
    const widthIncludingTimestamp = widthIncludingLabel + 5 + timestampMetrics.width;

    return {
      timestamp: event.timestamp,
      timestampLabel,
      type: markerType,
      timestampMetrics,
      widthIncludingLabel,
      widthIncludingTimestamp,
    };
  }

  #renderLabel(position: number, label: string, textMetrics: TextMetrics): void {
    this.context.save();
    this.context.font = '11px ' + Host.Platform.fontFamily();
    const height = textMetrics.actualBoundingBoxAscent - textMetrics.actualBoundingBoxDescent;
    this.context.fillStyle = this.theme.textPrimary;
    this.context.fillText(
        label, this.tX(position) + this.timeline.getLineHeight() * 0.5,
        0.5 * this.timeline.getLineHeight() + height * .5);
    this.context.restore();
  }

  #renderTimestamp(position: number, textWidth: number, timestamp: string, textMetrics: TextMetrics): void {
    this.context.save();
    this.context.font = '11px ' + Host.Platform.fontFamily();
    const height = textMetrics.actualBoundingBoxAscent - textMetrics.actualBoundingBoxDescent;
    this.context.fillStyle = this.theme.textSecondary;
    this.context.fillText(
        timestamp, this.tX(position) + this.timeline.getLineHeight() * 0.5 + textWidth + 5,
        0.5 * this.timeline.getLineHeight() + height * .5);
    this.context.restore();
  }

  #renderGoodMarkerSymbol(timestamp: number): void {
    const radius = 5;

    this.context.save();
    this.context.beginPath();
    this.context.strokeStyle = this.theme.good;
    this.context.moveTo(this.tX(timestamp), 2);
    this.context.lineTo(this.tX(timestamp), 5);
    this.context.moveTo(this.tX(timestamp), 19);
    this.context.lineTo(this.tX(timestamp), 22);
    this.context.stroke();

    this.context.beginPath();
    this.context.fillStyle = this.theme.good;
    this.context.arc(this.tX(timestamp), 0.5 * this.timeline.getLineHeight(), radius, 0, Math.PI * 2);
    this.context.fill();
    this.context.restore();
  }

  #renderMediumMarkerSymbol(timestamp: number): void {
    this.context.save();
    this.context.beginPath();
    this.context.strokeStyle = this.theme.medium;
    this.context.moveTo(this.tX(timestamp), 2);
    this.context.lineTo(this.tX(timestamp), 5);
    this.context.moveTo(this.tX(timestamp), 19);
    this.context.lineTo(this.tX(timestamp), 22);
    this.context.stroke();

    this.context.beginPath();
    this.context.fillStyle = this.theme.medium;
    this.context.rect(this.tX(timestamp) - 5, 0.5 * this.timeline.getLineHeight() - 5, 10, 10);
    this.context.fill();
    this.context.restore();
  }

  #renderBadMarkerSymbol(timestamp: number): void {
    this.context.save();
    this.context.beginPath();
    this.context.strokeStyle = this.theme.bad;
    this.context.moveTo(this.tX(timestamp), 2);
    this.context.lineTo(this.tX(timestamp), 5);
    this.context.moveTo(this.tX(timestamp), 19);
    this.context.lineTo(this.tX(timestamp), 22);
    this.context.stroke();

    this.context.beginPath();
    this.context.fillStyle = this.theme.bad;
    this.context.translate(this.tX(timestamp), 0.5 * this.timeline.getLineHeight());
    this.context.rotate(45 * Math.PI / 180);
    this.context.rect(-4, -4, 8, 8);
    this.context.rotate(-45 * Math.PI / 180);
    this.context.translate(-this.tX(timestamp), -0.5 * this.timeline.getLineHeight());
    this.context.fill();
    this.context.restore();
  }

  #renderMarker(marker: Marker, selected: boolean, hover: boolean, nextMarker: Marker|null): void {
    const timestampLabel = marker.timestampLabel;
    const labelMetrics = this.#labelMetrics;
    const timestampMetrics = marker.timestampMetrics;

    const showFrame = selected;
    const showDetails = hover || selected;
    const widthIncludingLabel = marker.widthIncludingLabel;
    const widthIncludingTimestamp = showDetails ? marker.widthIncludingTimestamp : widthIncludingLabel;

    const pixelDistance = nextMarker ? this.tD(nextMarker.timestamp - marker.timestamp) : null;
    const showLabel = showDetails || (pixelDistance !== null && pixelDistance > widthIncludingLabel + 5);

    if (showDetails) {
      this.context.save();
      const tX = this.tX(marker.timestamp) - 5 - 5;
      const tY = 1;
      const tWidth = widthIncludingTimestamp + 2 * 5;
      const tHeight = this.timeline.getLineHeight() - 2;

      this.context.fillStyle = this.theme.background;
      this.context.fillRect(tX, tY, tWidth, tHeight);

      if (showFrame) {
        this.context.strokeStyle = this.theme.frame;
        this.context.lineWidth = 2;
        this.context.strokeRect(tX, tY, tWidth, tHeight);
        this.context.lineWidth = 1;
      }

      this.context.restore();
    }

    if (showLabel) {
      if (labelMetrics) {
        this.#renderLabel(marker.timestamp, this.#label, labelMetrics);
      }

      if (showDetails) {
        this.#renderTimestamp(
            marker.timestamp, labelMetrics ? labelMetrics.width : 0, timestampLabel, timestampMetrics);
      }
    }

    if (marker.type === MarkerType.Good) {
      this.#renderGoodMarkerSymbol(marker.timestamp);
    } else if (marker.type === MarkerType.Medium) {
      this.#renderMediumMarkerSymbol(marker.timestamp);
    } else {
      this.#renderBadMarkerSymbol(marker.timestamp);
    }
  }

  render(): void {
    for (let i = 0; i < this.#markers.length; i++) {
      const event = this.#markers[i];
      if (event === this.#selectedMarker || event === this.#hoverMarker) {
        continue;
      }
      this.#renderMarker(event, false, false, i < this.#markers.length - 1 ? this.#markers[i + 1] : null);
    }

    if (this.#hoverMarker && this.#hoverMarker !== this.#selectedMarker) {
      this.#renderMarker(this.#hoverMarker, false, true, null);
    }

    if (this.#selectedMarker) {
      this.#renderMarker(this.#selectedMarker, true, false, null);
    }
  }
}

export class WebVitalsTimeboxLane extends WebVitalsLane {
  #longTaskPattern: CanvasPattern;
  #boxes: readonly Timebox[] = [];
  #label: string;
  #hoverBox: number = -1;
  #selectedBox: number = -1;
  #getTimeboxOverlay?: GetTimeboxOverlayCallback;

  constructor(timeline: WebVitalsTimeline, label: string, getTimeboxOverlay?: GetTimeboxOverlayCallback) {
    super(timeline);

    this.#label = label;
    const patternCanvas = document.createElement('canvas');
    const patternContext = patternCanvas.getContext('2d');

    assertInstanceOf(patternContext, CanvasRenderingContext2D);

    const size = 17;
    patternCanvas.width = size;
    patternCanvas.height = size;

    // Rotate the stripe by 45deg to the right.
    patternContext.translate(size * 0.5, size * 0.5);
    patternContext.rotate(Math.PI * 0.25);
    patternContext.translate(-size * 0.5, -size * 0.5);

    patternContext.fillStyle = '#000';
    for (let x = -size; x < size * 2; x += 3) {
      patternContext.fillRect(x, -size, 1, size * 3);
    }
    const canvasPattern = this.context.createPattern(patternCanvas, 'repeat');
    assertInstanceOf(canvasPattern, CanvasPattern);
    this.#longTaskPattern = canvasPattern;
    this.#getTimeboxOverlay = getTimeboxOverlay;
  }

  handlePointerMove(x: number|null): void {
    const prevHoverBox = this.#hoverBox;
    if (x === null) {
      this.#hoverBox = -1;
    } else {
      this.#hoverBox = this.#boxes.findIndex((box): boolean => {
        const start = this.tX(box.start);
        const end = this.tX(box.start + box.duration);
        return start <= x && x <= end;
      });
    }

    if (prevHoverBox !== this.#hoverBox) {
      if (this.#hoverBox !== -1 && this.#getTimeboxOverlay) {
        this.timeline.showOverlay(this.#getTimeboxOverlay(this.#boxes[this.#hoverBox]));
      } else {
        this.timeline.hideOverlay();
      }
    }
  }

  handleClick(_: number|null): void {
    this.#selectedBox = this.#hoverBox;
  }

  setTimeboxes(boxes: readonly Timebox[]): void {
    this.#selectedBox = -1;
    this.#hoverBox = -1;
    this.#boxes = boxes;
  }

  #renderTimebox(box: Timebox, hover: boolean): void {
    const r = 2;

    this.context.save();
    this.context.beginPath();
    this.context.fillStyle = this.theme.timeboxColor;
    // Draw a box with rounded corners.
    this.context.moveTo(this.tX(box.start) + r, 2);
    this.context.lineTo(this.tX(box.start + box.duration) - r, 2);
    this.context.quadraticCurveTo(
        this.tX(box.start + box.duration),
        2,
        this.tX(box.start + box.duration),
        2 + r,
    );
    this.context.lineTo(this.tX(box.start + box.duration), 22 - r);
    this.context.quadraticCurveTo(
        this.tX(box.start + box.duration),
        22 - r,
        this.tX(box.start + box.duration) - r,
        22,
    );
    this.context.lineTo(this.tX(box.start) + r, 22);
    this.context.quadraticCurveTo(
        this.tX(box.start) + r,
        22,
        this.tX(box.start),
        22 - r,
    );
    this.context.lineTo(this.tX(box.start), 2 + r);
    this.context.quadraticCurveTo(
        this.tX(box.start),
        2 + r,
        this.tX(box.start) + r,
        2,
    );
    this.context.closePath();
    this.context.fill();

    // Fill the box with a striped pattern for everything over 50ms.
    this.context.beginPath();
    this.context.fillStyle = this.#longTaskPattern;
    this.context.moveTo(this.tX(box.start + LONG_TASK_THRESHOLD) + r, 2);
    this.context.lineTo(this.tX(box.start + box.duration) - r, 2);
    this.context.quadraticCurveTo(
        this.tX(box.start + box.duration),
        2,
        this.tX(box.start + box.duration),
        2 + r,
    );
    this.context.lineTo(this.tX(box.start + box.duration), 22 - r);
    this.context.quadraticCurveTo(
        this.tX(box.start + box.duration),
        22 - r,
        this.tX(box.start + box.duration) - r,
        22,
    );
    this.context.lineTo(this.tX(box.start + 50), 22);
    this.context.lineTo(this.tX(box.start + 50), 2);
    this.context.closePath();
    this.context.fill();

    if (hover) {
      this.context.beginPath();
      this.context.strokeStyle = this.theme.frame;
      this.context.rect(this.tX(box.start) - 2, 0, this.tD(box.duration) + 4, 24);
      this.context.lineWidth = 2;
      this.context.stroke();
      this.context.lineWidth = 1;
    }

    this.context.restore();
  }

  render(): void {
    for (let i = 0; i < this.#boxes.length; i++) {
      if (i === this.#hoverBox || i === this.#selectedBox) {
        continue;
      }
      this.#renderTimebox(this.#boxes[i], false);
    }

    if (this.#hoverBox !== -1) {
      this.#renderTimebox(this.#boxes[this.#hoverBox], true);
    }

    if (this.#selectedBox !== -1) {
      this.#renderTimebox(this.#boxes[this.#selectedBox], true);
    }

    this.renderLaneLabel(this.#label);
  }
}