// Copyright (C) 2018 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import m from 'mithril';

import {findRef, toHTMLElement} from '../base/dom_utils';
import {clamp} from '../base/math_utils';
import {Time} from '../base/time';
import {Actions} from '../common/actions';
import {TrackCacheEntry} from '../common/track_cache';
import {featureFlags} from '../core/feature_flags';
import {raf} from '../core/raf_scheduler';
import {TrackTags} from '../public';

import {TRACK_SHELL_WIDTH} from './css_constants';
import {globals} from './globals';
import {NotesPanel} from './notes_panel';
import {OverviewTimelinePanel} from './overview_timeline_panel';
import {createPage} from './pages';
import {PanAndZoomHandler} from './pan_and_zoom_handler';
import {Panel, PanelContainer, PanelOrGroup} from './panel_container';
import {publishShowPanningHint} from './publish';
import {TabPanel} from './tab_panel';
import {TickmarkPanel} from './tickmark_panel';
import {TimeAxisPanel} from './time_axis_panel';
import {TimeSelectionPanel} from './time_selection_panel';
import {DISMISSED_PANNING_HINT_KEY} from './topbar';
import {TrackGroupPanel} from './track_group_panel';
import {TrackPanel} from './track_panel';
import {assertExists} from '../base/logging';
import {getLegacySelection} from '../common/state';

const OVERVIEW_PANEL_FLAG = featureFlags.register({
  id: 'overviewVisible',
  name: 'Overview Panel',
  description: 'Show the panel providing an overview of the trace',
  defaultValue: true,
});

// Checks if the mousePos is within 3px of the start or end of the
// current selected time range.
function onTimeRangeBoundary(mousePos: number): 'START' | 'END' | null {
  const selection = getLegacySelection(globals.state);
  if (selection !== null && selection.kind === 'AREA') {
    // If frontend selectedArea exists then we are in the process of editing the
    // time range and need to use that value instead.
    const area = globals.timeline.selectedArea
      ? globals.timeline.selectedArea
      : globals.state.areas[selection.areaId];
    const {visibleTimeScale} = globals.timeline;
    const start = visibleTimeScale.timeToPx(area.start);
    const end = visibleTimeScale.timeToPx(area.end);
    const startDrag = mousePos - TRACK_SHELL_WIDTH;
    const startDistance = Math.abs(start - startDrag);
    const endDistance = Math.abs(end - startDrag);
    const range = 3 * window.devicePixelRatio;
    // We might be within 3px of both boundaries but we should choose
    // the closest one.
    if (startDistance < range && startDistance <= endDistance) return 'START';
    if (endDistance < range && endDistance <= startDistance) return 'END';
  }
  return null;
}

/**
 * Top-most level component for the viewer page. Holds tracks, brush timeline,
 * panels, and everything else that's part of the main trace viewer page.
 */
class TraceViewer implements m.ClassComponent {
  private zoomContent?: PanAndZoomHandler;
  // Used to prevent global deselection if a pan/drag select occurred.
  private keepCurrentSelection = false;

  private overviewTimelinePanel = new OverviewTimelinePanel();
  private timeAxisPanel = new TimeAxisPanel();
  private timeSelectionPanel = new TimeSelectionPanel();
  private notesPanel = new NotesPanel();
  private tickmarkPanel = new TickmarkPanel();

  private readonly PAN_ZOOM_CONTENT_REF = 'pan-and-zoom-content';

  oncreate(vnode: m.CVnodeDOM) {
    const timeline = globals.timeline;
    const panZoomElRaw = findRef(vnode.dom, this.PAN_ZOOM_CONTENT_REF);
    const panZoomEl = toHTMLElement(assertExists(panZoomElRaw));

    this.zoomContent = new PanAndZoomHandler({
      element: panZoomEl,
      onPanned: (pannedPx: number) => {
        const {visibleTimeScale} = globals.timeline;

        this.keepCurrentSelection = true;
        const tDelta = visibleTimeScale.pxDeltaToDuration(pannedPx);
        timeline.panVisibleWindow(tDelta);

        // If the user has panned they no longer need the hint.
        localStorage.setItem(DISMISSED_PANNING_HINT_KEY, 'true');
        raf.scheduleRedraw();
      },
      onZoomed: (zoomedPositionPx: number, zoomRatio: number) => {
        // TODO(hjd): Avoid hardcoding TRACK_SHELL_WIDTH.
        // TODO(hjd): Improve support for zooming in overview timeline.
        const zoomPx = zoomedPositionPx - TRACK_SHELL_WIDTH;
        const rect = vnode.dom.getBoundingClientRect();
        const centerPoint = zoomPx / (rect.width - TRACK_SHELL_WIDTH);
        timeline.zoomVisibleWindow(1 - zoomRatio, centerPoint);
        raf.scheduleRedraw();
      },
      editSelection: (currentPx: number) => {
        return onTimeRangeBoundary(currentPx) !== null;
      },
      onSelection: (
        dragStartX: number,
        dragStartY: number,
        prevX: number,
        currentX: number,
        currentY: number,
        editing: boolean,
      ) => {
        const traceTime = globals.traceContext;
        const {visibleTimeScale} = timeline;
        this.keepCurrentSelection = true;
        if (editing) {
          const selection = getLegacySelection(globals.state);
          if (selection !== null && selection.kind === 'AREA') {
            const area = globals.timeline.selectedArea
              ? globals.timeline.selectedArea
              : globals.state.areas[selection.areaId];
            let newTime = visibleTimeScale
              .pxToHpTime(currentX - TRACK_SHELL_WIDTH)
              .toTime();
            // Have to check again for when one boundary crosses over the other.
            const curBoundary = onTimeRangeBoundary(prevX);
            if (curBoundary == null) return;
            const keepTime = curBoundary === 'START' ? area.end : area.start;
            // Don't drag selection outside of current screen.
            if (newTime < keepTime) {
              newTime = Time.max(
                newTime,
                visibleTimeScale.timeSpan.start.toTime(),
              );
            } else {
              newTime = Time.min(
                newTime,
                visibleTimeScale.timeSpan.end.toTime(),
              );
            }
            // When editing the time range we always use the saved tracks,
            // since these will not change.
            timeline.selectArea(
              Time.max(Time.min(keepTime, newTime), traceTime.start),
              Time.min(Time.max(keepTime, newTime), traceTime.end),
              globals.state.areas[selection.areaId].tracks,
            );
          }
        } else {
          let startPx = Math.min(dragStartX, currentX) - TRACK_SHELL_WIDTH;
          let endPx = Math.max(dragStartX, currentX) - TRACK_SHELL_WIDTH;
          if (startPx < 0 && endPx < 0) return;
          const {pxSpan} = visibleTimeScale;
          startPx = clamp(startPx, pxSpan.start, pxSpan.end);
          endPx = clamp(endPx, pxSpan.start, pxSpan.end);
          timeline.selectArea(
            visibleTimeScale.pxToHpTime(startPx).toTime('floor'),
            visibleTimeScale.pxToHpTime(endPx).toTime('ceil'),
          );
          timeline.areaY.start = dragStartY;
          timeline.areaY.end = currentY;
          publishShowPanningHint();
        }
        raf.scheduleRedraw();
      },
      endSelection: (edit: boolean) => {
        globals.timeline.areaY.start = undefined;
        globals.timeline.areaY.end = undefined;
        const area = globals.timeline.selectedArea;
        // If we are editing we need to pass the current id through to ensure
        // the marked area with that id is also updated.
        if (edit) {
          const selection = getLegacySelection(globals.state);
          if (selection !== null && selection.kind === 'AREA' && area) {
            globals.dispatch(
              Actions.editArea({area, areaId: selection.areaId}),
            );
          }
        } else if (area) {
          globals.makeSelection(Actions.selectArea({area}));
        }
        // Now the selection has ended we stored the final selected area in the
        // global state and can remove the in progress selection from the
        // timeline.
        globals.timeline.deselectArea();
        // Full redraw to color track shell.
        raf.scheduleFullRedraw();
      },
    });
  }

  onremove() {
    if (this.zoomContent) this.zoomContent.dispose();
  }

  view() {
    const scrollingPanels: PanelOrGroup[] = globals.state.scrollingTracks.map(
      (key) => {
        const trackBundle = this.resolveTrack(key);
        return new TrackPanel({
          trackKey: key,
          title: trackBundle.title,
          tags: trackBundle.tags,
          trackFSM: trackBundle.trackFSM,
          closeable: trackBundle.closeable,
        });
      },
    );

    for (const group of Object.values(globals.state.trackGroups)) {
      const key = group.summaryTrack;
      let headerPanel;
      if (key) {
        const trackBundle = this.resolveTrack(key);
        headerPanel = new TrackGroupPanel({
          groupKey: group.key,
          trackFSM: trackBundle.trackFSM,
          labels: trackBundle.labels,
          tags: trackBundle.tags,
          collapsed: group.collapsed,
          title: group.name,
        });
      } else {
        headerPanel = new TrackGroupPanel({
          groupKey: group.key,
          collapsed: group.collapsed,
          title: group.name,
        });
      }

      const childTracks: Panel[] = [];
      if (!group.collapsed) {
        for (const key of group.tracks) {
          const trackBundle = this.resolveTrack(key);
          const panel = new TrackPanel({
            trackKey: key,
            title: trackBundle.title,
            tags: trackBundle.tags,
            trackFSM: trackBundle.trackFSM,
            closeable: trackBundle.closeable,
          });
          childTracks.push(panel);
        }
      }

      scrollingPanels.push({
        kind: 'group',
        collapsed: group.collapsed,
        childPanels: childTracks,
        header: headerPanel,
      });
    }

    const overviewPanel = [];
    if (OVERVIEW_PANEL_FLAG.get()) {
      overviewPanel.push(this.overviewTimelinePanel);
    }

    const result = m(
      '.page.viewer-page',
      m(
        '.pan-and-zoom-content',
        {
          ref: this.PAN_ZOOM_CONTENT_REF,
          onclick: () => {
            // We don't want to deselect when panning/drag selecting.
            if (this.keepCurrentSelection) {
              this.keepCurrentSelection = false;
              return;
            }
            globals.clearSelection();
          },
        },
        m(
          '.pf-timeline-header',
          m(PanelContainer, {
            className: 'header-panel-container',
            panels: [
              ...overviewPanel,
              this.timeAxisPanel,
              this.timeSelectionPanel,
              this.notesPanel,
              this.tickmarkPanel,
            ],
          }),
          m('.scrollbar-spacer-vertical'),
        ),
        m(PanelContainer, {
          className: 'pinned-panel-container',
          panels: globals.state.pinnedTracks.map((key) => {
            const trackBundle = this.resolveTrack(key);
            return new TrackPanel({
              trackKey: key,
              title: trackBundle.title,
              tags: trackBundle.tags,
              trackFSM: trackBundle.trackFSM,
              revealOnCreate: true,
              closeable: trackBundle.closeable,
            });
          }),
        }),
        m(PanelContainer, {
          className: 'scrolling-panel-container',
          panels: scrollingPanels,
          onPanelStackResize: (width) => {
            const timelineWidth = width - TRACK_SHELL_WIDTH;
            globals.timeline.updateLocalLimits(0, timelineWidth);
          },
        }),
      ),
      this.renderTabPanel(),
    );

    globals.trackManager.flushOldTracks();
    return result;
  }

  // Resolve a track and its metadata through the track cache
  private resolveTrack(key: string): TrackBundle {
    const trackState = globals.state.tracks[key];
    const {uri, params, name, labels, closeable} = trackState;
    const trackDesc = globals.trackManager.resolveTrackInfo(uri);
    const trackCacheEntry =
      trackDesc && globals.trackManager.resolveTrack(key, trackDesc, params);
    const trackFSM = trackCacheEntry;
    const tags = trackCacheEntry?.desc.tags;
    const trackIds = trackCacheEntry?.desc.trackIds;
    return {
      title: name,
      tags,
      trackFSM,
      labels,
      trackIds,
      closeable: closeable ?? false,
    };
  }

  private renderTabPanel() {
    return m(TabPanel);
  }
}

interface TrackBundle {
  title: string;
  closeable: boolean;
  trackFSM?: TrackCacheEntry;
  tags?: TrackTags;
  labels?: string[];
  trackIds?: number[];
}

export const ViewerPage = createPage({
  view() {
    return m(TraceViewer);
  },
});