/**
 * Copyright (c) Microsoft Corporation.
 *
 * 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 fs from 'fs';
import path from 'path';
import * as trace from '../common/traceEvents';
import { ContextResources, ResourceSnapshot } from '../../snapshot/snapshotTypes';
import { BaseSnapshotStorage, SnapshotStorage } from '../../snapshot/snapshotStorage';
export * as trace from '../common/traceEvents';

export class TraceModel {
  contextEntry: ContextEntry | undefined;
  pageEntries = new Map<string, PageEntry>();
  contextResources = new Map<string, ContextResources>();
  private _snapshotStorage: PersistentSnapshotStorage;

  constructor(snapshotStorage: PersistentSnapshotStorage) {
    this._snapshotStorage = snapshotStorage;
  }

  appendEvents(events: trace.TraceEvent[], snapshotStorage: SnapshotStorage) {
    for (const event of events)
      this.appendEvent(event);
    const actions: trace.ActionTraceEvent[] = [];
    for (const page of this.contextEntry!.pages)
      actions.push(...page.actions);
    this.contextEntry!.resources = snapshotStorage.resources();
  }

  appendEvent(event: trace.TraceEvent) {
    switch (event.type) {
      case 'context-metadata': {
        this.contextEntry = {
          startTime: Number.MAX_VALUE,
          endTime: Number.MIN_VALUE,
          created: event,
          pages: [],
          resources: []
        };
        break;
      }
      case 'page-created': {
        const pageEntry: PageEntry = {
          created: event,
          destroyed: undefined as any,
          actions: [],
          events: [],
          screencastFrames: [],
        };
        this.pageEntries.set(event.pageId, pageEntry);
        this.contextEntry!.pages.push(pageEntry);
        break;
      }
      case 'page-destroyed': {
        this.pageEntries.get(event.pageId)!.destroyed = event;
        break;
      }
      case 'screencast-frame': {
        this.pageEntries.get(event.pageId)!.screencastFrames.push(event);
        break;
      }
      case 'action': {
        const metadata = event.metadata;
        const pageEntry = this.pageEntries.get(metadata.pageId!)!;
        pageEntry.actions.push(event);
        break;
      }
      case 'event': {
        const metadata = event.metadata;
        const pageEntry = this.pageEntries.get(metadata.pageId!);
        if (pageEntry)
          pageEntry.events.push(event);
        break;
      }
      case 'resource-snapshot':
        this._snapshotStorage.addResource(event.snapshot);
        break;
      case 'frame-snapshot':
        this._snapshotStorage.addFrameSnapshot(event.snapshot);
        break;
    }
    if (event.type === 'action' || event.type === 'event') {
      this.contextEntry!.startTime = Math.min(this.contextEntry!.startTime, event.metadata.startTime);
      this.contextEntry!.endTime = Math.max(this.contextEntry!.endTime, event.metadata.endTime);
    }
  }
}

export type ContextEntry = {
  startTime: number;
  endTime: number;
  created: trace.ContextCreatedTraceEvent;
  pages: PageEntry[];
  resources: ResourceSnapshot[];
}

export type PageEntry = {
  created: trace.PageCreatedTraceEvent;
  destroyed: trace.PageDestroyedTraceEvent;
  actions: trace.ActionTraceEvent[];
  events: trace.ActionTraceEvent[];
  screencastFrames: {
    sha1: string,
    timestamp: number,
    width: number,
    height: number,
  }[]
}

export class PersistentSnapshotStorage extends BaseSnapshotStorage {
  private _resourcesDir: string;

  constructor(resourcesDir: string) {
    super();
    this._resourcesDir = resourcesDir;
  }

  resourceContent(sha1: string): Buffer | undefined {
    return fs.readFileSync(path.join(this._resourcesDir, sha1));
  }
}