dev@460: /**
dev@460:  * Created by lucast on 08/06/2017.
dev@460:  */
dev@460: import {
dev@460:   Item,
dev@460:   RootAudioItem
dev@460: } from './analysis-item/AnalysisItem';
dev@460: 
dev@460: export const exampleSession: SerialisedNotebook = {
dev@460:   root: {
dev@460:     id: '1',
dev@460:     hasSharedTimeline: true,
dev@460:     title: 'Drum Loop',
dev@460:     description: 'Remotely hosted audio file',
dev@460:     uri: 'https://piper-audio.github.io/waves-ui-piper/examples/assets/drum-loop.wav'
dev@460:   },
dev@460:   analyses: [
dev@460:     {
dev@460:       id: '2',
dev@460:       hasSharedTimeline: true,
dev@460:       extractorKey: 'vamp-example-plugins:amplitudefollower',
dev@460:       outputId: 'amplitude',
dev@460:       title: 'Amplitude',
dev@460:       description: 'amplitude'
dev@460:     },
dev@460:     {
dev@460:       id: '3',
dev@460:       hasSharedTimeline: true,
dev@460:       extractorKey: 'vamp-example-plugins:powerspectrum',
dev@460:       outputId: 'powerspectrum',
dev@460:       title: 'Simple Power Spectrum',
dev@460:       description: 'powerspectrum'
dev@460:     },
dev@460: 
dev@460:   ]
dev@460: };
dev@460: 
dev@460: export interface SerialisedAnalysisItem extends Item {
dev@460:   extractorKey: string;
dev@460:   outputId: string;
dev@460: }
dev@460: 
dev@460: export interface SerialisedNotebook {
dev@460:   root: RootAudioItem;
dev@460:   analyses: SerialisedAnalysisItem[];
dev@460: }
dev@460: 
dev@460: export type ResourceRetriever = (url: string) => Promise<Blob>;
dev@460: 
dev@460: export const downloadResource: ResourceRetriever = async (url) => {
dev@460:   const response = await fetch(url);
dev@460:   const mimeType = response.headers.get('content-type');
dev@460:   // Safari's fetch.blob implementation doesn't populate the type property
dev@460:   // causing the audio player to fail due to an unsupported type.
dev@460:   // Manually create a blob from an array buffer and the content type in
dev@460:   // the response object
dev@460:   const arrayBufferToBlob = async () => {
dev@460:     const arrayBuffer = await response.arrayBuffer();
dev@460:     return new Blob([arrayBuffer], {type: mimeType});
dev@460:   };
dev@460:   return mimeType ? arrayBufferToBlob() : response.blob();
dev@460: };
dev@460: 
dev@460: export class PersistentStack<T> {
dev@460:   private stack: T[];
dev@460:   private history: T[][];
dev@462:   private historyOffset: number;
dev@460: 
dev@460:   constructor() {
dev@460:     this.stack = [];
dev@462:     this.history = [[]];
dev@462:     this.historyOffset = 0;
dev@460:   }
dev@460: 
dev@465:   shiftMutating(): T {
dev@460:     const item = this.stack[0];
dev@460:     this.stack = this.stack.slice(1);
dev@465:     return item;
dev@465:   }
dev@465: 
dev@465:   shift(): T {
dev@465:     const item = this.shiftMutating();
dev@467:     this.updateHistory();
dev@460:     return item;
dev@460:   }
dev@460: 
dev@465:   unshiftMutating(item: T): number {
dev@465:     this.stack = [item, ...this.stack];
dev@465:     return this.stack.length;
dev@465:   }
dev@465: 
dev@460:   unshift(item: T): number {
dev@508:     const newLength = this.unshiftMutating(item);
dev@467:     this.updateHistory();
dev@465:     return newLength;
dev@460:   }
dev@460: 
dev@460:   findIndex(predicate: (value: T,
dev@460:                         index: number,
dev@460:                         array: T[]) => boolean): number {
dev@460:     return this.stack.findIndex(predicate);
dev@460:   }
dev@460: 
dev@485:   findIndexAndUse(predicate: (value: T,
dev@485:                               index: number,
dev@485:                               array: T[]) => boolean,
dev@485:                   use: (index: number) => void): boolean {
dev@485:     const index = this.stack.findIndex(predicate);
dev@485:     const didFind = index !== -1;
dev@485:     if (didFind) {
dev@485:       use(index);
dev@485:     }
dev@485:     return didFind;
dev@485:   }
dev@485: 
dev@460:   filter(predicate: (value: T, index: number, array: T[]) => boolean): T[] {
dev@460:     return this.stack.filter(predicate);
dev@460:   }
dev@460: 
dev@460:   get(index: number): T {
dev@460:     return this.stack[index];
dev@460:   }
dev@460: 
dev@460:   set(index: number, value: T) {
dev@465:     this.setMutating(index, value);
dev@467:     this.updateHistory();
dev@465:   }
dev@465: 
dev@465:   setMutating(index: number, value: T) {
dev@460:     this.stack = [
dev@460:       ...this.stack.slice(0, index),
dev@460:       value,
dev@460:       ...this.stack.slice(index + 1)
dev@460:     ];
dev@460:   }
dev@460: 
dev@460:   map<U>(transform: (value: T, index: number, array: T[]) => U): U[] {
dev@460:     return this.stack.map(transform);
dev@460:   }
dev@460: 
dev@460:   reduce<U>(reducer: (previousValue: U,
dev@460:                       currentValue: T,
dev@460:                       currentIndex: number,
dev@460:                       array: T[]) => U,
dev@460:             initialValue: U): U {
dev@460:     return this.stack.reduce(reducer, initialValue);
dev@460:   }
dev@460: 
dev@460:   remove(...indices: number[]) {
dev@460:     this.stack = this.stack.reduce((acc, item, i) => {
dev@460:       if (!indices.includes(i)) {
dev@460:         acc.push(item);
dev@460:       }
dev@460:       return acc;
dev@460:     }, [] as T[]);
dev@467:     this.updateHistory();
dev@462:   }
dev@462: 
dev@462:   stepBack(): void {
dev@462:     const latest = this.history.length - 1;
dev@462:     if (++this.historyOffset <= latest) {
dev@462:       this.stack = this.history[latest - this.historyOffset];
dev@462:     } else {
dev@462:       this.historyOffset = latest;
dev@462:     }
dev@462:   }
dev@462: 
dev@462:   stepForward(): void {
dev@462:     const latest = this.history.length - 1;
dev@462:     if (--this.historyOffset >= 0) {
dev@462:       this.stack = this.history[latest - this.historyOffset];
dev@462:     } else {
dev@462:       this.historyOffset = 0;
dev@462:     }
dev@460:   }
dev@460: 
dev@468:   toIterable(): Iterable<T> {
dev@468:     return this.stack;
dev@468:   }
dev@468: 
dev@468:   private updateHistory(): void {
dev@467:     if (this.historyOffset !== 0) {
dev@467:       this.history = this.history.slice(
dev@467:         0,
dev@467:         this.history.length - this.historyOffset
dev@467:       );
dev@467:       this.historyOffset = 0;
dev@467:     }
dev@467:     this.history.push([...this.stack]);
dev@467:   }
dev@460: }