import * as Token from 'token-types';
import type {ITokenizer} from 'strtok3';

import type {IPageHeader} from '../Ogg.js';
import {VorbisParser} from '../vorbis/VorbisParser.js';
import type {IOptions} from '../../type.js';
import type {INativeMetadataCollector} from '../../common/MetadataCollector.js';

import * as Opus from './Opus.js';
import { OpusContentError } from './Opus.js';

/**
 * Opus parser
 * Internet Engineering Task Force (IETF) - RFC 6716
 * Used by OggParser
 */
export class OpusParser extends VorbisParser {

  private idHeader: Opus.IIdHeader = null as unknown as Opus.IIdHeader;
  private lastPos = -1;

  constructor(metadata: INativeMetadataCollector, options: IOptions, private tokenizer: ITokenizer) {
    super(metadata, options);
  }

  /**
   * Parse first Opus Ogg page
   * @param {IPageHeader} header
   * @param {Uint8Array} pageData
   */
  protected parseFirstPage(header: IPageHeader, pageData: Uint8Array) {
    this.metadata.setFormat('codec', 'Opus');
    // Parse Opus ID Header
    this.idHeader = new Opus.IdHeader(pageData.length).get(pageData, 0);
    if (this.idHeader.magicSignature !== "OpusHead")
      throw new OpusContentError("Illegal ogg/Opus magic-signature");
    this.metadata.setFormat('sampleRate', this.idHeader.inputSampleRate);
    this.metadata.setFormat('numberOfChannels', this.idHeader.channelCount);
  }

  protected async parseFullPage(pageData: Uint8Array): Promise<void> {
    const magicSignature = new Token.StringType(8, 'ascii').get(pageData, 0);
    switch (magicSignature) {

      case 'OpusTags':
        await this.parseUserCommentList(pageData, 8);
        this.lastPos = this.tokenizer.position - pageData.length;
        break;

      default:
        break;
    }
  }

  public calculateDuration(header: IPageHeader) {
    if (this.metadata.format.sampleRate && header.absoluteGranulePosition >= 0) {
      // Calculate duration
      const pos_48bit = header.absoluteGranulePosition - this.idHeader.preSkip;
      this.metadata.setFormat('numberOfSamples', pos_48bit);
      this.metadata.setFormat('duration', pos_48bit / 48000);

      if (this.lastPos !== -1 && this.tokenizer.fileInfo.size && this.metadata.format.duration) {
        const dataSize = this.tokenizer.fileInfo.size - this.lastPos;
        this.metadata.setFormat('bitrate', 8 * dataSize / this.metadata.format.duration);
      }
    }
  }

}
