import type { IGetToken } from 'strtok3';
import * as util from '../common/Util.js';
import { UINT16_BE, UINT24_BE, Uint8ArrayType } from 'token-types';

/**
 * FLAC supports up to 128 kinds of metadata blocks; currently the following are defined:
 * ref: https://xiph.org/flac/format.html#metadata_block
 */
export const BlockType = {
  STREAMINFO: 0, // STREAMINFO
  PADDING: 1, // PADDING
  APPLICATION: 2, // APPLICATION
  SEEKTABLE: 3, // SEEKTABLE
  VORBIS_COMMENT: 4, // VORBIS_COMMENT
  CUESHEET: 5, // CUESHEET
  PICTURE: 6 // PICTURE
};

export type BlockType = typeof BlockType[keyof typeof BlockType];

/**
 * METADATA_BLOCK_DATA
 * Ref: https://xiph.org/flac/format.html#metadata_block_streaminfo
 */
export interface IBlockHeader {
  // Last-metadata-block flag: '1' if this block is the last metadata block before the audio blocks, '0' otherwise.
  lastBlock: boolean,
  // BLOCK_TYPE
  type: BlockType,
  // Length (in bytes) of metadata to follow (does not include the size of the METADATA_BLOCK_HEADER)
  length: number;
}

export const BlockHeader: IGetToken<IBlockHeader> = {
  len: 4,

  get: (buf: Uint8Array, off: number): IBlockHeader => {
    return {
      lastBlock: util.getBit(buf, off, 7),
      type: util.getBitAllignedNumber(buf, off, 1, 7),
      length: UINT24_BE.get(buf, off + 1)
    };
  }
};

/**
 * METADATA_BLOCK_DATA
 * Ref: https://xiph.org/flac/format.html#metadata_block_streaminfo
 */
export interface IBlockStreamInfo {
  minimumBlockSize: number,
  // The maximum block size (in samples) used in the stream.
  // (Minimum blocksize == maximum blocksize) implies a fixed-blocksize stream.
  maximumBlockSize: number,
  // The minimum frame size (in bytes) used in the stream.
  // May be 0 to imply the value is not known.
  minimumFrameSize: number,
  // The maximum frame size (in bytes) used in the stream.
  // May be 0 to imply the value is not known.
  maximumFrameSize: number,
  // Sample rate in Hz. Though 20 bits are available,
  // the maximum sample rate is limited by the structure of frame headers to 655350Hz.
  // Also, a value of 0 is invalid.
  sampleRate: number,
  // probably slower: sampleRate: common.getBitAllignedNumber(buf, off + 10, 0, 20),
  // (number of channels)-1. FLAC supports from 1 to 8 channels
  channels: number,
  // bits per sample)-1.
  // FLAC supports from 4 to 32 bits per sample. Currently the reference encoder and decoders only support up to 24 bits per sample.
  bitsPerSample: number,
  // Total samples in stream.
  // 'Samples' means inter-channel sample, i.e. one second of 44.1Khz audio will have 44100 samples regardless of the number of channels.
  // A value of zero here means the number of total samples is unknown.
  totalSamples: number,
  // the MD5 hash of the file (see notes for usage... it's a littly tricky)
  fileMD5: Uint8Array;
}

/**
 * METADATA_BLOCK_DATA
 * Ref: https://xiph.org/flac/format.html#metadata_block_streaminfo
 */
export const BlockStreamInfo: IGetToken<IBlockStreamInfo> = {
  len: 34,

  get: (buf: Uint8Array, off: number): IBlockStreamInfo => {
    return {
      // The minimum block size (in samples) used in the stream.
      minimumBlockSize: UINT16_BE.get(buf, off),
      // The maximum block size (in samples) used in the stream.
      // (Minimum blocksize == maximum blocksize) implies a fixed-blocksize stream.
      maximumBlockSize: UINT16_BE.get(buf, off + 2) / 1000,
      // The minimum frame size (in bytes) used in the stream.
      // May be 0 to imply the value is not known.
      minimumFrameSize: UINT24_BE.get(buf, off + 4),
      // The maximum frame size (in bytes) used in the stream.
      // May be 0 to imply the value is not known.
      maximumFrameSize: UINT24_BE.get(buf, off + 7),
      // Sample rate in Hz. Though 20 bits are available,
      // the maximum sample rate is limited by the structure of frame headers to 655350Hz.
      // Also, a value of 0 is invalid.
      sampleRate: UINT24_BE.get(buf, off + 10) >> 4,
      // probably slower: sampleRate: common.getBitAllignedNumber(buf, off + 10, 0, 20),
      // (number of channels)-1. FLAC supports from 1 to 8 channels
      channels: util.getBitAllignedNumber(buf, off + 12, 4, 3) + 1,
      // bits per sample)-1.
      // FLAC supports from 4 to 32 bits per sample. Currently the reference encoder and decoders only support up to 24 bits per sample.
      bitsPerSample: util.getBitAllignedNumber(buf, off + 12, 7, 5) + 1,
      // Total samples in stream.
      // 'Samples' means inter-channel sample, i.e. one second of 44.1Khz audio will have 44100 samples regardless of the number of channels.
      // A value of zero here means the number of total samples is unknown.
      totalSamples: util.getBitAllignedNumber(buf, off + 13, 4, 36),
      // the MD5 hash of the file (see notes for usage... it's a littly tricky)
      fileMD5: new Uint8ArrayType(16).get(buf, off + 18)
    };
  }
};