/*
NAME
  adpcm_test.go

DESCRIPTION
  adpcm_test.go contains tests for the adpcm package.

AUTHOR
  Trek Hopton <trek@ausocean.org>

LICENSE
  adpcm_test.go is Copyright (C) 2018 the Australian Ocean Lab (AusOcean)

  It is free software: you can redistribute it and/or modify them
  under the terms of the GNU General Public License as published by the
  Free Software Foundation, either version 3 of the License, or (at your
  option) any later version.

  It is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  for more details.

  You should have received a copy of the GNU General Public License in gpl.txt.
  If not, see [GNU licenses](http://www.gnu.org/licenses).
*/

package adpcm

import (
	"bytes"
	"io/ioutil"
	"log"
	"testing"
)

// TestEncodeBlock will read PCM data, encode it in blocks and generate ADPCM
// then compare the result with expected ADPCM.
func TestEncodeBlock(t *testing.T) {
	//read input pcm
	pcm, err := ioutil.ReadFile("../../../test/test-data/av/input/raw-voice.pcm")
	if err != nil {
		t.Errorf("Unable to read input PCM file: %v", err)
	}

	//encode adpcm
	inBSize := 1010
	numBlocks := len(pcm) / inBSize
	outBSize := int(float64(inBSize)/4 + 3.5) // compression is 4:1 and 3.5 bytes of info are added to each block
	comp := make([]byte, 0, outBSize*numBlocks)
	for i := 0; i < numBlocks; i++ {
		block := pcm[inBSize*i : inBSize*(i+1)]
		encBlock, err := EncodeBlock(block)
		if err != nil {
			log.Fatal(err)
		}
		comp = append(comp, encBlock...)
	}

	//read expected adpcm file
	exp, err := ioutil.ReadFile("../../../test/test-data/av/output/encoded-voice.adpcm")
	if err != nil {
		t.Errorf("Unable to read expected ADPCM file: %v", err)
	}

	if !bytes.Equal(comp, exp) {
		t.Error("ADPCM generated does not match expected ADPCM")
	}
}

// TestDecodeBlock will read encoded ADPCM, decode it in blocks and then compare the
// resulting PCM with the expected decoded PCM.
func TestDecodeBlock(t *testing.T) {
	//read adpcm
	comp, err := ioutil.ReadFile("../../../test/test-data/av/input/encoded-voice.adpcm")
	if err != nil {
		t.Errorf("Unable to read input ADPCM file: %v", err)
	}

	//decode adpcm
	inBSize := 256
	numBlocks := len(comp) / inBSize
	outBSize := 2 + (inBSize-4)*4 // 2 bytes are copied, 2 are used as block header info, the remaining bytes are decompressed 1:4
	decoded := make([]byte, 0, outBSize*numBlocks)
	for i := 0; i < numBlocks; i++ {
		block := comp[inBSize*i : inBSize*(i+1)]
		decBlock, err := DecodeBlock(block)
		if err != nil {
			log.Fatal(err)
		}
		decoded = append(decoded, decBlock...)
	}

	//read expected pcm file
	exp, err := ioutil.ReadFile("../../../test/test-data/av/output/decoded-voice.pcm")
	if err != nil {
		t.Errorf("Unable to read expected PCM file: %v", err)
	}

	if !bytes.Equal(decoded, exp) {
		t.Error("PCM generated does not match expected PCM")
	}
}