package normalized

import (
    "encoding/binary"
    "math"
)

const (
    isLittleEndian = true
)

func NormalizePCM(input []byte, isLittleEndian bool) []byte {
    var maxSample int16
    numSamples := len(input) / 2
    samples := make([]int16, numSamples)
    for i := 0; i < numSamples; i++ {
        if isLittleEndian {
            samples[i] = int16(binary.LittleEndian.Uint16(input[i*2 : (i+1)*2]))
        } else {
            samples[i] = int16(binary.BigEndian.Uint16(input[i*2 : (i+1)*2]))
        }
        if math.Abs(float64(samples[i])) > float64(maxSample) {
            maxSample = samples[i]
        }
    }
    normalized := make([]byte, len(input))
    for i := 0; i < numSamples; i++ {
        if maxSample != 0 {
            normalizedSample := int16(float64(samples[i]) * (32767.0 / float64(maxSample)))
            if isLittleEndian {
                binary.LittleEndian.PutUint16(normalized[i*2:(i+1)*2], uint16(normalizedSample))
            } else {
                binary.BigEndian.PutUint16(normalized[i*2:(i+1)*2], uint16(normalizedSample))
            }
        }
    }
    return normalized
}
/*
func main() {
    input := []byte{0x01, 0x02, 0xff, 0xfe}
    normalized := normalizePCM(input, isLittleEndian)
    fmt.Printf("Normalized data: %v\n", normalized)
}
*/