/*
 * AudioFile.cpp
 *
 *  Created on: 6 déc. 2023
 *      Author: fanch
 */

#include "AudioFile.h"
#include <unistd.h>
#include <cstring>
#include <fcntl.h>
#include <errno.h>
#include <cstdio>
#include "errors.h"
#include "cmath"
#include "Window.h"


void default_audio_file_option(AudioFileOption* out){
	out->time_per_window = 1/30.0; // 30 fps
	out->buffer_size = 2<<24; // 32 Mo
}


AudioFile::~AudioFile() {
}

AudioFile::AudioFile(const std::string& filename) {
	m_buffer = NULL;
	m_buffer_start = m_buffer_end = -1;
	m_fd = fopen(filename.c_str(), "r");
	if(!m_fd){
		std::string err = std::string("Erreur impossible de lire le fichier")+filename+")";
		throw FileNotFoundError(err);
	}
	_init();
}

AudioFile::AudioFile(FILE* fd){
	m_buffer = NULL;
	m_buffer_start = m_buffer_end = -1;
	m_fd = fd;
	_init();
}



char* AudioFile::_base_read(size_t size, size_t count, char* buffer){
	size_t readed=0;
	if((readed=fread(buffer, size, count, m_fd))!=count){
		printf("Deamndé : %ld lu %ld\n",size*count, readed );
		throw IOError(strerror(errno));
	}
	return  buffer;
}

void AudioFile::_init(){
	default_audio_file_option(&m_options);
	_base_read(sizeof(m_header), 1, (char*)&m_header);
	fseek(m_fd, 0, SEEK_END);
	int total = ftell(m_fd) - sizeof(m_header);
	m_total_time = total / ((float)m_header.byte_per_sec);
}


int8_t* AudioFile::_bufferize(size_t start){
	size_t end = start + m_options.time_per_window * m_header.bit_per_sample * m_header.sample_rate;
	const int byte_per_sample = m_header.bit_per_sample>>3;
	if(start>=m_buffer_start && start<m_buffer_end && end>=m_buffer_start && end<m_buffer_end){
		return &m_buffer[start - m_buffer_start];
	}
	if(m_buffer) delete[] m_buffer;
	m_buffer = new int8_t[m_options.buffer_size];
	fseek(m_fd, sizeof(m_header) + start, SEEK_SET);

	int to_read = m_options.buffer_size/byte_per_sample;
	if(start+to_read > m_header.data_size){
		to_read = m_header.data_size-start;
	}
	fread(m_buffer, byte_per_sample, m_options.buffer_size/byte_per_sample, m_fd);
	return m_buffer;
}

Window** AudioFile::window_at_time(float time) {
	if(time>m_total_time) return NULL;

	Window** windows = new Window*[m_header.channels];
	size_t sample_per_window = m_options.time_per_window * m_header.bit_per_sample * m_header.sample_rate;
	for(size_t i=0; i<m_header.channels; i++)
		windows[i] = new Window(this, sample_per_window);

	size_t sample_size = m_header.bit_per_sample >> 3;
	size_t start = sample_size * m_header.sample_rate * m_header.channels * time;
	printf("For time %f offset = %ld + %ld\n", time, sizeof(m_header), start);

	int8_t* buffer = _bufferize(start);
	for(size_t i=0; i<sample_per_window; i++){
		for(size_t channel=0; channel<m_header.channels; channel++){
			windows[channel]->data[i] = _val_to_float(buffer+(i*m_header.channels+channel)*sample_size, sample_size);
		}
	}
	return windows;
}
Window* AudioFile::window_channel_at_time(float time, int ch) {
	if(time>m_total_time) return NULL;

	size_t sample_per_window = m_options.time_per_window * m_header.bit_per_sample * m_header.sample_rate;

	Window* windows = new Window(this, sample_per_window);

	size_t sample_size = m_header.bit_per_sample >> 3;
	size_t start = sample_size * m_header.sample_rate * m_header.channels * time;
	printf("For time %f offset = %ld + %ld\n", time, sizeof(m_header), start);

	int8_t* buffer = _bufferize(start);
	for(size_t i=0; i<sample_per_window; i++){
		for(size_t channel=0; channel<m_header.channels; channel++){
			if(channel != (uint8_t)ch) continue;
			windows->data[i] = _val_to_float(buffer+(i*m_header.channels+channel)*sample_size, sample_size);
		}
	}
	return windows;
}