#include <cstdarg>
#include <string>
#include <unistd.h>

#include "print.h"

using namespace std;

static string va_stringf(va_list args, const char * fmt) {
	va_list args_copy;
	va_copy(args_copy, args);

	size_t sz = vsnprintf(NULL, 0, fmt, args_copy) + 1;
	char * msg = (char *) malloc(sz);
	va_end(args_copy);

	vsnprintf(msg, sz, fmt, args);

	string out = msg;
	free(msg);

	va_end(args);

	return out;
}

static string stringf(const char * fmt, ...) {
	va_list args;
	va_start(args, fmt);
	string out = va_stringf(args, fmt);
	va_end(args);
	return out;
}

void lprtf(const char * fmt, ...) {
	va_list args;
	va_start(args, fmt);
	string formatted = va_stringf(args, fmt);
	va_end(args);

	fwrite(formatted.c_str(), 1, formatted.size(), stdout);
	fflush(stdout);

	SessionLog::get().append(formatted);
}

SessionLog & SessionLog::get() {
	static SessionLog instance;
	return instance;
}

SessionLog::SessionLog() {
	if (!this->enable) return;

	string filename = stringf("%lu.log", getpid());
	FILE * file = fopen(filename.c_str(), "w+");
	this->file = { file, [] (FILE * file) { fclose(file); } };
}

void SessionLog::append(const string & str) const {
	this->append(str.data(), str.size());
}

void SessionLog::append(const char * str) const {
	this->append(str, strlen(str));
}

void SessionLog::append(const char * buf, size_t buf_size) const {
	if (this->file == nullptr) return;
	if (buf_size == 0) return;
	fwrite(buf, 1, buf_size, this->file.get());
}