// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <chrono>

#include "Common/CommonTypes.h"
#include "Common/FileUtil.h"
#include "Common/PcapFile.h"

namespace {

const u32 PCAP_MAGIC = 0xa1b2c3d4;
const u16 PCAP_VERSION_MAJOR = 2;
const u16 PCAP_VERSION_MINOR = 4;
const u32 PCAP_CAPTURE_LENGTH = 65535;

// TODO(delroth): Make this configurable at PCAP creation time?
const u32 PCAP_DATA_LINK_TYPE = 147;  // Reserved for internal use.

// Designed to be directly written into the PCAP file. The PCAP format is
// endian independent, so this works just fine.
#pragma pack(push, 1)
struct PCAPHeader
{
	u32 magic_number;
	u16 version_major;
	u16 version_minor;
	s32 tz_offset;       // Offset in seconds from the GMT timezone.
	u32 ts_accuracy;     // In practice, 0.
	u32 capture_length;  // Size at which we truncate packets.
	u32 data_link_type;
};

struct PCAPRecordHeader
{
	u32 ts_sec;
	u32 ts_usec;
	u32 size_in_file;  // Size after eventual truncation.
	u32 real_size;     // Size before eventual truncation.
};
#pragma pack(pop)

}  // namespace

void PCAP::AddHeader()
{
	PCAPHeader hdr = {
		PCAP_MAGIC, PCAP_VERSION_MAJOR, PCAP_VERSION_MINOR,
		0, 0, PCAP_CAPTURE_LENGTH, PCAP_DATA_LINK_TYPE
	};
	m_fp->WriteBytes(&hdr, sizeof (hdr));
}

void PCAP::AddPacket(const u8* bytes, size_t size)
{
	std::chrono::system_clock::time_point now(std::chrono::system_clock::now());
	auto ts = now.time_since_epoch();
	PCAPRecordHeader rec_hdr = {
		(u32)std::chrono::duration_cast<std::chrono::seconds>(ts).count(),
		(u32)(std::chrono::duration_cast<std::chrono::microseconds>(ts).count() % 1000000),
		(u32)size, (u32)size
	};
	m_fp->WriteBytes(&rec_hdr, sizeof (rec_hdr));
	m_fp->WriteBytes(bytes, size);
}
