#pragma once

namespace mp3_utils
{

	enum {
		MPG_MD_STEREO=0,
		MPG_MD_JOINT_STEREO=1,
		MPG_MD_DUAL_CHANNEL=2,
		MPG_MD_MONO=3,
	};

	typedef t_uint8 byte;

	enum {MPEG_1, MPEG_2, MPEG_25};

	struct TMPEGFrameInfo
	{
		unsigned m_bytes;
		unsigned m_bitrate_idx; // original bitrate index value
		unsigned m_bitrate; // kbps
		unsigned m_sample_rate_idx; // original samples per second index value
		unsigned m_sample_rate; // samples per second
		unsigned m_layer; // 1, 2 or 3
		unsigned m_mpegversion; // MPEG_1, MPEG_2, MPEG_25
		unsigned m_channels; // 1 or 2
		unsigned m_duration; // samples
		unsigned m_channel_mode; // MPG_MD_*
		unsigned m_channel_mode_ext;
		bool m_crc;
	};


	bool ParseMPEGFrameHeader(TMPEGFrameInfo & p_info,const t_uint8 p_header[4]);
	bool ParseMPEGFrameHeader(TMPEGFrameInfo & p_info, const void * bytes, size_t bytesAvail);
	bool IsValidMPEGFrameHeader(const void* fourbytes);
	bool ValidateFrameCRC(const t_uint8 * frameData, t_size frameSize);
	bool ValidateFrameCRC(const t_uint8 * frameData, t_size frameSize, TMPEGFrameInfo const & frameInfo);
	
	//! Assumes valid frame with CRC (frameInfo.m_crc set, frameInfo.m_bytes <= frameSize).
	t_uint16 ExtractFrameCRC(const t_uint8 * frameData, t_size frameSize, TMPEGFrameInfo const & frameInfo);
	//! Assumes valid frame with CRC (frameInfo.m_crc set, frameInfo.m_bytes <= frameSize).
	t_uint16 CalculateFrameCRC(const t_uint8 * frameData, t_size frameSize, TMPEGFrameInfo const & frameInfo);
	//! Assumes valid frame with CRC (frameInfo.m_crc set, frameInfo.m_bytes <= frameSize).
	void RecalculateFrameCRC(t_uint8 * frameData, t_size frameSize, TMPEGFrameInfo const & frameInfo);

	unsigned QueryMPEGFrameSize(const t_uint8 p_header[4]);
	bool IsSameStream(TMPEGFrameInfo const & p_frame1,TMPEGFrameInfo const & p_frame2);
};

class mp3header
{
	t_uint8 bytes[4];
public:

	inline void copy(const mp3header & src) {memcpy(bytes,src.bytes,4);}
	inline void copy_raw(const void * src) {memcpy(bytes,src,4);}

	inline void get_bytes(void * out) {memcpy(out,bytes,4);}
	inline unsigned get_frame_size() const {return mp3_utils::QueryMPEGFrameSize(bytes);}
	inline bool decode(mp3_utils::TMPEGFrameInfo & p_out) {return mp3_utils::ParseMPEGFrameHeader(p_out,bytes);}

	unsigned get_samples_per_frame();
};

static inline mp3header mp3header_from_buffer(const void * p_buffer)
{
	mp3header temp;
	temp.copy_raw(p_buffer);
	return temp;
}