// Code based on DOSBox-0.65

#include "AviWriter.hh"

#include "FileOperations.hh"
#include "MSXException.hh"
#include "Version.hh"

#include "cstdiop.hh" // for snprintf
#include "endian.hh"
#include "narrow.hh"
#include "ranges.hh"
#include "small_buffer.hh"
#include "stl.hh"
#include "zstring_view.hh"

#include <array>
#include <cassert>
#include <cstring>
#include <ctime>
#include <limits>

namespace openmsx {

static constexpr unsigned AVI_HEADER_SIZE = 500;

AviWriter::AviWriter(const std::string& filename_, unsigned width_,
                     unsigned height_, unsigned channels_, unsigned freq_)
	: file(filename_, "wb")
	, filename(filename_)
	, codec(width_, height_)
	, width(width_)
	, height(height_)
	, channels(channels_)
	, audioRate(freq_)
{
	std::array<uint8_t, AVI_HEADER_SIZE> dummy = {};
	file.write(dummy);

	index.resize(2);
}

AviWriter::~AviWriter()
{
	if (written == 0) {
		// no data written yet (a recording less than one video frame)
		file.close(); // close file (needed for windows?)
		FileOperations::unlink(filename);
		return;
	}
	assert(fps != 0.0f); // a decent fps should have been set

	// Possible cleanup: use structs for the different headers, that
	// also allows to use the aligned versions of the Endian routines.
	std::array<uint8_t, AVI_HEADER_SIZE> avi_header = {};
	unsigned header_pos = 0;

	auto AVIOUT4 = [&](std::string_view s) {
		assert(s.size() == 4);
		copy_to_range(s, subspan(avi_header, header_pos));
		header_pos += 4;
	};
	auto AVIOUTw = [&](uint16_t w) {
		Endian::write_UA_L16(&avi_header[header_pos], w);
		header_pos += sizeof(w);
	};
	auto AVIOUTd = [&](uint32_t d) {
		Endian::write_UA_L32(&avi_header[header_pos], d);
		header_pos += sizeof(d);
	};
	auto AVIOUTs = [&](zstring_view s) {
		auto len1 = s.size() + 1; // +1 for zero-terminator
		copy_to_range(std::span{s.data(), len1}, subspan(avi_header, header_pos));
		header_pos += narrow<unsigned>((len1 + 1) & ~1); // round-up to even
	};

	bool hasAudio = audioRate != 0;

	// write avi header
	AVIOUT4("RIFF");                    // Riff header
	AVIOUTd(AVI_HEADER_SIZE + written - 8 + unsigned(index.size() * sizeof(Endian::L32)));
	AVIOUT4("AVI ");
	AVIOUT4("LIST");                    // List header
	auto main_list = header_pos;
	AVIOUTd(0);                         // size of list, filled in later
	AVIOUT4("hdrl");

	AVIOUT4("avih");
	AVIOUTd(56);                        // # of bytes to follow
	AVIOUTd(uint32_t(1000000 / fps));   // Microseconds per frame
	AVIOUTd(0);
	AVIOUTd(0);                         // PaddingGranularity (whatever that might be)
	AVIOUTd(0x110);                     // Flags,0x10 has index, 0x100 interleaved
	AVIOUTd(frames);                    // TotalFrames
	AVIOUTd(0);                         // InitialFrames
	AVIOUTd(hasAudio? 2 : 1);           // Stream count
	AVIOUTd(0);                         // SuggestedBufferSize
	AVIOUTd(width);                     // Width
	AVIOUTd(height);                    // Height
	AVIOUTd(0);                         // TimeScale:  Unit used to measure time
	AVIOUTd(0);                         // DataRate:   Data rate of playback
	AVIOUTd(0);                         // StartTime:  Starting time of AVI data
	AVIOUTd(0);                         // DataLength: Size of AVI data chunk

	// Video stream list
	AVIOUT4("LIST");
	AVIOUTd(4 + 8 + 56 + 8 + 40);       // Size of the list
	AVIOUT4("strl");
	// video stream header
	AVIOUT4("strh");
	AVIOUTd(56);                        // # of bytes to follow
	AVIOUT4("vids");                    // Type
	AVIOUT4(ZMBVEncoder::CODEC_4CC);    // Handler
	AVIOUTd(0);                         // Flags
	AVIOUTd(0);                         // Reserved, MS says: wPriority, wLanguage
	AVIOUTd(0);                         // InitialFrames
	AVIOUTd(1000000);                   // Scale
	AVIOUTd(uint32_t(1000000 * fps));   // Rate: Rate/Scale == samples/second
	AVIOUTd(0);                         // Start
	AVIOUTd(frames);                    // Length
	AVIOUTd(0);                         // SuggestedBufferSize
	AVIOUTd(uint32_t(~0));              // Quality
	AVIOUTd(0);                         // SampleSize
	AVIOUTd(0);                         // Frame
	AVIOUTd(0);                         // Frame
	// The video stream format
	AVIOUT4("strf");
	AVIOUTd(40);                        // # of bytes to follow
	AVIOUTd(40);                        // Size
	AVIOUTd(width);                     // Width
	AVIOUTd(height);                    // Height
	AVIOUTd(0);
	AVIOUT4(ZMBVEncoder::CODEC_4CC);    // Compression
	AVIOUTd(width * height * 4);        // SizeImage (in bytes?)
	AVIOUTd(0);                         // XPelsPerMeter
	AVIOUTd(0);                         // YPelsPerMeter
	AVIOUTd(0);                         // ClrUsed: Number of colors used
	AVIOUTd(0);                         // ClrImportant: Number of colors important

	if (hasAudio) {
		// 1 fragment is 1 (for mono) or 2 (for stereo) samples
		uint16_t bitsPerSample = 16;
		unsigned bytesPerSample = bitsPerSample / 8;
		unsigned bytesPerFragment = bytesPerSample * channels;
		unsigned bytesPerSecond = audioRate * bytesPerFragment;
		unsigned fragments = audioWritten / channels;

		// Audio stream list
		AVIOUT4("LIST");
		AVIOUTd(4 + 8 + 56 + 8 + 16);// Length of list in bytes
		AVIOUT4("strl");
		// The audio stream header
		AVIOUT4("strh");
		AVIOUTd(56);                // # of bytes to follow
		AVIOUT4("auds");
		AVIOUTd(0);                 // Format (Optionally)
		AVIOUTd(0);                 // Flags
		AVIOUTd(0);                 // Reserved, MS says: wPriority, wLanguage
		AVIOUTd(0);                 // InitialFrames
		// Rate/Scale should be number of samples per second!
		AVIOUTd(bytesPerFragment);  // Scale
		AVIOUTd(bytesPerSecond);    // Rate, actual rate is scale/rate
		AVIOUTd(0);                 // Start
		AVIOUTd(fragments);         // Length
		AVIOUTd(0);                 // SuggestedBufferSize
		AVIOUTd(unsigned(~0));      // Quality
		AVIOUTd(bytesPerFragment);  // SampleSize (should be the same as BlockAlign)
		AVIOUTd(0);                 // Frame
		AVIOUTd(0);                 // Frame
		// The audio stream format
		AVIOUT4("strf");
		AVIOUTd(16);                // # of bytes to follow
		AVIOUTw(1);                 // Format, WAVE_ZMBV_FORMAT_PCM
		AVIOUTw(narrow<uint16_t>(channels)); // Number of channels
		AVIOUTd(audioRate);         // SamplesPerSec
		AVIOUTd(bytesPerSecond);    // AvgBytesPerSec
		AVIOUTw(narrow<uint16_t>(bytesPerFragment)); // BlockAlign: for PCM: nChannels * BitsPerSample / 8
		AVIOUTw(bitsPerSample);     // BitsPerSample
	}

	auto versionStr = Version::full();

	// The standard snprintf() function does always zero-terminate the
	// output it writes. Though windows doesn't have a snprintf() function,
	// instead we #define snprintf to _snprintf and the latter does NOT
	// properly zero-terminate. See also
	//   http://stackoverflow.com/questions/7706936/is-snprintf-always-null-terminating
	//
	// A buffer size of 11 characters is large enough till the year 9999.
	// But the compiler doesn't understand calendars and warns that the
	// snprintf output could be truncated (e.g. because the year is
	// -2147483647). To silence this warning (and also to work around the
	// windows _snprintf stuff) we add some extra buffer space.
	constexpr size_t size = (4 + 1 + 2 + 1 + 2 + 1) + 22;
	std::array<char, size> dateStr;
	time_t t = time(nullptr);
	const struct tm* tm = localtime(&t);
	size_t dateLen = snprintf(dateStr.data(), sizeof(dateStr), "%04d-%02d-%02d", 1900 + tm->tm_year,
		                  tm->tm_mon + 1, tm->tm_mday);
	assert(dateLen < size);

	AVIOUT4("LIST");
	AVIOUTd(narrow<uint32_t>(
			4 // list type
			+ (4 + 4 + ((versionStr.size() + 1 + 1) & ~1)) // 1st chunk
			+ (4 + 4 + ((dateLen + 1 + 1) & ~1)) // 2nd chunk
		)); // size of the list
	AVIOUT4("INFO");
	AVIOUT4("ISFT");
	AVIOUTd(unsigned(versionStr.size()) + 1); // # of bytes to follow
	AVIOUTs(versionStr);
	AVIOUT4("ICRD");
	AVIOUTd(unsigned(dateLen) + 1); // # of bytes to follow
	AVIOUTs(zstring_view{dateStr.data(), dateLen});
	// TODO: add artist (IART), comments (ICMT), name (INAM), etc.
	// use a loop over chunks (type + string) to create the above bytes in
	// a much nicer way

	// Finish stream list, i.e. put number of bytes in the list to proper pos
	auto nMain = header_pos - main_list - 4;
	auto nJunk = AVI_HEADER_SIZE - 8 - 12 - header_pos;
	assert(nJunk > 0); // increase AVI_HEADER_SIZE if this occurs
	AVIOUT4("JUNK");
	AVIOUTd(nJunk);
	// Fix the size of the main list
	header_pos = main_list;
	AVIOUTd(nMain);
	header_pos = AVI_HEADER_SIZE - 12;

	AVIOUT4("LIST");
	AVIOUTd(written + 4);               // Length of list in bytes
	AVIOUT4("movi");

	try {
		// First add the index table to the end
		unsigned idxSize = unsigned(index.size()) * sizeof(Endian::L32);
		index[0] = ('i' << 0) | ('d' << 8) | ('x' << 16) | ('1' << 24);
		index[1] = idxSize - 8;
		file.write(std::span{index});
		file.seek(0);
		file.write(avi_header);
	} catch (MSXException&) {
		// can't throw from destructor
	}
}

void AviWriter::addAviChunk(std::span<const char, 4> tag, std::span<const uint8_t> data, unsigned flags)
{
	struct {
		std::array<char, 4> t;
		Endian::L32 s;
	} chunk;

	auto size32 = narrow<uint32_t>(data.size());

	copy_to_range(tag, chunk.t);
	chunk.s = size32;
	file.write(std::span{&chunk, 1});

	file.write(data);
	unsigned pos = written + 4;
	written += size32 + 8;
	if (size32 & 1) {
		std::array<uint8_t, 1> padding = {0};
		file.write(padding);
		++written;
	}

	size_t idxSize = index.size();
	index.resize(idxSize + 4);
	memcpy(&index[idxSize], tag.data(), tag.size());
	index[idxSize + 1] = flags;
	index[idxSize + 2] = pos;
	index[idxSize + 3] = size32;
}

void AviWriter::addFrame(const FrameSource* video, std::span<const int16_t> audio)
{
	bool keyFrame = (frames++ % 300 == 0);
	auto buffer = codec.compressFrame(keyFrame, video);
	addAviChunk(subspan<4>("00dc"), buffer, keyFrame ? 0x10 : 0x0);

	if (!audio.empty()) {
		assert((audio.size() % channels) == 0);
		assert(audioRate != 0);
		if constexpr (Endian::BIG) {
			small_buffer<Endian::L16, 4096> buf(audio);
			addAviChunk(subspan<4>("01wb"), as_byte_span(std::span{buf}), 0);
		} else {
			addAviChunk(subspan<4>("01wb"), as_byte_span(audio), 0);
		}
		audioWritten += narrow<uint32_t>(audio.size());
	}
}

} // namespace openmsx