package flv

import (
	"io"
	"os"
	"encoding/binary"
)

type FLVWriter struct {
	w io.Writer
}

func NewFLVWriter(stream_dir string) (*FLVWriter, error) {
	writer := new(FLVWriter)
	base_dir, _ := os.UserHomeDir()
	filepipe, err := os.Create(base_dir + "/live/" + stream_dir + "/stream.flv")
	if err != nil {
		return nil, err
	}
	writer.w = filepipe
	if err = writer.write_flv_header(); err != nil {
		return nil, err
	}
	return writer, nil
}

func (writer *FLVWriter) Close() (error) {
	return writer.w.(*os.File).Close()
}

func (writer *FLVWriter) WriteMetadataTag(data *[]byte) (err error) {
	uint24_buf := make([]byte, 4)
	tag_header := make([]byte, 11)
	tag_header[0] = 18
	binary.BigEndian.PutUint32(uint24_buf, uint32(len((*data)[16:])))
	copy(tag_header[1:4], uint24_buf[1:])

	if _, err = writer.w.Write(tag_header); err != nil {
		return
	}
	if _, err = writer.w.Write((*data)[16:]); err != nil {
		return
	}


	tag_len_buf := make([]byte, 4)
	binary.BigEndian.PutUint32(tag_len_buf, uint32(len((*data)[16:]) + 11))
	_, err = writer.w.Write(tag_len_buf)
	return	
}


func (writer *FLVWriter) write_flv_header() (err error) {
	header := make([]byte, 13)
	copy(header[:3], "FLV")
	header[3] = 1
	header[4] = 5
	header[8] = 9
	
	_, err = writer.w.Write(header)
	return
}