package ts

import (
	"io"
)

const (
	ElementaryStreamTypeH264    = 0x1B
	ElementaryStreamTypeAdtsAAC = 0x0F
)

type PATEntry struct {
	ProgramNumber uint
	NetworkPID    uint
	ProgramMapPID uint
}

type PAT struct {
	Entries []PATEntry
}

type PMT struct {
	PCRPID                uint
	ProgramDescriptors    []Descriptor
	ElementaryStreamInfos []ElementaryStreamInfo
}

type Descriptor struct {
	Tag  uint
	Data []byte
}

type ElementaryStreamInfo struct {
	StreamType    uint
	ElementaryPID uint
	Descriptors   []Descriptor
}

type PSI struct {
	TableIdExtension uint
	TableId          uint
	SecNum           uint
	LastSecNum       uint
}

const (
	StreamIdH264 = 0xe0
	StreamIdAAC  = 0xc0
)

type PESHeader struct {
	StreamId   uint // H264=0xe0 AAC=0xc0
	DataLength uint
	PTS        uint64
	DTS        uint64
	ESCR       uint64
}

func PESUIntToTs(v uint64) (ts uint64) {
	// 0010	PTS 32..30 1	PTS 29..15 1 PTS 14..00 1
	return (((v >> 33) & 0x7) << 30) | (((v >> 17) & 0x7fff) << 15) | ((v >> 1) & 0x7fff)
}

func PESTsToUInt(ts uint64) (v uint64) {
	// 0010	PTS 32..30 1	PTS 29..15 1 PTS 14..00 1
	return ((ts>>30)&0x7)<<33 | ((ts>>15)&0x7fff)<<17 | (ts&0x7fff)<<1 | 0x100010001
}

const (
	PTS_HZ = 90000
	PCR_HZ = 27000000
)

func UIntToPCR(v uint64) uint64 {
	// base(33)+resverd(6)+ext(9)
	base := v >> 15
	ext := v & 0x1ff
	return base*300 + ext
}

func PCRToUInt(pcr uint64) uint64 {
	base := pcr / 300
	ext := pcr % 300
	return base<<15 | 0x3f<<9 | ext
}

type TSWriter struct {
	w   io.Writer
	ContinuityCounter uint
	tshdr []byte
}