package extension

import (
    "sync"
)

// CodecId 媒体编解码类型
type CodecId int

const (
    CodecH264 CodecId = iota + 96
    CodecH265
    CodecAAC
    CodecG711A
    CodecG711U
    CodecOpus
)

// Track 媒体通道描述接口
type Track interface {
    Ready() bool
    Clone() Track
    GetSdp(payloadType uint8) *Sdp
    GetBitRate() int
    SetBitRate(bitRate int)
    GetCodecId() CodecId
    GetExtraData() []byte
    SetExtraData(data []byte)
}

// BaseTrack 实现Track的公共方法
type BaseTrack struct {
    mutex    sync.Mutex
    bitRate  int
    codecId  CodecId
    extraData []byte
}

func (b *BaseTrack) GetBitRate() int {
    b.mutex.Lock()
    defer b.mutex.Unlock()
    return b.bitRate
}

func (b *BaseTrack) SetBitRate(bitRate int) {
    b.mutex.Lock()
    defer b.mutex.Unlock()
    b.bitRate = bitRate
}

func (b *BaseTrack) GetCodecId() CodecId {
    return b.codecId
}

func (b *BaseTrack) GetExtraData() []byte {
    b.mutex.Lock()
    defer b.mutex.Unlock()
    return b.extraData
}

func (b *BaseTrack) SetExtraData(data []byte) {
    b.mutex.Lock()
    defer b.mutex.Unlock()
    b.extraData = data
}

// VideoTrack 视频轨道接口
type VideoTrack interface {
    Track
    GetVideoWidth() int
    GetVideoHeight() int
    GetVideoFps() float32
    GetConfigFrames() []Frame
}

// VideoTrackImp 视频轨道具体实现
type VideoTrackImp struct {
    BaseTrack
    width  int
    height int
    fps    float32
}

// NewVideoTrackImp 创建视频轨道实例
func NewVideoTrackImp(codecId CodecId, width, height, fps int) *VideoTrackImp {
    return &VideoTrackImp{
        BaseTrack: BaseTrack{codecId: codecId},
        width:     width,
        height:    height,
        fps:       float32(fps),
    }
}

func (v *VideoTrackImp) Ready() bool {
    return true
}

func (v *VideoTrackImp) Clone() Track {
    v.mutex.Lock()
    defer v.mutex.Unlock()
    return &VideoTrackImp{
        BaseTrack: BaseTrack{
            bitRate:  v.bitRate,
            codecId:  v.codecId,
            extraData: v.extraData,
        },
        width:  v.width,
        height: v.height,
        fps:    v.fps,
    }
}

func (v *VideoTrackImp) GetSdp(payloadType uint8) *Sdp {
    // 实际实现应生成SDP描述
    return NewDefaultSdp(payloadType, v)
}

func (v *VideoTrackImp) GetVideoWidth() int {
    return v.width
}

func (v *VideoTrackImp) GetVideoHeight() int {
    return v.height
}

func (v *VideoTrackImp) GetVideoFps() float32 {
    return v.fps
}

func (v *VideoTrackImp) GetConfigFrames() []Frame {
    // 根据编解码器返回sps/pps等配置帧
    return nil
}

// AudioTrack 音频轨道接口
type AudioTrack interface {
    Track
    GetAudioSampleRate() int
    GetAudioSampleBit() int
    GetAudioChannel() int
}

// AudioTrackImp 音频轨道具体实现
type AudioTrackImp struct {
    BaseTrack
    sampleRate int
    channels   int
    sampleBit  int
}

// NewAudioTrackImp 创建音频轨道实例
func NewAudioTrackImp(codecId CodecId, sampleRate, channels, sampleBit int) *AudioTrackImp {
    return &AudioTrackImp{
        BaseTrack:  BaseTrack{codecId: codecId},
        sampleRate: sampleRate,
        channels:   channels,
        sampleBit:  sampleBit,
    }
}

func (a *AudioTrackImp) Ready() bool {
    return true
}

func (a *AudioTrackImp) Clone() Track {
    a.mutex.Lock()
    defer a.mutex.Unlock()
    return &AudioTrackImp{
        BaseTrack: BaseTrack{
            bitRate:  a.bitRate,
            codecId:  a.codecId,
            extraData: a.extraData,
        },
        sampleRate: a.sampleRate,
        channels:   a.channels,
        sampleBit:  a.sampleBit,
    }
}

func (a *AudioTrackImp) GetSdp(payloadType uint8) *Sdp {
    return NewDefaultSdp(payloadType, a)
}

func (a *AudioTrackImp) GetAudioSampleRate() int {
    if a.sampleRate != 0 {
        return a.sampleRate
    }
    return GetClockRateByCodec(a.codecId)
}

func (a *AudioTrackImp) GetAudioSampleBit() int {
    if a.sampleBit != 0 {
        return a.sampleBit
    }
    return 16
}

func (a *AudioTrackImp) GetAudioChannel() int {
    if a.channels != 0 {
        return a.channels
    }
    return 1
}

// 辅助函数
func GetClockRateByCodec(codecId CodecId) int {
    switch codecId {
    case CodecAAC:
        return 44100
    case CodecG711A, CodecG711U:
        return 8000
    case CodecOpus:
        return 48000
    default:
        return 0
    }
}