package core

import (
    "context"
    "encoding/json"
    "errors"
    "github.com/google/go-cmp/cmp"
    "github.com/google/go-cmp/cmp/cmpopts"
    "github.com/sirupsen/logrus"
    "golang.org/x/sync/semaphore"
    "sync"
    "time"
)

type pipeline struct {
    active        bool
    record        bool
    synchroniz    synchronizer
    buffer        pipeBuffer
    publisher     Publisher
    storer        Storer
    publishTicker *time.Ticker
    mu            sync.RWMutex
    sema          *semaphore.Weighted
}

// pipe implements Runner & Pusher
func NewPipeline(d Publisher, s Storer, conf *Configuration) *pipeline {
    return &pipeline{
        false,
        false,
        synchronizer{
            //bufferSize:   100,
            mutex:        &sync.RWMutex{},
            updateTicker: time.NewTicker(time.Duration(conf.Pipeline.SyncUpdateIntervalMs) * time.Millisecond),
        },
        pipeBuffer{
            tcpMutex:    &sync.Mutex{},
            serialMutex: &sync.Mutex{},
        },
        d,
        s,
        time.NewTicker(time.Duration(conf.Pipeline.PublishIntervalMs) * time.Millisecond),
        sync.RWMutex{},
        semaphore.NewWeighted(2),
    }
}

func (p *pipeline) isPipeActive() bool {
    p.mu.RLock()
    defer p.mu.RUnlock()
    return p.active
}

func (p *pipeline) Run() {
    p.sema.Acquire(context.Background(), 2)
    p.mu.Lock()
    p.active = true
    p.mu.Unlock()
    logrus.Println("pipe: processing service started")
    go func() {
        for p.isPipeActive() {
            <-p.synchroniz.updateTicker.C
            err := p.refreshDelay()
            if err != nil {
                logrus.Debugln(err)
            }
        }
        p.sema.Release(1)
        logrus.Println("pipe: updater stopped")
    }()
    go func() {
        for p.isPipeActive() {
            <-p.publishTicker.C
            err := p.publish()
            if err != nil && err.Error() != "no data available" {
                logrus.Debug(err)
            }
        }
        p.sema.Release(1)
        logrus.Println("pipe: publisher stopped")
    }()
}

func (p *pipeline) Record() {
    p.record = true
}
func (p *pipeline) StopRecord() {
    p.record = false
}

func (p *pipeline) publish() error {
    p.buffer.tcpMutex.Lock()
    p.buffer.serialMutex.Lock()

    if (p.buffer.MeasTcp == sensorData{} && p.buffer.MeasSerial == sensorData{}) {
        p.buffer.tcpMutex.Unlock()
        p.buffer.serialMutex.Unlock()
        return errors.New("no data available")
    }
    if cmp.Equal(p.buffer.MeasTcp, p.buffer.LastMeasTcp, cmpopts.IgnoreUnexported(sensorData{})) &&
        cmp.Equal(p.buffer.MeasSerial, p.buffer.LastMeasSerial, cmpopts.IgnoreUnexported(sensorData{})) {
        p.buffer.tcpMutex.Unlock()
        p.buffer.serialMutex.Unlock()
        return errors.New("same data")
    }
    logrus.Debug("––––––––––––––––––––––––––––––––––––")
    logrus.Debugf("SER old: %v", p.buffer.LastMeasSerial)
    logrus.Debugf("SER new: %v", p.buffer.MeasSerial)
    logrus.Debugf("TCP old: %v", p.buffer.LastMeasTcp)
    logrus.Debugf("TCP new: %v", p.buffer.MeasTcp)
    logrus.Debug("––––––––––––––––––––––––––––––––––––")
    p.buffer.LastMeasTcp = p.buffer.MeasTcp
    p.buffer.LastMeasSerial = p.buffer.MeasSerial
    p.storer.EnqueuePair(p.buffer.MeasTcp, p.buffer.MeasSerial)

    data := map[string]sensorData{
        string(SOURCE_TCP):    p.buffer.MeasTcp,
        string(SOURCE_SERIAL): p.buffer.MeasSerial,
    }

    p.buffer.tcpMutex.Unlock()
    p.buffer.serialMutex.Unlock()

    jdata, err := json.Marshal(data)
    //logrus.Println(string(pretty.Pretty(jdata)))
    if err != nil {
        return err
    }
    p.publisher.Publish(string(jdata))
    return nil
}

type pipeBuffer struct {
    MeasTcp        sensorData
    MeasSerial     sensorData
    LastMeasTcp    sensorData
    LastMeasSerial sensorData
    tcpMutex       *sync.Mutex
    serialMutex    *sync.Mutex
}

type UnixNanoTime int64

type synchronizer struct {
    tcpSerialDelayMs int64
    mutex            *sync.RWMutex
    updateTicker     *time.Ticker
}

func (p *pipeline) refreshDelay() error {
    p.synchroniz.mutex.RLock()
    if p.synchroniz.tcpSerialDelayMs != 0 {
        logrus.Println("Delay TCP/SERIAL", p.synchroniz.tcpSerialDelayMs)
    }
    p.synchroniz.mutex.RUnlock()
    p.buffer.serialMutex.Lock()
    p.buffer.tcpMutex.Lock()
    tcpTime := time.Unix(0, p.buffer.MeasTcp.Timestamp)
    serTime := time.Unix(0, p.buffer.MeasSerial.Timestamp)
    p.buffer.tcpMutex.Unlock()
    p.buffer.serialMutex.Unlock()
    if tcpTime.UnixNano() == 0 || serTime.UnixNano() == 0 {
        return errors.New("no sync possible. check if both Collectors running. otherwise check GPS fix")
    }
    currentDelay := tcpTime.Sub(serTime).Milliseconds()
    if currentDelay > 5000 || currentDelay < -5000 {
        p.synchroniz.mutex.Lock()
        p.synchroniz.tcpSerialDelayMs = 0
        p.synchroniz.mutex.Unlock()
        return errors.New("skipping synchronisation! time not properly configured or facing network problems.")
    }
    logrus.Debug("TCP", tcpTime.String())
    logrus.Debug("SER", serTime.String())
    logrus.Debug("Difference", tcpTime.Sub(serTime).Milliseconds(), "ms")
    delay := tcpTime.Sub(serTime).Milliseconds()
    p.synchroniz.mutex.Lock()
    p.synchroniz.tcpSerialDelayMs += delay
    p.synchroniz.mutex.Unlock()
    return nil
}

func (p *pipeline) Push(data *sensorData) error {
    if data == nil {
        return errors.New("nil processing not allowed")
    }
    //logrus.Println("push data to pipe:", string(data.source))
    p.storer.EnqueueRaw(*data)
    switch data.source {
    case SOURCE_TCP:
        go p.pushTcpDataToBuffer(*data)
    case SOURCE_SERIAL:
        go p.pushSerialDataToBuffer(*data)
    default:
        panic("pipe: invalid data source")
    }
    return nil
}

func (p *pipeline) pushTcpDataToBuffer(data sensorData) {
    p.synchroniz.mutex.RLock()
    if p.synchroniz.tcpSerialDelayMs > 0 {
        time.Sleep(time.Duration(p.synchroniz.tcpSerialDelayMs) * time.Millisecond)
    }
    p.synchroniz.mutex.RLock()
    p.buffer.tcpMutex.Lock()
    p.buffer.MeasTcp = p.buffer.MeasTcp.ConsolidateExTime(data)
    p.buffer.tcpMutex.Unlock()
}
func (p *pipeline) pushSerialDataToBuffer(data sensorData) {
    p.synchroniz.mutex.RLock()
    if p.synchroniz.tcpSerialDelayMs < 0 {
        time.Sleep(time.Duration(-p.synchroniz.tcpSerialDelayMs) * time.Millisecond)
    }
    p.synchroniz.mutex.RUnlock()
    p.buffer.serialMutex.Lock()
    p.buffer.MeasSerial = p.buffer.MeasSerial.ConsolidateEpochsOnly(data)
    p.buffer.serialMutex.Unlock()
}

func (p *pipeline) Close() {
    p.mu.Lock()
    p.active = false
    p.mu.Unlock()
}