package cmd

import (
	"os"
	"os/signal"
	"syscall"
	"time"

	"context"

	"github.com/mitchellh/mapstructure"
	"github.com/pkg/errors"
	"github.com/problame/go-streamrpc"
	"github.com/zrepl/zrepl/cmd/endpoint"
	"github.com/zrepl/zrepl/replication"
)

type PullJob struct {
	Name     string
	Connect  streamrpc.Connecter
	Interval time.Duration
	Mapping  *DatasetMapFilter
	// constructed from mapping during parsing
	pruneFilter       *DatasetMapFilter
	SnapshotPrefix    string
	Prune             PrunePolicy
	Debug             JobDebugSettings

	task *Task
	rep  *replication.Replication
}

func parsePullJob(c JobParsingContext, name string, i map[string]interface{}) (j *PullJob, err error) {

	var asMap struct {
		Connect           map[string]interface{}
		Interval          string
		Mapping           map[string]string
		InitialReplPolicy string `mapstructure:"initial_repl_policy"`
		Prune             map[string]interface{}
		SnapshotPrefix    string `mapstructure:"snapshot_prefix"`
		Debug             map[string]interface{}
	}

	if err = mapstructure.Decode(i, &asMap); err != nil {
		err = errors.Wrap(err, "mapstructure error")
		return nil, err
	}

	j = &PullJob{Name: name}

	j.Connect, err = parseConnect(asMap.Connect)
	if err != nil {
		err = errors.Wrap(err, "cannot parse 'connect'")
		return nil, err
	}

	if j.Interval, err = parsePostitiveDuration(asMap.Interval); err != nil {
		err = errors.Wrap(err, "cannot parse 'interval'")
		return nil, err
	}

	j.Mapping, err = parseDatasetMapFilter(asMap.Mapping, false)
	if err != nil {
		err = errors.Wrap(err, "cannot parse 'mapping'")
		return nil, err
	}

	if j.pruneFilter, err = j.Mapping.InvertedFilter(); err != nil {
		err = errors.Wrap(err, "cannot automatically invert 'mapping' for prune job")
		return nil, err
	}

	if j.SnapshotPrefix, err = parseSnapshotPrefix(asMap.SnapshotPrefix); err != nil {
		return
	}

	if j.Prune, err = parsePrunePolicy(asMap.Prune, false); err != nil {
		err = errors.Wrap(err, "cannot parse prune policy")
		return
	}

	if err = mapstructure.Decode(asMap.Debug, &j.Debug); err != nil {
		err = errors.Wrap(err, "cannot parse 'debug'")
		return
	}

	if j.Debug.Conn.ReadDump != "" || j.Debug.Conn.WriteDump != "" {
		logConnecter := logNetConnConnecter{
			Connecter: j.Connect,
			ReadDump:  j.Debug.Conn.ReadDump,
			WriteDump: j.Debug.Conn.WriteDump,
		}
		j.Connect = logConnecter
	}

	return
}

func (j *PullJob) JobName() string {
	return j.Name
}

func (j *PullJob) JobType() JobType { return JobTypePull }

func (j *PullJob) JobStart(ctx context.Context) {

	log := ctx.Value(contextKeyLog).(Logger)
	defer log.Info("exiting")
	j.task = NewTask("main", j, log)

	// j.task is idle here idle here
	usr1 := make(chan os.Signal)
	signal.Notify(usr1, syscall.SIGUSR1)
	defer signal.Stop(usr1)

	ticker := time.NewTicker(j.Interval)
	for {
		begin := time.Now()
		j.doRun(ctx)
		duration := time.Now().Sub(begin)
		if duration > j.Interval {
			j.task.Log().
				WithField("actual_duration", duration).
				WithField("configured_interval", j.Interval).
				Warn("pull run took longer than configured interval")
		}
		select {
		case <-ctx.Done():
			j.task.Log().WithError(ctx.Err()).Info("context")
			return
		case <-ticker.C:
		case <-usr1:
		}
	}
}

var STREAMRPC_CONFIG = &streamrpc.ConnConfig{ // FIXME oversight and configurability
	RxHeaderMaxLen:       4096,
	RxStructuredMaxLen:   4096 * 4096,
	RxStreamMaxChunkSize: 4096 * 4096,
	TxChunkSize:          4096 * 4096,
	RxTimeout: streamrpc.Timeout{
		Progress: 10 * time.Second,
	},
	TxTimeout: streamrpc.Timeout{
		Progress: 10 * time.Second,
	},
}

func (j *PullJob) doRun(ctx context.Context) {

	j.task.Enter("run")
	defer j.task.Finish()

	// FIXME
	clientConf := &streamrpc.ClientConfig{
		ConnConfig: STREAMRPC_CONFIG,
	}

	client, err := streamrpc.NewClient(j.Connect, clientConf)
	defer client.Close()

	j.task.Enter("pull")

	sender := endpoint.NewRemote(client)

	puller, err := endpoint.NewReceiver(
		j.Mapping,
		NewPrefixFilter(j.SnapshotPrefix),
	)
	if err != nil {
		j.task.Log().WithError(err).Error("error creating receiver endpoint")
		j.task.Finish()
		return
	}

	ctx = replication.WithLogger(ctx, replicationLogAdaptor{j.task.Log().WithField(logSubsysField, "replication")})
	ctx = streamrpc.ContextWithLogger(ctx, streamrpcLogAdaptor{j.task.Log().WithField(logSubsysField, "rpc.protocol")})
	ctx = endpoint.WithLogger(ctx, j.task.Log().WithField(logSubsysField, "rpc.endpoint"))

	j.rep = replication.NewReplication()
	j.rep.Drive(ctx, sender, puller)

	client.Close()
	j.task.Finish()

	j.task.Enter("prune")
	pruner, err := j.Pruner(j.task, PrunePolicySideDefault, false)
	if err != nil {
		j.task.Log().WithError(err).Error("error creating pruner")
	} else {
		pruner.Run(ctx)
	}
	j.task.Finish()

}

func (j *PullJob) Report() *replication.Report {
	return j.rep.Report()
}

func (j *PullJob) JobStatus(ctxt context.Context) (*JobStatus, error) {
	return &JobStatus{Tasks: []*TaskStatus{j.task.Status()}}, nil
}

func (j *PullJob) Pruner(task *Task, side PrunePolicySide, dryRun bool) (p Pruner, err error) {
	p = Pruner{
		task,
		time.Now(),
		dryRun,
		j.pruneFilter,
		j.SnapshotPrefix,
		j.Prune,
	}
	return
}