package service

import (
	"context"
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"reflect"
	"strconv"
	"time"

	cda "git.loafle.net/commons/di-go/annotation"
	cdr "git.loafle.net/commons/di-go/registry"
	"git.loafle.net/commons/logging-go"
	crc "git.loafle.net/commons/rpc-go/client"
	csc "git.loafle.net/commons/server-go/client"
	ocpcc "git.loafle.net/overflow/commons-go/probe/constants"
	"git.loafle.net/overflow/probe/client/container"
	"git.loafle.net/overflow/probe/config"

	// For annotation
	_ "git.loafle.net/overflow/commons-go/core/annotation"
)

var ContainerServiceType = reflect.TypeOf((*ContainerService)(nil))

func init() {
	cdr.RegisterType(ContainerServiceType)
}

type ContainerService struct {
	cda.TypeAnnotation `annotation:"@overflow:RPCService()"`

	discoveryService *DiscoveryService

	rpcServiceMap   map[ocpcc.ContainerType][]interface{}
	containerStates map[ocpcc.ContainerType]*containerState
	connectorMap    map[csc.Connector]*containerState
}

func (s *ContainerService) InitService() error {
	s.containerStates = make(map[ocpcc.ContainerType]*containerState)
	s.rpcServiceMap = make(map[ocpcc.ContainerType][]interface{})
	s.connectorMap = make(map[csc.Connector]*containerState)

	return nil
}

func (s *ContainerService) StartService() error {
	s.rpcServiceMap[ocpcc.ContainerDiscovery] = []interface{}{
		s.discoveryService,
	}
	s.rpcServiceMap[ocpcc.ContainerNetwork] = []interface{}{}
	s.rpcServiceMap[ocpcc.ContainerGenernal] = []interface{}{}

	return nil
}

func (s *ContainerService) StopService() {
	for containerType := range s.containerStates {
		s.removeContainerState(containerType)
	}
}

func (s *ContainerService) DestroyService() {

}

func (s *ContainerService) Call(containerType ocpcc.ContainerType, result interface{}, method string, params ...interface{}) error {
	client, err := s.getClient(containerType)
	if nil != err {
		return err
	}
	return client.Call(result, method, params...)
}

func (s *ContainerService) Send(containerType ocpcc.ContainerType, method string, params ...interface{}) error {
	client, err := s.getClient(containerType)
	if nil != err {
		return err
	}
	return client.Send(method, params...)
}

func (s *ContainerService) getClient(containerType ocpcc.ContainerType) (*crc.Client, error) {
	cs := s.checkContainer(containerType)
	if nil == cs {
		_cs, err := s.runContainer(containerType)
		if nil != err {
			return nil, err
		}
		cs = _cs
		s.containerStates[containerType] = cs
	}

	if nil == cs.client {
		client, err := container.NewClient(containerType, cs.port, s.rpcServiceMap[containerType])
		if nil != err {
			s.removeContainerState(containerType)
			return nil, err
		}
		cs.client = client
		cs.client.Connector.SetOnDisconnected(s.onDisconnected)
		s.connectorMap[cs.client.Connector] = cs
	}

	return cs.client, nil
}

func (s *ContainerService) onDisconnected(connector csc.Connector) {
	cs, ok := s.connectorMap[connector]
	if !ok || nil == cs {
		return
	}
	logging.Logger().Debugf("Client[%s] has been disconnected", cs.containerType.String())
}

func (s *ContainerService) runContainer(containerType ocpcc.ContainerType) (*containerState, error) {
	if cs := s.checkContainer(containerType); nil != cs {
		return cs, nil
	}

	cmd, pidFilePath := cotainerCommand(containerType)
	removePidFile(pidFilePath)

	if err := cmd.Start(); nil != err {
		logging.Logger().Errorf("to run Container[%s] failed err %v", containerType.String(), err)
		return nil, err
	}

	port, err := watchPidFileCreate(pidFilePath, time.Duration(time.Second*2))
	if nil != err {
		return nil, err
	}

	go func(containerType ocpcc.ContainerType, cmd *exec.Cmd) {
		if err := cmd.Wait(); nil != err {
			logging.Logger().Error(err)
		}
		logging.Logger().Infof("Container[%s] has been stopped", containerType.String())
	}(containerType, cmd)

	cs := &containerState{
		containerType: containerType,
		cmd:           cmd,
		port:          port,
	}

	return cs, nil
}

func (s *ContainerService) checkContainer(containerType ocpcc.ContainerType) *containerState {
	cs, ok := s.containerStates[containerType]
	if !ok || nil == cs {
		return nil
	}

	if nil != cs.cmd.ProcessState && cs.cmd.ProcessState.Exited() {
		s.removeContainerState(containerType)
		return nil
	}

	return cs
}

func (s *ContainerService) killContainer(containerType ocpcc.ContainerType) error {
	cs, ok := s.containerStates[containerType]
	if !ok || nil == cs {
		return nil
	}

	if nil == cs.cmd.ProcessState || !cs.cmd.ProcessState.Exited() {
		if err := cs.cmd.Process.Kill(); nil != err {
			return err
		}
	}
	return nil
}

func (s *ContainerService) removeContainerState(containerType ocpcc.ContainerType) {
	cs, ok := s.containerStates[containerType]
	if !ok || nil == cs {
		return
	}

	delete(s.connectorMap, cs.client.Connector)
	cs.client.Stop(context.Background())
	s.killContainer(containerType)
	delete(s.containerStates, containerType)
}

func cotainerCommand(containerType ocpcc.ContainerType) (cmd *exec.Cmd, pidFilePath string) {
	pidFilePath = config.ContainerPIDFilePath(containerType)
	loggingConfigFilePath := config.ContainerLoggingConfigFilePath(containerType)
	binFilePath := config.ContainerBinFilePath(containerType)

	switch containerType {
	case ocpcc.ContainerDiscovery, ocpcc.ContainerNetwork:
		args := []string{
			fmt.Sprintf("-%s=%s", ocpcc.FlagPidFilePathName, pidFilePath),
			fmt.Sprintf("-%s=%s", ocpcc.FlagLoggingConfigFilePathName, loggingConfigFilePath),
		}
		cmd = exec.Command(binFilePath, args...)
	case ocpcc.ContainerGenernal:
		args := []string{
			"-jar",
			binFilePath,
			pidFilePath,
			loggingConfigFilePath,
		}

		cmd = exec.Command(config.JavaBinPath(), args...)
	}
	return
}

func removePidFile(pidFilePath string) {
	if _, err := os.Stat(pidFilePath); err == nil {
		if err := os.Remove(pidFilePath); nil != err {
			logging.Logger().Errorf("removing pid file has been failed [%v]", err)
		}
	}
}

func watchPidFileCreate(pidFilePath string, waitTime time.Duration) (int, error) {
	startTime := time.Now()

	for {
		if _, err := os.Stat(pidFilePath); err == nil {
			buf, err := ioutil.ReadFile(pidFilePath)
			if nil != err {
				return 0, err
			}
			portNumber, err := strconv.ParseInt(string(buf), 10, 32)
			if nil != err {
				return 0, err
			}
			return int(portNumber), nil
		}

		if time.Since(startTime) > waitTime {
			return 0, fmt.Errorf("pid file not exist")
		}

		time.Sleep(time.Duration(time.Millisecond * 100))
	}
}

type containerState struct {
	containerType ocpcc.ContainerType
	cmd           *exec.Cmd
	port          int
	client        *crc.Client
}