/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package dubbo3

import (
	"context"
	"github.com/apache/dubbo-go/common/logger"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"time"
)

import (
	hessian2 "github.com/apache/dubbo-go-hessian2"
	dubbo3 "github.com/dubbogo/triple/pkg/triple"
)

import (
	"github.com/apache/dubbo-go/common"
	"github.com/apache/dubbo-go/common/constant"
	"github.com/apache/dubbo-go/config"
	"github.com/apache/dubbo-go/protocol"
	invocation_impl "github.com/apache/dubbo-go/protocol/invocation"
)

// DubboInvoker is implement of protocol.Invoker. A dubboInvoker refer to one service and ip.
type DubboInvoker struct {
	protocol.BaseInvoker
	// the net layer client, it is focus on network communication.
	client *dubbo3.TripleClient
	// quitOnce is used to make sure DubboInvoker is only destroyed once
	quitOnce sync.Once
	// timeout for service(interface) level.
	timeout time.Duration
	// clientGuard is the client lock of dubbo invoker
	clientGuard *sync.RWMutex
}

// NewDubboInvoker constructor
func NewDubboInvoker(url *common.URL) (*DubboInvoker, error) {
	requestTimeout := config.GetConsumerConfig().RequestTimeout
	requestTimeoutStr := url.GetParam(constant.TIMEOUT_KEY, config.GetConsumerConfig().Request_Timeout)
	if t, err := time.ParseDuration(requestTimeoutStr); err == nil {
		requestTimeout = t
	}

	key := url.GetParam(constant.BEAN_NAME_KEY, "")
	consumerService := config.GetConsumerService(key)
	client, err := dubbo3.NewTripleClient(url, consumerService)
	if err != nil {
		return nil, err
	}

	return &DubboInvoker{
		BaseInvoker: *protocol.NewBaseInvoker(url),
		client:      client,
		timeout:     requestTimeout,
		clientGuard: &sync.RWMutex{},
	}, nil
}

func (di *DubboInvoker) setClient(client *dubbo3.TripleClient) {
	di.clientGuard.Lock()
	defer di.clientGuard.Unlock()

	di.client = client
}

func (di *DubboInvoker) getClient() *dubbo3.TripleClient {
	di.clientGuard.RLock()
	defer di.clientGuard.RUnlock()

	return di.client
}

// Invoke call remoting.
func (di *DubboInvoker) Invoke(ctx context.Context, invocation protocol.Invocation) protocol.Result {
	var (
		result protocol.RPCResult
	)

	if !di.BaseInvoker.IsAvailable() {
		// Generally, the case will not happen, because the invoker has been removed
		// from the invoker list before destroy,so no new request will enter the destroyed invoker
		logger.Warnf("this dubboInvoker is destroyed")
		result.Err = protocol.ErrDestroyedInvoker
		return &result
	}

	di.clientGuard.RLock()
	defer di.clientGuard.RUnlock()

	if di.client == nil {
		result.Err = protocol.ErrClientClosed
		return &result
	}

	if !di.BaseInvoker.IsAvailable() {
		// Generally, the case will not happen, because the invoker has been removed
		// from the invoker list before destroy,so no new request will enter the destroyed invoker
		logger.Warnf("this grpcInvoker is destroying")
		result.Err = protocol.ErrDestroyedInvoker
		return &result
	}

	in := make([]reflect.Value, 0, 16)
	in = append(in, reflect.ValueOf(ctx))
	if len(invocation.ParameterValues()) > 0 {
		in = append(in, invocation.ParameterValues()...)
	}

	methodName := invocation.MethodName()
	method := di.client.Invoker.MethodByName(methodName)
	res := method.Call(in)

	result.Rest = res[0]
	// check err
	if !res[1].IsNil() {
		result.Err = res[1].Interface().(error)
	} else {
		_ = hessian2.ReflectResponse(res[0], invocation.Reply())
	}

	return &result
}

// get timeout including methodConfig
func (di *DubboInvoker) getTimeout(invocation *invocation_impl.RPCInvocation) time.Duration {
	timeout := di.GetUrl().GetParam(strings.Join([]string{constant.METHOD_KEYS, invocation.MethodName(), constant.TIMEOUT_KEY}, "."), "")
	if len(timeout) != 0 {
		if t, err := time.ParseDuration(timeout); err == nil {
			// config timeout into attachment
			invocation.SetAttachments(constant.TIMEOUT_KEY, strconv.Itoa(int(t.Milliseconds())))
			return t
		}
	}
	// set timeout into invocation at method level
	invocation.SetAttachments(constant.TIMEOUT_KEY, strconv.Itoa(int(di.timeout.Milliseconds())))
	return di.timeout
}

// IsAvailable check if invoker is available, now it is useless
func (di *DubboInvoker) IsAvailable() bool {
	client := di.getClient()
	if client != nil {
		return client.IsAvailable()
	}

	return false
}

// Destroy destroy dubbo3 client invoker.
func (di *DubboInvoker) Destroy() {
	di.quitOnce.Do(func() {
		di.BaseInvoker.Destroy()
		client := di.getClient()
		if client != nil {
			di.setClient(nil)
			client.Close()
		}
	})
}