// Copyright 2016 The etcd Authors
//
// Licensed 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 clientv3

import (
	"context"
	"crypto/tls"
	"time"

	"go.uber.org/zap"
	"google.golang.org/grpc"
)

type Config struct {
	// Endpoints is a list of URLs.
	Endpoints []string `json:"endpoints"`

	// AutoSyncInterval is the interval to update endpoints with its latest members.
	// 0 disables auto-sync. By default auto-sync is disabled.
	AutoSyncInterval time.Duration `json:"auto-sync-interval"`

	// DialTimeout is the timeout for failing to establish a connection.
	DialTimeout time.Duration `json:"dial-timeout"`

	// DialKeepAliveTime is the time after which client pings the server to see if
	// transport is alive.
	DialKeepAliveTime time.Duration `json:"dial-keep-alive-time"`

	// DialKeepAliveTimeout is the time that the client waits for a response for the
	// keep-alive probe. If the response is not received in this time, the connection is closed.
	DialKeepAliveTimeout time.Duration `json:"dial-keep-alive-timeout"`

	// MaxCallSendMsgSize is the client-side request send limit in bytes.
	// If 0, it defaults to 2.0 MiB (2 * 1024 * 1024).
	// Make sure that "MaxCallSendMsgSize" < server-side default send/recv limit.
	// ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
	MaxCallSendMsgSize int

	// MaxCallRecvMsgSize is the client-side response receive limit.
	// If 0, it defaults to "math.MaxInt32", because range response can
	// easily exceed request send limits.
	// Make sure that "MaxCallRecvMsgSize" >= server-side default send/recv limit.
	// ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
	MaxCallRecvMsgSize int

	// TLS holds the client secure credentials, if any.
	TLS *tls.Config

	// Username is a user name for authentication.
	Username string `json:"username"`

	// Password is a password for authentication.
	Password string `json:"password"`

	// RejectOldCluster when set will refuse to create a client against an outdated cluster.
	RejectOldCluster bool `json:"reject-old-cluster"`

	// DialOptions is a list of dial options for the grpc client (e.g., for interceptors).
	// For example, pass "grpc.WithBlock()" to block until the underlying connection is up.
	// Without this, Dial returns immediately and connecting the server happens in background.
	DialOptions []grpc.DialOption

	// Context is the default client context; it can be used to cancel grpc dial out and
	// other operations that do not have an explicit context.
	Context context.Context

	// LogConfig configures client-side logger.
	// If nil, use the default logger.
	// TODO: configure gRPC logger
	LogConfig *zap.Config

	// PermitWithoutStream when set will allow client to send keepalive pings to server without any active streams(RPCs).
	PermitWithoutStream bool `json:"permit-without-stream"`

	// MaxUnaryRetries is the maximum number of retries for unary RPCs.
	MaxUnaryRetries uint `json:"max-unary-retries"`

	// BackoffWaitBetween is the wait time before retrying an RPC.
	BackoffWaitBetween time.Duration `json:"backoff-wait-between"`

	// BackoffJitterFraction is the jitter fraction to randomize backoff wait time.
	BackoffJitterFraction float64 `json:"backoff-jitter-fraction"`

	// TODO: support custom balancer picker
}
