// Copyright 2017 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package config

import (
	"crypto/tls"
	"crypto/x509"
	"io/ioutil"
	"time"

	"github.com/BurntSushi/toml"
	"github.com/juju/errors"
	"github.com/pingcap/tidb/util/logutil"
	tracing "github.com/uber/jaeger-client-go/config"
)

// Config number limitations
const (
	MaxLogFileSize = 4096 // MB
)

// Valid config maps
var (
	ValidStorage = map[string]bool{
		"mocktikv": true,
		"tikv":     true,
	}
)

// Config contains configuration options.
type Config struct {
	Host            string `toml:"host" json:"host"`
	Port            uint   `toml:"port" json:"port"`
	Store           string `toml:"store" json:"store"`
	Path            string `toml:"path" json:"path"`
	Socket          string `toml:"socket" json:"socket"`
	Lease           string `toml:"lease" json:"lease"`
	RunDDL          bool   `toml:"run-ddl" json:"run-ddl"`
	SplitTable      bool   `toml:"split-table" json:"split-table"`
	TokenLimit      uint   `toml:"token-limit" json:"token-limit"`
	OOMAction       string `toml:"oom-action" json:"oom-action"`
	EnableStreaming bool   `toml:"enable-streaming" json:"enable-streaming"`
	// Set sys variable lower-case-table-names, ref: https://dev.mysql.com/doc/refman/5.7/en/identifier-case-sensitivity.html.
	// TODO: We actually only support mode 2, which keeps the original case, but the comparison is case-insensitive.
	LowerCaseTableNames int `toml:"lower-case-table-names" json:"lower-case-table-names"`

	Log               Log               `toml:"log" json:"log"`
	Security          Security          `toml:"security" json:"security"`
	Status            Status            `toml:"status" json:"status"`
	Performance       Performance       `toml:"performance" json:"performance"`
	XProtocol         XProtocol         `toml:"xprotocol" json:"xprotocol"`
	PlanCache         PlanCache         `toml:"plan-cache" json:"plan-cache"`
	PreparedPlanCache PreparedPlanCache `toml:"prepared-plan-cache" json:"prepared-plan-cache"`
	OpenTracing       OpenTracing       `toml:"opentracing" json:"opentracing"`
	ProxyProtocol     ProxyProtocol     `toml:"proxy-protocol" json:"proxy-protocol"`
	TiKVClient        TiKVClient        `toml:"tikv-client" json:"tikv-client"`
	Binlog            Binlog            `toml:"binlog" json:"binlog"`
}

// Log is the log section of config.
type Log struct {
	// Log level.
	Level string `toml:"level" json:"level"`
	// Log format. one of json, text, or console.
	Format string `toml:"format" json:"format"`
	// Disable automatic timestamps in output.
	DisableTimestamp bool `toml:"disable-timestamp" json:"disable-timestamp"`
	// File log config.
	File logutil.FileLogConfig `toml:"file" json:"file"`

	SlowQueryFile      string `toml:"slow-query-file" json:"slow-query-file"`
	SlowThreshold      uint   `toml:"slow-threshold" json:"slow-threshold"`
	ExpensiveThreshold uint   `toml:"expensive-threshold" json:"expensive-threshold"`
	QueryLogMaxLen     uint   `toml:"query-log-max-len" json:"query-log-max-len"`
}

// Security is the security section of the config.
type Security struct {
	SkipGrantTable bool   `toml:"skip-grant-table" json:"skip-grant-table"`
	SSLCA          string `toml:"ssl-ca" json:"ssl-ca"`
	SSLCert        string `toml:"ssl-cert" json:"ssl-cert"`
	SSLKey         string `toml:"ssl-key" json:"ssl-key"`
	ClusterSSLCA   string `toml:"cluster-ssl-ca" json:"cluster-ssl-ca"`
	ClusterSSLCert string `toml:"cluster-ssl-cert" json:"cluster-ssl-cert"`
	ClusterSSLKey  string `toml:"cluster-ssl-key" json:"cluster-ssl-key"`
}

// ToTLSConfig generates tls's config based on security section of the config.
func (s *Security) ToTLSConfig() (*tls.Config, error) {
	var tlsConfig *tls.Config
	if len(s.ClusterSSLCA) != 0 {
		var certificates = make([]tls.Certificate, 0)
		if len(s.ClusterSSLCert) != 0 && len(s.ClusterSSLKey) != 0 {
			// Load the client certificates from disk
			certificate, err := tls.LoadX509KeyPair(s.ClusterSSLCert, s.ClusterSSLKey)
			if err != nil {
				return nil, errors.Errorf("could not load client key pair: %s", err)
			}
			certificates = append(certificates, certificate)
		}

		// Create a certificate pool from the certificate authority
		certPool := x509.NewCertPool()
		ca, err := ioutil.ReadFile(s.ClusterSSLCA)
		if err != nil {
			return nil, errors.Errorf("could not read ca certificate: %s", err)
		}

		// Append the certificates from the CA
		if !certPool.AppendCertsFromPEM(ca) {
			return nil, errors.New("failed to append ca certs")
		}

		tlsConfig = &tls.Config{
			Certificates: certificates,
			RootCAs:      certPool,
		}
	}

	return tlsConfig, nil
}

// Status is the status section of the config.
type Status struct {
	ReportStatus    bool   `toml:"report-status" json:"report-status"`
	StatusPort      uint   `toml:"status-port" json:"status-port"`
	MetricsAddr     string `toml:"metrics-addr" json:"metrics-addr"`
	MetricsInterval uint   `toml:"metrics-interval" json:"metrics-interval"`
}

// Performance is the performance section of the config.
type Performance struct {
	MaxProcs            uint    `toml:"max-procs" json:"max-procs"`
	TCPKeepAlive        bool    `toml:"tcp-keep-alive" json:"tcp-keep-alive"`
	RetryLimit          uint    `toml:"retry-limit" json:"retry-limit"`
	CrossJoin           bool    `toml:"cross-join" json:"cross-join"`
	StatsLease          string  `toml:"stats-lease" json:"stats-lease"`
	RunAutoAnalyze      bool    `toml:"run-auto-analyze" json:"run-auto-analyze"`
	StmtCountLimit      uint    `toml:"stmt-count-limit" json:"stmt-count-limit"`
	FeedbackProbability float64 `toml:"feedback-probability" json:"feedback-probability"`
	QueryFeedbackLimit  uint    `toml:"query-feedback-limit" json:"query-feedback-limit"`
	PseudoEstimateRatio float64 `toml:"pseudo-estimate-ratio" json:"pseudo-estimate-ratio"`
}

// XProtocol is the XProtocol section of the config.
type XProtocol struct {
	XServer bool   `toml:"xserver" json:"xserver"`
	XHost   string `toml:"xhost" json:"xhost"`
	XPort   uint   `toml:"xport" json:"xport"`
	XSocket string `toml:"xsocket" json:"xsocket"`
}

// PlanCache is the PlanCache section of the config.
type PlanCache struct {
	Enabled  bool `toml:"enabled" json:"enabled"`
	Capacity uint `toml:"capacity" json:"capacity"`
	Shards   uint `toml:"shards" json:"shards"`
}

// PreparedPlanCache is the PreparedPlanCache section of the config.
type PreparedPlanCache struct {
	Enabled  bool `toml:"enabled" json:"enabled"`
	Capacity uint `toml:"capacity" json:"capacity"`
}

// OpenTracing is the opentracing section of the config.
type OpenTracing struct {
	Enable     bool                `toml:"enable" json:"enbale"`
	Sampler    OpenTracingSampler  `toml:"sampler" json:"sampler"`
	Reporter   OpenTracingReporter `toml:"reporter" json:"reporter"`
	RPCMetrics bool                `toml:"rpc-metrics" json:"rpc-metrics"`
}

// OpenTracingSampler is the config for opentracing sampler.
// See https://godoc.org/github.com/uber/jaeger-client-go/config#SamplerConfig
type OpenTracingSampler struct {
	Type                    string        `toml:"type" json:"type"`
	Param                   float64       `toml:"param" json:"param"`
	SamplingServerURL       string        `toml:"sampling-server-url" json:"sampling-server-url"`
	MaxOperations           int           `toml:"max-operations" json:"max-operations"`
	SamplingRefreshInterval time.Duration `toml:"sampling-refresh-interval" json:"sampling-refresh-interval"`
}

// OpenTracingReporter is the config for opentracing reporter.
// See https://godoc.org/github.com/uber/jaeger-client-go/config#ReporterConfig
type OpenTracingReporter struct {
	QueueSize           int           `toml:"queue-size" json:"queue-size"`
	BufferFlushInterval time.Duration `toml:"buffer-flush-interval" json:"buffer-flush-interval"`
	LogSpans            bool          `toml:"log-spans" json:"log-spans"`
	LocalAgentHostPort  string        `toml:"local-agent-host-port" json:"local-agent-host-port"`
}

// ProxyProtocol is the PROXY protocol section of the config.
type ProxyProtocol struct {
	// PROXY protocol acceptable client networks.
	// Empty string means disable PROXY protocol,
	// * means all networks.
	Networks string `toml:"networks" json:"networks"`
	// PROXY protocol header read timeout, Unit is second.
	HeaderTimeout uint `toml:"header-timeout" json:"header-timeout"`
}

// TiKVClient is the config for tikv client.
type TiKVClient struct {
	// GrpcConnectionCount is the max gRPC connections that will be established
	// with each tikv-server.
	GrpcConnectionCount uint `toml:"grpc-connection-count" json:"grpc-connection-count"`
	// CommitTimeout is the max time which command 'commit' will wait.
	CommitTimeout string `toml:"commit-timeout" json:"commit-timeout"`
}

// Binlog is the config for binlog.
type Binlog struct {
	BinlogSocket string `toml:"binlog-socket" json:"binlog-socket"`
	WriteTimeout string `toml:"write-timeout" json:"write-timeout"`
	// If IgnoreError is true, when writting binlog meets error, TiDB would
	// ignore the error.
	IgnoreError bool `toml:"ignore-error" json:"ignore-error"`
}

var defaultConf = Config{
	Host:                "0.0.0.0",
	Port:                4000,
	Store:               "mocktikv",
	Path:                "/tmp/tidb",
	RunDDL:              true,
	SplitTable:          true,
	Lease:               "45s",
	TokenLimit:          1000,
	OOMAction:           "log",
	EnableStreaming:     false,
	LowerCaseTableNames: 2,
	Log: Log{
		Level:  "info",
		Format: "text",
		File: logutil.FileLogConfig{
			LogRotate: true,
			MaxSize:   logutil.DefaultLogMaxSize,
		},
		SlowThreshold:      300,
		ExpensiveThreshold: 10000,
		QueryLogMaxLen:     2048,
	},
	Status: Status{
		ReportStatus:    true,
		StatusPort:      10080,
		MetricsInterval: 15,
	},
	Performance: Performance{
		TCPKeepAlive:        true,
		RetryLimit:          10,
		CrossJoin:           true,
		StatsLease:          "3s",
		RunAutoAnalyze:      true,
		StmtCountLimit:      5000,
		FeedbackProbability: 0,
		QueryFeedbackLimit:  1024,
		PseudoEstimateRatio: 0.7,
	},
	XProtocol: XProtocol{
		XHost: "",
		XPort: 0,
	},
	ProxyProtocol: ProxyProtocol{
		Networks:      "",
		HeaderTimeout: 5,
	},
	PlanCache: PlanCache{
		Enabled:  false,
		Capacity: 2560,
		Shards:   256,
	},
	PreparedPlanCache: PreparedPlanCache{
		Enabled:  false,
		Capacity: 100,
	},
	OpenTracing: OpenTracing{
		Enable: false,
		Sampler: OpenTracingSampler{
			Type:  "const",
			Param: 1.0,
		},
		Reporter: OpenTracingReporter{},
	},
	TiKVClient: TiKVClient{
		GrpcConnectionCount: 16,
		CommitTimeout:       "41s",
	},
	Binlog: Binlog{
		WriteTimeout: "15s",
	},
}

var globalConf = defaultConf

// NewConfig creates a new config instance with default value.
func NewConfig() *Config {
	conf := defaultConf
	return &conf
}

// GetGlobalConfig returns the global configuration for this server.
// It should store configuration from command line and configuration file.
// Other parts of the system can read the global configuration use this function.
func GetGlobalConfig() *Config {
	return &globalConf
}

// Load loads config options from a toml file.
func (c *Config) Load(confFile string) error {
	_, err := toml.DecodeFile(confFile, c)
	if c.TokenLimit <= 0 {
		c.TokenLimit = 1000
	}
	return errors.Trace(err)
}

// ToLogConfig converts *Log to *logutil.LogConfig.
func (l *Log) ToLogConfig() *logutil.LogConfig {
	return &logutil.LogConfig{
		Level:            l.Level,
		Format:           l.Format,
		DisableTimestamp: l.DisableTimestamp,
		File:             l.File,
		SlowQueryFile:    l.SlowQueryFile,
	}
}

// ToTracingConfig converts *OpenTracing to *tracing.Configuration.
func (t *OpenTracing) ToTracingConfig() *tracing.Configuration {
	ret := &tracing.Configuration{
		Disabled:   !t.Enable,
		RPCMetrics: t.RPCMetrics,
		Reporter:   &tracing.ReporterConfig{},
		Sampler:    &tracing.SamplerConfig{},
	}
	ret.Reporter.QueueSize = t.Reporter.QueueSize
	ret.Reporter.BufferFlushInterval = t.Reporter.BufferFlushInterval
	ret.Reporter.LogSpans = t.Reporter.LogSpans
	ret.Reporter.LocalAgentHostPort = t.Reporter.LocalAgentHostPort

	ret.Sampler.Type = t.Sampler.Type
	ret.Sampler.Param = t.Sampler.Param
	ret.Sampler.SamplingServerURL = t.Sampler.SamplingServerURL
	ret.Sampler.MaxOperations = t.Sampler.MaxOperations
	ret.Sampler.SamplingRefreshInterval = t.Sampler.SamplingRefreshInterval
	return ret
}

// The following constants represents the valid action configurations for OOMAction.
// NOTE: Althrough the values is case insensitiv, we should use lower-case
// strings because the configuration value will be transformed to lower-case
// string and compared with these constants in the further usage.
const (
	OOMActionCancel = "cancel"
	OOMActionLog    = "log"
)