package config

import (
	"crypto/tls"
	"fmt"
	"net"
	"reflect"
	"strings"
	"time"

	"github.com/hashicorp/consul/agent/structs"
	"github.com/hashicorp/consul/tlsutil"
	"github.com/hashicorp/consul/types"
	"golang.org/x/time/rate"
)

// RuntimeConfig specifies the configuration the consul agent actually
// uses. Is is derived from one or more Config structures which can come
// from files, flags and/or environment variables.
type RuntimeConfig struct {
	// non-user configurable values
	AEInterval                 time.Duration
	ACLDisabledTTL             time.Duration
	CheckDeregisterIntervalMin time.Duration
	CheckReapInterval          time.Duration
	SegmentLimit               int
	SegmentNameLimit           int
	SyncCoordinateRateTarget   float64
	SyncCoordinateIntervalMin  time.Duration
	Revision                   string
	Version                    string
	VersionPrerelease          string

	// consul config
	ConsulCoordinateUpdateMaxBatches int
	ConsulCoordinateUpdateBatchSize  int
	ConsulCoordinateUpdatePeriod     time.Duration
	ConsulRaftElectionTimeout        time.Duration
	ConsulRaftHeartbeatTimeout       time.Duration
	ConsulRaftLeaderLeaseTimeout     time.Duration
	ConsulSerfLANGossipInterval      time.Duration
	ConsulSerfLANProbeInterval       time.Duration
	ConsulSerfLANProbeTimeout        time.Duration
	ConsulSerfLANSuspicionMult       int
	ConsulSerfWANGossipInterval      time.Duration
	ConsulSerfWANProbeInterval       time.Duration
	ConsulSerfWANProbeTimeout        time.Duration
	ConsulSerfWANSuspicionMult       int
	ConsulServerHealthInterval       time.Duration

	ACLAgentMasterToken    string
	ACLAgentToken          string
	ACLDatacenter          string
	ACLDefaultPolicy       string
	ACLDownPolicy          string
	ACLEnforceVersion8     bool
	ACLEnableKeyListPolicy bool
	ACLMasterToken         string
	ACLReplicationToken    string
	ACLTTL                 time.Duration
	ACLToken               string

	// AutopilotCleanupDeadServers enables the automatic cleanup of dead servers when new ones
	// are added to the peer list. Defaults to true.
	//
	// hcl: autopilot { cleanup_dead_servers = (true|false) }
	AutopilotCleanupDeadServers bool

	// AutopilotDisableUpgradeMigration will disable Autopilot's upgrade migration
	// strategy of waiting until enough newer-versioned servers have been added to the
	// cluster before promoting them to voters. (Enterprise-only)
	//
	// hcl: autopilot { disable_upgrade_migration = (true|false)
	AutopilotDisableUpgradeMigration bool

	// AutopilotLastContactThreshold is the limit on the amount of time a server can go
	// without leader contact before being considered unhealthy.
	//
	// hcl: autopilot { last_contact_threshold = "duration" }
	AutopilotLastContactThreshold time.Duration

	// AutopilotMaxTrailingLogs is the amount of entries in the Raft Log that a server can
	// be behind before being considered unhealthy. The value must be positive.
	//
	// hcl: autopilot { max_trailing_logs = int }
	AutopilotMaxTrailingLogs int

	// AutopilotRedundancyZoneTag is the Meta tag to use for separating servers
	// into zones for redundancy. If left blank, this feature will be disabled.
	// (Enterprise-only)
	//
	// hcl: autopilot { redundancy_zone_tag = string }
	AutopilotRedundancyZoneTag string

	// AutopilotServerStabilizationTime is the minimum amount of time a server must be
	// in a stable, healthy state before it can be added to the cluster. Only
	// applicable with Raft protocol version 3 or higher.
	//
	// hcl: autopilot { server_stabilization_time = "duration" }
	AutopilotServerStabilizationTime time.Duration

	// AutopilotUpgradeVersionTag is the node tag to use for version info when
	// performing upgrade migrations. If left blank, the Consul version will be used.
	//
	// (Entrprise-only)
	//
	// hcl: autopilot { upgrade_version_tag = string }
	AutopilotUpgradeVersionTag string

	// DNSAllowStale is used to enable lookups with stale
	// data. This gives horizontal read scalability since
	// any Consul server can service the query instead of
	// only the leader.
	//
	// hcl: dns_config { allow_stale = (true|false) }
	DNSAllowStale bool

	// DNSDisableCompression is used to control whether DNS responses are
	// compressed. In Consul 0.7 this was turned on by default and this
	// config was added as an opt-out.
	//
	// hcl: dns_config { disable_compression = (true|false) }
	DNSDisableCompression bool

	// DNSDomain is the DNS domain for the records. Should end with a dot.
	// Defaults to "consul."
	//
	// hcl: domain = string
	// flag: -domain string
	DNSDomain string

	// DNSEnableTruncate is used to enable setting the truncate
	// flag for UDP DNS queries.  This allows unmodified
	// clients to re-query the consul server using TCP
	// when the total number of records exceeds the number
	// returned by default for UDP.
	//
	// hcl: dns_config { enable_truncate = (true|false) }
	DNSEnableTruncate bool

	// DNSMaxStale is used to bound how stale of a result is
	// accepted for a DNS lookup. This can be used with
	// AllowStale to limit how old of a value is served up.
	// If the stale result exceeds this, another non-stale
	// stale read is performed.
	//
	// hcl: dns_config { max_stale = "duration" }
	DNSMaxStale time.Duration

	// DNSNodeTTL provides the TTL value for a node query.
	//
	// hcl: dns_config { node_ttl = "duration" }
	DNSNodeTTL time.Duration

	// DNSOnlyPassing is used to determine whether to filter nodes
	// whose health checks are in any non-passing state. By
	// default, only nodes in a critical state are excluded.
	//
	// hcl: dns_config { only_passing = "duration" }
	DNSOnlyPassing bool

	// DNSRecursorTimeout specifies the timeout in seconds
	// for Consul's internal dns client used for recursion.
	// This value is used for the connection, read and write timeout.
	//
	// hcl: dns_config { recursor_timeout = "duration" }
	DNSRecursorTimeout time.Duration

	// DNSServiceTTL provides the TTL value for a service
	// query for given service. The "*" wildcard can be used
	// to set a default for all services.
	//
	// hcl: dns_config { service_ttl = map[string]"duration" }
	DNSServiceTTL map[string]time.Duration

	// DNSUDPAnswerLimit is used to limit the maximum number of DNS Resource
	// Records returned in the ANSWER section of a DNS response. This is
	// not normally useful and will be limited based on the querying
	// protocol, however systems that implemented §6 Rule 9 in RFC3484
	// may want to set this to `1` in order to subvert §6 Rule 9 and
	// re-obtain the effect of randomized resource records (i.e. each
	// answer contains only one IP, but the IP changes every request).
	// RFC3484 sorts answers in a deterministic order, which defeats the
	// purpose of randomized DNS responses.  This RFC has been obsoleted
	// by RFC6724 and restores the desired behavior of randomized
	// responses, however a large number of Linux hosts using glibc(3)
	// implemented §6 Rule 9 and may need this option (e.g. CentOS 5-6,
	// Debian Squeeze, etc).
	//
	// hcl: dns_config { udp_answer_limit = int }
	DNSUDPAnswerLimit int

	// DNSRecursors can be set to allow the DNS servers to recursively
	// resolve non-consul domains.
	//
	// hcl: recursors = []string
	// flag: -recursor string [-recursor string]
	DNSRecursors []string

	// HTTPBlockEndpoints is a list of endpoint prefixes to block in the
	// HTTP API. Any requests to these will get a 403 response.
	//
	// hcl: http_config { block_endpoints = []string }
	HTTPBlockEndpoints []string

	// HTTPResponseHeaders are used to add HTTP header response fields to the HTTP API responses.
	//
	// hcl: http_config { response_headers = map[string]string }
	HTTPResponseHeaders map[string]string

	// TelemetryCirconus*: see https://github.com/circonus-labs/circonus-gometrics
	// for more details on the various configuration options.
	// Valid configuration combinations:
	//    - CirconusAPIToken
	//      metric management enabled (search for existing check or create a new one)
	//    - CirconusSubmissionUrl
	//      metric management disabled (use check with specified submission_url,
	//      broker must be using a public SSL certificate)
	//    - CirconusAPIToken + CirconusCheckSubmissionURL
	//      metric management enabled (use check with specified submission_url)
	//    - CirconusAPIToken + CirconusCheckID
	//      metric management enabled (use check with specified id)

	// TelemetryCirconusAPIApp is an app name associated with API token.
	// Default: "consul"
	//
	// hcl: telemetry { circonus_api_app = string }
	TelemetryCirconusAPIApp string

	// TelemetryCirconusAPIToken is a valid API Token used to create/manage check. If provided,
	// metric management is enabled.
	// Default: none
	//
	// hcl: telemetry { circonous_api_token = string }
	TelemetryCirconusAPIToken string

	// TelemetryCirconusAPIURL is the base URL to use for contacting the Circonus API.
	// Default: "https://api.circonus.com/v2"
	//
	// hcl: telemetry { circonus_api_url = string }
	TelemetryCirconusAPIURL string

	// TelemetryCirconusBrokerID is an explicit broker to use when creating a new check. The numeric portion
	// of broker._cid. If metric management is enabled and neither a Submission URL nor Check ID
	// is provided, an attempt will be made to search for an existing check using Instance ID and
	// Search Tag. If one is not found, a new HTTPTRAP check will be created.
	// Default: use Select Tag if provided, otherwise, a random Enterprise Broker associated
	// with the specified API token or the default Circonus Broker.
	// Default: none
	//
	// hcl: telemetry { circonus_broker_id = string }
	TelemetryCirconusBrokerID string

	// TelemetryCirconusBrokerSelectTag is a special tag which will be used to select a broker when
	// a Broker ID is not provided. The best use of this is to as a hint for which broker
	// should be used based on *where* this particular instance is running.
	// (e.g. a specific geo location or datacenter, dc:sfo)
	// Default: none
	//
	// hcl: telemetry { circonus_broker_select_tag = string }
	TelemetryCirconusBrokerSelectTag string

	// TelemetryCirconusCheckDisplayName is the name for the check which will be displayed in the Circonus UI.
	// Default: value of CirconusCheckInstanceID
	//
	// hcl: telemetry { circonus_check_display_name = string }
	TelemetryCirconusCheckDisplayName string

	// TelemetryCirconusCheckForceMetricActivation will force enabling metrics, as they are encountered,
	// if the metric already exists and is NOT active. If check management is enabled, the default
	// behavior is to add new metrics as they are encoutered. If the metric already exists in the
	// check, it will *NOT* be activated. This setting overrides that behavior.
	// Default: "false"
	//
	// hcl: telemetry { circonus_check_metrics_activation = (true|false)
	TelemetryCirconusCheckForceMetricActivation string

	// TelemetryCirconusCheckID is the check id (not check bundle id) from a previously created
	// HTTPTRAP check. The numeric portion of the check._cid field.
	// Default: none
	//
	// hcl: telemetry { circonus_check_id = string }
	TelemetryCirconusCheckID string

	// TelemetryCirconusCheckInstanceID serves to uniquely identify the metrics coming from this "instance".
	// It can be used to maintain metric continuity with transient or ephemeral instances as
	// they move around within an infrastructure.
	// Default: hostname:app
	//
	// hcl: telemetry { circonus_check_instance_id = string }
	TelemetryCirconusCheckInstanceID string

	// TelemetryCirconusCheckSearchTag is a special tag which, when coupled with the instance id, helps to
	// narrow down the search results when neither a Submission URL or Check ID is provided.
	// Default: service:app (e.g. service:consul)
	//
	// hcl: telemetry { circonus_check_search_tag = string }
	TelemetryCirconusCheckSearchTag string

	// TelemetryCirconusCheckSearchTag is a special tag which, when coupled with the instance id, helps to
	// narrow down the search results when neither a Submission URL or Check ID is provided.
	// Default: service:app (e.g. service:consul)
	//
	// hcl: telemetry { circonus_check_tags = string }
	TelemetryCirconusCheckTags string

	// TelemetryCirconusSubmissionInterval is the interval at which metrics are submitted to Circonus.
	// Default: 10s
	//
	// hcl: telemetry { circonus_submission_interval = "duration" }
	TelemetryCirconusSubmissionInterval string

	// TelemetryCirconusCheckSubmissionURL is the check.config.submission_url field from a
	// previously created HTTPTRAP check.
	// Default: none
	//
	// hcl: telemetry { circonus_submission_url = string }
	TelemetryCirconusSubmissionURL string

	// DisableHostname will disable hostname prefixing for all metrics.
	//
	// hcl: telemetry { disable_hostname = (true|false)
	TelemetryDisableHostname bool

	// TelemetryDogStatsdAddr is the address of a dogstatsd instance. If provided,
	// metrics will be sent to that instance
	//
	// hcl: telemetry { dogstatsd_addr = string }
	TelemetryDogstatsdAddr string

	// TelemetryDogStatsdTags are the global tags that should be sent with each packet to dogstatsd
	// It is a list of strings, where each string looks like "my_tag_name:my_tag_value"
	//
	// hcl: telemetry { dogstatsd_tags = []string }
	TelemetryDogstatsdTags []string

	// TelemetryFilterDefault is the default for whether to allow a metric that's not
	// covered by the filter.
	//
	// hcl: telemetry { filter_default = (true|false) }
	TelemetryFilterDefault bool

	// TelemetryAllowedPrefixes is a list of filter rules to apply for allowing metrics
	// by prefix. Use the 'prefix_filter' option and prefix rules with '+' to be
	// included.
	//
	// hcl: telemetry { prefix_filter = []string{"+<expr>", "+<expr>", ...} }
	TelemetryAllowedPrefixes []string

	// TelemetryBlockedPrefixes is a list of filter rules to apply for blocking metrics
	// by prefix. Use the 'prefix_filter' option and prefix rules with '-' to be
	// excluded.
	//
	// hcl: telemetry { prefix_filter = []string{"-<expr>", "-<expr>", ...} }
	TelemetryBlockedPrefixes []string

	// TelemetryMetricsPrefix is the prefix used to write stats values to.
	// Default: "consul."
	//
	// hcl: telemetry { metrics_prefix = string }
	TelemetryMetricsPrefix string

	// TelemetryStatsdAddr is the address of a statsd instance. If provided,
	// metrics will be sent to that instance.
	//
	// hcl: telemetry { statsd_addr = string }
	TelemetryStatsdAddr string

	// TelemetryStatsiteAddr is the address of a statsite instance. If provided,
	// metrics will be streamed to that instance.
	//
	// hcl: telemetry { statsite_addr = string }
	TelemetryStatsiteAddr string

	// Datacenter and NodeName are exposed via /v1/agent/self from here and
	// used in lots of places like CLI commands. Treat this as an interface
	// that must be stable.
	Datacenter string
	NodeName   string

	AdvertiseAddrLAN            *net.IPAddr
	AdvertiseAddrWAN            *net.IPAddr
	BindAddr                    *net.IPAddr
	Bootstrap                   bool
	BootstrapExpect             int
	CAFile                      string
	CAPath                      string
	CertFile                    string
	CheckUpdateInterval         time.Duration
	Checks                      []*structs.CheckDefinition
	ClientAddrs                 []*net.IPAddr
	DNSAddrs                    []net.Addr
	DNSPort                     int
	DataDir                     string
	DevMode                     bool
	DisableAnonymousSignature   bool
	DisableCoordinates          bool
	DisableHostNodeID           bool
	DisableKeyringFile          bool
	DisableRemoteExec           bool
	DisableUpdateCheck          bool
	DiscardCheckOutput          bool
	EnableACLReplication        bool
	EnableDebug                 bool
	EnableScriptChecks          bool
	EnableSyslog                bool
	EnableUI                    bool
	EncryptKey                  string
	EncryptVerifyIncoming       bool
	EncryptVerifyOutgoing       bool
	HTTPAddrs                   []net.Addr
	HTTPPort                    int
	HTTPSAddrs                  []net.Addr
	HTTPSPort                   int
	KeyFile                     string
	LeaveDrainTime              time.Duration
	LeaveOnTerm                 bool
	LogLevel                    string
	NodeID                      types.NodeID
	NodeMeta                    map[string]string
	NonVotingServer             bool
	PidFile                     string
	RPCAdvertiseAddr            *net.TCPAddr
	RPCBindAddr                 *net.TCPAddr
	RPCHoldTimeout              time.Duration
	RPCMaxBurst                 int
	RPCProtocol                 int
	RPCRateLimit                rate.Limit
	RaftProtocol                int
	ReconnectTimeoutLAN         time.Duration
	ReconnectTimeoutWAN         time.Duration
	RejoinAfterLeave            bool
	RetryJoinIntervalLAN        time.Duration
	RetryJoinIntervalWAN        time.Duration
	RetryJoinLAN                []string
	RetryJoinMaxAttemptsLAN     int
	RetryJoinMaxAttemptsWAN     int
	RetryJoinWAN                []string
	SegmentName                 string
	Segments                    []structs.NetworkSegment
	SerfAdvertiseAddrLAN        *net.TCPAddr
	SerfAdvertiseAddrWAN        *net.TCPAddr
	SerfBindAddrLAN             *net.TCPAddr
	SerfBindAddrWAN             *net.TCPAddr
	SerfPortLAN                 int
	SerfPortWAN                 int
	ServerMode                  bool
	ServerName                  string
	ServerPort                  int
	Services                    []*structs.ServiceDefinition
	SessionTTLMin               time.Duration
	SkipLeaveOnInt              bool
	StartJoinAddrsLAN           []string
	StartJoinAddrsWAN           []string
	SyslogFacility              string
	TLSCipherSuites             []uint16
	TLSMinVersion               string
	TLSPreferServerCipherSuites bool
	TaggedAddresses             map[string]string
	TranslateWANAddrs           bool
	UIDir                       string
	UnixSocketGroup             string
	UnixSocketMode              string
	UnixSocketUser              string
	VerifyIncoming              bool
	VerifyIncomingHTTPS         bool
	VerifyIncomingRPC           bool
	VerifyOutgoing              bool
	VerifyServerHostname        bool
	Watches                     []map[string]interface{}
}

// IncomingHTTPSConfig returns the TLS configuration for HTTPS
// connections to consul.
func (c *RuntimeConfig) IncomingHTTPSConfig() (*tls.Config, error) {
	tc := &tlsutil.Config{
		VerifyIncoming:           c.VerifyIncoming || c.VerifyIncomingHTTPS,
		VerifyOutgoing:           c.VerifyOutgoing,
		CAFile:                   c.CAFile,
		CAPath:                   c.CAPath,
		CertFile:                 c.CertFile,
		KeyFile:                  c.KeyFile,
		NodeName:                 c.NodeName,
		ServerName:               c.ServerName,
		TLSMinVersion:            c.TLSMinVersion,
		CipherSuites:             c.TLSCipherSuites,
		PreferServerCipherSuites: c.TLSPreferServerCipherSuites,
	}
	return tc.IncomingTLSConfig()
}

// Sanitized returns a JSON/HCL compatible representation of the runtime
// configuration where all fields with potential secrets had their
// values replaced by 'hidden'. In addition, network addresses and
// time.Duration values are formatted to improve readability.
func (c *RuntimeConfig) Sanitized() map[string]interface{} {
	return sanitize("rt", reflect.ValueOf(c)).Interface().(map[string]interface{})
}

// isSecret determines whether a field name represents a field which
// may contain a secret.
func isSecret(name string) bool {
	name = strings.ToLower(name)
	return strings.Contains(name, "key") || strings.Contains(name, "token") || strings.Contains(name, "secret")
}

// cleanRetryJoin sanitizes the go-discover config strings key=val key=val...
// by scrubbing the individual key=val combinations.
func cleanRetryJoin(a string) string {
	var fields []string
	for _, f := range strings.Fields(a) {
		if isSecret(f) {
			kv := strings.SplitN(f, "=", 2)
			fields = append(fields, kv[0]+"=hidden")
		} else {
			fields = append(fields, f)
		}
	}
	return strings.Join(fields, " ")
}

func sanitize(name string, v reflect.Value) reflect.Value {
	typ := v.Type()
	switch {

	// check before isStruct and isPtr
	case isNetAddr(typ):
		if v.IsNil() {
			return reflect.ValueOf("")
		}
		switch x := v.Interface().(type) {
		case *net.TCPAddr:
			return reflect.ValueOf("tcp://" + x.String())
		case *net.UDPAddr:
			return reflect.ValueOf("udp://" + x.String())
		case *net.UnixAddr:
			return reflect.ValueOf("unix://" + x.String())
		case *net.IPAddr:
			return reflect.ValueOf(x.IP.String())
		default:
			return v
		}

	// check before isNumber
	case isDuration(typ):
		x := v.Interface().(time.Duration)
		return reflect.ValueOf(x.String())

	case isString(typ):
		if strings.HasPrefix(name, "RetryJoinLAN[") || strings.HasPrefix(name, "RetryJoinWAN[") {
			x := v.Interface().(string)
			return reflect.ValueOf(cleanRetryJoin(x))
		}
		if isSecret(name) {
			return reflect.ValueOf("hidden")
		}
		return v

	case isNumber(typ) || isBool(typ):
		return v

	case isPtr(typ):
		if v.IsNil() {
			return v
		}
		return sanitize(name, v.Elem())

	case isStruct(typ):
		m := map[string]interface{}{}
		for i := 0; i < typ.NumField(); i++ {
			key := typ.Field(i).Name
			m[key] = sanitize(key, v.Field(i)).Interface()
		}
		return reflect.ValueOf(m)

	case isArray(typ) || isSlice(typ):
		ma := make([]interface{}, 0)
		for i := 0; i < v.Len(); i++ {
			ma = append(ma, sanitize(fmt.Sprintf("%s[%d]", name, i), v.Index(i)).Interface())
		}
		return reflect.ValueOf(ma)

	case isMap(typ):
		m := map[string]interface{}{}
		for _, k := range v.MapKeys() {
			key := k.String()
			m[key] = sanitize(key, v.MapIndex(k)).Interface()
		}
		return reflect.ValueOf(m)

	default:
		return v
	}
}

func isDuration(t reflect.Type) bool { return t == reflect.TypeOf(time.Second) }
func isMap(t reflect.Type) bool      { return t.Kind() == reflect.Map }
func isNetAddr(t reflect.Type) bool  { return t.Implements(reflect.TypeOf((*net.Addr)(nil)).Elem()) }
func isPtr(t reflect.Type) bool      { return t.Kind() == reflect.Ptr }
func isArray(t reflect.Type) bool    { return t.Kind() == reflect.Array }
func isSlice(t reflect.Type) bool    { return t.Kind() == reflect.Slice }
func isString(t reflect.Type) bool   { return t.Kind() == reflect.String }
func isStruct(t reflect.Type) bool   { return t.Kind() == reflect.Struct }
func isBool(t reflect.Type) bool     { return t.Kind() == reflect.Bool }
func isNumber(t reflect.Type) bool   { return isInt(t) || isUint(t) || isFloat(t) || isComplex(t) }
func isInt(t reflect.Type) bool {
	return t.Kind() == reflect.Int ||
		t.Kind() == reflect.Int8 ||
		t.Kind() == reflect.Int16 ||
		t.Kind() == reflect.Int32 ||
		t.Kind() == reflect.Int64
}
func isUint(t reflect.Type) bool {
	return t.Kind() == reflect.Uint ||
		t.Kind() == reflect.Uint8 ||
		t.Kind() == reflect.Uint16 ||
		t.Kind() == reflect.Uint32 ||
		t.Kind() == reflect.Uint64
}
func isFloat(t reflect.Type) bool { return t.Kind() == reflect.Float32 || t.Kind() == reflect.Float64 }
func isComplex(t reflect.Type) bool {
	return t.Kind() == reflect.Complex64 || t.Kind() == reflect.Complex128
}