/*
Copyright 2019 The Kubernetes 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.
*/

/******************************************************************************
Template Functions are what map functions in the models, to internal logic in
kops. This is the point where we connect static YAML configuration to dynamic
runtime values in memory.

When defining a new function:
	- Build the new function here
	- Define the new function in AddTo()
		dest["MyNewFunction"] = MyNewFunction // <-- Function Pointer
******************************************************************************/

package cloudup

import (
	"encoding/json"
	"fmt"
	"os"
	"strconv"
	"strings"
	"text/template"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/kops/pkg/apis/kops"
	"k8s.io/kops/pkg/dns"
	"k8s.io/kops/pkg/featureflag"
	"k8s.io/kops/pkg/model"
	"k8s.io/kops/pkg/resources/spotinst"
	"k8s.io/kops/upup/pkg/fi"
	"k8s.io/kops/upup/pkg/fi/cloudup/gce"
	"k8s.io/kops/util/pkg/env"

	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/klog"
)

// TemplateFunctions provides a collection of methods used throughout the templates
type TemplateFunctions struct {
	cluster        *kops.Cluster
	instanceGroups []*kops.InstanceGroup
	modelContext   *model.KopsModelContext
	region         string
	tags           sets.String
}

// This will define the available functions we can use in our YAML models
// If we are trying to get a new function implemented it MUST
// be defined here.
func (tf *TemplateFunctions) AddTo(dest template.FuncMap, secretStore fi.SecretStore) (err error) {
	dest["EtcdScheme"] = tf.EtcdScheme
	dest["SharedVPC"] = tf.SharedVPC
	dest["ToJSON"] = tf.ToJSON
	dest["UseBootstrapTokens"] = tf.modelContext.UseBootstrapTokens
	dest["UseEtcdTLS"] = tf.modelContext.UseEtcdTLS
	// Remember that we may be on a different arch from the target.  Hard-code for now.
	dest["Arch"] = func() string { return "amd64" }
	dest["replace"] = func(s, find, replace string) string {
		return strings.Replace(s, find, replace, -1)
	}
	dest["join"] = func(a []string, sep string) string {
		return strings.Join(a, sep)
	}

	dest["ClusterName"] = tf.modelContext.ClusterName
	dest["HasTag"] = tf.HasTag
	dest["WithDefaultBool"] = func(v *bool, defaultValue bool) bool {
		if v != nil {
			return *v
		}
		return defaultValue
	}

	dest["GetInstanceGroup"] = tf.GetInstanceGroup
	dest["CloudTags"] = tf.modelContext.CloudTagsForInstanceGroup
	dest["KubeDNS"] = func() *kops.KubeDNSConfig {
		return tf.cluster.Spec.KubeDNS
	}

	dest["KopsControllerArgv"] = tf.KopsControllerArgv
	dest["DnsControllerArgv"] = tf.DnsControllerArgv
	dest["ExternalDnsArgv"] = tf.ExternalDnsArgv

	// TODO: Only for GCE?
	dest["EncodeGCELabel"] = gce.EncodeGCELabel
	dest["Region"] = func() string {
		return tf.region
	}

	dest["ProxyEnv"] = tf.ProxyEnv

	dest["KopsSystemEnv"] = tf.KopsSystemEnv

	dest["DO_TOKEN"] = func() string {
		return os.Getenv("DIGITALOCEAN_ACCESS_TOKEN")
	}

	if featureflag.Spotinst.Enabled() {
		if creds, err := spotinst.LoadCredentials(); err == nil {
			dest["SpotinstToken"] = func() string { return creds.Token }
			dest["SpotinstAccount"] = func() string { return creds.Account }
		}
	}

	if tf.cluster.Spec.Networking != nil && tf.cluster.Spec.Networking.Flannel != nil {
		flannelBackendType := tf.cluster.Spec.Networking.Flannel.Backend
		if flannelBackendType == "" {
			klog.Warningf("Defaulting flannel backend to udp (not a recommended configuration)")
			flannelBackendType = "udp"
		}
		dest["FlannelBackendType"] = func() string { return flannelBackendType }
	}

	if tf.cluster.Spec.Networking != nil && tf.cluster.Spec.Networking.Weave != nil {
		weavesecretString := ""
		weavesecret, _ := secretStore.Secret("weavepassword")
		if weavesecret != nil {
			weavesecretString, err = weavesecret.AsString()
			if err != nil {
				return err
			}
			klog.V(4).Info("Weave secret function successfully registered")
		}

		dest["WeaveSecret"] = func() string { return weavesecretString }
	}

	return nil
}

// ToJSON returns a json representation of the struct or on error an empty string
func (tf *TemplateFunctions) ToJSON(data interface{}) string {
	encoded, err := json.Marshal(data)
	if err != nil {
		return ""
	}

	return string(encoded)
}

// EtcdScheme parses and grabs the protocol to the etcd cluster
func (tf *TemplateFunctions) EtcdScheme() string {
	if tf.modelContext.UseEtcdTLS() {
		return "https"
	}

	return "http"
}

// SharedVPC is a simple helper function which makes the templates for a shared VPC clearer
func (tf *TemplateFunctions) SharedVPC() bool {
	return tf.cluster.SharedVPC()
}

// HasTag returns true if the specified tag is set
func (tf *TemplateFunctions) HasTag(tag string) bool {
	_, found := tf.tags[tag]
	return found
}

// GetInstanceGroup returns the instance group with the specified name
func (tf *TemplateFunctions) GetInstanceGroup(name string) (*kops.InstanceGroup, error) {
	for _, ig := range tf.instanceGroups {
		if ig.ObjectMeta.Name == name {
			return ig, nil
		}
	}
	return nil, fmt.Errorf("InstanceGroup %q not found", name)
}

// DnsControllerArgv returns the args to the DNS controller
func (tf *TemplateFunctions) DnsControllerArgv() ([]string, error) {
	var argv []string

	argv = append(argv, "/usr/bin/dns-controller")

	// @check if the dns controller has custom configuration
	if tf.cluster.Spec.ExternalDNS == nil {
		argv = append(argv, []string{"--watch-ingress=false"}...)

		klog.V(4).Infof("watch-ingress=false set on dns-controller")
	} else {
		// @check if the watch ingress is set
		var watchIngress bool
		if tf.cluster.Spec.ExternalDNS.WatchIngress != nil {
			watchIngress = fi.BoolValue(tf.cluster.Spec.ExternalDNS.WatchIngress)
		}

		if watchIngress {
			klog.Warningln("--watch-ingress=true set on dns-controller")
			klog.Warningln("this may cause problems with previously defined services: https://github.com/kubernetes/kops/issues/2496")
		}
		argv = append(argv, fmt.Sprintf("--watch-ingress=%t", watchIngress))
		if tf.cluster.Spec.ExternalDNS.WatchNamespace != "" {
			argv = append(argv, fmt.Sprintf("--watch-namespace=%s", tf.cluster.Spec.ExternalDNS.WatchNamespace))
		}
	}

	if dns.IsGossipHostname(tf.cluster.Spec.MasterInternalName) {
		argv = append(argv, "--dns=gossip")
		argv = append(argv, "--gossip-seed=127.0.0.1:3999")
	} else {
		switch kops.CloudProviderID(tf.cluster.Spec.CloudProvider) {
		case kops.CloudProviderAWS:
			if strings.HasPrefix(os.Getenv("AWS_REGION"), "cn-") {
				argv = append(argv, "--dns=gossip")
			} else {
				argv = append(argv, "--dns=aws-route53")
			}
		case kops.CloudProviderGCE:
			argv = append(argv, "--dns=google-clouddns")
		case kops.CloudProviderDO:
			argv = append(argv, "--dns=digitalocean")
		case kops.CloudProviderVSphere:
			argv = append(argv, "--dns=coredns")
			argv = append(argv, "--dns-server="+*tf.cluster.Spec.CloudConfig.VSphereCoreDNSServer)

		default:
			return nil, fmt.Errorf("unhandled cloudprovider %q", tf.cluster.Spec.CloudProvider)
		}
	}

	zone := tf.cluster.Spec.DNSZone
	if zone != "" {
		if strings.Contains(zone, ".") {
			// match by name
			argv = append(argv, "--zone="+zone)
		} else {
			// match by id
			argv = append(argv, "--zone=*/"+zone)
		}
	}
	// permit wildcard updates
	argv = append(argv, "--zone=*/*")
	// Verbose, but not crazy logging
	argv = append(argv, "-v=2")

	return argv, nil
}

// KopsControllerArgv returns the args to kops-controller
func (tf *TemplateFunctions) KopsControllerArgv() ([]string, error) {
	var argv []string

	argv = append(argv, "/usr/bin/kops-controller")

	argv = append(argv, "--cloud="+tf.cluster.Spec.CloudProvider)
	argv = append(argv, "--config="+tf.cluster.Spec.ConfigBase)

	// Disable metrics (avoid port conflicts, also risky because we are host network)
	argv = append(argv, "--metrics-addr=0")

	// Verbose, but not crazy logging
	argv = append(argv, "--v=2")

	return argv, nil
}

func (tf *TemplateFunctions) ExternalDnsArgv() ([]string, error) {
	var argv []string

	cloudProvider := tf.cluster.Spec.CloudProvider

	switch kops.CloudProviderID(cloudProvider) {
	case kops.CloudProviderAWS:
		argv = append(argv, "--provider=aws")
	case kops.CloudProviderGCE:
		project := tf.cluster.Spec.Project
		argv = append(argv, "--provider=google")
		argv = append(argv, "--google-project="+project)
	default:
		return nil, fmt.Errorf("unhandled cloudprovider %q", tf.cluster.Spec.CloudProvider)
	}

	argv = append(argv, "--source=ingress")

	return argv, nil
}

func (tf *TemplateFunctions) ProxyEnv() map[string]string {
	envs := map[string]string{}
	proxies := tf.cluster.Spec.EgressProxy
	if proxies == nil {
		return envs
	}
	httpProxy := proxies.HTTPProxy
	if httpProxy.Host != "" {
		var portSuffix string
		if httpProxy.Port != 0 {
			portSuffix = ":" + strconv.Itoa(httpProxy.Port)
		} else {
			portSuffix = ""
		}
		url := "http://" + httpProxy.Host + portSuffix
		envs["http_proxy"] = url
		envs["https_proxy"] = url
	}
	if proxies.ProxyExcludes != "" {
		envs["no_proxy"] = proxies.ProxyExcludes
		envs["NO_PROXY"] = proxies.ProxyExcludes
	}
	return envs
}

// KopsSystemEnv builds the env vars for a system component
func (tf *TemplateFunctions) KopsSystemEnv() []corev1.EnvVar {
	envMap := env.BuildSystemComponentEnvVars(&tf.cluster.Spec)

	return envMap.ToEnvVars()
}