package cmd

import (
	"bytes"
	"fmt"
	"io"
	"os"
	"regexp"
	"text/template"

	"github.com/runconduit/conduit/cli/install"
	"github.com/runconduit/conduit/pkg/k8s"
	uuid "github.com/satori/go.uuid"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/cobra"
)

type installConfig struct {
	Namespace                string
	ControllerImage          string
	WebImage                 string
	PrometheusImage          string
	GrafanaImage             string
	ControllerReplicas       uint
	WebReplicas              uint
	PrometheusReplicas       uint
	ImagePullPolicy          string
	UUID                     string
	CliVersion               string
	ControllerLogLevel       string
	ControllerComponentLabel string
	CreatedByAnnotation      string
	ProxyAPIPort             uint
	EnableTLS                bool
}

type installOptions struct {
	dockerRegistry     string
	controllerReplicas uint
	webReplicas        uint
	prometheusReplicas uint
	controllerLogLevel string
	enableTLS          bool
	*proxyConfigOptions
}

func newInstallOptions() *installOptions {
	return &installOptions{
		dockerRegistry:     "gcr.io/runconduit",
		controllerReplicas: 1,
		webReplicas:        1,
		prometheusReplicas: 1,
		controllerLogLevel: "info",
		enableTLS:          false,
		proxyConfigOptions: newProxyConfigOptions(),
	}
}

func newCmdInstall() *cobra.Command {
	options := newInstallOptions()

	cmd := &cobra.Command{
		Use:   "install [flags]",
		Short: "Output Kubernetes configs to install Conduit",
		Long:  "Output Kubernetes configs to install Conduit.",
		RunE: func(cmd *cobra.Command, args []string) error {
			config, err := validateAndBuildConfig(options)
			if err != nil {
				return err
			}
			return render(*config, os.Stdout, options)
		},
	}

	addProxyConfigFlags(cmd, options.proxyConfigOptions)
	cmd.PersistentFlags().StringVar(&options.dockerRegistry, "registry", options.dockerRegistry, "Docker registry to pull images from")
	cmd.PersistentFlags().UintVar(&options.controllerReplicas, "controller-replicas", options.controllerReplicas, "Replicas of the controller to deploy")
	cmd.PersistentFlags().UintVar(&options.webReplicas, "web-replicas", options.webReplicas, "Replicas of the web server to deploy")
	cmd.PersistentFlags().UintVar(&options.prometheusReplicas, "prometheus-replicas", options.prometheusReplicas, "Replicas of prometheus to deploy")
	cmd.PersistentFlags().StringVar(&options.controllerLogLevel, "controller-log-level", options.controllerLogLevel, "Log level for the controller and web components")
	cmd.PersistentFlags().BoolVar(&options.enableTLS, "enable-tls", options.enableTLS, "Enable TLS connections among pods in the service mesh")
	cmd.PersistentFlags().MarkHidden("enable-tls")

	return cmd
}

func validateAndBuildConfig(options *installOptions) (*installConfig, error) {
	if err := validate(options); err != nil {
		return nil, err
	}
	return &installConfig{
		Namespace:                controlPlaneNamespace,
		ControllerImage:          fmt.Sprintf("%s/controller:%s", options.dockerRegistry, options.conduitVersion),
		WebImage:                 fmt.Sprintf("%s/web:%s", options.dockerRegistry, options.conduitVersion),
		PrometheusImage:          "prom/prometheus:v2.2.1",
		GrafanaImage:             fmt.Sprintf("%s/grafana:%s", options.dockerRegistry, options.conduitVersion),
		ControllerReplicas:       options.controllerReplicas,
		WebReplicas:              options.webReplicas,
		PrometheusReplicas:       options.prometheusReplicas,
		ImagePullPolicy:          options.imagePullPolicy,
		UUID:                     uuid.NewV4().String(),
		CliVersion:               k8s.CreatedByAnnotationValue(),
		ControllerLogLevel:       options.controllerLogLevel,
		ControllerComponentLabel: k8s.ControllerComponentLabel,
		CreatedByAnnotation:      k8s.CreatedByAnnotation,
		ProxyAPIPort:             options.proxyAPIPort,
		EnableTLS:                options.enableTLS,
	}, nil
}

func render(config installConfig, w io.Writer, options *installOptions) error {
	template, err := template.New("conduit").Parse(install.Template)
	if err != nil {
		return err
	}
	buf := &bytes.Buffer{}
	err = template.Execute(buf, config)
	if err != nil {
		return err
	}
	injectOptions := newInjectOptions()
	injectOptions.proxyConfigOptions = options.proxyConfigOptions
	return InjectYAML(buf, w, injectOptions)
}

var alphaNumDash = regexp.MustCompile("^[a-zA-Z0-9-]+$")
var alphaNumDashDot = regexp.MustCompile("^[\\.a-zA-Z0-9-]+$")
var alphaNumDashDotSlash = regexp.MustCompile("^[\\./a-zA-Z0-9-]+$")

func validate(options *installOptions) error {
	// These regexs are not as strict as they could be, but are a quick and dirty
	// sanity check against illegal characters.
	if !alphaNumDash.MatchString(controlPlaneNamespace) {
		return fmt.Errorf("%s is not a valid namespace", controlPlaneNamespace)
	}
	if !alphaNumDashDot.MatchString(options.conduitVersion) {
		return fmt.Errorf("%s is not a valid version", options.conduitVersion)
	}
	if !alphaNumDashDotSlash.MatchString(options.dockerRegistry) {
		return fmt.Errorf("%s is not a valid Docker registry", options.dockerRegistry)
	}
	if options.imagePullPolicy != "Always" && options.imagePullPolicy != "IfNotPresent" && options.imagePullPolicy != "Never" {
		return fmt.Errorf("--image-pull-policy must be one of: Always, IfNotPresent, Never")
	}
	if _, err := log.ParseLevel(options.controllerLogLevel); err != nil {
		return fmt.Errorf("--controller-log-level must be one of: panic, fatal, error, warn, info, debug")
	}
	return nil
}