package internal

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"html/template"

	log "github.com/sirupsen/logrus"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/client-go/kubernetes/scheme"
	"k8s.io/client-go/rest"
)

var CILIUM_GROUP_VERSION = schema.GroupVersion{
	Group:   "cilium.io",
	Version: "v2alpha1",
}

var IP_POOL_TEMPLATE = `
{
    "apiVersion": "cilium.io/v2alpha1",
    "kind": "CiliumLoadBalancerIPPool",
    "metadata": {
        "name": "{{ .Name }}",
        "annotations": {
            "argocd.argoproj.io/tracking-id": "cilium-lb:cilium.io/CiliumLoadBalancerIPPool:kube-system/covidnetes-pool",
            "managed-by": "canada-kaktus"
        }
    },
    "spec": {
        "blocks": [
            {{- range $i, $ip := .IPs }}
            {{- if $i}},{{ end }}
            {
                "cidr": "{{ $ip }}/32"
            }
            {{- end }}
        ],
        "disabled": false
    }
}
`

type CrdConfig struct {
	Name string
	IPs  []string
}

func RecreateIPPoolCrd(cfg *Config, name string, ips []string) error {

	if len(ips) == 0 {
		return fmt.Errorf("no IPs provided to create IP Pool CRD")
	}

	routeclient, err := createRestClient()
	if err != nil {
		return fmt.Errorf("error creating REST Client: %v", err.Error())
	}

	resourceVersion, err := getResourceVersion(routeclient, name)
	if err != nil {
		return fmt.Errorf("error getting resourceVersion: %v", err.Error())
	}

	body, err := generateIpPool(name, ips)
	if err != nil {
		return fmt.Errorf("error generating CRD: %v", err.Error())
	}

	// Inject resourceVersion into the JSON
	var obj map[string]interface{}
	if err := json.Unmarshal([]byte(body), &obj); err != nil {
		return fmt.Errorf("could not unmarshal generated CRD: %v", err)
	}
	if meta, ok := obj["metadata"].(map[string]interface{}); ok {
		meta["resourceVersion"] = resourceVersion
	}
	finalBody, err := json.Marshal(obj)
	if err != nil {
		return fmt.Errorf("could not marshal final CRD: %v", err)
	}

	res := routeclient.Put().
		Resource("ciliumloadbalancerippools").
		Name(name).
		Body(finalBody).
		Do(context.TODO())

	var status int
	res.StatusCode(&status)

	if status < 200 || status >= 400 {
		return fmt.Errorf("failed to post CRD to kube api: %v", res.Error())
	}
	raw, rawErr := res.Raw()
	log.WithFields(log.Fields{
		"Caller": "RecreateIPPoolCrd",
	}).Infof("Response from k8s api server: %s", string(raw))

	if rawErr != nil {
		log.WithFields(log.Fields{
			"Caller": "RecreateIPPoolCrd",
		}).Warnf("Could not get raw response from k8s api server: %v", rawErr)
	}

	return nil
}
func createRestClient() (*rest.RESTClient, error) {
	k8s_config, err := rest.InClusterConfig()
	if err != nil {
		return nil, fmt.Errorf("could not create in cluster k8s config: %v", err)
	}

	k8s_config.APIPath = "/apis"
	k8s_config.NegotiatedSerializer = scheme.Codecs.WithoutConversion()
	k8s_config.GroupVersion = &CILIUM_GROUP_VERSION

	routeclient, err := rest.RESTClientFor(k8s_config)

	if err != nil {
		return nil, fmt.Errorf("could not create k8s client: %v", err)
	}
	return routeclient, nil

}

func generateIpPool(name string, ips []string) (string, error) {
	config := CrdConfig{
		Name: name,
		IPs:  ips,
	}
	tmpl, err := template.New("ippool").Parse(IP_POOL_TEMPLATE)
	if err != nil {
		return "", fmt.Errorf("errors in ippool template: %s", err.Error())
	}
	var buf bytes.Buffer
	err = tmpl.Execute(&buf, &config)
	if err != nil {
		return "", fmt.Errorf("could not render ippool template: %s", err.Error())
	}
	return buf.String(), nil
}

func getResourceVersion(client *rest.RESTClient, name string) (string, error) {
	res := client.Get().
		Resource("ciliumloadbalancerippools").
		Name(name).
		Do(context.TODO())
	raw, err := res.Raw()
	if err != nil {
		return "", fmt.Errorf("could not fetch CRD: %v", err)
	}
	var obj map[string]interface{}
	if err := json.Unmarshal(raw, &obj); err != nil {
		return "", fmt.Errorf("could not unmarshal CRD: %v", err)
	}
	meta, ok := obj["metadata"].(map[string]interface{})
	if !ok {
		return "", fmt.Errorf("metadata missing in CRD")
	}
	rv, ok := meta["resourceVersion"].(string)
	if !ok {
		return "", fmt.Errorf("resourceVersion missing in metadata")
	}
	return rv, nil
}