package server

import (
	"encoding/base64"
	"encoding/json"
	"io"
	"net/http"
	"path"
	"regexp"
	"strings"

	"github.com/rancher/fleet/pkg/apis/fleet.cattle.io/v1alpha1"
	v1 "github.com/rancher/os2/pkg/apis/rancheros.cattle.io/v1"
	values "github.com/rancher/wrangler/pkg/data"
	"github.com/sirupsen/logrus"
	"gopkg.in/yaml.v3"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

const defaultName = "m-${System Information/Manufacturer}-${System Information/Product Name}-${System Information/Serial Number}-"

var (
	sanitize   = regexp.MustCompile("[^0-9a-zA-Z]")
	doubleDash = regexp.MustCompile("--+")
	start      = regexp.MustCompile("^[a-zA-Z]")
)

func (i *InventoryServer) register(resp http.ResponseWriter, req *http.Request) {
	machineInventory, machineRegister, data, err := i.buildResponse(req)
	if err != nil {
		http.Error(resp, err.Error(), http.StatusUnauthorized)
		return
	}

	machine, writer, err := i.authMachine(resp, req, machineInventory.Namespace)
	if err != nil {
		http.Error(resp, err.Error(), http.StatusUnauthorized)
		return
	}
	if writer == nil {
		if err := i.sampleConfig(machineRegister, resp); err != nil {
			http.Error(resp, "authorization required", http.StatusUnauthorized)
		}
		return
	}
	defer writer.Close()

	if err := i.saveMachine(machine.Spec.TPMHash, machineInventory); err != nil {
		http.Error(resp, err.Error(), http.StatusInternalServerError)
		return
	}

	_, _ = writer.Write(data)
}

func (i *InventoryServer) sampleConfig(machineRegistration *v1.MachineRegistration, writer io.Writer) error {
	_, err := writer.Write([]byte("#cloud-config\n"))
	if err != nil {
		return err
	}
	return yaml.NewEncoder(writer).Encode(map[string]interface{}{
		"rancheros": map[string]interface{}{
			"install": map[string]interface{}{
				"registrationURL": machineRegistration.Status.RegistrationURL,
			},
		},
	})
}

func (i *InventoryServer) saveMachine(tpmHash string, machineInventory *v1.MachineInventory) error {
	machines, err := i.machineCache.GetByIndex(tpmHashIndex, tpmHash)
	if err != nil || len(machines) > 0 {
		return err
	}

	machineInventory.Spec.TPMHash = tpmHash
	_, err = i.machineClient.Create(machineInventory)
	return err
}

func buildName(data map[string]interface{}, name string) string {
	str := name
	result := &strings.Builder{}
	for {
		i := strings.Index(str, "${")
		if i == -1 {
			result.WriteString(str)
			break
		}
		j := strings.Index(str[i:], "}")
		if j == -1 {
			result.WriteString(str)
			break
		}

		result.WriteString(str[:i])
		obj := values.GetValueN(data, strings.Split(str[i+2:j+i], "/")...)
		if str, ok := obj.(string); ok {
			result.WriteString(str)
		}
		str = str[j+i+1:]
	}

	resultStr := sanitize.ReplaceAllString(result.String(), "-")
	resultStr = doubleDash.ReplaceAllString(resultStr, "-")
	if !start.MatchString(resultStr) {
		resultStr = "m" + resultStr
	}
	if len(resultStr) > 58 {
		resultStr = resultStr[:58]
	}
	return strings.ToLower(resultStr)
}

func (i *InventoryServer) buildResponse(req *http.Request) (*v1.MachineInventory, *v1.MachineRegistration, []byte, error) {
	token := path.Base(req.URL.Path)

	smbios, err := getSMBios(req)
	if err != nil {
		return nil, nil, nil, err
	}

	machineRegisters, err := i.machineRegistrationCache.GetByIndex(registrationTokenIndex, token)
	if apierrors.IsNotFound(err) || len(machineRegisters) != 1 {
		if len(machineRegisters) > 1 {
			logrus.Errorf("Multiple MachineRegistrations have the same token %s: %v", token, machineRegisters)
		}
		return nil, nil, nil, err
	}
	machineRegister := machineRegisters[0]

	name := machineRegister.Spec.MachineName
	if name == "" {
		name = defaultName
	}

	installConfig := map[string]interface{}{}
	if machineRegister.Spec.CloudConfig != nil && len(machineRegister.Spec.CloudConfig.Data) > 0 {
		installConfig = values.MergeMapsConcatSlice(installConfig, machineRegister.Spec.CloudConfig.Data)
	}

	serverURL, err := i.serverURL()
	if err != nil {
		return nil, nil, nil, err
	}
	values.PutValue(installConfig, serverURL, "rancherd", "server")
	values.PutValue(installConfig, "tpm://", "rancherd", "token")
	values.PutValue(installConfig, true, "rancheros", "install", "automatic")

	data, err := json.Marshal(installConfig)
	if err != nil {
		return nil, nil, nil, err
	}

	return &v1.MachineInventory{
		ObjectMeta: metav1.ObjectMeta{
			GenerateName: buildName(smbios, name),
			Namespace:    machineRegister.Namespace,
			Labels:       machineRegisters[0].Spec.MachineInventoryLabels,
			Annotations:  machineRegisters[0].Spec.MachineInventoryAnnotations,
		},
		Spec: v1.MachineInventorySpec{
			SMBIOS: &v1alpha1.GenericMap{
				Data: smbios,
			},
		},
	}, machineRegister, data, nil
}

func getSMBios(req *http.Request) (map[string]interface{}, error) {
	smbios := req.Header.Get("X-Cattle-Smbios")
	if smbios == "" {
		return nil, nil
	}
	smbiosData, err := base64.StdEncoding.DecodeString(smbios)
	if err != nil {
		return nil, err
	}
	data := map[string]interface{}{}
	return data, json.Unmarshal(smbiosData, &data)
}