package k8s

import (
	"fmt"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/tools/clientcmd/api"
	"os"
	"strings"
)

type config struct {
	Host        string   `json:"host"`        // K8S地址
	AuthType    AuthType `json:"authType"`    // 认证方式 0:config 1:token
	Config      string   `json:"config"`      // 认证配置文件
	Token       string   `json:"token"`       // 认证Token
	IsSkipTls   bool     `json:"isSkipTls"`   // 是否跳过TLS认证
	CaCrt       string   `json:"caCrt"`       // CA证书
	ClusterName string   `json:"clusterName"` // 集群名称

	resetConf *rest.Config
}

type option func(c *config)

func WithHost(host string) option {
	return func(c *config) {
		c.Host = host
	}
}

func WithAuthType(authType string) option {
	return func(c *config) {
		switch strings.ToUpper(authType) {
		case "CONFIG":
			c.AuthType = AuthConfig
		case "TOKEN":
			c.AuthType = AuthToken
		}
	}
}

func WithConfig(conf string) option {
	return func(c *config) {
		c.Config = conf
	}
}

func WithToken(token string) option {
	return func(c *config) {
		c.Token = token
	}
}

func WithIsSkipTls(isSkipTls bool) option {
	return func(c *config) {
		c.IsSkipTls = isSkipTls
	}
}

func WithCaCrt(caCrt string) option {
	return func(c *config) {
		c.CaCrt = caCrt
	}
}

func WithCluster(cluster string) option {
	return func(c *config) {
		c.ClusterName = cluster
	}
}

func NewConfig(opts ...option) (*config, error) {
	c := &config{}
	for _, opt := range opts {
		opt(c)
	}

	if err := c.valid(); err != nil {
		return nil, err
	}

	var restConfig *rest.Config
	var err error

	switch c.AuthType {
	case AuthToken:

		restConfig, err = clientcmd.BuildConfigFromKubeconfigGetter(c.Host, func() (*api.Config, error) {
			apiConf := &api.Config{
				Clusters: map[string]*api.Cluster{
					c.ClusterName: {
						Server:                   c.Host,
						InsecureSkipTLSVerify:    c.IsSkipTls,
						CertificateAuthorityData: []byte(c.CaCrt),
					},
				},
				AuthInfos: map[string]*api.AuthInfo{
					c.ClusterName: {
						Token: c.Token,
					},
				},
				Contexts: map[string]*api.Context{
					c.ClusterName: {
						Cluster:  c.ClusterName,
						AuthInfo: c.ClusterName,
					},
				},
				CurrentContext: c.ClusterName,
			}

			// 如果跳过TLS认证，则清空CA证书
			if c.IsSkipTls {
				apiConf.Clusters[c.ClusterName].InsecureSkipTLSVerify = c.IsSkipTls
				apiConf.Clusters[c.ClusterName].CertificateAuthorityData = nil
			}

			return apiConf, nil
		})

	case AuthConfig:
		restConfig, err = clientcmd.BuildConfigFromFlags(c.Host, c.GetConfigPath())
	}

	if err != nil {
		return nil, err
	}

	c.resetConf = restConfig

	return c, nil
}

func (c *config) valid() error {
	if !strings.HasPrefix(c.Host, "https://") && !strings.HasPrefix(c.Host, "http://") {
		c.Host = fmt.Sprintf("https://%s", c.Host)
	}

	if c.Token == "" && c.Config == "" {
		return fmt.Errorf("auth token or auth config not empty")
	}

	if c.ClusterName == "" {
		c.ClusterName = "default"
	}

	return nil
}

func (c *config) GetConfigPath() string {
	if err := os.WriteFile("./kubernetes", []byte(c.Config), 0644); err != nil {
		panic(err)
	}

	return "./kubernetes"
}