/*
 * Please refer to the LICENSE file in the root directory of the project.
 * https://github.com/kubesphere/kubesphere/blob/master/LICENSE
 */

package oauth

import (
	"net/http"

	restfulspec "github.com/emicklei/go-restful-openapi/v2"
	"github.com/emicklei/go-restful/v3"
	"gopkg.in/square/go-jose.v2"

	"kubesphere.io/kubesphere/pkg/api"
	"kubesphere.io/kubesphere/pkg/apiserver/authentication/oauth"
	"kubesphere.io/kubesphere/pkg/apiserver/authentication/token"
)

const (
	contentTypeFormData = "application/x-www-form-urlencoded"
	root                = "/oauth"
)

// AddToContainer ks-apiserver includes a built-in OAuth server. Users obtain OAuth access tokens to authenticate themselves to the API.
// The OAuth server supports standard authorization code grant and the implicit grant OAuth authorization flows.
// All requests for OAuth tokens involve a request to <ks-apiserver>/oauth/authorize.
// Most authentication integrations place an authenticating proxy in front of this endpoint, or configure ks-apiserver
// to validate credentials against a backing identity provider.
// Requests to <ks-apiserver>/oauth/authorize can come from user-agents that cannot display interactive login pages, such as the CLI.
func (h *handler) AddToContainer(c *restful.Container) error {
	wellKnown := &restful.WebService{}
	wellKnown.Consumes(restful.MIME_JSON).Produces(restful.MIME_JSON)
	wellKnown.Path("/").Route(wellKnown.GET(".well-known/openid-configuration").
		To(h.discovery).
		Doc("OpenID provider configuration information").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Notes("The OpenID Provider's configuration information can be retrieved.").
		Operation("openid-configuration").
		Returns(http.StatusOK, api.StatusOK, ProviderMetadata{}))
	c.Add(wellKnown)

	ws := &restful.WebService{}
	ws.Path(root).Consumes(restful.MIME_JSON).Produces(restful.MIME_JSON)

	ws.Route(ws.GET("/keys").
		To(h.keys).
		Doc("JSON Web Key Set").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Operation("openid-keys").
		Notes("This contains the signing key(s) the RP uses to validate signatures from the OP. ").
		Returns(http.StatusOK, api.StatusOK, jose.JSONWebKeySet{}))
	ws.Route(ws.GET("/userinfo").
		To(h.userinfo).
		Doc("User info endpoint").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Notes("UserInfo Endpoint is an OAuth 2.0 Protected Resource that returns Claims about the authenticated End-User.").
		Operation("openid-userinfo").
		Returns(http.StatusOK, api.StatusOK, token.Claims{}))

	// Implement webhook authentication interface
	// https://kubernetes.io/docs/reference/access-authn-authz/authentication/#webhook-token-authentication
	ws.Route(ws.POST("/authenticate").
		To(h.tokenReview).
		Deprecate().
		Doc("Token review").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Notes("Token Review attempts to authenticate a token to a known user. "+
			"Note: TokenReview requests may be cached by the webhook token authenticator plugin in the kube-apiserver.").
		Operation("token-review").
		Reads(TokenReview{}).
		Returns(http.StatusOK, api.StatusOK, TokenReview{}))

	// https://datatracker.ietf.org/doc/html/rfc6749#section-3.1
	ws.Route(ws.GET("/authorize").
		To(h.authorize).
		Doc("Authorization endpoint").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Notes("The authorization endpoint is used to interact with the resource owner and obtain an authorization grant.").
		Operation("openid-authorize-get").
		Param(ws.QueryParameter("response_type", "The value MUST be one of \"code\" for requesting an "+
			"authorization code as described by [RFC6749] Section 4.1.1, \"token\" for requesting an access token (implicit grant)"+
			" as described by [RFC6749] Section 4.2.2.").Required(true)).
		Param(ws.QueryParameter("client_id", "OAuth 2.0 Client Identifier valid at the Authorization Server.").Required(true)).
		Param(ws.QueryParameter("redirect_uri", "Redirection URI to which the response will be sent. "+
			"This URI MUST exactly match one of the Redirection URI values for the Client pre-registered at the OpenID Provider.").Required(true)).
		Param(ws.QueryParameter("scope", "OpenID Connect requests MUST contain the openid scope value. "+
			"If the openid scope value is not present, the behavior is entirely unspecified.").Required(false)).
		Param(ws.QueryParameter("state", "Opaque value used to maintain state between the request and the callback.").Required(false)))

	// Authorization Servers MUST support the use of the HTTP GET and POST methods
	// defined in RFC 2616 [RFC2616] at the Authorization Endpoint.
	ws.Route(ws.POST("/authorize").
		Consumes(contentTypeFormData).
		To(h.authorize).
		Doc("Authorization endpoint").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Notes("The authorization endpoint is used to interact with the resource owner and obtain an authorization grant.").
		Operation("openid-authorize-post").
		Param(ws.FormParameter("response_type", "The value MUST be one of \"code\" for requesting an "+
			"authorization code as described by [RFC6749] Section 4.1.1, \"token\" for requesting an access token (implicit grant)"+
			" as described by [RFC6749] Section 4.2.2.")).
		Param(ws.FormParameter("client_id", "OAuth 2.0 Client Identifier valid at the Authorization Server.").Required(true)).
		Param(ws.FormParameter("redirect_uri", "Redirection URI to which the response will be sent. "+
			"This URI MUST exactly match one of the Redirection URI values for the Client pre-registered at the OpenID Provider.").Required(true)).
		Param(ws.FormParameter("scope", "OpenID Connect requests MUST contain the openid scope value. "+
			"If the openid scope value is not present, the behavior is entirely unspecified.").Required(false)).
		Param(ws.FormParameter("state", "Opaque value used to maintain state between the request and the callback.").Required(false)))

	// https://datatracker.ietf.org/doc/html/rfc6749#section-3.2
	ws.Route(ws.POST("/token").
		Consumes(contentTypeFormData).
		To(h.token).
		Doc("Token endpoint").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Notes("The resource owner password credentials grant type is suitable in\n"+
			"cases where the resource owner has a trust relationship with the\n"+
			"client, such as the device operating system or a highly privileged application.").
		Operation("openid-token").
		Param(ws.FormParameter("grant_type", "OAuth defines four grant types: "+
			"authorization code, implicit, resource owner password credentials, and client credentials.").
			Required(true)).
		Param(ws.FormParameter("client_id", "Valid client credential.").Required(true)).
		Param(ws.FormParameter("client_secret", "Valid client credential.").Required(true)).
		Param(ws.FormParameter("username", "The resource owner username.").Required(false)).
		Param(ws.FormParameter("password", "The resource owner password.").Required(false)).
		Param(ws.FormParameter("code", "Valid authorization code.").Required(false)).
		Returns(http.StatusOK, api.StatusOK, &oauth.Token{}))

	// Authorization callback URL, where the end of the URL contains the identity provider name.
	// The provider name is also used to build the callback URL.
	ws.Route(ws.GET("/callback/{callback}").
		To(h.oauthCallback).
		Doc("OAuth2 callback").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Operation("oauth-callback").
		Param(ws.PathParameter("callback", "The identity provider name.")).
		Param(ws.QueryParameter("access_token", "The access token issued by the authorization server.").
			Required(true)).
		Param(ws.QueryParameter("token_type", "The type of the token issued as described in [RFC6479] Section 7.1. "+
			"Value is case insensitive.").Required(true)).
		Param(ws.QueryParameter("expires_in", "The lifetime in seconds of the access token.  For "+
			"example, the value \"3600\" denotes that the access token will "+
			"expire in one hour from the time the response was generated."+
			"If omitted, the authorization server SHOULD provide the "+
			"expiration time via other means or document the default value.")).
		Param(ws.QueryParameter("scope", "if identical to the scope requested by the client;"+
			"otherwise, REQUIRED.  The scope of the access token as described by [RFC6479] Section 3.3.").Required(false)).
		Param(ws.QueryParameter("state", "if the \"state\" parameter was present in the client authorization request."+
			"The exact value received from the client.").Required(true)).
		Returns(http.StatusOK, api.StatusOK, oauth.Token{}))

	// https://openid.net/specs/openid-connect-rpinitiated-1_0.html
	ws.Route(ws.GET("/logout").
		To(h.logout).
		Doc("Logout").
		Metadata(restfulspec.KeyOpenAPITags, []string{api.TagAuthentication}).
		Notes("This endpoint takes an ID token and logs the user out of KubeSphere if the "+
			"subject matches the current session.").
		Operation("logout").
		Param(ws.QueryParameter("id_token_hint", "ID Token previously issued by the OP "+
			"to the RP passed to the Logout Endpoint as a hint about the End-User's current authenticated "+
			"session with the Client. This is used as an indication of the identity of the End-User that "+
			"the RP is requesting be logged out by the OP.").Required(false)).
		Param(ws.QueryParameter("post_logout_redirect_uri", "URL to which the RP is requesting "+
			"that the End-User's User Agent be redirected after a logout has been performed. ").Required(false)).
		Param(ws.QueryParameter("state", "Opaque value used by the RP to maintain state between "+
			"the logout request and the callback to the endpoint specified by the post_logout_redirect_uri parameter.").
			Required(false)).
		Returns(http.StatusOK, http.StatusText(http.StatusOK), ""))

	c.Add(ws)
	return nil
}