/*
Copyright 2019 The Jetstack cert-manager contributors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package certmanager

import metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// Certificate is a type to represent a Certificate from ACME
type Certificate struct {
	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`

	Spec   CertificateSpec   `json:"spec,omitempty"`
	Status CertificateStatus `json:"status,omitempty"`
}

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// CertificateList is a list of Certificates
type CertificateList struct {
	metav1.TypeMeta `json:",inline"`
	metav1.ListMeta `json:"metadata"`

	Items []Certificate `json:"items"`
}

type KeyAlgorithm string

const (
	RSAKeyAlgorithm   KeyAlgorithm = "rsa"
	ECDSAKeyAlgorithm KeyAlgorithm = "ecdsa"
)

type KeyEncoding string

const (
	PKCS1 KeyEncoding = "pkcs1"
	PKCS8 KeyEncoding = "pkcs8"
)

// CertificateSpec defines the desired state of Certificate
type CertificateSpec struct {
	// CommonName is a common name to be used on the Certificate.
	// If no CommonName is given, then the first entry in DNSNames is used as
	// the CommonName.
	// The CommonName should have a length of 64 characters or fewer to avoid
	// generating invalid CSRs; in order to have longer domain names, set the
	// CommonName (or first DNSNames entry) to have 64 characters or fewer,
	// and then add the longer domain name to DNSNames.
	// +optional
	CommonName string `json:"commonName,omitempty"`

	// Organization is the organization to be used on the Certificate
	// +optional
	Organization []string `json:"organization,omitempty"`

	// Certificate default Duration
	// +optional
	Duration *metav1.Duration `json:"duration,omitempty"`

	// Certificate renew before expiration duration
	// +optional
	RenewBefore *metav1.Duration `json:"renewBefore,omitempty"`

	// DNSNames is a list of subject alt names to be used on the Certificate.
	// If no CommonName is given, then the first entry in DNSNames is used as
	// the CommonName and must have a length of 64 characters or fewer.
	// +optional
	DNSNames []string `json:"dnsNames,omitempty"`

	// IPAddresses is a list of IP addresses to be used on the Certificate
	// +optional
	IPAddresses []string `json:"ipAddresses,omitempty"`

	// SecretName is the name of the secret resource to store this secret in
	SecretName string `json:"secretName"`

	// IssuerRef is a reference to the issuer for this certificate.
	// If the 'kind' field is not set, or set to 'Issuer', an Issuer resource
	// with the given name in the same namespace as the Certificate will be used.
	// If the 'kind' field is set to 'ClusterIssuer', a ClusterIssuer with the
	// provided name will be used.
	// The 'name' field in this stanza is required at all times.
	IssuerRef ObjectReference `json:"issuerRef"`

	// IsCA will mark this Certificate as valid for signing.
	// This implies that the 'signing' usage is set
	// +optional
	IsCA bool `json:"isCA,omitempty"`

	// Usages is the set of x509 actions that are enabled for a given key. Defaults are ('digital signature', 'key encipherment') if empty
	// +optional
	Usages []KeyUsage `json:"usages,omitempty"`

	// ACME contains configuration specific to ACME Certificates.
	// Notably, this contains details on how the domain names listed on this
	// Certificate resource should be 'solved', i.e. mapping HTTP01 and DNS01
	// providers to DNS names.
	// +optional
	ACME *ACMECertificateConfig `json:"acme,omitempty"`

	// KeySize is the key bit size of the corresponding private key for this certificate.
	// If provided, value must be between 2048 and 8192 inclusive when KeyAlgorithm is
	// empty or is set to "rsa", and value must be one of (256, 384, 521) when
	// KeyAlgorithm is set to "ecdsa".
	// +optional
	KeySize int `json:"keySize,omitempty"`

	// KeyAlgorithm is the private key algorithm of the corresponding private key
	// for this certificate. If provided, allowed values are either "rsa" or "ecdsa"
	// If KeyAlgorithm is specified and KeySize is not provided,
	// key size of 256 will be used for "ecdsa" key algorithm and
	// key size of 2048 will be used for "rsa" key algorithm.
	// +optional
	KeyAlgorithm KeyAlgorithm `json:"keyAlgorithm,omitempty"`

	// KeyEncoding is the private key cryptography standards (PKCS)
	// for this certificate's private key to be encoded in. If provided, allowed
	// values are "pkcs1" and "pkcs8" standing for PKCS#1 and PKCS#8, respectively.
	// If KeyEncoding is not specified, then PKCS#1 will be used by default.
	KeyEncoding KeyEncoding `json:"keyEncoding,omitempty"`
}

// ACMECertificateConfig contains the configuration for the ACME certificate provider
type ACMECertificateConfig struct {
	Config []DomainSolverConfig `json:"config"`
}

// CertificateStatus defines the observed state of Certificate
type CertificateStatus struct {
	// +optional
	Conditions []CertificateCondition `json:"conditions,omitempty"`

	// +optional
	LastFailureTime *metav1.Time `json:"lastFailureTime,omitempty"`

	// The expiration time of the certificate stored in the secret named
	// by this resource in spec.secretName.
	// +optional
	NotAfter *metav1.Time `json:"notAfter,omitempty"`
}

// CertificateCondition contains condition information for an Certificate.
type CertificateCondition struct {
	// Type of the condition, currently ('Ready').
	Type CertificateConditionType `json:"type"`

	// Status of the condition, one of ('True', 'False', 'Unknown').
	Status ConditionStatus `json:"status"`

	// LastTransitionTime is the timestamp corresponding to the last status
	// change of this condition.
	// +optional
	LastTransitionTime *metav1.Time `json:"lastTransitionTime,omitempty"`

	// Reason is a brief machine readable explanation for the condition's last
	// transition.
	// +optional
	Reason string `json:"reason,omitempty"`

	// Message is a human readable description of the details of the last
	// transition, complementing reason.
	// +optional
	Message string `json:"message,omitempty"`
}

// CertificateConditionType represents an Certificate condition value.
type CertificateConditionType string

const (
	// CertificateConditionReady indicates that a certificate is ready for use.
	// This is defined as:
	// - The target secret exists
	// - The target secret contains a certificate that has not expired
	// - The target secret contains a private key valid for the certificate
	// - The commonName and dnsNames attributes match those specified on the Certificate
	CertificateConditionReady CertificateConditionType = "Ready"
)
