// Copyright 2014 The Kubernetes Authors.
// Copyright 2020 Authors of Cilium
//
// 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 v1

import (
	"encoding/json"
	"time"

	fuzz "github.com/google/gofuzz"
)

// Time is a wrapper around time.Time which supports correct
// marshaling to YAML and JSON.  Wrappers are provided for many
// of the factory methods that the time package offers.
//
// +protobuf.options.marshal=false
// +protobuf.as=Timestamp
// +protobuf.options.(gogoproto.goproto_stringer)=false
//
// +kubebuilder:validation:Format=date-time
// +kubebuilder:validation:Type=string
type Time struct {
	time.Time `protobuf:"-" json:"-"`
}

// DeepCopyInto creates a deep-copy of the Time value.  The underlying time.Time
// type is effectively immutable in the time API, so it is safe to
// copy-by-assign, despite the presence of (unexported) Pointer fields.
func (t *Time) DeepCopyInto(out *Time) {
	*out = *t
}

func (in *Time) DeepEqual(other *Time) bool {
	switch {
	case (in == nil) != (other == nil):
		return false
	case (in == nil) && (other == nil):
		return true
	}
	return in.Time.Equal(other.Time)
}

// NewTime returns a wrapped instance of the provided time
func NewTime(time time.Time) Time {
	return Time{time}
}

// Date returns the Time corresponding to the supplied parameters
// by wrapping time.Date.
func Date(year int, month time.Month, day, hour, min, sec, nsec int, loc *time.Location) Time {
	return Time{time.Date(year, month, day, hour, min, sec, nsec, loc)}
}

// Now returns the current local time.
func Now() Time {
	return Time{time.Now()}
}

// IsZero returns true if the value is nil or time is zero.
func (t *Time) IsZero() bool {
	if t == nil {
		return true
	}
	return t.Time.IsZero()
}

// Before reports whether the time instant t is before u.
func (t *Time) Before(u *Time) bool {
	if t != nil && u != nil {
		return t.Time.Before(u.Time)
	}
	return false
}

// Equal reports whether the time instant t is equal to u.
func (t *Time) Equal(u *Time) bool {
	if t == nil && u == nil {
		return true
	}
	if t != nil && u != nil {
		return t.Time.Equal(u.Time)
	}
	return false
}

// Unix returns the local time corresponding to the given Unix time
// by wrapping time.Unix.
func Unix(sec int64, nsec int64) Time {
	return Time{time.Unix(sec, nsec)}
}

// Rfc3339Copy returns a copy of the Time at second-level precision.
func (t Time) Rfc3339Copy() Time {
	copied, _ := time.Parse(time.RFC3339, t.Format(time.RFC3339))
	return Time{copied}
}

// UnmarshalJSON implements the json.Unmarshaller interface.
func (t *Time) UnmarshalJSON(b []byte) error {
	if len(b) == 4 && string(b) == "null" {
		t.Time = time.Time{}
		return nil
	}

	var str string
	err := json.Unmarshal(b, &str)
	if err != nil {
		return err
	}

	pt, err := time.Parse(time.RFC3339, str)
	if err != nil {
		return err
	}

	t.Time = pt.Local()
	return nil
}

// UnmarshalQueryParameter converts from a URL query parameter value to an object
func (t *Time) UnmarshalQueryParameter(str string) error {
	if len(str) == 0 {
		t.Time = time.Time{}
		return nil
	}
	// Tolerate requests from older clients that used JSON serialization to build query params
	if len(str) == 4 && str == "null" {
		t.Time = time.Time{}
		return nil
	}

	pt, err := time.Parse(time.RFC3339, str)
	if err != nil {
		return err
	}

	t.Time = pt.Local()
	return nil
}

// MarshalJSON implements the json.Marshaler interface.
func (t Time) MarshalJSON() ([]byte, error) {
	if t.IsZero() {
		// Encode unset/nil objects as JSON's "null".
		return []byte("null"), nil
	}
	buf := make([]byte, 0, len(time.RFC3339)+2)
	buf = append(buf, '"')
	// time cannot contain non escapable JSON characters
	buf = t.UTC().AppendFormat(buf, time.RFC3339)
	buf = append(buf, '"')
	return buf, nil
}

// ToUnstructured implements the value.UnstructuredConverter interface.
func (t Time) ToUnstructured() interface{} {
	if t.IsZero() {
		return nil
	}
	buf := make([]byte, 0, len(time.RFC3339))
	buf = t.UTC().AppendFormat(buf, time.RFC3339)
	return string(buf)
}

// OpenAPISchemaType is used by the kube-openapi generator when constructing
// the OpenAPI spec of this type.
//
// See: https://github.com/kubernetes/kube-openapi/tree/master/pkg/generators
func (_ Time) OpenAPISchemaType() []string { return []string{"string"} }

// OpenAPISchemaFormat is used by the kube-openapi generator when constructing
// the OpenAPI spec of this type.
func (_ Time) OpenAPISchemaFormat() string { return "date-time" }

// MarshalQueryParameter converts to a URL query parameter value
func (t Time) MarshalQueryParameter() (string, error) {
	if t.IsZero() {
		// Encode unset/nil objects as an empty string
		return "", nil
	}

	return t.UTC().Format(time.RFC3339), nil
}

// Fuzz satisfies fuzz.Interface.
func (t *Time) Fuzz(c fuzz.Continue) {
	if t == nil {
		return
	}
	// Allow for about 1000 years of randomness.  Leave off nanoseconds
	// because JSON doesn't represent them so they can't round-trip
	// properly.
	t.Time = time.Unix(c.Rand.Int63n(1000*365*24*60*60), 0)
}

var _ fuzz.Interface = &Time{}
