/*
Copyright 2014 The Kubernetes Authors.

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 validation

import (
	"fmt"
	"strings"

	"k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/resource"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/apimachinery/pkg/util/validation/field"
	"k8s.io/kubernetes/pkg/apis/core/helper"
	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
	apivalidation "k8s.io/kubernetes/pkg/apis/core/validation"
)

const isNegativeErrorMsg string = `must be greater than or equal to 0`
const isNotIntegerErrorMsg string = `must be an integer`

// ValidateResourceRequirements will check if any of the resource
// Limits/Requests are of a valid value. Any incorrect value will be added to
// the ErrorList.
func ValidateResourceRequirements(requirements *v1.ResourceRequirements, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	limPath := fldPath.Child("limits")
	reqPath := fldPath.Child("requests")
	for resourceName, quantity := range requirements.Limits {
		fldPath := limPath.Key(string(resourceName))
		// Validate resource name.
		allErrs = append(allErrs, ValidateContainerResourceName(string(resourceName), fldPath)...)

		// Validate resource quantity.
		allErrs = append(allErrs, ValidateResourceQuantityValue(string(resourceName), quantity, fldPath)...)

	}
	for resourceName, quantity := range requirements.Requests {
		fldPath := reqPath.Key(string(resourceName))
		// Validate resource name.
		allErrs = append(allErrs, ValidateContainerResourceName(string(resourceName), fldPath)...)
		// Validate resource quantity.
		allErrs = append(allErrs, ValidateResourceQuantityValue(string(resourceName), quantity, fldPath)...)

		// Check that request <= limit.
		limitQuantity, exists := requirements.Limits[resourceName]
		if exists {
			// For GPUs, not only requests can't exceed limits, they also can't be lower, i.e. must be equal.
			if quantity.Cmp(limitQuantity) != 0 && !v1helper.IsOvercommitAllowed(resourceName) {
				allErrs = append(allErrs, field.Invalid(reqPath, quantity.String(), fmt.Sprintf("must be equal to %s limit", resourceName)))
			} else if quantity.Cmp(limitQuantity) > 0 {
				allErrs = append(allErrs, field.Invalid(reqPath, quantity.String(), fmt.Sprintf("must be less than or equal to %s limit", resourceName)))
			}
		}
	}

	return allErrs
}

// ValidateContainerResourceName checks the name of resource specified for a container
func ValidateContainerResourceName(value string, fldPath *field.Path) field.ErrorList {
	allErrs := validateResourceName(value, fldPath)
	if len(strings.Split(value, "/")) == 1 {
		if !helper.IsStandardContainerResourceName(value) {
			return append(allErrs, field.Invalid(fldPath, value, "must be a standard resource for containers"))
		}
	} else if !v1helper.IsNativeResource(v1.ResourceName(value)) {
		if !v1helper.IsExtendedResourceName(v1.ResourceName(value)) {
			return append(allErrs, field.Invalid(fldPath, value, "doesn't follow extended resource name standard"))
		}
	}
	return allErrs
}

// ValidateResourceQuantityValue enforces that specified quantity is valid for specified resource
func ValidateResourceQuantityValue(resource string, value resource.Quantity, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	allErrs = append(allErrs, ValidateNonnegativeQuantity(value, fldPath)...)
	if helper.IsIntegerResourceName(resource) {
		if value.MilliValue()%int64(1000) != int64(0) {
			allErrs = append(allErrs, field.Invalid(fldPath, value, isNotIntegerErrorMsg))
		}
	}
	return allErrs
}

// ValidateNonnegativeQuantity checks that a Quantity is not negative.
func ValidateNonnegativeQuantity(value resource.Quantity, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	if value.Cmp(resource.Quantity{}) < 0 {
		allErrs = append(allErrs, field.Invalid(fldPath, value.String(), isNegativeErrorMsg))
	}
	return allErrs
}

// Validate compute resource typename.
// Refer to docs/design/resources.md for more details.
func validateResourceName(value string, fldPath *field.Path) field.ErrorList {
	allErrs := apivalidation.ValidateQualifiedName(value, fldPath)
	if len(allErrs) != 0 {
		return allErrs
	}

	if len(strings.Split(value, "/")) == 1 {
		if !helper.IsStandardResourceName(value) {
			return append(allErrs, field.Invalid(fldPath, value, "must be a standard resource type or fully qualified"))
		}
	}

	return allErrs
}

// ValidatePodLogOptions checks if options that are set are at the correct
// value. Any incorrect value will be returned to the ErrorList.
func ValidatePodLogOptions(opts *v1.PodLogOptions) field.ErrorList {
	allErrs := field.ErrorList{}
	if opts.TailLines != nil && *opts.TailLines < 0 {
		allErrs = append(allErrs, field.Invalid(field.NewPath("tailLines"), *opts.TailLines, isNegativeErrorMsg))
	}
	if opts.LimitBytes != nil && *opts.LimitBytes < 1 {
		allErrs = append(allErrs, field.Invalid(field.NewPath("limitBytes"), *opts.LimitBytes, "must be greater than 0"))
	}
	switch {
	case opts.SinceSeconds != nil && opts.SinceTime != nil:
		allErrs = append(allErrs, field.Forbidden(field.NewPath(""), "at most one of `sinceTime` or `sinceSeconds` may be specified"))
	case opts.SinceSeconds != nil:
		if *opts.SinceSeconds < 1 {
			allErrs = append(allErrs, field.Invalid(field.NewPath("sinceSeconds"), *opts.SinceSeconds, "must be greater than 0"))
		}
	}
	return allErrs
}

// AccumulateUniqueHostPorts checks all the containers for duplicates ports. Any
// duplicate port will be returned in the ErrorList.
func AccumulateUniqueHostPorts(containers []v1.Container, accumulator *sets.String, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	for ci, ctr := range containers {
		idxPath := fldPath.Index(ci)
		portsPath := idxPath.Child("ports")
		for pi := range ctr.Ports {
			idxPath := portsPath.Index(pi)
			port := ctr.Ports[pi].HostPort
			if port == 0 {
				continue
			}
			str := fmt.Sprintf("%d/%s", port, ctr.Ports[pi].Protocol)
			if accumulator.Has(str) {
				allErrs = append(allErrs, field.Duplicate(idxPath.Child("hostPort"), str))
			} else {
				accumulator.Insert(str)
			}
		}
	}
	return allErrs
}
