// Copyright 2013 The Prometheus 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 rules

import (
	"html/template"

	clientmodel "github.com/prometheus/client_golang/model"

	"github.com/prometheus/prometheus/promql"
)

// A Rule encapsulates a vector expression which is evaluated at a specified
// interval and acted upon (currently either recorded or used for alerting).
type Rule interface {
	// Name returns the name of the rule.
	Name() string
	// Eval evaluates the rule, including any associated recording or alerting actions.
	eval(clientmodel.Timestamp, *promql.Engine) (promql.Vector, error)
	// String returns a human-readable string representation of the rule.
	String() string
	// HTMLSnippet returns a human-readable string representation of the rule,
	// decorated with HTML elements for use the web frontend.
	HTMLSnippet(pathPrefix string) template.HTML
}