// 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 web

import (
	"net/http"
	"sync"
	"time"

	"github.com/prometheus/prometheus/config"
	"github.com/prometheus/prometheus/retrieval"
	"github.com/prometheus/prometheus/rules"
)

// PrometheusStatusHandler implements http.Handler.
type PrometheusStatusHandler struct {
	mu sync.RWMutex

	BuildInfo map[string]string
	Config    string
	Flags     map[string]string

	RuleManager *rules.Manager
	TargetPools func() map[string][]*retrieval.Target

	Birth      time.Time
	PathPrefix string
}

// TargetHealthToClass returns a map of TargetHealth to the name of a Bootstrap CSS class.
func (h *PrometheusStatusHandler) TargetHealthToClass() map[retrieval.TargetHealth]string {
	return map[retrieval.TargetHealth]string{
		retrieval.HealthUnknown: "warning",
		retrieval.HealthGood:    "success",
		retrieval.HealthBad:     "danger",
	}
}

func (h *PrometheusStatusHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	h.mu.RLock()
	executeTemplate(w, "status", h, h.PathPrefix)
	h.mu.RUnlock()
}

// ApplyConfig updates the status handler's state as the new config requires.
// Returns true on success.
func (h *PrometheusStatusHandler) ApplyConfig(conf *config.Config) bool {
	h.mu.Lock()
	h.Config = conf.String()
	h.mu.Unlock()
	return true
}