// HTTP request handlers for accessing statistics data and configuration settings

package stats

import (
	"encoding/json"
	"net/http"
	"sync/atomic"
	"time"

	"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
	"github.com/AdguardTeam/golibs/log"
)

// topAddrs is an alias for the types of the TopFoo fields of statsResponse.
// The key is either a client's address or a requested address.
type topAddrs = map[string]uint64

// StatsResp is a response to the GET /control/stats.
type StatsResp struct {
	TimeUnits string `json:"time_units"`

	TopQueried []topAddrs `json:"top_queried_domains"`
	TopClients []topAddrs `json:"top_clients"`
	TopBlocked []topAddrs `json:"top_blocked_domains"`

	DNSQueries []uint64 `json:"dns_queries"`

	BlockedFiltering     []uint64 `json:"blocked_filtering"`
	ReplacedSafebrowsing []uint64 `json:"replaced_safebrowsing"`
	ReplacedParental     []uint64 `json:"replaced_parental"`

	NumDNSQueries           uint64 `json:"num_dns_queries"`
	NumBlockedFiltering     uint64 `json:"num_blocked_filtering"`
	NumReplacedSafebrowsing uint64 `json:"num_replaced_safebrowsing"`
	NumReplacedSafesearch   uint64 `json:"num_replaced_safesearch"`
	NumReplacedParental     uint64 `json:"num_replaced_parental"`

	AvgProcessingTime float64 `json:"avg_processing_time"`
}

// handleStats handles requests to the GET /control/stats endpoint.
func (s *StatsCtx) handleStats(w http.ResponseWriter, r *http.Request) {
	limit := atomic.LoadUint32(&s.limitHours)

	start := time.Now()
	resp, ok := s.getData(limit)
	log.Debug("stats: prepared data in %v", time.Since(start))

	if !ok {
		// Don't bring the message to the lower case since it's a part of UI
		// text for the moment.
		aghhttp.Error(r, w, http.StatusInternalServerError, "Couldn't get statistics data")

		return
	}

	_ = aghhttp.WriteJSONResponse(w, r, resp)
}

// configResp is the response to the GET /control/stats_info.
type configResp struct {
	IntervalDays uint32 `json:"interval"`
}

// handleStatsInfo handles requests to the GET /control/stats_info endpoint.
func (s *StatsCtx) handleStatsInfo(w http.ResponseWriter, r *http.Request) {
	resp := configResp{IntervalDays: atomic.LoadUint32(&s.limitHours) / 24}
	_ = aghhttp.WriteJSONResponse(w, r, resp)
}

// handleStatsConfig handles requests to the POST /control/stats_config
// endpoint.
func (s *StatsCtx) handleStatsConfig(w http.ResponseWriter, r *http.Request) {
	reqData := configResp{}
	err := json.NewDecoder(r.Body).Decode(&reqData)
	if err != nil {
		aghhttp.Error(r, w, http.StatusBadRequest, "json decode: %s", err)

		return
	}

	if !checkInterval(reqData.IntervalDays) {
		aghhttp.Error(r, w, http.StatusBadRequest, "Unsupported interval")

		return
	}

	s.setLimit(int(reqData.IntervalDays))
	s.configModified()
}

// handleStatsReset handles requests to the POST /control/stats_reset endpoint.
func (s *StatsCtx) handleStatsReset(w http.ResponseWriter, r *http.Request) {
	err := s.clear()
	if err != nil {
		aghhttp.Error(r, w, http.StatusInternalServerError, "stats: %s", err)
	}
}

// initWeb registers the handlers for web endpoints of statistics module.
func (s *StatsCtx) initWeb() {
	if s.httpRegister == nil {
		return
	}

	s.httpRegister(http.MethodGet, "/control/stats", s.handleStats)
	s.httpRegister(http.MethodPost, "/control/stats_reset", s.handleStatsReset)
	s.httpRegister(http.MethodPost, "/control/stats_config", s.handleStatsConfig)
	s.httpRegister(http.MethodGet, "/control/stats_info", s.handleStatsInfo)
}