package http

import (
	"encoding/json"
	"fmt"
	"net/http"

	"git.loyso.art/frx/devsim/internal/entities"
	"git.loyso.art/frx/devsim/internal/store"
)

// ListenAndServe runs server to accept incoming connections. This function blocks on
// handling connections.
func listStatsHandler(sr store.Stats) http.HandlerFunc {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
			return
		}

		stats, err := sr.List(r.Context())
		if err != nil {
			http.Error(w, fmt.Errorf("listing stats: %w", err).Error(), http.StatusInternalServerError)
			return
		}

		w.Header().Set("content-type", "application/json")
		err = json.NewEncoder(w).Encode(stats)
		if err != nil {
			http.Error(w, fmt.Errorf("encoding payload: %w", err).Error(), http.StatusInternalServerError)
		}
	})
}

func postStatsHandler(sr store.Stats) http.HandlerFunc {
	type request struct {
		IncomingTraffic int `json:"incoming_traffic"`
		OutgoingTraffic int `json:"outgoing_traffic"`
		IncomingRPS     int `json:"incoming_rps"`
		ReadRPS         int `json:"read_rps"`
		WriteRPS        int `json:"write_rps"`
	}

	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
			return
		}

		id := r.PathValue("id")
		if id == "" {
			http.Error(w, "no id provided", http.StatusBadRequest)
			return
		}

		var reqbody request
		err := json.NewDecoder(r.Body).Decode(&reqbody)
		if err != nil {
			http.Error(w, fmt.Errorf("decoding body: %w", err).Error(), http.StatusBadRequest)
			return
		}

		ctx := r.Context()
		err = sr.Upsert(ctx, entities.DeviceStatistics{
			ID:                   entities.DeviceID(id),
			IncomingTrafficBytes: reqbody.IncomingTraffic,
			OutgoingTrafficBytes: reqbody.OutgoingTraffic,
			IncomingRPS:          reqbody.IncomingRPS,
			ReadRPS:              reqbody.ReadRPS,
			WriteRPS:             reqbody.WriteRPS,
		})
		if err != nil {
			http.Error(w, fmt.Errorf("upserting stat metric: %w", err).Error(), http.StatusInternalServerError)
			return
		}

		w.WriteHeader(http.StatusOK)
	})
}