package app

import (
	"encoding/json"
	"io"
	"net/http"
	"strings"
)

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

	var body TransportHealthRefreshRequest
	if r.Body != nil {
		defer r.Body.Close()
		if err := json.NewDecoder(io.LimitReader(r.Body, 1<<20)).Decode(&body); err != nil && err != io.EOF {
			http.Error(w, "bad json", http.StatusBadRequest)
			return
		}
	}

	force := bool(body.Force)

	transportMu.Lock()
	st := loadTransportClientsState()
	transportHealthSWR.syncKnownClients(st.Items)
	transportMu.Unlock()

	items := make([]TransportHealthRefreshItem, 0, len(st.Items))
	queued := 0
	skipped := 0
	seen := map[string]struct{}{}

	appendItem := func(it TransportClient, reason string, wasQueued bool) {
		id := strings.TrimSpace(it.ID)
		if id == "" {
			return
		}
		if _, ok := seen[id]; ok {
			return
		}
		seen[id] = struct{}{}
		items = append(items, TransportHealthRefreshItem{
			ClientID: id,
			Status:   it.Status,
			Queued:   wasQueued,
			Reason:   strings.TrimSpace(reason),
		})
		if wasQueued {
			queued++
		} else {
			skipped++
		}
	}

	if len(body.ClientIDs) == 0 {
		for _, it := range st.Items {
			if !force && !transportHealthCandidate(it) {
				appendItem(it, "not eligible for background probe", false)
				continue
			}
			if transportQueueHealthProbe(it, force) {
				appendItem(it, "queued", true)
			} else {
				appendItem(it, "throttled or already fresh", false)
			}
		}
	} else {
		for _, raw := range body.ClientIDs {
			id := sanitizeID(raw)
			if id == "" {
				continue
			}
			idx := findTransportClientIndex(st.Items, id)
			if idx < 0 {
				items = append(items, TransportHealthRefreshItem{
					ClientID: id,
					Queued:   false,
					Reason:   "not found",
				})
				skipped++
				continue
			}
			it := st.Items[idx]
			if !force && !transportHealthCandidate(it) {
				appendItem(it, "not eligible for background probe", false)
				continue
			}
			if transportQueueHealthProbe(it, force) {
				appendItem(it, "queued", true)
			} else {
				appendItem(it, "throttled or already fresh", false)
			}
		}
	}

	resp := TransportHealthRefreshResponse{
		OK:      true,
		Message: "health refresh queued",
		Count:   len(items),
		Queued:  queued,
		Skipped: skipped,
		Items:   items,
	}
	if resp.Count == 0 {
		resp.OK = false
		resp.Code = "TRANSPORT_HEALTH_REFRESH_NO_TARGETS"
		resp.Message = "no target clients"
	}
	writeJSON(w, http.StatusOK, resp)
}