package app

import (
	"sort"
	"strings"
)

func findSingBoxProfileIndexForClient(st singBoxProfilesState, clientID string) int {
	cid := sanitizeID(clientID)
	if cid == "" {
		return -1
	}

	best := -1
	for i := range st.Items {
		meta := st.Items[i].Meta
		if meta == nil {
			continue
		}
		if sanitizeID(asString(meta["client_id"])) != cid {
			continue
		}
		if best < 0 || st.Items[i].ProfileRevision > st.Items[best].ProfileRevision {
			best = i
		}
	}
	if best >= 0 {
		return best
	}

	for i := range st.Items {
		if sanitizeID(st.Items[i].ID) == cid {
			return i
		}
	}

	if len(st.Items) == 1 {
		return 0
	}
	return -1
}

func resolveSingBoxApplyClient(reqClientID, fallbackClientID string) (*TransportClient, string, string) {
	target := strings.TrimSpace(reqClientID)
	if target == "" {
		target = strings.TrimSpace(fallbackClientID)
	}

	transportMu.Lock()
	st := loadTransportClientsState()
	transportMu.Unlock()

	if len(st.Items) == 0 {
		return nil, singBoxProfileCodeNoClient, "transport client not found"
	}
	if target != "" {
		idx := findTransportClientIndex(st.Items, target)
		if idx < 0 {
			return nil, singBoxProfileCodeNoClient, "transport client not found"
		}
		cl := st.Items[idx]
		if cl.Kind != TransportClientSingBox {
			return nil, singBoxProfileCodeClientKind, "target client is not singbox"
		}
		return &cl, "", ""
	}

	candidates := make([]TransportClient, 0)
	for _, it := range st.Items {
		if it.Kind == TransportClientSingBox {
			candidates = append(candidates, it)
		}
	}
	if len(candidates) == 0 {
		return nil, singBoxProfileCodeNoClient, "singbox client not found"
	}
	sort.Slice(candidates, func(i, j int) bool {
		if candidates[i].Enabled != candidates[j].Enabled {
			return candidates[i].Enabled
		}
		return candidates[i].ID < candidates[j].ID
	})
	cl := candidates[0]
	return &cl, "", ""
}