package app

import (
	"sort"
	"strings"
)

func normalizeTransportIfaceID(raw string) string {
	id := sanitizeID(raw)
	if strings.TrimSpace(id) == "" {
		return transportDefaultIfaceID
	}
	return id
}

func normalizeTransportInterfaceMode(raw TransportInterfaceMode, ifaceID string) TransportInterfaceMode {
	mode := TransportInterfaceMode(strings.ToLower(strings.TrimSpace(string(raw))))
	switch mode {
	case TransportInterfaceModeShared, TransportInterfaceModeDedicated:
		return mode
	default:
		if normalizeTransportIfaceID(ifaceID) == transportDefaultIfaceID {
			return TransportInterfaceModeShared
		}
		return TransportInterfaceModeDedicated
	}
}

func defaultTransportInterfaceName(ifaceID string) string {
	if normalizeTransportIfaceID(ifaceID) == transportDefaultIfaceID {
		return "Shared interface"
	}
	return ifaceID
}

func transportInterfaceRoutingTableHint(iface TransportInterface) string {
	if strings.TrimSpace(iface.RoutingTable) != "" {
		return strings.TrimSpace(iface.RoutingTable)
	}
	if iface.Config == nil {
		return ""
	}
	if v := strings.TrimSpace(transportConfigString(iface.Config, "routing_table")); v != "" {
		return v
	}
	if v := strings.TrimSpace(transportConfigString(iface.Config, "table")); v != "" {
		return v
	}
	return ""
}

func resolveTransportInterfaceRoutingTable(iface TransportInterface, ifaceID string) string {
	hint := transportInterfaceRoutingTableHint(iface)
	if hint != "" {
		return normalizeTransportRoutingTable(hint, transportRoutingTableForIfaceID(ifaceID))
	}
	if normalizeTransportIfaceID(ifaceID) == transportDefaultIfaceID {
		return ""
	}
	return transportRoutingTableForIfaceID(ifaceID)
}

func normalizeTransportInterfacesState(st transportInterfacesState, clients []TransportClient) (transportInterfacesState, bool) {
	changed := false
	st.Version = transportStateVersion
	if st.Items == nil {
		st.Items = nil
	}

	byID := map[string]int{}
	out := make([]TransportInterface, 0, len(st.Items)+1)
	for _, raw := range st.Items {
		it := raw
		id := normalizeTransportIfaceID(it.ID)
		if id == "" {
			changed = true
			continue
		}
		if it.ID != id {
			it.ID = id
			changed = true
		}
		if strings.TrimSpace(it.Name) == "" {
			it.Name = defaultTransportInterfaceName(id)
			changed = true
		}
		mode := normalizeTransportInterfaceMode(it.Mode, id)
		if it.Mode != mode {
			it.Mode = mode
			changed = true
		}
		wantTable := resolveTransportInterfaceRoutingTable(it, id)
		if strings.TrimSpace(it.RoutingTable) != wantTable {
			it.RoutingTable = wantTable
			changed = true
		}
		if it.Config != nil {
			it.Config = cloneMap(it.Config)
		}
		if idx, ok := byID[id]; ok {
			if preferTransportInterface(it, out[idx]) {
				out[idx] = it
			}
			changed = true
			continue
		}
		byID[id] = len(out)
		out = append(out, it)
	}

	ensureIface := func(id string) {
		normID := normalizeTransportIfaceID(id)
		if normID == "" {
			return
		}
		if _, ok := byID[normID]; ok {
			return
		}
		it := TransportInterface{
			ID:   normID,
			Name: defaultTransportInterfaceName(normID),
			Mode: normalizeTransportInterfaceMode("", normID),
		}
		it.RoutingTable = resolveTransportInterfaceRoutingTable(it, normID)
		out = append(out, it)
		byID[normID] = len(out) - 1
		changed = true
	}

	ensureIface(transportDefaultIfaceID)
	for _, it := range clients {
		ensureIface(it.IfaceID)
	}

	sort.Slice(out, func(i, j int) bool { return out[i].ID < out[j].ID })
	st.Items = out
	return st, changed
}

func preferTransportInterface(cand, cur TransportInterface) bool {
	cu := strings.TrimSpace(cand.UpdatedAt)
	ou := strings.TrimSpace(cur.UpdatedAt)
	if cu != ou {
		if cu == "" {
			return false
		}
		if ou == "" {
			return true
		}
		return cu > ou
	}
	return strings.TrimSpace(cand.Name) > strings.TrimSpace(cur.Name)
}

func buildTransportInterfaceItems(ifaces []TransportInterface, clients []TransportClient) []TransportInterfaceItem {
	group := map[string][]TransportClient{}
	for _, it := range clients {
		id := normalizeTransportIfaceID(it.IfaceID)
		group[id] = append(group[id], it)
	}

	items := make([]TransportInterfaceItem, 0, len(ifaces))
	seen := map[string]struct{}{}
	for _, iface := range ifaces {
		id := normalizeTransportIfaceID(iface.ID)
		if id == "" {
			continue
		}
		seen[id] = struct{}{}
		clientsForIface := append([]TransportClient(nil), group[id]...)
		sort.Slice(clientsForIface, func(i, j int) bool { return clientsForIface[i].ID < clientsForIface[j].ID })
		clientIDs := make([]string, 0, len(clientsForIface))
		upCount := 0
		for _, cl := range clientsForIface {
			clientIDs = append(clientIDs, cl.ID)
			if cl.Status == TransportClientUp {
				upCount++
			}
		}
		items = append(items, TransportInterfaceItem{
			ID:           id,
			Name:         strings.TrimSpace(iface.Name),
			Mode:         normalizeTransportInterfaceMode(iface.Mode, id),
			RuntimeIface: strings.TrimSpace(iface.RuntimeIface),
			NetnsName:    strings.TrimSpace(iface.NetnsName),
			RoutingTable: strings.TrimSpace(iface.RoutingTable),
			Config:       cloneMap(iface.Config),
			UpdatedAt:    strings.TrimSpace(iface.UpdatedAt),
			ClientIDs:    clientIDs,
			ClientCount:  len(clientIDs),
			UpCount:      upCount,
		})
	}

	for id, clientsForIface := range group {
		if _, ok := seen[id]; ok {
			continue
		}
		sort.Slice(clientsForIface, func(i, j int) bool { return clientsForIface[i].ID < clientsForIface[j].ID })
		clientIDs := make([]string, 0, len(clientsForIface))
		upCount := 0
		routingTable := ""
		for _, cl := range clientsForIface {
			clientIDs = append(clientIDs, cl.ID)
			if cl.Status == TransportClientUp {
				upCount++
			}
			if routingTable == "" && strings.TrimSpace(cl.RoutingTable) != "" {
				routingTable = strings.TrimSpace(cl.RoutingTable)
			}
		}
		if routingTable == "" && id != transportDefaultIfaceID {
			routingTable = transportRoutingTableForIfaceID(id)
		}
		items = append(items, TransportInterfaceItem{
			ID:           id,
			Name:         defaultTransportInterfaceName(id),
			Mode:         normalizeTransportInterfaceMode("", id),
			RoutingTable: routingTable,
			ClientIDs:    clientIDs,
			ClientCount:  len(clientIDs),
			UpCount:      upCount,
		})
	}

	sort.Slice(items, func(i, j int) bool { return items[i].ID < items[j].ID })
	return items
}

func appendTransportVirtualInterfaceItems(items []TransportInterfaceItem, clients []TransportClient) []TransportInterfaceItem {
	if len(clients) == 0 {
		return items
	}
	byID := map[string]int{}
	for idx, it := range items {
		byID[normalizeTransportIfaceID(it.ID)] = idx
		if id := strings.TrimSpace(sanitizeID(it.ID)); id != "" {
			byID[id] = idx
		}
	}
	for _, client := range clients {
		if !isTransportPolicyVirtualClient(client) {
			continue
		}
		id := strings.TrimSpace(sanitizeID(client.ID))
		if id == "" {
			continue
		}
		item := TransportInterfaceItem{
			ID:           id,
			Name:         strings.TrimSpace(client.Name),
			Mode:         normalizeTransportInterfaceMode("", client.IfaceID),
			RuntimeIface: strings.TrimSpace(client.Iface),
			NetnsName:    "",
			RoutingTable: strings.TrimSpace(client.RoutingTable),
			UpdatedAt:    strings.TrimSpace(client.UpdatedAt),
			ClientIDs:    []string{id},
			ClientCount:  1,
			UpCount:      transportInterfaceItemUpCountForStatus(client.Status),
			Config: map[string]any{
				"virtual":       true,
				"virtual_owner": id,
			},
		}
		if item.Name == "" {
			item.Name = id
		}
		if idx, ok := byID[id]; ok {
			items[idx] = item
			continue
		}
		items = append(items, item)
		byID[id] = len(items) - 1
	}
	sort.Slice(items, func(i, j int) bool { return items[i].ID < items[j].ID })
	return items
}

func transportInterfaceItemUpCountForStatus(status TransportClientStatus) int {
	if normalizeTransportStatus(status) == TransportClientUp {
		return 1
	}
	return 0
}