package app

import "strings"

type transportInterfacesStateSnapshot struct {
	ClientsUpdatedAt    string
	InterfacesUpdatedAt string
}

type transportInterfacesOnlySnapshot struct {
	InterfacesUpdatedAt string
}

type transportPolicyPlanStateSnapshot struct {
	PolicyRevision     int64
	PlanPolicyRevision int64
}

type transportOwnershipStateSnapshot struct {
	PolicyRevision          int64
	OwnershipPolicyRevision int64
	OwnershipUpdatedAt      string
	OwnershipPlanDigest     string
}

func captureTransportInterfacesStateSnapshot(clients transportClientsState, ifaces transportInterfacesState) transportInterfacesStateSnapshot {
	return transportInterfacesStateSnapshot{
		ClientsUpdatedAt:    clients.UpdatedAt,
		InterfacesUpdatedAt: ifaces.UpdatedAt,
	}
}

func captureTransportInterfacesOnlySnapshot(ifaces transportInterfacesState) transportInterfacesOnlySnapshot {
	return transportInterfacesOnlySnapshot{InterfacesUpdatedAt: ifaces.UpdatedAt}
}

func captureTransportPolicyPlanStateSnapshot(policy TransportPolicyState, plan TransportPolicyCompilePlan) transportPolicyPlanStateSnapshot {
	return transportPolicyPlanStateSnapshot{
		PolicyRevision:     policy.Revision,
		PlanPolicyRevision: plan.PolicyRevision,
	}
}

func captureTransportOwnershipStateSnapshot(policy TransportPolicyState, ownership TransportOwnershipState) transportOwnershipStateSnapshot {
	return transportOwnershipStateSnapshot{
		PolicyRevision:          policy.Revision,
		OwnershipPolicyRevision: ownership.PolicyRevision,
		OwnershipUpdatedAt:      ownership.UpdatedAt,
		OwnershipPlanDigest:     ownership.PlanDigest,
	}
}

func compileTransportPolicyPlanForSnapshot(
	policy TransportPolicyState,
	clients []TransportClient,
	plan TransportPolicyCompilePlan,
) (TransportPolicyCompilePlan, bool) {
	if !transportPolicyPlanNeedsRecompile(policy, plan) {
		return plan, false
	}
	compiled, _ := compileTransportPolicyPlan(policy.Intents, clients, policy.Revision)
	return compiled, true
}

func transportPolicyPlanNeedsRecompile(policy TransportPolicyState, plan TransportPolicyCompilePlan) bool {
	if plan.PolicyRevision != policy.Revision {
		return true
	}
	for _, iface := range plan.Interfaces {
		ifaceID := normalizeTransportIfaceID(iface.IfaceID)
		for _, set := range iface.Sets {
			ownerScope := strings.TrimSpace(set.OwnerScope)
			if ownerScope == "" {
				return true
			}
			expected := transportPolicyNftSetName(ownerScope, set.SelectorType)
			if strings.TrimSpace(set.Name) != expected {
				return true
			}
		}
		for _, rule := range iface.Rules {
			ownerScope := strings.TrimSpace(rule.OwnerScope)
			expectedScope := transportPolicyNftOwnerScope(ifaceID, rule.ClientID)
			if ownerScope == "" || ownerScope != expectedScope {
				return true
			}
			expectedSet := transportPolicyNftSetName(ownerScope, rule.SelectorType)
			if strings.TrimSpace(rule.NftSet) != expectedSet {
				return true
			}
		}
	}
	return false
}

func saveTransportInterfacesIfSnapshotCurrent(snapshot transportInterfacesStateSnapshot, next transportInterfacesState) error {
	transportMu.Lock()
	defer transportMu.Unlock()

	currentClients := loadTransportClientsState()
	currentIfaces := loadTransportInterfacesState()
	if snapshot.ClientsUpdatedAt != currentClients.UpdatedAt {
		return nil
	}
	if snapshot.InterfacesUpdatedAt != currentIfaces.UpdatedAt {
		return nil
	}
	return saveTransportInterfacesState(next)
}

func saveTransportInterfacesIfUnchanged(snapshot transportInterfacesOnlySnapshot, next transportInterfacesState) error {
	transportMu.Lock()
	defer transportMu.Unlock()

	currentIfaces := loadTransportInterfacesState()
	if snapshot.InterfacesUpdatedAt != currentIfaces.UpdatedAt {
		return nil
	}
	return saveTransportInterfacesState(next)
}

func saveTransportPlanIfSnapshotCurrent(snapshot transportPolicyPlanStateSnapshot, next TransportPolicyCompilePlan) error {
	transportMu.Lock()
	defer transportMu.Unlock()

	currentPolicy := loadTransportPolicyState()
	if currentPolicy.Revision != snapshot.PolicyRevision {
		return nil
	}
	currentPlan := loadTransportPolicyCompilePlan()
	if currentPlan.PolicyRevision != snapshot.PlanPolicyRevision {
		return nil
	}
	if next.PolicyRevision != currentPolicy.Revision {
		return nil
	}
	return saveTransportPolicyCompilePlan(next)
}

func saveTransportOwnershipIfSnapshotCurrent(snapshot transportOwnershipStateSnapshot, next TransportOwnershipState) error {
	transportMu.Lock()
	defer transportMu.Unlock()

	currentPolicy := loadTransportPolicyState()
	if currentPolicy.Revision != snapshot.PolicyRevision {
		return nil
	}
	currentOwnership := loadTransportOwnershipState()
	if currentOwnership.PolicyRevision != snapshot.OwnershipPolicyRevision {
		return nil
	}
	if currentOwnership.UpdatedAt != snapshot.OwnershipUpdatedAt {
		return nil
	}
	if currentOwnership.PlanDigest != snapshot.OwnershipPlanDigest {
		return nil
	}
	if next.PolicyRevision != currentPolicy.Revision {
		return nil
	}
	return saveTransportOwnershipState(next)
}