// Ported from filius-ipad (GPLv2/GPLv3):
//   State/TopologyEditorState.swift (runtime configuration value types)

import type { Id } from '../ids.js';
import { maskAddress, parseIPv4 } from './ipv4.js';

/** The IP settings of a PC or notebook (its single interface) — and a router's gateway. */
export interface DeviceConfiguration {
  readonly ipAddress: string;
  readonly subnetMask: string;
  readonly defaultGateway: string;
  readonly dnsServer: string;
}

export function deviceConfiguration(
  ipAddress: string,
  subnetMask: string,
  defaultGateway = '',
  dnsServer = '',
): DeviceConfiguration {
  return { ipAddress, subnetMask, defaultGateway, dnsServer };
}

/** One interface of a router or gateway. */
export interface InterfaceConfiguration {
  readonly ipAddress: string;
  readonly subnetMask: string;
}

/** Map key for an interface: node and port. */
export type InterfaceKey = string;

export function interfaceKey(nodeId: Id, portId: Id): InterfaceKey {
  return `${nodeId}/${portId}`;
}

/** A row of the manual routing table (Java `Weiterleitungstabelle`). */
export interface ManualRoute {
  readonly destinationNetwork: string;
  readonly subnetMask: string;
  readonly gateway: string;
  readonly interfaceIPAddress: string;
}

/** Longest numeric mask wins; on a tie the first row stays. */
export function bestMatchingManualRoute(
  targetIPAddress: string,
  routes: readonly ManualRoute[],
): ManualRoute | undefined {
  const target = parseIPv4(targetIPAddress);
  if (target === undefined) return undefined;
  let best: ManualRoute | undefined;
  let bestMask: number | undefined;
  for (const route of routes) {
    const destination = parseIPv4(route.destinationNetwork);
    const mask = parseIPv4(route.subnetMask);
    if (destination === undefined || mask === undefined) continue;
    if (destination !== maskAddress(target, mask)) continue;
    if (bestMask !== undefined && mask <= bestMask) continue;
    bestMask = mask;
    best = route;
  }
  return best;
}

export interface SwitchConfiguration {
  readonly ssid: string;
  readonly retentionTimeMilliseconds: number;
}

/** Java SwitchFirmware keeps a learned MAC address for five minutes. */
export const DEFAULT_SWITCH_RETENTION_MILLISECONDS = 300_000;

export function switchConfiguration(
  ssid: string,
  retentionTimeMilliseconds = DEFAULT_SWITCH_RETENTION_MILLISECONDS,
): SwitchConfiguration {
  return { ssid, retentionTimeMilliseconds };
}

/** The first six hex digits of the node's UUID, lower case. */
export function defaultSwitchConfiguration(nodeId: Id): SwitchConfiguration {
  const compact = nodeId.replaceAll('-', '').toLowerCase();
  return switchConfiguration(compact.slice(0, 6));
}

/** A PC or notebook joining a switch's wireless network (Java Betriebssystem.ssid). */
export interface HostWirelessConfiguration {
  readonly isEnabled: boolean;
  readonly ssid: string;
}

// ── DHCP (Java filius.software.dhcp) ─────────────────────────────────────────

export interface DhcpClientConfiguration {
  readonly isEnabled: boolean;
}

export interface DhcpStaticAssignment {
  readonly id: Id;
  readonly macAddress: string;
  readonly ipAddress: string;
}

export interface DhcpServerConfiguration {
  readonly isActive: boolean;
  readonly lowerBoundIPAddress: string;
  readonly upperBoundIPAddress: string;
  readonly gatewayIPAddress: string;
  readonly dnsServerIPAddress: string;
  /** Hand out the gateway and DNS server set here instead of the server's own. */
  readonly useOwnSettings: boolean;
  readonly staticAssignments: readonly DhcpStaticAssignment[];
}

/** Java's DHCPServer as its constructor leaves it: off, all addresses 0.0.0.0. */
export function dhcpServerConfiguration(fields: Partial<DhcpServerConfiguration> = {}): DhcpServerConfiguration {
  return {
    isActive: fields.isActive ?? false,
    lowerBoundIPAddress: fields.lowerBoundIPAddress ?? '0.0.0.0',
    upperBoundIPAddress: fields.upperBoundIPAddress ?? '0.0.0.0',
    gatewayIPAddress: fields.gatewayIPAddress ?? '0.0.0.0',
    dnsServerIPAddress: fields.dnsServerIPAddress ?? '0.0.0.0',
    useOwnSettings: fields.useOwnSettings ?? false,
    staticAssignments: fields.staticAssignments ?? [],
  };
}

// ── Gateway NAT and remote links ────────────────────────────────────────────

/** A row of a home router's port forwarding (Java GatewayFirmware.staticNAT), as text. */
export interface GatewayPortForwardingRow {
  readonly protocolValue: string;
  readonly publicPortValue: string;
  readonly lanIPAddress: string;
  readonly lanPortValue: string;
}

/**
 * The in-project pairing of two remote links (Java Modem). Swift's LAN
 * transport settings belong to its Network-framework controller and are not
 * part of the port.
 */
export interface RemoteLinkConfiguration {
  readonly pairIdentifier: string;
  readonly latencyMilliseconds: number;
  readonly isEnabled: boolean;
}

export const DEFAULT_REMOTE_LINK_LATENCY_MILLISECONDS = 20;

// ── Installed programs (Java installierteAnwendungen) ──────────────────────

/** Swift's TopologyRuntimeInstallableProgram. */
export type InstallableProgram =
  | 'commandPrompt'
  | 'fileExplorer'
  | 'imageViewer'
  | 'textEditor'
  | 'webServer'
  | 'webBrowser'
  | 'echoServer'
  | 'simpleClient'
  | 'dnsServer'
  | 'dhcpServer'
  | 'firewall'
  | 'emailClient'
  | 'emailServer'
  | 'gnutella';

export interface WebServerConfiguration {
  readonly port: number;
  /** Where the served files are: Java keeps them in /webserver, Swift moves them to /www. */
  readonly documentRoot: string;
  /** Serve by host name, from the hosts named in www.conf/vhosts (Java's useVHost). */
  readonly virtualHosts: boolean;
}

export const DEFAULT_WEB_SERVER_PORT = 80;

export interface GnutellaConfiguration {
  readonly maximumKnownPeers: number;
}

export type DnsRecordType = 'A' | 'MX' | 'NS';

/**
 * One record a DNS server answers with (Swift's TopologyDNSResourceRecord):
 * `name` in lower case without the final dot (the root is "."), `target` an
 * IPv4 address for A, an absolute name ("mail.filius.de.") for MX and NS.
 */
export interface DnsResourceRecord {
  readonly name: string;
  readonly type: DnsRecordType;
  readonly ttlSeconds: number;
  readonly target: string;
}

export interface DnsServerConfiguration {
  readonly recursiveResolutionEnabled: boolean;
  readonly forwardingServerIPAddress?: string;
  /** In the order of Java's /dns/hosts, which stays in the file system as it is. */
  readonly records: readonly DnsResourceRecord[];
}

/**
 * An e-mail address as Java's AddressEntry holds it: a display name, an
 * address, or both (Swift's TopologyRuntimeEmailAddress wants the address).
 */
export interface EmailAddress {
  readonly name: string | null;
  readonly mailAddress: string | null;
}

/** An e-mail (Swift's TopologyRuntimeEmailMessage without its run-time delivery identity). */
export interface EmailMessage {
  /** Numbered from 1 per program, in folder order, as Swift numbers them. */
  readonly id: number;
  readonly from: EmailAddress;
  readonly to: readonly EmailAddress[];
  readonly cc: readonly EmailAddress[];
  readonly bcc: readonly EmailAddress[];
  readonly subject: string;
  readonly body: string;
  /** Only when the file gives one; Java never sets it. */
  readonly receivedAtMilliseconds?: number;
  readonly isNew: boolean;
  readonly isMarkedForDeletion: boolean;
  /** A message of the sent folder. */
  readonly isSent: boolean;
}

/** The account an e-mail client uses. First and last name stay apart, as Java keeps them. */
export interface EmailClientAccount {
  readonly pop3Host: string;
  readonly pop3Port: number;
  readonly smtpHost: string;
  readonly smtpPort: number;
  readonly username: string;
  readonly password: string;
  readonly firstName: string;
  readonly lastName: string;
  readonly email: string;
}

/** Java's Kontakt: an address book entry. */
export interface EmailContact {
  readonly name: string;
  readonly firstName: string;
  readonly street: string;
  readonly houseNumber: number;
  readonly postalCode: number;
  readonly city: string;
  readonly email: string;
  readonly phone: string;
}

export interface EmailClientConfiguration {
  /** Null when the client has none (Java opens it without one). */
  readonly account: EmailClientAccount | null;
  readonly inbox: readonly EmailMessage[];
  readonly sent: readonly EmailMessage[];
  readonly drafts: readonly EmailMessage[];
  readonly addressBook: readonly EmailContact[];
  readonly nextMessageID: number;
}

export interface EmailServerAccount {
  readonly username: string;
  readonly password: string;
  readonly firstName: string;
  readonly lastName: string;
  readonly mailbox: readonly EmailMessage[];
}

export interface EmailServerConfiguration {
  readonly domain: string;
  readonly pop3Port: number;
  readonly accounts: readonly EmailServerAccount[];
  readonly nextMessageID: number;
}

export const DEFAULT_POP3_PORT = 110;
export const DEFAULT_SMTP_PORT = 25;

/**
 * Java's echo server (ServerBaustein) and generic client (ClientBaustein)
 * keep their port and target in the file; Swift asks for them at run time.
 */
export interface EchoServerConfiguration {
  readonly port: number;
}

export interface SimpleClientConfiguration {
  readonly targetAddress: string;
  readonly targetPort: number;
}

// ── Firewall (Java filius.software.firewall.Firewall, FirewallRule) ─────────

export const FIREWALL_PROTOCOL = { all: -1, icmp: 1, tcp: 6, udp: 17 } as const;
export type FirewallProtocol = keyof typeof FIREWALL_PROTOCOL;

export type FirewallAction = 'drop' | 'accept';

/** Java writes this as the source of a rule that means "any directly connected network". */
export const DIRECTLY_CONNECTED_SOURCE_MARKER = '999.999.999.999';
export const ALL_PORTS = -1;

export interface FirewallRule {
  readonly sourceIPAddress: string;
  readonly sourceSubnetMask: string;
  readonly destinationIPAddress: string;
  readonly destinationSubnetMask: string;
  /** A port number or ALL_PORTS. */
  readonly port: number;
  readonly protocol: FirewallProtocol;
  readonly action: FirewallAction;
}

export function firewallRule(fields: Partial<FirewallRule> = {}): FirewallRule {
  return {
    sourceIPAddress: fields.sourceIPAddress ?? '',
    sourceSubnetMask: fields.sourceSubnetMask ?? '',
    destinationIPAddress: fields.destinationIPAddress ?? '',
    destinationSubnetMask: fields.destinationSubnetMask ?? '',
    port: fields.port ?? ALL_PORTS,
    protocol: fields.protocol ?? 'tcp',
    action: fields.action ?? 'drop',
  };
}

export interface FirewallConfiguration {
  readonly isActive: boolean;
  readonly defaultPolicy: FirewallAction;
  readonly dropIcmp: boolean;
  readonly filterSynSegmentsOnly: boolean;
  readonly filterUdp: boolean;
  readonly rules: readonly FirewallRule[];
}

/** What a router or gateway has without a firewall configured: inactive. */
export function firewallConfiguration(fields: Partial<FirewallConfiguration> = {}): FirewallConfiguration {
  return {
    isActive: fields.isActive ?? false,
    defaultPolicy: fields.defaultPolicy ?? 'drop',
    dropIcmp: fields.dropIcmp ?? false,
    filterSynSegmentsOnly: fields.filterSynSegmentsOnly ?? true,
    filterUdp: fields.filterUdp ?? true,
    rules: fields.rules ?? [],
  };
}

/** What Java installs as the personal firewall of a PC: active, drop by default. */
export const JAVA_PERSONAL_FIREWALL_DEFAULTS: FirewallConfiguration = firewallConfiguration({
  isActive: true,
  defaultPolicy: 'drop',
  dropIcmp: false,
  filterSynSegmentsOnly: true,
  filterUdp: true,
  rules: [],
});