/**
 * Cloud Sync Domain Types & Interfaces
 *
 * Zero-Knowledge Encrypted Multi-Cloud Sync System
 * Supports: GitHub Gist, Google Drive, Microsoft OneDrive, WebDAV, S3 Compatible
 */

import type { ShrinkFinding } from './syncGuards';
import type {
  ConvergentFieldConflict,
  ConvergentSyncEnvelopeV2,
  ConvergentSyncStateV2,
} from './convergentSync';
import {
  BUILTIN_CLOUD_PROVIDERS,
  isBuiltinCloudProvider,
  providerConnectionStorageKey,
  type BuiltinCloudProvider,
  type CloudProviderId,
} from './cloudProviderIds';

export type {
  ConvergentFieldConflict,
  ConvergentSyncEnvelopeV2,
  ConvergentSyncStateV2,
} from './convergentSync';

export {
  BUILTIN_CLOUD_PROVIDERS,
  isBuiltinCloudProvider,
  providerConnectionStorageKey,
  type BuiltinCloudProvider,
};

/** Built-in short IDs or namespaced plugin contribution IDs. */
export type CloudProvider = CloudProviderId;

// ============================================================================
// Security State Machine
// ============================================================================

/**
 * Global Security State Machine
 * Controls access to sync operations based on master key status
 */
export type SecurityState = 
  | 'NO_KEY'     // User has not set up a master key - block all sync
  | 'LOCKED'     // Master key exists but not in memory - show unlock screen
  | 'UNLOCKED';  // Master key in memory - sync operations allowed

/**
 * Sync Operation State Machine
 * Tracks the current sync operation status
 */
export type SyncState =
  | 'IDLE'       // Waiting for sync trigger
  | 'SYNCING'    // Active sync operation in progress
  | 'CONFLICT'   // Version conflict detected - needs resolution
  | 'BLOCKED'    // Outgoing payload would delete too much — user must choose restore or force-push
  | 'ERROR';     // Operation failed - needs attention

/**
 * Conflict Resolution Strategy
 */
export type ConflictResolution =
  | 'USE_REMOTE'   // Download cloud data, overwrite local
  | 'USE_LOCAL'    // Upload local data, overwrite cloud
  | 'AUTO_MERGED'; // Three-way merge was applied automatically

// ============================================================================
// Cloud Provider Types
// ============================================================================

export type WebDAVAuthType = 'basic' | 'digest' | 'token';

export interface WebDAVConfig {
  endpoint: string;
  authType: WebDAVAuthType;
  username?: string;
  password?: string;
  token?: string;
  allowInsecure?: boolean;
}

export interface S3Config {
  endpoint: string;
  region: string;
  bucket: string;
  accessKeyId: string;
  secretAccessKey: string;
  sessionToken?: string;
  prefix?: string;
  forcePathStyle?: boolean;
  allowInsecure?: boolean;
}

/**
 * Provider-specific connection status
 */
type ProviderConnectionStatus =
  | 'disconnected'
  | 'connecting'
  | 'connected'
  | 'syncing'
  | 'error';

/**
 * OAuth token storage structure
 */
export interface OAuthTokens {
  accessToken: string;
  refreshToken?: string;
  expiresAt?: number;  // Unix timestamp
  tokenType: string;
  scope?: string;
}

/**
 * Marker prefixed onto OneDrive refresh errors when Microsoft reports the
 * refresh token can no longer be used (expired / revoked / consent withdrawn).
 * Only an error's `message` survives the Electron IPC boundary, so the marker is
 * the stable signal that the OneDrive session must be re-authorized. It is added
 * in the bridge (electron/bridges/onedriveAuthBridge.cjs) and detected/cleaned
 * here so the same logic is shared by infrastructure and UI layers.
 */
export const ONEDRIVE_REAUTH_REQUIRED_MARKER = 'ONEDRIVE_REAUTH_REQUIRED';

/**
 * True when an error indicates the OneDrive refresh token is dead and the user
 * must reconnect. Robust to the error being re-wrapped (e.g. `new
 * Error(String(err))`) as it bubbles through the provider-agnostic pipeline.
 */
export const isOneDriveReauthRequiredMessage = (message: string): boolean =>
  message.includes(ONEDRIVE_REAUTH_REQUIRED_MARKER);

/**
 * Produce a clean, user-facing message from a (possibly multiply-wrapped) error
 * string by dropping everything up to and including the internal reauth marker,
 * e.g. "Error: OneDriveReauthRequiredError: ONEDRIVE_REAUTH_REQUIRED: OneDrive
 * session expired..." -> "OneDrive session expired...". Returns the original
 * string unchanged when the marker is absent.
 */
export const cleanOneDriveErrorMessage = (message: string): string => {
  const token = `${ONEDRIVE_REAUTH_REQUIRED_MARKER}:`;
  const markerIndex = message.lastIndexOf(token);
  if (markerIndex === -1) return message;
  return message.slice(markerIndex + token.length).trim();
};

/**
 * Provider account information
 */
export interface ProviderAccount {
  id: string;
  email?: string;
  name?: string;
  avatarUrl?: string;
}

/**
 * Cloud provider connection state
 */
/**
 * Opaque host-owned sync credential reference (SecretRef / CredentialRef shape).
 * Never stores plaintext secrets — only the reference the plugin connect path needs.
 * Secret leases are one-shot and must not be persisted for reconnect.
 */
export interface PluginSyncCredentialRef {
  kind: 'secret' | 'credential';
  id: string;
  key?: string;
}

/** Reasonable upper bounds for durable opaque ref strings persisted at rest. */
const MAX_PLUGIN_SYNC_CREDENTIAL_ID_CHARS = 512;
const MAX_PLUGIN_SYNC_CREDENTIAL_KEY_CHARS = 256;

/**
 * Normalize a value into a durable PluginSyncCredentialRef for reconnect
 * persistence. Rejects arrays, leases, and oversized / malformed shapes.
 */
export function normalizeDurablePluginSyncCredentialRef(
  value: unknown,
): PluginSyncCredentialRef | undefined {
  if (value == null || typeof value !== 'object' || Array.isArray(value)) {
    return undefined;
  }
  const record = value as Record<string, unknown>;
  const kind = record.kind;
  const id = record.id;
  if (kind !== 'secret' && kind !== 'credential') return undefined;
  if (typeof id !== 'string' || id.length < 1 || id.length > MAX_PLUGIN_SYNC_CREDENTIAL_ID_CHARS) {
    return undefined;
  }
  if (!Object.prototype.hasOwnProperty.call(record, 'key') || record.key === undefined) {
    return { kind, id };
  }
  const key = record.key;
  if (typeof key !== 'string' || key.length < 1 || key.length > MAX_PLUGIN_SYNC_CREDENTIAL_KEY_CHARS) {
    return undefined;
  }
  return { kind, id, key };
}

export interface ProviderConnection {
  provider: CloudProvider;
  status: ProviderConnectionStatus;
  account?: ProviderAccount;
  tokens?: OAuthTokens;
  config?: WebDAVConfig | S3Config;
  /** Plugin sync providers: persisted SyncConnectPayload.credential for reconnect. */
  credential?: PluginSyncCredentialRef;
  lastSync?: number;        // Unix timestamp
  lastSyncVersion?: number;
  resourceId?: string;      // gistId / fileId / itemId
  error?: string;
}

/**
 * Whether a connection still has usable credentials/config to retry.
 * Plugin configs may be valid falsy JSON scalars (`false`, `0`, `""`) or even
 * JSON `null` when a schema uses `type: "null"`. Presence is property
 * existence for `config`; do not use truthiness (`||` / `Boolean`).
 */
export const hasProviderConnectionData = (
  connection: Pick<ProviderConnection, 'tokens' | 'config' | 'credential'>,
): boolean =>
  connection.tokens != null
  || Object.prototype.hasOwnProperty.call(connection, 'config')
  || connection.credential != null;

export const isProviderReadyForSync = (
  connection: Pick<ProviderConnection, 'status' | 'tokens' | 'config'>,
): boolean =>
  connection.status === 'connected'
  || connection.status === 'syncing'
  || (connection.status === 'error' && hasProviderConnectionData(connection));

// ============================================================================
// Encrypted Sync File Schema
// ============================================================================

/**
 * Sync file metadata (stored in plaintext for version control)
 */
export interface SyncFileMeta {
  version: number;          // Incremental version number
  updatedAt: number;        // Unix timestamp (ms)
  deviceId: string;         // UUID identifying the device
  deviceName?: string;      // Human-readable device name
  appVersion: string;       // App version that created this sync
  iv: string;               // AES-GCM initialization vector (Base64)
  salt: string;             // KDF salt for key derivation (Base64)
  algorithm: 'AES-256-GCM'; // Encryption algorithm identifier
  kdf: 'PBKDF2' | 'Argon2id'; // Key derivation function
  kdfIterations?: number;   // PBKDF2 iterations (if applicable)
  /** Present only for convergent-sync payloads. Unknown future versions fail closed. */
  syncSchemaVersion?: 2;
}

/**
 * Complete synced file structure
 * The payload contains all encrypted user data
 */
export interface SyncedFile {
  meta: SyncFileMeta;
  payload: string;          // Base64 encrypted ciphertext
}

/**
 * Decrypted payload structure - contains all syncable data
 */
export interface SyncPayload {
  // Core vault data
  hosts: import('./models').Host[];
  keys: import('./models').SSHKey[];
  identities?: import('./models').Identity[];
  proxyProfiles?: import('./models').ProxyProfile[];
  snippets: import('./models').Snippet[];
  customGroups: string[];
  snippetPackages?: string[];
  notes?: import('./models').VaultNote[];
  noteGroups?: string[];

  // Group configs (connection defaults per host group)
  groupConfigs?: import('./models').GroupConfig[];

  // Port forwarding rules
  portForwardingRules?: import('./models').PortForwardingRule[];
  
  // Known hosts
  knownHosts?: import('./models').KnownHost[];
  
  // Settings
  settings?: {
    // Theme & Appearance
    theme?: 'light' | 'dark' | 'system';
    lightUiThemeId?: string;
    darkUiThemeId?: string;
    accentMode?: 'theme' | 'custom';
    customAccent?: string;
    uiFontFamilyId?: string;
    uiLanguage?: string;
    customCSS?: string;
    noteFontFamily?: string;
    noteFontSize?: number;
    noteCodeFontSize?: number;
    // Terminal
    terminalTheme?: string;
    followAppTerminalTheme?: boolean;
    terminalThemeDark?: string;
    terminalThemeLight?: string;
    terminalFontFamily?: string;
    terminalFontSize?: number;
    terminalSettings?: Record<string, unknown>;
    terminalSidePanelAutoOpen?: boolean;
    terminalSidePanelAutoOpenTab?: import('./terminalSidePanelAutoOpen').TerminalSidePanelAutoOpenTab;
    customTerminalThemes?: Array<{ id: string; name: string; colors: Record<string, string> }>;
    // Keyboard
    customKeyBindings?: Record<string, { mac?: string; pc?: string }>;
    // Editor
    editorWordWrap?: boolean;
    // SFTP
    sftpDoubleClickBehavior?: 'open' | 'transfer';
    sftpAutoSync?: boolean;
    sftpShowHiddenFiles?: boolean;
    sftpUseCompressedUpload?: boolean;
    sftpSkipUnchanged?: boolean;
    sftpAutoOpenSidebar?: boolean;
    sftpFollowTerminalCwd?: boolean;
    sftpDefaultViewMode?: 'list' | 'tree';
    sftpGlobalBookmarks?: import('./models').SftpBookmark[];
    // Vault: show recently connected hosts
    showRecentHosts?: boolean;
    // Vault: host click activates immediately, or select-then-click-again
    hostClickBehavior?: 'connect' | 'select';
    // Vault: root list shows only ungrouped hosts
    showOnlyUngroupedHostsInRoot?: boolean;
    // Top tabs: show standalone SFTP view tab
    showSftpTab?: boolean;
    // Shortcuts: Cmd/Ctrl+[1...9] and Ctrl+Tab skip pinned Vault/SFTP tabs
    shellOnlyTabNumberShortcuts?: boolean;
    // Shortcuts: show 1...9 badges on tabs matching number switch shortcuts
    showTabNumberBadges?: boolean;
    // Shortcuts: disable terminal font zoom shortcuts
    disableTerminalFontZoom?: boolean;
    // Terminal/editor tabs: show left host list sidebar
    showHostTreeSidebar?: boolean;
    // Workspace focus indicator style
    workspaceFocusStyle?: 'dim' | 'border';
    // AI configuration
    ai?: {
      providers?: Array<Record<string, unknown>>;
      activeProviderId?: string;
      activeModelId?: string;
      globalPermissionMode?: 'observer' | 'confirm' | 'auto';
      toolIntegrationMode?: 'mcp' | 'skills';
      hostPermissions?: Array<Record<string, unknown>>;
      // externalAgents intentionally omitted: command/args/env are device-local
      // (binary paths, OS-specific values) and don't survive cross-device sync.
      defaultAgentId?: string;
      commandBlocklist?: string[];
      commandTimeout?: number;
      responseIdleTimeout?: number;
      maxIterations?: number;
      agentModelMap?: Record<string, string>;
      agentProviderMap?: Record<string, string>;
      agentThinkingMap?: Record<string, string>;
      webSearchConfig?: Record<string, unknown> | null;
      quickMessages?: Array<Record<string, unknown>>;
      showTerminalSelectionAction?: boolean;
    };
  };

  /**
   * Encrypted-sidecar envelope for plugin user data that must survive missing
   * plugins (sync:true settings, account/CRDT baselines). Secrets never appear here.
   */
  pluginSidecars?: import('./pluginSyncSidecar').PluginSyncSidecarBundle;

  // Sync metadata
  syncedAt: number;         // When this payload was created

  // Reliability metadata used to make sync decisions auditable across devices.
  syncMeta?: SyncReliabilityMeta;

  /** Encrypted convergent-sync metadata. The adjacent fields remain a complete v1 snapshot. */
  convergentSync?: ConvergentSyncEnvelopeV2;
}

/**
 * Strip device-local connection telemetry from hosts before any sync
 * comparison or upload (#2629). `lastConnectedAt` updates on every successful
 * SSH connect and must not dirty auto-sync hashes, three-way merges, or
 * inflate cloud versions. Legacy stored bases / remote payloads still carry
 * the field, so all three merge sides are normalized with this helper.
 */
export function sanitizeHostsForSync(
  hosts: import('./models').Host[] | undefined,
): import('./models').Host[] | undefined {
  if (!hosts) return hosts;
  return hosts.map((host) => ({ ...host, lastConnectedAt: undefined }));
}

/** Copy a payload with device-local host telemetry stripped for compare/convert. */
export function withHostsSanitizedForSync(payload: SyncPayload): SyncPayload {
  return {
    ...payload,
    hosts: sanitizeHostsForSync(payload.hosts) ?? payload.hosts,
  };
}

/**
 * Re-attach this device's Recently Connected timestamps when a cloud payload
 * omits `lastConnectedAt`. Incoming timestamps (local backups, legacy cloud
 * snapshots) still win when present.
 */
export function retainLocalHostLastConnectedAt(
  incoming: import('./models').Host[] | undefined,
  local: import('./models').Host[] | undefined,
): import('./models').Host[] | undefined {
  if (!incoming) return incoming;
  if (!local?.length) return incoming;
  const localById = new Map(local.map((host) => [host.id, host.lastConnectedAt]));
  return incoming.map((host) => {
    if (host.lastConnectedAt != null) return host;
    const localTs = localById.get(host.id);
    if (localTs == null) return host;
    return { ...host, lastConnectedAt: localTs };
  });
}

export const SYNC_PAYLOAD_ENTITY_KEYS = [
  'hosts',
  'keys',
  'identities',
  'proxyProfiles',
  'snippets',
  'customGroups',
  'snippetPackages',
  'notes',
  'noteGroups',
  'portForwardingRules',
  'knownHosts',
  'groupConfigs',
] as const;

export const CLOUD_SYNC_PAYLOAD_ENTITY_KEYS = [
  'hosts',
  'keys',
  'identities',
  'proxyProfiles',
  'snippets',
  'customGroups',
  'snippetPackages',
  'notes',
  'noteGroups',
  'portForwardingRules',
  'groupConfigs',
] as const;

export type SyncPayloadEntityKey = typeof SYNC_PAYLOAD_ENTITY_KEYS[number];
export type CloudSyncPayloadEntityKey = typeof CLOUD_SYNC_PAYLOAD_ENTITY_KEYS[number];
export type SyncChangeEntityKey = CloudSyncPayloadEntityKey | 'settings';

export interface SyncEntityChangeCounts {
  added: { local: number; remote: number };
  modified: { local: number; remote: number };
  deleted: { local: number; remote: number };
}

export interface SyncConflictDetail {
  entityType: SyncChangeEntityKey;
  id?: string;
  kind:
    | 'both-added'
    | 'both-modified'
    | 'local-deleted-remote-modified'
    | 'remote-deleted-local-modified';
}

export interface SyncChangeSummary {
  hasLocalChanges: boolean;
  hasRemoteChanges: boolean;
  hasConflicts: boolean;
  byEntity: Partial<Record<SyncChangeEntityKey, SyncEntityChangeCounts>>;
  conflicts: SyncConflictDetail[];
}

export interface SyncDeletionRecord {
  entityType: CloudSyncPayloadEntityKey;
  id: string;
  deletedAt: number;
  deviceId?: string;
}

export interface SyncReliabilityMeta {
  schemaVersion: 1;
  generatedAt: number;
  deviceId?: string;
  baseSyncedAt?: number;
  localChanged: boolean;
  deletions: SyncDeletionRecord[];
  changeSummary: SyncChangeSummary;
}

export interface SyncSnapshotEntry {
  id: string;
  timestamp: number;
  provider?: CloudProvider;
  payload: SyncPayload;
}

export interface ConvergentProviderMigrationStatus {
  provider: CloudProvider;
  status: 'ready' | 'empty' | 'unavailable' | 'blocked';
  schemaVersion: 1 | 2 | 'future' | 'invalid';
  entityCount: number;
  hasTrustedBaseline: boolean;
  message?: string;
}

export interface ConvergentMigrationPreview {
  schemaVersion: 2;
  canInitialize: boolean;
  entityCounts: Partial<Record<CloudSyncPayloadEntityKey, number>>;
  settingsLeafCount: number;
  conflictCount: number;
  conflicts: ConvergentFieldConflict[];
  shrinkFindings: Array<{ provider: CloudProvider; finding: Extract<ShrinkFinding, { suspicious: true }> }>;
  providers: ConvergentProviderMigrationStatus[];
  oldClientCompatibility: 'materialized-v1-snapshot';
  blockedReasons: string[];
}

export interface ConvergentReplicaRecordV2 {
  schemaVersion: 2;
  state: ConvergentSyncStateV2;
  updatedAt: number;
}

export interface ConvergentProviderBaselineV2 {
  schemaVersion: 2;
  provider: CloudProvider;
  remoteVersion: number;
  remoteUpdatedAt: number;
  remoteDeviceId: string;
  materializedPayload: SyncPayload;
  state: ConvergentSyncStateV2;
}

export function hasSyncPayloadEntityData(
  payload: SyncPayload,
  keys: readonly SyncPayloadEntityKey[] = SYNC_PAYLOAD_ENTITY_KEYS,
): boolean {
  return keys.some((key) => {
    const value = payload[key];
    return Array.isArray(value) && value.length > 0;
  });
}

// ============================================================================
// Encryption Types
// ============================================================================

/**
 * Encryption result
 */
export interface EncryptionResult {
  ciphertext: Uint8Array;
  iv: Uint8Array;
  salt: Uint8Array;
  algorithm: 'AES-256-GCM';
  kdf: 'PBKDF2' | 'Argon2id';
  kdfIterations?: number;
}

/**
 * Decryption input
 */
export interface DecryptionInput {
  ciphertext: Uint8Array;
  iv: Uint8Array;
  salt: Uint8Array;
  kdf: 'PBKDF2' | 'Argon2id';
  kdfIterations?: number;
}

// ============================================================================
// Master Key Types
// ============================================================================

/**
 * Master key configuration stored in safeStorage
 */
export interface MasterKeyConfig {
  // Verification hash to confirm correct password
  verificationHash: string; // Base64 of hash(derived_key)
  salt: string;             // Base64 KDF salt
  kdf: 'PBKDF2' | 'Argon2id';
  kdfIterations?: number;
  createdAt: number;
}

/**
 * Unlocked master key state (in memory only)
 */
export interface UnlockedMasterKey {
  derivedKey: CryptoKey;    // AES-256-GCM key
  salt: Uint8Array;
  unlockedAt: number;
}

// ============================================================================
// Sync Manager Types
// ============================================================================

/**
 * Sync operation result
 */
export interface SyncResult {
  success: boolean;
  provider: CloudProvider;
  action: 'upload' | 'download' | 'merge' | 'none';
  version?: number;
  error?: string;
  conflictDetected?: boolean;
  /** Present when sync produced or selected a payload that caller should apply locally */
  mergedPayload?: import('./sync').SyncPayload;
  /** True when convergent sync already applied mergedPayload and committed its replica atomically. */
  mergedPayloadApplied?: boolean;
  /** Present with a downloaded payload so callers can commit the remote anchor after local apply succeeds. */
  remoteFile?: SyncedFile;
  /** True when a shrink-detection guard blocked the upload */
  shrinkBlocked?: boolean;
  /** The finding that triggered the shrink block or force-push */
  finding?: ShrinkFinding;
  /** Field-level conflicts retained by convergent sync v2. */
  convergentConflicts?: ConvergentFieldConflict[];
  /** Number of retained v2 conflicts; duplicated for lightweight status views. */
  convergentConflictCount?: number;
}

export interface RemoteSyncPayload {
  provider: CloudProvider;
  payload: SyncPayload;
  remoteFile: SyncedFile;
}

/**
 * Conflict information for UI
 */
export interface ConflictInfo {
  provider: CloudProvider;
  localVersion: number;
  localUpdatedAt: number;
  localDeviceName?: string;
  remoteVersion: number;
  remoteUpdatedAt: number;
  remoteDeviceName?: string;
  changeSummary?: SyncChangeSummary;
}

/**
 * Sync history record entry
 */
export interface SyncHistoryEntry {
  id: string;
  timestamp: number;
  provider: CloudProvider;
  action: 'upload' | 'download' | 'merge' | 'conflict_resolved';
  success: boolean;
  localVersion: number;
  remoteVersion?: number;
  deviceName?: string;
  error?: string;
}

// ============================================================================
// OAuth Flow Types
// ============================================================================

/**
 * GitHub Device Flow response
 */
export interface GitHubDeviceCodeResponse {
  device_code: string;
  user_code: string;
  verification_uri: string;
  expires_in: number;
  interval: number;
}

/**
 * OAuth PKCE challenge
 */
export interface PKCEChallenge {
  codeVerifier: string;
  codeChallenge: string;
  state: string;
}

// ============================================================================
// Event Types
// ============================================================================

/**
 * Sync event for UI updates
 */
export type SyncEvent = 
  | { type: 'SYNC_STARTED'; provider: CloudProvider }
  | { type: 'SYNC_PROGRESS'; provider: CloudProvider; progress: number; message: string }
  | { type: 'SYNC_COMPLETED'; provider: CloudProvider; result: SyncResult }
  | { type: 'SYNC_ERROR'; provider: CloudProvider; error: string }
  | { type: 'CONFLICT_DETECTED'; conflict: ConflictInfo }
  | { type: 'SYNC_BLOCKED_SHRINK'; provider: CloudProvider; finding: ShrinkFinding }
  | { type: 'SYNC_FORCED'; provider: CloudProvider; finding: ShrinkFinding }
  | { type: 'CONFLICT_RESOLVED'; resolution: ConflictResolution }
  | { type: 'AUTH_REQUIRED'; provider: CloudProvider }
  | { type: 'AUTH_COMPLETED'; provider: CloudProvider; account: ProviderAccount }
  | { type: 'SECURITY_STATE_CHANGED'; state: SecurityState }
  | { type: 'SYNC_BLOCKED_CLEARED' }
  | {
      type: 'PROVIDERS_DIVERGED';
      summaries: Array<{
        provider: CloudProvider;
        hosts: number;
        keys: number;
        snippets: number;
      }>;
    };

// ============================================================================
// Storage Keys
// ============================================================================

export const SYNC_STORAGE_KEYS = {
  MASTER_KEY_CONFIG: 'netcatty_master_key_config_v1',
  DEVICE_ID: 'netcatty_device_id_v1',
  DEVICE_NAME: 'netcatty_device_name_v1',
  SYNC_CONFIG: 'netcatty_sync_config_v2',
  /** Auto-sync prefs (autoSync / interval / syncStrategy); kept separate from version stamps. */
  SYNC_PREFERENCES: 'netcatty_sync_preferences_v1',
  PROVIDER_GITHUB: 'netcatty_provider_github_v1',
  PROVIDER_GOOGLE: 'netcatty_provider_google_v1',
  PROVIDER_ONEDRIVE: 'netcatty_provider_onedrive_v1',
  PROVIDER_WEBDAV: 'netcatty_provider_webdav_v1',
  PROVIDER_S3: 'netcatty_provider_s3_v1',
  PROVIDER_SMB: 'netcatty_provider_smb_v1',
  /** Registry of connected namespaced plugin sync provider IDs. */
  PLUGIN_CLOUD_PROVIDERS: 'netcatty_plugin_cloud_providers_v1',
  /** Contribution-available plugin sync provider IDs (live catalog membership). */
  AVAILABLE_PLUGIN_SYNC_PROVIDERS: 'netcatty_available_plugin_sync_providers_v1',
  /** Last successful sidecar collect (upload fallback when host is offline). */
  PLUGIN_SIDECARS_LAST_KNOWN: 'netcatty_plugin_sidecars_last_known_v1',
  /** Remote sidecar apply queued while the plugin host was unavailable. */
  PLUGIN_SIDECARS_PENDING_REMOTE: 'netcatty_plugin_sidecars_pending_remote_v1',
  LOCAL_SYNC_META: 'netcatty_local_sync_meta_v1',
  SYNC_BASE_PAYLOAD: 'netcatty_sync_base_payload_v1',
  CONVERGENT_REPLICA: 'netcatty_convergent_sync_replica_v2',
  CONVERGENT_PROVIDER_BASELINE: 'netcatty_convergent_sync_provider_baseline_v2',
} as const;

// ============================================================================
// Constants
// ============================================================================

const readBuildEnv = (key: string): string | undefined => {
  const env = (import.meta as { env?: Record<string, string | undefined> }).env;
  const value = env?.[key];
  return value && value.trim().length ? value : undefined;
};

export const SYNC_CONSTANTS = {
  // Encryption
  AES_KEY_LENGTH: 256,
  GCM_IV_LENGTH: 12,        // bytes
  GCM_TAG_LENGTH: 128,      // bits
  SALT_LENGTH: 32,          // bytes
  
  // PBKDF2
  PBKDF2_ITERATIONS: 600000, // OWASP recommended minimum
  PBKDF2_HASH: 'SHA-256',
  
  // Sync
  SYNC_FILE_NAME: 'netcatty-vault.json',
  GIST_DESCRIPTION: 'Netcatty Encrypted Vault (DO NOT EDIT MANUALLY)',
  
  // Auto-sync
  DEFAULT_AUTO_SYNC_INTERVAL: 5, // minutes
  MIN_SYNC_INTERVAL: 1,          // minutes
  MAX_SYNC_INTERVAL: 60,         // minutes
  
  // OAuth
  GITHUB_CLIENT_ID: readBuildEnv('VITE_SYNC_GITHUB_CLIENT_ID') || '', // Public client ID for Device Flow
  GOOGLE_CLIENT_ID: readBuildEnv('VITE_SYNC_GOOGLE_CLIENT_ID') || '',
  GOOGLE_CLIENT_SECRET: readBuildEnv('VITE_SYNC_GOOGLE_CLIENT_SECRET') || '',
  ONEDRIVE_CLIENT_ID: readBuildEnv('VITE_SYNC_ONEDRIVE_CLIENT_ID') || '',
  
  // API endpoints
  GITHUB_DEVICE_CODE_URL: 'https://github.com/login/device/code',
  GITHUB_ACCESS_TOKEN_URL: 'https://github.com/login/oauth/access_token',
  GITHUB_API_BASE: 'https://api.github.com',
  
  GOOGLE_AUTH_URL: 'https://accounts.google.com/o/oauth2/v2/auth',
  GOOGLE_TOKEN_URL: 'https://oauth2.googleapis.com/token',
  GOOGLE_DRIVE_API: 'https://www.googleapis.com/drive/v3',
  
  ONEDRIVE_AUTH_URL: 'https://login.microsoftonline.com/consumers/oauth2/v2.0/authorize',
  ONEDRIVE_TOKEN_URL: 'https://login.microsoftonline.com/consumers/oauth2/v2.0/token',
  ONEDRIVE_GRAPH_API: 'https://graph.microsoft.com/v1.0',
} as const;

// ============================================================================
// Helper Functions
// ============================================================================

/**
 * Generate a unique device ID
 */
export const generateDeviceId = (): string => {
  return crypto.randomUUID();
};

/**
 * Get default device name based on OS
 */
export const getDefaultDeviceName = (): string => {
  const platform = navigator.platform || 'Unknown';
  const hostname = 'Netcatty';
  return `${hostname} (${platform})`;
};

/**
 * Format a sync timestamp as `yyyymmdd hhmm` (e.g. `20250628 1430`).
 */
export const formatSyncDateTime = (timestamp: number): string => {
  const date = new Date(timestamp);
  const year = date.getFullYear();
  const month = String(date.getMonth() + 1).padStart(2, '0');
  const day = String(date.getDate()).padStart(2, '0');
  const hours = String(date.getHours()).padStart(2, '0');
  const minutes = String(date.getMinutes()).padStart(2, '0');
  return `${year}${month}${day} ${hours}${minutes}`;
};

/**
 * Format last sync time for display
 */
export const formatLastSync = (timestamp?: number): string => {
  if (!timestamp) return 'Never synced';

  const now = Date.now();
  const diff = now - timestamp;

  if (diff < 60000) return 'Just now';
  if (diff < 3600000) return `${Math.floor(diff / 60000)} min ago`;

  return formatSyncDateTime(timestamp);
};

/**
 * Get status dot color class
 */
export const getSyncDotColor = (status: ProviderConnectionStatus): string => {
  switch (status) {
    case 'connected': return 'bg-green-500';
    case 'syncing': return 'bg-blue-500';
    case 'error': return 'bg-red-500';
    case 'connecting': return 'bg-yellow-500';
    default: return 'bg-muted-foreground';
  }
};