// ---------------------------------------------------------------------------
// Core event types
// ---------------------------------------------------------------------------

export interface AnalyticsEvent {
  name: string;
  properties?: Record<string, any>;
  timestamp: number;
  sessionId?: string;
  userId?: string;
  anonymousId: string;
  context?: EventContext;
}

export interface ScreenEvent {
  name: string;
  properties?: Record<string, any>;
  timestamp: number;
  sessionId?: string;
  userId?: string;
  anonymousId: string;
  previousScreen?: string;
}

export interface IdentifyPayload {
  userId: string;
  traits?: UserTraits;
  timestamp: number;
  anonymousId: string;
}

export interface GroupPayload {
  groupId: string;
  traits?: Record<string, any>;
  timestamp: number;
  userId?: string;
  anonymousId: string;
}

export interface AliasPayload {
  newId: string;
  previousId: string;
  timestamp: number;
}

// ---------------------------------------------------------------------------
// User traits
// ---------------------------------------------------------------------------

export interface UserTraits {
  name?: string;
  email?: string;
  phone?: string;
  avatar?: string;
  createdAt?: string | Date;
  [key: string]: any;
}

// ---------------------------------------------------------------------------
// Event context (enriched metadata)
// ---------------------------------------------------------------------------

export interface EventContext {
  app?: {
    name?: string;
    version?: string;
    build?: string;
  };
  device?: {
    type?: string;
    model?: string;
    manufacturer?: string;
    os?: string;
    osVersion?: string;
  };
  locale?: string;
  timezone?: string;
  screen?: {
    width?: number;
    height?: number;
    density?: number;
  };
  network?: {
    wifi?: boolean;
    cellular?: boolean;
    carrier?: string;
  };
  campaign?: {
    name?: string;
    source?: string;
    medium?: string;
    term?: string;
    content?: string;
  };
  [key: string]: any;
}

// ---------------------------------------------------------------------------
// Session
// ---------------------------------------------------------------------------

export interface SessionInfo {
  sessionId: string;
  startTime: number;
  lastActiveTime: number;
  screenCount: number;
  eventCount: number;
  isActive: boolean;
}

// ---------------------------------------------------------------------------
// Provider adapter interface — every analytics provider implements this
// ---------------------------------------------------------------------------

export interface AnalyticsAdapter {
  /** Unique identifier for this adapter */
  name: string;

  /** Called once when AnalyticsManager initializes */
  initialize(): Promise<void>;

  /** Track a custom event */
  track(event: AnalyticsEvent): Promise<void>;

  /** Track a screen view */
  screen(event: ScreenEvent): Promise<void>;

  /** Identify a user */
  identify(payload: IdentifyPayload): Promise<void>;

  /** Associate user with a group/org (optional) */
  group?(payload: GroupPayload): Promise<void>;

  /** Alias two user identities (optional) */
  alias?(payload: AliasPayload): Promise<void>;

  /** Reset user identity (e.g. on logout) */
  reset(): Promise<void>;

  /** Force flush any internal queues (optional) */
  flush?(): Promise<void>;
}

// ---------------------------------------------------------------------------
// Middleware
// ---------------------------------------------------------------------------

export type EventMiddlewareFn = (
  event: AnalyticsEvent,
  next: (event: AnalyticsEvent) => void
) => void;

export type ScreenMiddlewareFn = (
  event: ScreenEvent,
  next: (event: ScreenEvent) => void
) => void;

// ---------------------------------------------------------------------------
// Privacy / GDPR config
// ---------------------------------------------------------------------------

export interface PrivacyConfig {
  /** Fields to mask in all events (e.g. 'email', 'phone') */
  maskFields?: string[];
  /** Replacement value for masked fields */
  maskValue?: string;
  /** Whether to start in opted-out state */
  defaultOptOut?: boolean;
}

// ---------------------------------------------------------------------------
// Event queue config
// ---------------------------------------------------------------------------

export interface QueueConfig {
  /** Max events to hold before forcing a flush (default: 20) */
  maxBatchSize?: number;
  /** How often to flush in ms (default: 10000) */
  flushInterval?: number;
  /** Max retry attempts for failed flushes (default: 3) */
  maxRetries?: number;
  /** Persist queue to storage for offline support (default: true) */
  persistQueue?: boolean;
}

// ---------------------------------------------------------------------------
// Session config
// ---------------------------------------------------------------------------

export interface SessionConfig {
  /** Inactivity timeout in ms before a new session starts (default: 30 min) */
  sessionTimeout?: number;
  /** Auto-track session_start and session_end events (default: true) */
  autoTrackSessionEvents?: boolean;
}

// ---------------------------------------------------------------------------
// Main config
// ---------------------------------------------------------------------------

export interface AnalyticsConfig {
  /** Provider adapters to use */
  adapters: AnalyticsAdapter[];
  /** Privacy / GDPR settings */
  privacy?: PrivacyConfig;
  /** Event queue settings */
  queue?: QueueConfig;
  /** Session tracking settings */
  session?: SessionConfig;
  /** Global properties added to every event */
  globalProperties?: Record<string, any>;
  /** Called when an event fails to send after all retries */
  onError?: (error: Error, event: AnalyticsEvent | ScreenEvent) => void;
  /** Enable debug logging (default: false) */
  debug?: boolean;
}