┌──────────────────────────────────────────────────────────┐
│                    API / UI Layer                         │
│   Express routes, Next.js API routes, CLI commands       │
├──────────────────────────────────────────────────────────┤
│                   Service Layer                          │
│   BoardService, ItemService, SyncService                 │
│   (business logic, orchestration, validation)            │
├──────────────────────────────────────────────────────────┤
│                  Miro Client Layer                        │
│   MiroApiClient (REST v2), TokenManager (OAuth 2.0)      │
│   ItemFactory (typed creation), ConnectorBuilder          │
├──────────────────────────────────────────────────────────┤
│                Infrastructure Layer                       │
│   Cache (LRU/Redis), Queue (PQueue), Monitor (metrics)   │
│   WebhookProcessor (signature + idempotency)             │
└──────────────────────────────────────────────────────────┘
                         │
                         ▼
            https://api.miro.com/v2/

src/
├── miro/
│   ├── client.ts              # MiroApiClient — wraps fetch with auth, retries, monitoring
│   ├── token-manager.ts       # OAuth 2.0 token lifecycle (refresh, storage)
│   ├── item-factory.ts        # Typed item creation (sticky notes, shapes, cards, etc.)
│   ├── connector-builder.ts   # Fluent API for creating connectors
│   ├── types.ts               # TypeScript types for all Miro v2 responses
│   └── errors.ts              # MiroApiError, MiroAuthError, MiroRateLimitError
├── services/
│   ├── board-service.ts       # Board CRUD + member management
│   ├── item-service.ts        # Item CRUD + tag operations
│   ├── sync-service.ts        # Two-way sync between Miro and your database
│   └── search-service.ts      # Find items by content, type, or tag
├── webhooks/
│   ├── handler.ts             # Express/serverless webhook endpoint
│   ├── processor.ts           # Event routing and processing
│   └── idempotency.ts         # Duplicate event prevention
├── cache/
│   ├── board-cache.ts         # Board metadata cache
│   └── item-cache.ts          # Item data cache with webhook invalidation
├── config/
│   ├── miro.ts                # Environment-based Miro configuration
│   └── index.ts               # Config loader
└── monitoring/
    ├── metrics.ts             # Prometheus counters/histograms for Miro API
    └── health.ts              # Health check endpoint

// src/miro/client.ts
export class MiroApiClient {
  constructor(
    private tokenManager: TokenManager,
    private cache: ItemCache,
    private monitor: MiroMetrics,
  ) {}

  async fetch<T>(path: string, method = 'GET', body?: unknown): Promise<T> {
    const token = await this.tokenManager.getValidToken();
    const start = performance.now();

    const response = await fetch(`https://api.miro.com${path}`, {
      method,
      headers: {
        'Authorization': `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      ...(body ? { body: JSON.stringify(body) } : {}),
    });

    const duration = performance.now() - start;
    this.monitor.recordRequest(method, path, response.status, duration);
    this.monitor.updateRateLimit(response);

    if (response.status === 429) {
      const retryAfter = parseInt(response.headers.get('Retry-After') ?? '5', 10);
      throw new MiroRateLimitError(retryAfter);
    }

    if (!response.ok) {
      const error = await response.json().catch(() => ({}));
      throw new MiroApiError(response.status, error.message, error.code);
    }

    if (response.status === 204) return null as T;
    return response.json() as T;
  }

  // Paginated fetch — returns all pages
  async fetchAll<T>(path: string, limit = 50): Promise<T[]> {
    const items: T[] = [];
    let cursor: string | undefined;

    do {
      const params = new URLSearchParams({ limit: String(limit) });
      if (cursor) params.set('cursor', cursor);

      const result = await this.fetch<PaginatedResponse<T>>(
        `${path}?${params}`
      );
      items.push(...result.data);
      cursor = result.cursor;
    } while (cursor);

    return items;
  }
}

// src/services/board-service.ts
export class BoardService {
  constructor(
    private api: MiroApiClient,
    private cache: BoardCache,
  ) {}

  async getBoard(boardId: string): Promise<MiroBoard> {
    const cached = await this.cache.get(boardId);
    if (cached) return cached;

    const board = await this.api.fetch<MiroBoard>(`/v2/boards/${boardId}`);
    await this.cache.set(boardId, board, 120);  // 2 min TTL
    return board;
  }

  async createBoard(params: CreateBoardParams): Promise<MiroBoard> {
    return this.api.fetch<MiroBoard>('/v2/boards', 'POST', {
      name: params.name,
      description: params.description,
      teamId: params.teamId,
      policy: {
        sharingPolicy: { access: params.access ?? 'private' },
        permissionsPolicy: { sharingAccess: 'team_members_and_collaborators' },
      },
    });
  }

  async shareBoard(boardId: string, emails: string[], role: BoardRole): Promise<void> {
    await this.api.fetch(`/v2/boards/${boardId}/members`, 'POST', {
      emails,
      role,  // 'viewer' | 'commenter' | 'editor' | 'coowner'
    });
  }

  async getMembers(boardId: string): Promise<BoardMember[]> {
    return this.api.fetchAll(`/v2/boards/${boardId}/members`);
  }
}

// src/webhooks/processor.ts
export class WebhookProcessor {
  private handlers = new Map<string, EventHandler[]>();

  on(eventType: string, handler: EventHandler): void {
    const existing = this.handlers.get(eventType) ?? [];
    existing.push(handler);
    this.handlers.set(eventType, existing);
  }

  async process(event: MiroBoardEvent): Promise<void> {
    // Type-based routing
    const key = `${event.item.type}:${event.type}`;  // e.g., 'sticky_note:create'
    const handlers = [
      ...(this.handlers.get(key) ?? []),
      ...(this.handlers.get(`*:${event.type}`) ?? []),  // Wildcard item type
      ...(this.handlers.get('*:*') ?? []),               // Catch-all
    ];

    for (const handler of handlers) {
      await handler(event);
    }
  }
}

// Usage
const processor = new WebhookProcessor();

processor.on('sticky_note:create', async (event) => {
  console.log(`New sticky note on board ${event.boardId}: ${event.item.id}`);
  await syncService.syncItem(event.boardId, event.item.id);
});

processor.on('*:delete', async (event) => {
  console.log(`Item deleted from board ${event.boardId}: ${event.item.id}`);
  await database.deleteItem(event.item.id);
});

// src/miro/connector-builder.ts
export class ConnectorBuilder {
  private config: any = { style: {} };

  constructor(private api: MiroApiClient, private boardId: string) {}

  from(itemId: string, snapTo?: SnapPosition): this {
    this.config.startItem = { id: itemId, ...(snapTo ? { snapTo } : {}) };
    return this;
  }

  to(itemId: string, snapTo?: SnapPosition): this {
    this.config.endItem = { id: itemId, ...(snapTo ? { snapTo } : {}) };
    return this;
  }

  caption(text: string, position = 0.5): this {
    this.config.captions = [{ content: text, position }];
    return this;
  }

  dashed(): this { this.config.style.strokeStyle = 'dashed'; return this; }
  curved(): this { this.config.shape = 'curved'; return this; }
  arrow(): this { this.config.style.endStrokeCap = 'stealth'; return this; }

  async build(): Promise<MiroConnector> {
    return this.api.fetch(`/v2/boards/${this.boardId}/connectors`, 'POST', this.config);
  }
}

// Usage
const connector = await new ConnectorBuilder(api, boardId)
  .from(taskId, 'right')
  .to(dependencyId, 'left')
  .caption('depends on')
  .dashed()
  .arrow()
  .build();

User Action (or cron job)
     │
     ▼
┌─────────────┐
│   Service   │  ←── Business logic
│   Layer     │
└──────┬──────┘
       │
  ┌────┴────┐
  │         │
  ▼         ▼
┌──────┐ ┌──────┐
│Cache │ │ Miro │  ←── api.miro.com/v2
│Layer │ │Client│
└──────┘ └──────┘

Miro Board Change
     │
     ▼
┌─────────────┐
│  Webhook    │  ←── Signature verification
│  Handler    │
└──────┬──────┘
       │
       ▼
┌─────────────┐
│ Processor   │  ←── Idempotency + routing
└──────┬──────┘
       │
  ┌────┴────┐
  │         │
  ▼         ▼
┌──────┐ ┌──────┐
│Cache │ │  DB  │  ←── Sync + invalidation
│Inval │ │Sync  │
└──────┘ └──────┘

// src/config/miro.ts
export interface MiroConfig {
  clientId: string;
  clientSecret: string;
  accessToken?: string;
  environment: 'development' | 'staging' | 'production';
  cache: { enabled: boolean; ttlSeconds: number };
  rateLimit: { maxConcurrency: number; requestsPerSecond: number };
  webhook: { secret: string; callbackUrl: string };
}

export function loadMiroConfig(): MiroConfig {
  return {
    clientId: requireEnv('MIRO_CLIENT_ID'),
    clientSecret: requireEnv('MIRO_CLIENT_SECRET'),
    accessToken: process.env.MIRO_ACCESS_TOKEN,
    environment: (process.env.NODE_ENV ?? 'development') as MiroConfig['environment'],
    cache: {
      enabled: process.env.MIRO_CACHE_ENABLED !== 'false',
      ttlSeconds: parseInt(process.env.MIRO_CACHE_TTL ?? '120'),
    },
    rateLimit: {
      maxConcurrency: parseInt(process.env.MIRO_MAX_CONCURRENCY ?? '5'),
      requestsPerSecond: parseInt(process.env.MIRO_RPS ?? '10'),
    },
    webhook: {
      secret: process.env.MIRO_WEBHOOK_SECRET ?? '',
      callbackUrl: process.env.MIRO_WEBHOOK_URL ?? '',
    },
  };
}