# Task ID: 1
# Title: Implement NextCloud API Client
# Status: done
# Dependencies: None
# Priority: high
# Description: Create a robust API client to interact with NextCloud Tasks API, handling authentication, requests, and responses.

# Details:
Develop a dedicated client class that encapsulates all NextCloud API interactions. Implement token-based authentication, request formatting, response parsing, error handling, and retry logic. Support batching for efficient API usage and handle rate limits. The client should be designed with an interface that allows for easy mocking in tests.

# Test Strategy:
Write unit tests with mocked HTTP responses to test client behavior. Create integration tests against a test NextCloud instance. Test edge cases like network failures, rate limiting, and authentication issues.

# Subtasks:
## 1. Implement Token-Based Authentication [done]
### Dependencies: None
### Priority: medium
### Description: Create authentication mechanism for NextCloud API with token management
### Details:
Develop an authentication module that handles OAuth2 token acquisition, storage, and renewal. Implement secure token storage, expiration tracking, and automatic refresh. Include configuration options for different authentication flows (client credentials, authorization code). Ensure tokens are properly included in API requests and handle 401 responses appropriately.

## 2. Build Core Request/Response Handler [done]
### Dependencies: 1.1
### Priority: medium
### Description: Develop the central request/response processing system with error handling
### Details:
Create a robust HTTP client wrapper that formats requests for NextCloud Tasks API, properly sets headers and serializes payloads. Implement response parsing with appropriate data models, HTTP status code handling, and NextCloud-specific error detection. Create a comprehensive error classification system with custom exceptions for different error types. Add logging for debugging and monitoring purposes.

## 3. Implement Rate Limiting and Request Batching [done]
### Dependencies: 1.2
### Priority: medium
### Description: Add mechanisms to handle API rate limits and batch requests for efficiency
### Details:
Create a rate limiter that tracks API usage and prevents exceeding NextCloud's limits. Implement request queuing with configurable concurrency limits. Develop a batching system that combines multiple operations into single API calls where supported. Add backpressure mechanisms to prevent memory issues with large request volumes. Include metrics for monitoring batch efficiency.

## 4. Add Retry Logic and Resilience Patterns [done]
### Dependencies: 1.2, 1.3
### Priority: medium
### Description: Implement retry mechanisms and fault tolerance strategies
### Details:
Create a configurable retry system with exponential backoff for transient errors. Implement circuit breaker pattern to prevent cascading failures. Add timeout handling with configurable limits. Develop fallback mechanisms for degraded operation modes. Include jitter in retry delays to prevent thundering herd problems. Create hooks for custom retry policies based on specific error conditions.

## 5. Design Testable Interface and Documentation [done]
### Dependencies: 1.1, 1.2, 1.3, 1.4
### Priority: medium
### Description: Create a clean API interface with comprehensive documentation and test support
### Details:
Design a clear, consistent interface for all NextCloud API operations. Implement interface segregation for better modularity. Add dependency injection points to facilitate mocking in tests. Create comprehensive inline documentation with examples. Develop mock implementations for testing. Generate API reference documentation. Create example code for common use cases. Include integration test helpers for end-to-end testing.
