# Task ID: 1
# Title: Implement Task Data Structure
# Status: done
# Dependencies: None
# Priority: high
# Description: Design and implement the core tasks.json structure that will serve as the single source of truth for the system.
# Details:
Create the foundational data structure including:
- JSON schema for tasks.json
- Task model with all required fields (id, title, description, status, dependencies, priority, details, testStrategy, subtasks)
- Validation functions for the task model
- Basic file system operations for reading/writing tasks.json
- Error handling for file operations

# Test Strategy:
Verify that the tasks.json structure can be created, read, and validated. Test with sample data to ensure all fields are properly handled and that validation correctly identifies invalid structures.

# Subtasks:
## Subtask ID: 1
## Title: Design JSON Schema for tasks.json
## Status: done
## Dependencies: None
## Description: Create a formal JSON Schema definition that validates the structure of the tasks.json file. The schema should enforce the data model specified in the PRD, including the Task Model and Tasks Collection Model with all required fields (id, title, description, status, dependencies, priority, details, testStrategy, subtasks). Include type validation, required fields, and constraints on enumerated values (like status and priority options).
## Acceptance Criteria:
- JSON Schema file is created with proper validation for all fields in the Task and Tasks Collection models
- Schema validates that task IDs are unique integers
- Schema enforces valid status values ("pending", "done", "deferred")
- Schema enforces valid priority values ("high", "medium", "low")
- Schema validates the nested structure of subtasks
- Schema includes validation for the meta object with projectName, version, timestamps, etc.

## Subtask ID: 2
## Title: Implement Task Model Classes
## Status: done
## Dependencies: 1.1 ✅
## Description: Create JavaScript classes that represent the Task and Tasks Collection models. Implement constructor methods that validate input data, getter/setter methods for properties, and utility methods for common operations (like adding subtasks, changing status, etc.). These classes will serve as the programmatic interface to the task data structure.
## Acceptance Criteria:
- Task class with all required properties from the PRD
- TasksCollection class that manages an array of Task objects
- Methods for creating, retrieving, updating tasks
- Methods for managing subtasks within a task
- Input validation in constructors and setters
- Proper TypeScript/JSDoc type definitions for all classes and methods

## Subtask ID: 3
## Title: Create File System Operations for tasks.json
## Status: done
## Dependencies: 1.1 ✅, 1.2 ✅
## Description: Implement functions to read from and write to the tasks.json file. These functions should handle file system operations asynchronously, manage file locking to prevent corruption during concurrent operations, and ensure atomic writes (using temporary files and rename operations). Include initialization logic to create a default tasks.json file if one doesn't exist.
## Acceptance Criteria:
- Asynchronous read function that parses tasks.json into model objects
- Asynchronous write function that serializes model objects to tasks.json
- File locking mechanism to prevent concurrent write operations
- Atomic write operations to prevent file corruption
- Initialization function that creates default tasks.json if not present
- Functions properly handle relative and absolute paths

## Subtask ID: 4
## Title: Implement Validation Functions
## Status: done
## Dependencies: 1.1 ✅, 1.2 ✅
## Description: Create a comprehensive set of validation functions that can verify the integrity of the task data structure. These should include validation of individual tasks, validation of the entire tasks collection, dependency cycle detection, and validation of relationships between tasks. These functions will be used both when loading data and before saving to ensure data integrity.
## Acceptance Criteria:
- Functions to validate individual task objects against schema
- Function to validate entire tasks collection
- Dependency cycle detection algorithm
- Validation of parent-child relationships in subtasks
- Validation of task ID uniqueness
- Functions return detailed error messages for invalid data
- Unit tests covering various validation scenarios

## Subtask ID: 5
## Title: Implement Error Handling System
## Status: done
## Dependencies: 1.1 ✅, 1.3 ✅, 1.4 ✅
## Description: Create a robust error handling system for file operations and data validation. Implement custom error classes for different types of errors (file not found, permission denied, invalid data, etc.), error logging functionality, and recovery mechanisms where appropriate. This system should provide clear, actionable error messages to users while maintaining system stability.
## Acceptance Criteria:
- Custom error classes for different error types (FileError, ValidationError, etc.)
- Consistent error format with error code, message, and details
- Error logging functionality with configurable verbosity
- Recovery mechanisms for common error scenarios
- Graceful degradation when non-critical errors occur
- User-friendly error messages that suggest solutions
- Unit tests for error handling in various scenarios