Changes in version 1.2.0                        

Major Changes

Architecture Refactoring

  - Complete API separation: Created dedicated R/api.R module to handle
    all API interactions with IPEA's database, removing hardcoded
    endpoints from main business logic.

  - Simplified package interface: Removed five wrapper functions
    (ipca(), igpm(), igpdi(), ipc(), inpc()) in favor of a unified
    deflate() function with an index parameter. This reduces code
    duplication and provides a cleaner, more maintainable interface.

  - Enhanced error handling: Added retry mechanisms for API requests
    with configurable retry attempts and delays.

New Features

Data Caching System

  - Local data caching: Added comprehensive caching system that stores
    downloaded price index data locally in a "cache" directory,
    significantly improving performance for repeated API calls.

  - Automatic cache management: Cache files are automatically validated
    for structure and content. Invalid or corrupted cache files are
    automatically re-downloaded.

  - Cache control: Added cache parameter to deflate() function (default
    TRUE) allowing users to disable caching when fresh data is always
    required.

  - Smart cache loading: First call downloads and caches data;
    subsequent calls load from cache with detailed progress messages
    showing cache status.

Enhanced Function Interface

  - Flexible date input: The real_date parameter now accepts both
    character strings in 'MM/YYYY' format and Date objects (e.g.,
    as.Date("2018-01-01")), providing more flexibility for users.

  - Verbose control: Added verbose parameter to deflate() function to
    control progress messages and progress bars during data download.
    Default is TRUE for backward compatibility.

  - Improved user agent: API requests now include a proper user agent
    string identifying the deflateBR package.

API Improvements

  - Centralized configuration: All API endpoints and price index codes
    are now centrally managed in R/api.R.

  - Better HTTP handling: Enhanced HTTP request handling with proper
    status checking and informative error messages.

  - Progress feedback: Optional progress bars during data download for
    better user experience.

Documentation

  - Comprehensive examples: Updated documentation with examples showing
    both string and Date object usage for the real_date parameter.

  - Simplified README: Removed references to deprecated wrapper
    functions and updated examples to showcase the unified interface.

  - Enhanced function documentation: Improved parameter descriptions and
    added detailed examples for all new features.

Breaking Changes

  - Removed wrapper functions: The convenience functions ipca(), igpm(),
    igpdi(), ipc(), and inpc() have been removed. Users should now use
    deflate() with the appropriate index parameter instead.
    
    # Old (deprecated):
    ipca(100, as.Date("2020-01-01"), "01/2021")
    
    # New:
    deflate(100, as.Date("2020-01-01"), "01/2021", index = "ipca")

Migration Guide

For users upgrading from version 1.1.x:

1.  Replace wrapper function calls: Change ipca(), igpm(), etc. calls to
    use deflate() with the index parameter.

2.  Optional: Use Date objects: Take advantage of the new Date object
    support for the real_date parameter.

3.  Optional: Control verbosity: Use the verbose = FALSE parameter for
    silent operation.

                 Changes in version 1.1.2 (2018-09-28)                  

  - Added a NEWS.md file to track changes to the package.