Changelog

All notable changes to Chess Analyzer Pro are documented here.

v1.5 - Themes, Stats Overhaul & Polish

New Features

• Splash Screen: Added a beautiful branded splash screen that displays during application startup for a more polished launch experience.
• Board Themes: Introduced multiple board color themes in the Settings, allowing users to customize the look of the chessboard (Default, Brown, Blue, Purple, Grey).
• Piece Themes: Added support for different piece sets (cburnett, merida, alpha, cardinal, chess7), letting users choose their preferred piece style.
• Stats by Piece Color: The Stats page now displays performance metrics broken down by piece color (White vs Black), giving deeper insight into your play.
• Live Settings Update: All configuration changes now apply immediately without requiring an application restart (Gemini API Key, Lichess Token, Usernames).

Improvements

• Stats Page Overhaul: Completely redesigned the Metrics/Stats dashboard for better visual presentation and more insightful data visualization.
• Accuracy Algorithm Overhaul: Complete rewrite of the accuracy calculation system:
  • Implemented Lichess-style volatility-weighted harmonic mean for game accuracy.
  • Added proper Win Probability conversion formula from centipawns.
  • Tuned decay constant and thresholds to better match Chess.com accuracy values.
• Move Classification Improvements:
  • Checkmate Fix: Moves delivering checkmate are now always classified as "Best" (was incorrectly showing as "Miss").
  • Tightened WPL thresholds for more accurate Inaccuracy/Mistake/Blunder detection.
  • Book moves now receive 100% accuracy (theoretical best play).
• Classification Summary Logging: Detailed breakdown of move classifications now logged after each analysis for debugging.
• GUI Restructuring: Major overhaul of the GUI code structure with new subpackages (views/, dialogs/, board/, analysis/, components/, metrics/) for better maintainability.
• Code Refactoring:
  • Created gui_utils.py with reusable utility functions to reduce code duplication.
  • Refactored the metric widget for cleaner architecture.
  • Removed redundant code across the codebase.
• Backend Improvements: Refactored backend code for better performance and cleaner architecture.

Bug Fixes

• Final Position Score Bug: Fixed a critical bug where _analyze_final_position wasn't returning the score, causing the last move to always get incorrect accuracy.
• 0% Accuracy Moves: Added 10% minimum floor to prevent single moves from getting 0% accuracy (which destroyed harmonic mean calculations).
• Metric Widget: Fixed multiple bugs related to the metric widget display and statistics calculations.
• Stats Display: Resolved issues where stats were not updating correctly in certain scenarios.
• UI Update Bug: Fixed a bug where UI elements were not refreshing properly after certain actions.

v1.4 - Load Options, Data Backup & UI Overhaul

New Features

• Enhanced Game Loading:
  • Load from Lichess URL: Direct support for loading games via Lichess game links (e.g., https://lichess.org/AbCdEfGh).
  • Paste PGN: Quick option to load games by pasting PGN text directly from the clipboard.
  • Consolidated Menu: Grouped all loading options (File, User, URL, Paste) into a cleaner dropdown menu structure.
• Data Management:
  • CSV Export/Import: Added functionality to export all your saved games to a CSV file for backup and import them back into your history.
• Settings Overhaul:
  • Official Website Links: Added direct links to the official website and feedback page in the Settings tab.
  • UI Redesign: Completely overhauled the Settings UI for better aesthetics, centered layout, and improved color blending.

Improvements

• Game History:
  • Added visual indicators (icons) to show the source of the game (Lichess, Chess.com, PGN file) in the history list.
• Code Quality:
  • Major refactoring to reduce redundancy and improve overall code quality.
  • Added integrity tests to ensure stability.

Bug Fixes

• Settings Navigation: Fixed an issue where the "Go to Settings" button was unresponsive.
• Engine Lines: Resolved a graphical glitch where engine evaluation lines would display incorrectly.
• Data Consistency: Fixed a bug where loaded games were occasionally missing ELO ratings.
• Game Duplication: Resolved an issue where importing games could create duplicate entries in the database.

v1.3 - Data, UI Polish & AI Coach

New Features

• Lichess Support:
  • Added ability to load games directly from Lichess.org usernames.
  • Application now remembers your last used Lichess username.
• Loading Experience:
  • Implemented a Beautiful UI Loader that displays a non-blocking overlay while fetching games from online APIs (Chess.com/Lichess).
• Ending Distribution:
  • Added a new Ending Distribution chart to the Metrics Dashboard, visualizing game outcomes by type (Checkmate, Resignation, Time, Abandon).

Improvements

• AI Coach Insights:
  • Completely refreshed the AI Coach section with a cleaner UI.
  • Added a specific Refresh Button for generating insights.
  • Improved text processing to remove markdown/emojis for a professional look.
  • Added "Placeholder" state for better UX before analysis.
• Metrics Dashboard:
  • Enhanced visual styling of the Saved Games section.
• Game List:
  • Game results (1-0, 0-1, etc.) are now clearly visible in the "Select Game" dialog list.
• Data Enrichment:
  • Database now stores richer metadata including Opening, Player Ratings, Termination, and FEN.
  • Added support for saving usernames to config.json for convenience.

Bug Fixes

• Analysis Accuracy:
  • Fixed a critical bug where Checkmates were sometimes incorrectly classified as Blunders.
  • Fixed a Move Count Mismatch where "Book" moves were being double-counted in summaries.

v1.2 - UI Overhaul & Metrics Dashboard

New Features

• Metrics Dashboard:
  • Added a new Stats page providing comprehensive insights into your chess performance.
  • Overview Tab: View total games analyzed, win/loss/draw rates, and average accuracy across all games.
  • Move Quality Tab: Visual breakdown of move classifications (Brilliant, Great, Blunder, etc.) using interactive pie charts.
  • Openings Tab: Analyze your most frequent openings with a bar chart display.
• Enhanced Navigation & Aesthetics:
  • Modern Sidebar UI: Replaced the traditional top menu bar with a sleek, integrated sidebar for seamless navigation between Analyze, History, Stats, and Settings views.
  • Visual Consistency: Unified the application's look and feel with a consistent design language, improved icon set, and refined accent color usage across all panels.
  • Consolidated Load Menu: Unified game loading options into a single "Load Game" button with a dropdown menu for PGN, User, and Link imports.
• Chess.com Integration:
  • Game Selection Dialog: When loading from a Chess.com user, a new dialog now appears listing the last 5 games with details (Date, Opponent, Rating), allowing you to choose exactly which game to analyze.

User Interface Refinements

• Layout Optimization:
  • Improved the spacing and arrangement of the analysis panel to prevent UI squeezing.
  • Made the "Analyze Game" button more prominent for better accessibility.
• Visual Polish:
  • Fixed QFont warnings that were cluttering the logs, ensuring smoother font rendering in the Evaluation Bar.
  • Added a new "Exit" button to the sidebar for quick application closure.

v1.1 - Analysis Refinements & UI Fixes

New Features

• Game History:
  • Automatically saves analyzed games to a local database.
  • Restores the last analyzed game on application startup.
  • Added "Clear History" option to the File menu.

Analysis & Classification

• New "Miss" Classification:
  • Implemented logic to identify "Missed Wins" (significant drop in win probability from a winning position).
  • Added detection for "Missed Mates" (failing to find a forced checkmate sequence).
• Accuracy Fix:
  • Resolved a bug where games containing checkmates could result in 0.0% accuracy.
  • Mate scores are now correctly converted to a capped CP value (±2000) for ACPL calculation.
• "Great" Move Tuning:
  • Significantly increased the threshold for "Great" moves to a 15% win probability difference. This makes "Great" moves much rarer and more meaningful, appearing only when a move is vastly superior to alternatives.
• Accuracy Formula:
  • Reverted the accuracy formula to exponential decay for consistent and familiar scoring.

User Interface

• "Best" Move Visibility:
  • Fixed a persistent issue where "Best" move icons were not appearing in the move list or on the board.
  • Updated the best.svg icon structure and renamed it to best_v2.svg to bypass potential caching issues.
  • Explicitly enforced icon sizing in the Move List to ensure proper rendering.
• Game Info Display:
  • Added a new header in the main window displaying "White (Elo) vs Black (Elo) [Result]" for the currently loaded game.

Bug Fixes

• Fixed a NameError crash caused by a missing QSize import.
• Fixed an AttributeError related to the removal of the game_list component.

v1.0 - Initial Release

Core Features

• Stockfish Integration: Deep move-by-move analysis using the world's strongest chess engine.
• Move Classification: Automatic classification of every move (Brilliant, Great, Best, Excellent, Good, Inaccuracy, Mistake, Blunder).
• Win Probability Graph: Dynamic evaluation curve visualization.
• PGN Support: Load games from .pgn files.
• Chess.com Import: Fetch recent games from Chess.com usernames.
• Interactive Board: Visual chessboard with move navigation and best move arrows.
• Dark Theme: Modern dark UI for comfortable analysis sessions.