🎵 Cue Sheet Audio Format Updater

📌 Overview

A robust Rust utility that automatically updates .cue sheet references when migrating from WAV to lossless formats (FLAC/APE). This tool recursively processes cue files in your music library, intelligently replacing .wav references based on actual audio files present in each directory.

⚙️ Core Functionality

graph TD
    A[Start in Current Directory] --> B{Recursive Scan}
    B --> C[Find .cue Files]
    C --> D{Check Directory Contents}
    D -->|FLAC files exist| E[Replace .wav → .flac]
    D -->|APE files exist| F[Replace .wav → .ape]
    E --> G[Preserve Original Encoding]
    F --> G
    G --> H[In-Place Update]

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Key Features

• Intelligent Format Detection:
  Automatically selects replacement format based on actual files present:

  • Prioritizes .flac if any FLAC files exist in the directory
  • Falls back to .ape if APE files exist (and no FLACs)
  • Skips directories with neither format

• Encoding-Aware Processing:
  Handles legacy cue sheets with proper encoding detection:

  1. Tries UTF-8 decoding first
  2. Falls back to Windows-1252 (common for Windows-created cue sheets)
  3. Preserves original character encoding in output

• Recursive Directory Traversal:
  Processes all subdirectories depth-first starting from execution point

• Atomic Updates:
  Only modifies files when actual changes are needed (no unnecessary writes)

🛠️ Technical Implementation

// Core workflow pseudocode
fn process_cue_file(path) {
    content = detect_encoding_and_read(path); // UTF-8 → Win1252 fallback
    
    if directory_contains("*.flac") {
        content.replace(".wav", ".flac"); 
    } else if directory_contains("*.ape") {
        content.replace(".wav", ".ape");
    }
    
    if content_changed { 
        write_with_original_encoding(path, content); 
    }
}

Critical Design Choices

1. Case-Sensitive Replacement
   Only replaces lowercase .wav (common in cue sheets) - avoids unintended replacements in metadata

2. Directory Context Awareness
   Checks actual files present before making replacements - prevents broken references

3. Encoding Preservation
   Maintains original character encoding through Windows-1252 fallback handling

4. Minimal-Impact Updates
   Skips unchanged files and avoids backup clutter (intentional design choice)

⚠️ Important Limitations

Consideration	Impact	Mitigation
No backups created	Original files overwritten	Use with version control or manual backups
Only replaces .wav	Won't fix .WAV or mixed case	Pre-process files with case normalization
String-based replacement	May replace in comments	Verify critical cue sheets manually
FLAC priority	Prefers FLAC even if APE is primary	Organize libraries by format type

🚀 Usage Instructions

You can donwload binary from repo, build locally, or build inside docker (linux, windows). Docker-compose build up - generates windows executable by default (target\x86_64-pc-windows-gnu\release\cue_editor.exe).

🔒 Safety Recommendations

1. Test first on a small directory subset
2. Version control: Run in a Git-tracked directory (git add . && git commit -m "pre-update")
3. Verify critical albums after processing:

   grep -r "\.wav" . --include=*.cue  # Check for missed replacements

4. Combine with verification tools like cuetools for integrity checks

💡 Pro Tip: For large libraries, pair with rclone or restic to create point-in-time snapshots before processing.

📦 Dependencies

• encoding_rs crate for robust Windows-1252 handling
• Standard Rust filesystem and encoding libraries
• No external system dependencies required