Add split command to CLI for splitting PDF files by page ranges

[Copilot]

This PR implements a new split command for the PrivatePdfConverter CLI tool that allows users to split PDF files into smaller PDFs based on page ranges or individual pages.

Features

The new split command supports flexible page specification formats:

# Split by page ranges
ppc split --path "input.pdf" --pages "1-5,10-15" --output "part"
# Creates: part_1-5.pdf, part_10-15.pdf

# Split individual pages  
ppc split --path "input.pdf" --pages "1,3,5" --output "page"
# Creates: page_1.pdf, page_3.pdf, page_5.pdf

# Split all pages individually
ppc split --path "input.pdf" --pages "all" --output "single"
# Creates: single_1.pdf, single_2.pdf, etc.

Implementation Details

• Command Class: Added SplitPdf.cs following existing codebase patterns
• Page Range Parser: Robust parsing logic handles ranges ("1-5"), individual pages ("1,3,5"), mixed formats ("1-3,5,8-10"), and special "all" keyword
• Error Handling: Validates page ranges against actual PDF page count, checks file existence, and ensures PDF format
• Output Naming: Supports custom output patterns with automatic PDF extension handling
• Logging: Comprehensive Serilog integration following existing patterns
• CLI Integration: Properly registered command with help text

Testing

Added comprehensive integration test suite (SplitPdfIntegrationTests.cs) with 8 test cases covering:

• Valid scenarios: page ranges, individual pages, mixed formats, "all" keyword
• Error scenarios: invalid ranges, missing files, non-PDF files
• Output validation: correct file creation and page counts

All existing tests continue to pass (17/17 total tests).

Technical Approach

The implementation leverages the existing iText PDF library used throughout the codebase and follows established patterns for command structure, error handling, and logging. The page range parsing is designed to be intuitive and handles edge cases gracefully with clear error messages.

Original prompt

Implement a new split command for the CLI tool that allows users to split PDF files into smaller PDFs based on page ranges or individual pages.

Requirements:

Command Interface

• Add a new split command to the CLI
• Support splitting by page ranges (e.g., "1-5", "10-15")
• Support splitting individual pages (e.g., "1", "3", "7")
• Support comma-separated combinations (e.g., "1-3,5,8-10")
• Allow custom output naming pattern

Command Syntax

ppc split --path "input.pdf" --pages "1-5,10-15" --output "part"
# Should create: part_1-5.pdf, part_10-15.pdf

ppc split --path "input.pdf" --pages "1,3,5" --output "page"  
# Should create: page_1.pdf, page_3.pdf, page_5.pdf

ppc split --path "input.pdf" --pages "all" --output "single"
# Should create individual PDFs for each page: single_1.pdf, single_2.pdf, etc.

Implementation Details

1. Create a new SplitPdf.cs command class in the Commands folder
2. Add the command registration in Program.cs
3. Use existing PDF library (likely iTextSharp or similar) for PDF manipulation
4. Follow the existing code patterns and logging style
5. Add proper error handling for:
   • Invalid page ranges
   • Non-existent pages
   • File access issues
   • Invalid PDF files

Error Handling

• Validate page ranges against actual PDF page count
• Handle invalid page numbers gracefully
• Provide clear error messages with suggestions
• Log operations with Serilog following existing patterns

Output Naming

• Default output pattern: {filename}_pages_{range}.pdf
• Support custom naming with --output parameter
• Ensure no file overwrites without confirmation

The implementation should follow the existing codebase patterns, use the same logging approach, and integrate seamlessly with the current CLI structure.

This pull request was created as a result of the following prompt from Copilot chat.

Implement a new split command for the CLI tool that allows users to split PDF files into smaller PDFs based on page ranges or individual pages.

Requirements:

Command Interface

• Add a new split command to the CLI
• Support splitting by page ranges (e.g., "1-5", "10-15")
• Support splitting individual pages (e.g., "1", "3", "7")
• Support comma-separated combinations (e.g., "1-3,5,8-10")
• Allow custom output naming pattern

Command Syntax

ppc split --path "input.pdf" --pages "1-5,10-15" --output "part"
# Should create: part_1-5.pdf, part_10-15.pdf

ppc split --path "input.pdf" --pages "1,3,5" --output "page"  
# Should create: page_1.pdf, page_3.pdf, page_5.pdf

ppc split --path "input.pdf" --pages "all" --output "single"
# Should create individual PDFs for each page: single_1.pdf, single_2.pdf, etc.

Implementation Details

1. Create a new SplitPdf.cs command class in the Commands folder
2. Add the command registration in Program.cs
3. Use existing PDF library (likely iTextSharp or similar) for PDF manipulation
4. Follow the existing code patterns and logging style
5. Add proper error handling for:
   • Invalid page ranges
   • Non-existent pages
   • File access issues
   • Invalid PDF files

Error Handling

• Validate page ranges against actual PDF page count
• Handle invalid page numbers gracefully
• Provide clear error messages with suggestions
• Log operations with Serilog following existing patterns

Output Naming

• Default output pattern: {filename}_pages_{range}.pdf
• Support custom naming with --output parameter
• Ensure no file overwrites without confirmation

The implementation should follow the existing codebase patterns, use the same logging approach, and integrate seamlessly with the current CLI structure.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud