"""
Shared utility functions for official mixins
"""
from typing import Optional, List
def parse_pages_parameter(pages: Optional[str]) -> Optional[List[int]]:
"""Parse pages parameter from string to list of 0-based page numbers
Supports formats:
- Single page: "5"
- Comma-separated: "1,3,5"
- Ranges: "1-10" or "11-30"
- Mixed: "1,3-5,7,10-15"
Args:
pages: Page specification string (1-based page numbers)
Returns:
List of 0-based page indices, or None if pages is None
"""
if not pages:
return None
try:
result = []
parts = pages.split(',')
for part in parts:
part = part.strip()
# Handle range (e.g., "1-10" or "11-30")
if '-' in part:
range_parts = part.split('-')
if len(range_parts) == 2:
start = int(range_parts[0].strip())
end = int(range_parts[1].strip())
# Convert 1-based to 0-based and create range
result.extend(range(start - 1, end))
else:
return None
# Handle single page
else:
result.append(int(part) - 1)
return result
except (ValueError, AttributeError):
return None
