Parses the first page content of a PDF document and extracts bibliographic information such as title, author, abstract, keywords, and other relevant metadata. This method processes the content line-by-line and uses custom parsing logic to identify and assemble information blocks from academic papers.

idea: split[] contains the different lines, blocks are separated by empty lines, treat each block or do special treatment at authors (which are not broken). Therefore, we do a line-based and not a block-based splitting i points to the current line curString (mostly) contains the current block, the different lines are joined into one and thereby separated by " "

This method follows the structure typically found in academic paper PDFs:

• First, it attempts to detect the title by font size, if available, or by text position.
• Authors are then processed line-by-line until reaching the next section.
• Abstract and keywords, if found, are extracted as they appear on the page.
• Finally, conference details, DOI, and publication information are parsed from the lower blocks.

The parsing logic also identifies and categorizes entries based on keywords such as "Abstract" or "Keywords" and specific terms that denote sections. Additionally, this method can handle publisher-specific formats like Springer or IEEE, extracting data like series, volume, and conference titles.

Parameters

firstpageContents:String

The raw content of the PDF's first page, which may contain metadata and main content.

lineSeparator:String

The line separator used to format and unify line breaks in the text content.

titleByFontSize:Optional<String>

An optional title string determined by font size; if provided, this overrides the default title parsing.

Returns:Optional<BibEntry>

An Optional containing a BibEntry with the parsed bibliographic data if extraction is successful. Otherwise, an empty Optional.

Annotations

@VisibleForTesting