From 4f30f5938299b5faf7b5882daf13b6743f629a0a Mon Sep 17 00:00:00 2001
From: LUIS NOVO <lfnovo@gmail.com>
Date: Fri, 25 Oct 2024 08:16:00 -0300
Subject: [PATCH] fix encoding errors on content creation

---
 open_notebook/graphs/content_process.py | 90 ++++++++++++++++++++++++-
 open_notebook/utils.py                  |  7 +-
 2 files changed, 92 insertions(+), 5 deletions(-)

diff --git a/open_notebook/graphs/content_process.py b/open_notebook/graphs/content_process.py
index 6075c42..653d9c6 100644
--- a/open_notebook/graphs/content_process.py
+++ b/open_notebook/graphs/content_process.py
@@ -1,4 +1,5 @@
 import re
+import unicodedata
 
 import fitz  # type: ignore
 import magic
@@ -66,13 +67,100 @@ def file_type(state: SourceState):
     return return_dict
 
 
+def clean_pdf_text(text):
+    """
+    Clean text extracted from PDFs with enhanced space handling.
+
+    Args:
+        text (str): The raw text extracted from a PDF
+    Returns:
+        str: Cleaned text with minimal necessary spacing
+    """
+    if not text:
+        return text
+
+    # Step 1: Normalize Unicode characters
+    text = unicodedata.normalize("NFKC", text)
+
+    # Step 2: Replace common PDF artifacts
+    replacements = {
+        # Common ligatures
+        "fi": "fi",
+        "fl": "fl",
+        "ff": "ff",
+        "ffi": "ffi",
+        "ffl": "ffl",
+        # Quotation marks and apostrophes
+        """: "'", """: "'",
+        '"': '"',
+        "′": "'",
+        "‚": ",",
+        "„": '"',
+        # Dashes and hyphens
+        "‒": "-",
+        "–": "-",
+        "—": "-",
+        "―": "-",
+        # Other common replacements
+        "…": "...",
+        "•": "*",
+        "°": " degrees ",
+        "¹": "1",
+        "²": "2",
+        "³": "3",
+        "©": "(c)",
+        "®": "(R)",
+        "™": "(TM)",
+    }
+    for old, new in replacements.items():
+        text = text.replace(old, new)
+
+    # Step 3: Advanced space cleaning
+    # Remove control characters while preserving essential whitespace
+    text = "".join(
+        char for char in text if unicodedata.category(char)[0] != "C" or char in "\n\t "
+    )
+
+    # Step 4: Enhanced space cleaning
+    text = re.sub(r"[ \t]+", " ", text)  # Consolidate horizontal whitespace
+    text = re.sub(r" +\n", "\n", text)  # Remove spaces before newlines
+    text = re.sub(r"\n +", "\n", text)  # Remove spaces after newlines
+    text = re.sub(r"\n\t+", "\n", text)  # Remove tabs at start of lines
+    text = re.sub(r"\t+\n", "\n", text)  # Remove tabs at end of lines
+    text = re.sub(r"\t+", " ", text)  # Replace tabs with single space
+
+    # Step 5: Remove empty lines while preserving paragraph structure
+    text = re.sub(r"\n{3,}", "\n\n", text)  # Max two consecutive newlines
+    text = re.sub(r"^\s+", "", text)  # Remove leading whitespace
+    text = re.sub(r"\s+$", "", text)  # Remove trailing whitespace
+
+    # Step 6: Clean up around punctuation
+    text = re.sub(r"\s+([.,;:!?)])", r"\1", text)  # Remove spaces before punctuation
+    text = re.sub(r"(\()\s+", r"\1", text)  # Remove spaces after opening parenthesis
+    text = re.sub(
+        r"\s+([.,])\s+", r"\1 ", text
+    )  # Ensure single space after periods and commas
+
+    # Step 7: Remove zero-width and invisible characters
+    text = re.sub(r"[\u200b\u200c\u200d\ufeff\u200e\u200f]", "", text)
+
+    # Step 8: Fix hyphenation and line breaks
+    text = re.sub(
+        r"(?<=\w)-\s*\n\s*(?=\w)", "", text
+    )  # Remove hyphenation at line breaks
+
+    return text.strip()
+
+
 def _extract_text_from_pdf(pdf_path):
     doc = fitz.open(pdf_path)
     text = ""
     for page in doc:
         text += page.get_text()
     doc.close()
-    return text
+
+    normalized_text = clean_pdf_text(text)
+    return normalized_text
 
 
 def extract_pdf(state: SourceState):
diff --git a/open_notebook/utils.py b/open_notebook/utils.py
index 27ae092..5dbeeb5 100644
--- a/open_notebook/utils.py
+++ b/open_notebook/utils.py
@@ -78,13 +78,12 @@ def remove_non_ascii(text):
 
 
 def remove_non_printable(text):
-    # Remove caracteres de controle, exceto quebras de linha e tabulações
+    # Remove control characters, except newlines and tabs
     text = "".join(
         char for char in text if unicodedata.category(char)[0] != "C" or char in "\n\t"
     )
-    # Manter letras (incluindo acentuadas), números, espaços, quebras de linha, tabulações e pontuação básica
-    allowed = r"a-zA-Z0-9\s.,!?\-\n\t"
-    return re.sub(f"[^{allowed}]", "", text, flags=re.UNICODE)
+    # Keep letters (including accented ones), numbers, spaces, newlines, tabs, and basic punctuation
+    return re.sub(r"[^\w\s.,!?\-\n\t]", "", text, flags=re.UNICODE)
 
 
 def surreal_clean(text):