test version

application/parser/chunking.py

@@ -0,0 +1,118 @@
+import re
+from typing import List, Tuple, Union
+import logging
+from application.parser.schema.base import Document
+from application.utils import get_encoding
+
+logger = logging.getLogger(__name__)
+
+class Chunker:
+    def __init__(
+        self,
+        chunking_strategy: str = "classic_chunk",
+        max_tokens: int = 2000,
+        min_tokens: int = 150,
+        duplicate_headers: bool = False,
+    ):
+        if chunking_strategy not in ["classic_chunk"]:
+            raise ValueError(f"Unsupported chunking strategy: {chunking_strategy}")
+        self.chunking_strategy = chunking_strategy
+        self.max_tokens = max_tokens
+        self.min_tokens = min_tokens
+        self.duplicate_headers = duplicate_headers
+        self.encoding = get_encoding()
+
+    def separate_header_and_body(self, text: str) -> Tuple[str, str]:
+        header_pattern = r"^(.*?\n){3}"
+        match = re.match(header_pattern, text)
+        if match:
+            header = match.group(0)
+            body = text[len(header):]
+        else:
+            header, body = "", text  # No header, treat entire text as body
+        return header, body
+
+    def combine_documents(self, doc: Document, next_doc: Document) -> Document:
+        combined_text = doc.text + " " + next_doc.text
+        combined_token_count = len(self.encoding.encode(combined_text))
+        new_doc = Document(
+            text=combined_text,
+            doc_id=doc.doc_id,
+            embedding=doc.embedding,
+            extra_info={**(doc.extra_info or {}), "token_count": combined_token_count}
+        )
+        return new_doc
+    
+    def split_document(self, doc: Document) -> List[Document]:
+        split_docs = []
+        header, body = self.separate_header_and_body(doc.text)
+        header_tokens = self.encoding.encode(header) if header else []
+        body_tokens = self.encoding.encode(body)
+
+        current_position = 0
+        part_index = 0
+        while current_position < len(body_tokens):
+            end_position = current_position + self.max_tokens - len(header_tokens)
+            chunk_tokens = (header_tokens + body_tokens[current_position:end_position]
+                            if self.duplicate_headers or part_index == 0 else body_tokens[current_position:end_position])
+            chunk_text = self.encoding.decode(chunk_tokens)
+            new_doc = Document(
+                text=chunk_text,
+                doc_id=f"{doc.doc_id}-{part_index}",
+                embedding=doc.embedding,
+                extra_info={**(doc.extra_info or {}), "token_count": len(chunk_tokens)}
+            )
+            split_docs.append(new_doc)
+            current_position = end_position
+            part_index += 1
+            header_tokens = []
+        return split_docs
+
+    def classic_chunk(self, documents: List[Document]) -> List[Document]:
+        processed_docs = []
+        i = 0
+        while i < len(documents):
+            doc = documents[i]
+            tokens = self.encoding.encode(doc.text)
+            token_count = len(tokens)
+
+            if self.min_tokens <= token_count <= self.max_tokens:
+                doc.extra_info = doc.extra_info or {}
+                doc.extra_info["token_count"] = token_count
+                processed_docs.append(doc)
+                i += 1
+            elif token_count < self.min_tokens:
+                if i + 1 < len(documents):
+                    next_doc = documents[i + 1]
+                    next_tokens = self.encoding.encode(next_doc.text)
+                    if token_count + len(next_tokens) <= self.max_tokens:
+                        # Combine small documents
+                        combined_doc = self.combine_documents(doc, next_doc)
+                        processed_docs.append(combined_doc)
+                        i += 2
+                    else:
+                        # Keep the small document as is if adding next_doc would exceed max_tokens
+                        doc.extra_info = doc.extra_info or {}
+                        doc.extra_info["token_count"] = token_count
+                        processed_docs.append(doc)
+                        i += 1
+                else:
+                    # No next document to combine with; add the small document as is
+                    doc.extra_info = doc.extra_info or {}
+                    doc.extra_info["token_count"] = token_count
+                    processed_docs.append(doc)
+                    i += 1
+            else:
+                # Split large documents
+                processed_docs.extend(self.split_document(doc))
+                i += 1
+        return processed_docs
+
+    def chunk(
+        self,
+        documents: List[Document]
+    ) -> List[Document]:
+        if self.chunking_strategy == "classic_chunk":
+            return self.classic_chunk(documents)
+        else:
+            raise ValueError("Unsupported chunking strategy")