app/parser/parser.py

from fastapi import UploadFile
from docx import Document
from docx.text.paragraph import Paragraph
from docx.table import Table
from enum import Enum
from dataclasses import dataclass, field
from typing import Optional
import uuid
from pathlib import Path
import zipfile
import xml.etree.ElementTree as ET
import io


class BlockType(str, Enum):
    TEXT = "text"
    TABLE = "table"
    IMAGE = "image"
    HEADING = "heading"

@dataclass    
class ParsedBlock:
    BLOCK_TYPE: BlockType
    content: str
    elem_index: int
    page_index: int
    heading_level: Optional[int] = None
    table_data: Optional[int] = None
    image_id: str = None
    image_format: str = None
    storage_id: str = None
    source_file: str = ""
    metadata: dict = field(default_factory=dict)

#the logic depends on the tag encountered right now. images are inside p tags, and table are there own tag just like p
#the main return value is the block here, so when we encounter a p tag we append its block to our List -> block
#so for reusablity i will define reusable helper functions for each tag

def para_text(para: Paragraph) -> str:
    text = para.text.strip()
    return text

def read_table(table: Table) -> str:
   data = []
   for row in table.rows:
      row_data = []
      for cell in row.cells:
         row_data.append(cell.text.strip())
      data.append(row_data)
   return data  

#later add a description for a table along with the table, same can be done for image

def table_to_markdown(table_data: list[list[str]]) -> str:
    lines = []
    headings = table_data[0]
    seperator = ["---"] * len(headings)
    rows = table_data[1:]
    
    heading_line = []
    for heading in headings:
        heading_line.append("| " + str(heading) + " ")
    lines.append("".join(heading_line) + " |")

    seperator_line = []
    for sep in seperator:
        seperator_line.append("| " + str(sep) + " ")
    lines.append("".join(seperator_line) + " |")
    
    for row in rows:
        row_line = []
        for cell in row:
            row_line.append(" | " + str(cell) + " ")
        lines.append("".join(row_line) + " |")    
    return "\n".join(lines)

def get_level_score(para: Paragraph) -> int:
    f_size = 0
    font_size = []
    score = 0
    for run in para.runs:
        font_size.append(run.font.size.pt)
    if(len(font_size) > 0):
        f_size = sum(font_size) / len(font_size)    

    if(para.style.name == "SectionHeader"):
        score += 1
        
    if(f_size > 11):
        score += 2

    return score

def get_image_from_para(para: Paragraph, i: int, image_map: dict[str, tuple[bytes, str]]) -> list[ParsedBlock]:
    data = []
    for run in para.runs:
        for elem in run._r.iter():
           tag = elem.tag.split("}")[-1]
           if(tag == "blip"):
               r_id = elem.get('{http://schemas.openxmlformats.org/officeDocument/2006/relationships}embed')
               if r_id and r_id in image_map:
                 image_bytes, image_ext = image_map[r_id]
                 s_id = uuid.uuid4()
                 data.append(ParsedBlock(
                     BLOCK_TYPE= "image",
                     content = f"[Image Here, IMG ID - `{r_id}`]",
                     elem_index= i,
                     page_index = 0,
                     image_id = r_id,
                     image_format = image_ext,
                     storage_id = s_id
                    ))
    return data                     



async def parse_doc(file: UploadFile) -> list[ParsedBlock]:
     content = await file.read()
     file_stream = io.BytesIO(content)
     doc = Document(file_stream)
     doc_zip = zipfile.ZipFile(file_stream)
     body = doc.element.body
     blocks : list[ParsedBlock] = []
     rels_xml = doc_zip.read("word/_rels/document.xml.rels")
     rel_tree = ET.fromstring(rels_xml)

     image_map: dict[str, tuple[bytes, str]] = {}
     for rel in rel_tree:
      rel_type = rel.get("Type", "")
      rel_target = rel.get("Target", "")
      rel_id = rel.get("Id", "")
      if "image" in rel_type.lower():
        image_path = "word/" + rel_target
        image_bytes = doc_zip.read(image_path)
        image_ext = Path(rel_target).suffix.lstrip(".").lower()
        image_map[rel_id] = (image_bytes, image_ext)

     for i, child in enumerate(body):
       tag = child.tag.split("}")[-1] if "}" in child.tag else child.tag    
       para = Paragraph(child, doc)
       if(tag == "p"):
        text = para_text(para)
        level = get_level_score(para)
        
        if(text != ""):
           block = ParsedBlock(
             BLOCK_TYPE= "text",
             content = text,
             elem_index= i,
             page_index = 0,
             heading_level=level
           )
           blocks.append(block)
        image_blocks = get_image_from_para(para, i, image_map)
        if(len(image_blocks) > 0):
          blocks.extend(image_blocks)

       elif(tag == "tbl"):
          para = Table(child, doc)
          raw_data = read_table(para)
          table_data = table_to_markdown(raw_data)
          block = ParsedBlock(
           BLOCK_TYPE= "table",
           content = table_data,
           elem_index = i,
           page_index = 0
        )
          blocks.append(block)
     return blocks



if __name__ == "__main__":
    doc = Document("./documents/Champion_Petfoods_CSS_SOP_Final 1 1.docx")
    blocks = parse_doc(doc)
    
    with open("output.txt", "w") as file:
        for block in blocks:
            # Write directly to the file in each iteration
            file.write(f"type: {block.BLOCK_TYPE}\n{block.content}\n\n")
            
    print("Done! Data saved to output.txt")