# pdf_processing.py
import fitz  # PyMuPDF
import pymupdf4llm
import os
import traceback
from typing import Any, Dict, List # Use standard List, Dict
from collections import Counter

def convert_rect_to_dict(rect: fitz.Rect) -> Dict[str, float] | None:
    """Converts a fitz.Rect object to a dictionary."""
    if not rect or not isinstance(rect, fitz.Rect):
        # print(f"Warning: Invalid rect object received: {rect}") # Can be verbose
        return None
    return {
        "x0": rect.x0, "y0": rect.y0, "x1": rect.x1, "y1": rect.y1,
        "width": rect.width, "height": rect.height
    }

def try_map_issues_to_page_rects(
    issues_to_map_for_context: List[Dict[str, Any]],
    pdf_rects: List[fitz.Rect],
    page_number_for_mapping: int
) -> int:
    mapped_count = 0
    limit = min(len(issues_to_map_for_context), len(pdf_rects))
    for i in range(limit):
        issue_to_update = issues_to_map_for_context[i]
        if issue_to_update['is_mapped_to_pdf']: continue
        pdf_rect = pdf_rects[i]
        coord_dict = convert_rect_to_dict(pdf_rect)
        if coord_dict:
            issue_to_update['pdf_coordinates_list'] = [coord_dict]
            issue_to_update['is_mapped_to_pdf'] = True
            issue_to_update['mapped_page_number'] = page_number_for_mapping
            mapped_count += 1
    return mapped_count

def extract_font_filtered_markdown(pdf_path: str) -> str:
    """
    Extracts text from PDF at pdf_path, filters by majority font,
    builds a new PDF in memory, and converts it to Markdown using PyMuPDF4LLM.
    Expects pdf_path to be a valid path to a PDF file.
    """
    original_doc = None
    new_doc = None
    try:
        original_doc = fitz.open(pdf_path)
        if not original_doc.page_count:
            print("FontFilter: PDF has no pages.")
            return ""

        all_spans_details: List[Dict[str, Any]] = []
        font_char_counts: Counter = Counter()

        pdf_basename = os.path.basename(pdf_path)
        print(f"FontFilter: Analyzing fonts in '{pdf_basename}' ({original_doc.page_count} pages)...")
        for page_num in range(original_doc.page_count):
            page = original_doc[page_num]
            text_dict = page.get_text("dict") 
            for block in text_dict.get("blocks", []):
                if block.get("type") == 0: 
                    for line in block.get("lines", []):
                        for span in line.get("spans", []):
                            font_name = span["font"]
                            font_size_rounded = int(round(span["size"])) 
                            text = span["text"]
                            span_detail = {
                                "text": text, "font_name": font_name,
                                "font_size_rounded": font_size_rounded,
                                "original_font_size": span["size"],
                                "bbox": span["bbox"], "page_num": page_num
                            }
                            all_spans_details.append(span_detail)
                            font_char_counts[(font_name, font_size_rounded)] += len(text)
        
        if not font_char_counts:
            print("FontFilter: No text with font information found in PDF.")
            return ""

        majority_font_tuple_info = font_char_counts.most_common(1)[0]
        (majority_font_name, majority_font_size_rounded) = majority_font_tuple_info[0]
        char_count = majority_font_tuple_info[1]
        print(f"FontFilter: Majority font: Name='{majority_font_name}', RoundedSize={majority_font_size_rounded}pt ({char_count} chars).")

        new_doc = fitz.Document()
        # print("FontFilter: Constructing new PDF with majority font text...") # Can be verbose
        for p_num in range(original_doc.page_count):
            original_page_for_dim = original_doc[p_num]
            new_pdf_page = new_doc.new_page(width=original_page_for_dim.rect.width, 
                                            height=original_page_for_dim.rect.height)
            spans_to_write = [
                s_detail for s_detail in all_spans_details 
                if s_detail["page_num"] == p_num and \
                   s_detail["font_name"] == majority_font_name and \
                   s_detail["font_size_rounded"] == majority_font_size_rounded
            ]
            for span_data in spans_to_write:
                text_to_insert = span_data["text"]
                original_bbox = fitz.Rect(span_data["bbox"])
                font_size_for_render = span_data["original_font_size"]
                new_pdf_page.insert_textbox(
                    original_bbox, text_to_insert, fontsize=font_size_for_render,
                    fontname="helv", align=0 
                ) # Ignoring insertion_result for brevity here
        
        # print(f"FontFilter: New PDF constructed with {new_doc.page_count} pages.")
        markdown_text = ""
        if new_doc.page_count > 0:
            # print(f"FontFilter: Converting filtered PDF Document object to Markdown...") # Verbose
            markdown_text = pymupdf4llm.to_markdown(new_doc)
        else:
            print("FontFilter: The new PDF (filtered) is empty. No markdown generated.")
        
        # print(f"FontFilter: Markdown from filtered PDF length: {len(markdown_text)} chars.")
        return markdown_text
    except Exception as e:
        print(f"Error in extract_font_filtered_markdown for '{pdf_path}': {e}\n{traceback.format_exc()}")
        return ""
    finally:
        if original_doc: original_doc.close()
        if new_doc: new_doc.close()

def extract_plain_text_from_original_pdf(pdf_path: str) -> str:
    """
    Extracts raw plain text from the PDF at pdf_path without any filtering.
    Expects pdf_path to be a valid path to a PDF file.
    """
    doc_orig_text = None
    try:
        doc_orig_text = fitz.open(pdf_path)
        full_text_parts = [page.get_text("text") for page in doc_orig_text]
        # print(f"OriginalTextExtract: Extracted {len(doc_orig_text.page_count)} pages of plain text from '{os.path.basename(pdf_path)}'.")
        return "".join(full_text_parts)
    except Exception as e:
        print(f"Error extracting plain text from original PDF '{pdf_path}': {e}\n{traceback.format_exc()}")
        return ""
    finally:
        if doc_orig_text: doc_orig_text.close()