import pandas as pd
import logging
from openpyxl import load_workbook
from openpyxl.drawing.image import Image as OpenPyXLImage
from typing import Optional
from PIL import Image, UnidentifiedImageError
import io
import xlrd
from modules.ocr import ReaderForEasyOCR
import asyncio
import os
logger = logging.getLogger()


class ExcelParser:
    def __init__(self, use_ocr: bool, ocr_reader: Optional[ReaderForEasyOCR] = None):
        self.use_ocr = use_ocr
        self.ocr_reader = ocr_reader

    async def parse(self, contents: bytes, filename: str) -> list:
        document_name = filename
        parsed_content = []
        file_extension = os.path.splitext(filename)[1].lower()  # 확장자만 소문자로 변환

        if file_extension == '.csv':
            df = pd.read_csv(io.BytesIO(contents))
            df_csv = df.to_csv(index=False, header=False)
            sheet_name = 'Sheet1'
            entry = {
                "document_id": f"{document_name}@{sheet_name}",
                "text": df_csv
            }
            parsed_content.append(entry)

        elif file_extension == '.xls':
            workbook = xlrd.open_workbook(io.BytesIO(contents), formatting_info=True)

            for sheet in workbook.sheets():
                data = [sheet.row_values(row) for row in range(sheet.nrows)]
                df = pd.DataFrame(data)
                df = self.fill_merged_cells_xls(df, sheet)
                df_csv = df.to_csv(index=False, header=False)
                sheet_name = sheet.name
                entry = {
                    "document_id": f"{document_name}@{sheet_name}",
                    "text": df_csv
                }
                parsed_content.append(entry)

        elif file_extension == '.xlsx':
            workbook = load_workbook(filename=io.BytesIO(contents), data_only=True)

            for sheet_name in workbook.sheetnames:
                sheet = workbook[sheet_name]
                data = sheet.values
                df = pd.DataFrame(data)

                # 이미지 및 OCR 처리
                for img in sheet._images:
                    # 이미지의 위치 계산
                    img_cell = img.anchor._from.row - 1, img.anchor._from.col - 1  # 이미지의 위치 (행, 열)

                    # DataFrame 크기 조정 (필요한 경우)
                    max_row, max_col = img_cell
                    if max_row >= len(df):
                        df = df.reindex(range(max_row + 1), fill_value='')
                    if max_col >= len(df.columns):
                        df = df.reindex(columns=range(max_col + 1), fill_value='')

                    img_data = img._data()  # 이미지 데이터
                    try:

                        img_obj = Image.open(io.BytesIO(img_data))

                        # WMF 형식 처리 방지
                        if img_obj.format == "WMF":
                            logger.warning(f"Skipping WMF image in sheet {sheet_name} as it cannot be processed.")
                            continue

                        ocr_text = ""
                        width, height = img_obj.size
                        if self.use_ocr and self.ocr_reader and (width >= 150 and height >= 150): 
                            # 이미지를 흑백으로 변환
                            img_obj = img_obj.convert('L')

                            ocr_results = await self.ocr_reader(img_obj)
                            ocr_text = "\n".join([text for bbox, text in ocr_results])
                            ocr_text = f"(ocr)\n{ocr_text}\n(/ocr)"

                        # OCR 텍스트를 셀에 삽입
                        df.iat[img_cell[0], img_cell[1]] = f"(image)\n{ocr_text}\n(/image)"
                        # logger.info(f"Inserted OCR text at cell ({img_cell[0]}, {img_cell[1]}): {df.iat[img_cell[0], img_cell[1]]}")
                    except UnidentifiedImageError:
                        logger.error(f"Unable to identify image format in sheet {sheet_name}. Skipping this image.")
                        continue

                df = self.fill_merged_cells_xlsx(df, sheet)
                df_csv = df.to_csv(index=False, header=False)
                entry = {
                    "document_id": f"{document_name}@{sheet_name}",
                    "text": df_csv
                }
                parsed_content.append(entry)

        else:
            raise ValueError("Unsupported file format")

        return parsed_content


    def fill_merged_cells_xlsx(self, df, sheet):
        for merged_cell in sheet.merged_cells.ranges:
            min_col, min_row, max_col, max_row = merged_cell.bounds
            top_left_cell_value = sheet.cell(row=min_row, column=min_col).value
            for row in range(min_row, max_row + 1):
                for col in range(min_col, max_col + 1):
                    if pd.isna(df.iat[row - 1, col - 1]):  # 기존 값이 비어 있는 경우에만 채우기
                        df.iat[row - 1, col - 1] = top_left_cell_value
        return df


    def fill_merged_cells_xls(self, df, sheet):
        for merged_cell in sheet.merged_cells:
            min_row, max_row, min_col, max_col = merged_cell
            top_left_cell_value = sheet.cell_value(min_row, min_col)
            for row in range(min_row, max_row):
                for col in range(min_col, max_col):
                    if pd.isna(df.iat[row, col]) or df.iat[row, col] == '' or df.iat[row, col] is None:  # 기존 값이 비어 있는 경우에만 채우기
                        df.iat[row, col] = top_left_cell_value
        return df