# -*- coding: utf-8 -*-
"""
文档解析器 - 支持多种文件格式
"""
import os
import chardet
from config import SUPPORTED_EXTENSIONS

def detect_encoding(file_path):
    """检测文件编码"""
    with open(file_path, 'rb') as f:
        raw_data = f.read(10000)
        result = chardet.detect(raw_data)
        return result['encoding'] or 'utf-8'

def parse_txt(file_path):
    """解析纯文本文件"""
    encoding = detect_encoding(file_path)
    try:
        with open(file_path, 'r', encoding=encoding, errors='ignore') as f:
            return f.read()
    except Exception as e:
        print(f"解析TXT文件失败 {file_path}: {e}")
        return ""

def parse_md(file_path):
    """解析Markdown文件"""
    return parse_txt(file_path)

def parse_pdf(file_path):
    """解析PDF文件（支持大文件）"""
    try:
        from PyPDF2 import PdfReader
        
        file_size = os.path.getsize(file_path)
        file_size_mb = file_size / (1024 * 1024)
        print(f"  PDF文件大小: {file_size_mb:.1f} MB")
        
        reader = PdfReader(file_path)
        total_pages = len(reader.pages)
        print(f"  PDF总页数: {total_pages}")
        
        text_parts = []
        for i, page in enumerate(reader.pages):
            if (i + 1) % 50 == 0 or i == 0:
                print(f"  解析进度: {i + 1}/{total_pages} 页")
            try:
                text = page.extract_text()
                if text:
                    text_parts.append(text)
            except Exception as e:
                print(f"  警告: 第 {i + 1} 页解析失败: {e}")
                continue
        
        print(f"  PDF解析完成，提取文本 {len(''.join(text_parts))} 字符")
        return "\n".join(text_parts)
    except Exception as e:
        print(f"解析PDF文件失败 {file_path}: {e}")
        return ""

def parse_docx(file_path):
    """解析Word文档"""
    try:
        from docx import Document
        doc = Document(file_path)
        text_parts = []
        for para in doc.paragraphs:
            if para.text.strip():
                text_parts.append(para.text)
        return "\n".join(text_parts)
    except Exception as e:
        print(f"解析DOCX文件失败 {file_path}: {e}")
        return ""

def parse_document(file_path):
    """根据文件类型解析文档"""
    ext = os.path.splitext(file_path)[1].lower()
    
    if ext not in SUPPORTED_EXTENSIONS:
        print(f"不支持的文件类型: {ext}")
        return ""
    
    parsers = {
        '.txt': parse_txt,
        '.md': parse_md,
        '.pdf': parse_pdf,
        '.docx': parse_docx,
        '.doc': parse_docx,
    }
    
    parser = parsers.get(ext, parse_txt)
    return parser(file_path)

def is_supported_file(filename):
    """检查文件是否支持"""
    ext = os.path.splitext(filename)[1].lower()
    return ext in SUPPORTED_EXTENSIONS