"""
统一文档处理入口 - DocumentProcessor

功能：
- 自动检测文件类型
- 调用对应的处理器
- 统一输出 Markdown 格式

支持格式：
- PDF (.pdf) → pymupdf4llm
- Word (.docx) → mammoth
- Excel (.xlsx) → pandas
- CSV (.csv) → pandas
- PPT (.pptx) → python-pptx
- 纯文本 (.txt, .md) → 直接读取
"""

from pathlib import Path
from typing import Dict, Any, Optional
from loguru import logger
import chardet


class DocumentProcessor:
    """统一文档处理器"""
    
    # 支持的文件类型
    SUPPORTED_TYPES = {
        '.pdf': 'pdf',
        '.docx': 'word',
        '.doc': 'word',
        '.xlsx': 'excel',
        '.xls': 'excel',
        '.csv': 'csv',
        '.pptx': 'ppt',
        '.ppt': 'ppt',
        '.txt': 'text',
        '.md': 'text',
        '.markdown': 'text',
    }
    
    def to_markdown(self, file_path: str) -> Dict[str, Any]:
        """
        将文档转换为 Markdown
        
        Args:
            file_path: 文件路径
        
        Returns:
            {
                "success": True,
                "markdown": "Markdown 内容",
                "file_type": "pdf",
                "metadata": { ... }
            }
        """
        path = Path(file_path)
        filename = path.name
        suffix = path.suffix.lower()
        
        # 检查文件类型
        if suffix not in self.SUPPORTED_TYPES:
            return {
                "success": False,
                "error": f"不支持的文件类型: {suffix}",
                "supported_types": list(self.SUPPORTED_TYPES.keys())
            }
        
        file_type = self.SUPPORTED_TYPES[suffix]
        logger.info(f"处理文档: {filename}, 类型: {file_type}")
        
        try:
            # 根据类型调用对应处理器
            if file_type == 'pdf':
                result = self._process_pdf(file_path)
            elif file_type == 'word':
                result = self._process_word(file_path)
            elif file_type == 'excel':
                result = self._process_excel(file_path)
            elif file_type == 'csv':
                result = self._process_csv(file_path)
            elif file_type == 'ppt':
                result = self._process_ppt(file_path)
            elif file_type == 'text':
                result = self._process_text(file_path)
            else:
                result = {
                    "success": False,
                    "error": f"未实现的处理器: {file_type}"
                }
            
            # 添加通用信息
            if result.get("success"):
                result["file_type"] = file_type
                result["filename"] = filename
            
            return result
            
        except Exception as e:
            logger.error(f"文档处理失败: {filename}, 错误: {e}")
            return {
                "success": False,
                "error": str(e),
                "file_type": file_type,
                "filename": filename
            }
    
    def _process_pdf(self, file_path: str) -> Dict[str, Any]:
        """处理 PDF"""
        from .pdf_markdown_processor import PdfMarkdownProcessor
        
        processor = PdfMarkdownProcessor()
        return processor.to_markdown(file_path)
    
    def _process_word(self, file_path: str) -> Dict[str, Any]:
        """处理 Word 文档"""
        import mammoth
        
        try:
            with open(file_path, "rb") as f:
                result = mammoth.convert_to_markdown(f)
                markdown = result.value
                messages = result.messages
            
            # 添加文件名上下文
            filename = Path(file_path).name
            markdown_with_context = f"## 文档: {filename}\n\n{markdown}"
            
            return {
                "success": True,
                "markdown": markdown_with_context,
                "metadata": {
                    "char_count": len(markdown),
                    "warnings": [str(m) for m in messages] if messages else []
                }
            }
        except Exception as e:
            return {
                "success": False,
                "error": str(e),
                "markdown": f"> **系统提示**：Word 文档解析失败: {str(e)}"
            }
    
    def _process_excel(self, file_path: str) -> Dict[str, Any]:
        """处理 Excel"""
        import pandas as pd
        
        try:
            filename = Path(file_path).name
            xlsx = pd.ExcelFile(file_path, engine='openpyxl')
            
            md_parts = []
            total_rows = 0
            
            for sheet_name in xlsx.sheet_names:
                df = pd.read_excel(xlsx, sheet_name=sheet_name)
                rows = len(df)
                total_rows += rows
                
                # 添加 Sheet 信息
                md_parts.append(f"## 数据: {filename} - {sheet_name}")
                md_parts.append(f"- **行列**: {rows} 行 × {len(df.columns)} 列\n")
                
                # 截断大数据
                max_rows = 200
                if rows > max_rows:
                    md_parts.append(f"> ⚠️ 数据量较大，仅显示前 {max_rows} 行（共 {rows} 行）\n")
                    df = df.head(max_rows)
                
                # 转换为 Markdown 表格
                df = df.fillna('')
                md_parts.append(df.to_markdown(index=False))
                md_parts.append("\n---\n")
            
            return {
                "success": True,
                "markdown": "\n".join(md_parts),
                "metadata": {
                    "sheet_count": len(xlsx.sheet_names),
                    "total_rows": total_rows,
                    "sheets": xlsx.sheet_names
                }
            }
        except Exception as e:
            return {
                "success": False,
                "error": str(e),
                "markdown": f"> **系统提示**：Excel 文档解析失败: {str(e)}"
            }
    
    def _process_csv(self, file_path: str) -> Dict[str, Any]:
        """处理 CSV"""
        import pandas as pd
        
        try:
            filename = Path(file_path).name
            
            # 自动检测编码
            with open(file_path, 'rb') as f:
                raw = f.read(10000)
                detected = chardet.detect(raw)
                encoding = detected.get('encoding', 'utf-8')
            
            df = pd.read_csv(file_path, encoding=encoding)
            rows = len(df)
            
            md_parts = []
            md_parts.append(f"## 数据: {filename}")
            md_parts.append(f"- **行列**: {rows} 行 × {len(df.columns)} 列")
            md_parts.append(f"- **编码**: {encoding}\n")
            
            # 截断大数据
            max_rows = 200
            if rows > max_rows:
                md_parts.append(f"> ⚠️ 数据量较大，仅显示前 {max_rows} 行（共 {rows} 行）\n")
                df = df.head(max_rows)
            
            df = df.fillna('')
            md_parts.append(df.to_markdown(index=False))
            
            return {
                "success": True,
                "markdown": "\n".join(md_parts),
                "metadata": {
                    "row_count": rows,
                    "column_count": len(df.columns),
                    "encoding": encoding
                }
            }
        except Exception as e:
            return {
                "success": False,
                "error": str(e),
                "markdown": f"> **系统提示**：CSV 文件解析失败: {str(e)}"
            }
    
    def _process_ppt(self, file_path: str) -> Dict[str, Any]:
        """处理 PPT"""
        from pptx import Presentation
        
        try:
            filename = Path(file_path).name
            prs = Presentation(file_path)
            
            md_parts = []
            md_parts.append(f"## 演示文稿: {filename}\n")
            
            for slide_num, slide in enumerate(prs.slides, 1):
                md_parts.append(f"### 幻灯片 {slide_num}")
                
                # 获取标题
                if slide.shapes.title:
                    md_parts.append(f"**{slide.shapes.title.text}**\n")
                
                # 获取所有文本
                for shape in slide.shapes:
                    if shape.has_text_frame:
                        for para in shape.text_frame.paragraphs:
                            text = para.text.strip()
                            if text:
                                md_parts.append(f"- {text}")
                
                md_parts.append("")
            
            return {
                "success": True,
                "markdown": "\n".join(md_parts),
                "metadata": {
                    "slide_count": len(prs.slides)
                }
            }
        except Exception as e:
            return {
                "success": False,
                "error": str(e),
                "markdown": f"> **系统提示**：PPT 文档解析失败: {str(e)}"
            }
    
    def _process_text(self, file_path: str) -> Dict[str, Any]:
        """处理纯文本"""
        try:
            filename = Path(file_path).name
            
            # 自动检测编码
            with open(file_path, 'rb') as f:
                raw = f.read()
                detected = chardet.detect(raw)
                encoding = detected.get('encoding', 'utf-8')
            
            with open(file_path, 'r', encoding=encoding) as f:
                content = f.read()
            
            # 如果是 .md 文件，直接返回
            if file_path.endswith('.md') or file_path.endswith('.markdown'):
                markdown = content
            else:
                # 纯文本添加文件名上下文
                markdown = f"## 文档: {filename}\n\n{content}"
            
            return {
                "success": True,
                "markdown": markdown,
                "metadata": {
                    "char_count": len(content),
                    "encoding": encoding
                }
            }
        except Exception as e:
            return {
                "success": False,
                "error": str(e),
                "markdown": f"> **系统提示**：文本文件读取失败: {str(e)}"
            }


# 便捷函数
async def convert_to_markdown(file_path: str, file_type: Optional[str] = None) -> Dict[str, Any]:
    """
    将文档转换为 Markdown（便捷函数，异步版本）
    
    Args:
        file_path: 文件路径
        file_type: 可选，指定文件类型（如不指定则自动检测）
    
    Returns:
        处理结果字典，格式：
        {
            "success": True,
            "text": "Markdown 内容",
            "format": "markdown",
            "metadata": { ... }
        }
    """
    processor = DocumentProcessor()
    result = processor.to_markdown(file_path)
    
    # 转换输出格式以匹配 API 预期
    if result.get("success"):
        return {
            "success": True,
            "text": result.get("markdown", ""),
            "format": "markdown",
            "metadata": {
                "original_file_type": result.get("file_type"),
                "char_count": len(result.get("markdown", "")),
                **result.get("metadata", {})
            }
        }
    else:
        return {
            "success": False,
            "error": result.get("error", "处理失败"),
            "metadata": result.get("metadata", {})
        }