import os
import re
import json
from typing import Optional, List
from sqlalchemy.orm import Session
from fastapi import HTTPException, status

from app.models.metadata import UnstructuredFile
from app.core.events import minio_client
from app.core.config import settings


def extract_text_from_file(file_path: str, file_type: str) -> str:
    text = ""
    ft = file_type.lower()
    if ft in ("word", "docx"):
        try:
            from docx import Document
            doc = Document(file_path)
            text = "\n".join([p.text for p in doc.paragraphs if p.text])
        except Exception as e:
            raise ValueError(f"解析Word失败: {e}")
    elif ft in ("excel", "xlsx", "xls"):
        try:
            from openpyxl import load_workbook
            wb = load_workbook(file_path, data_only=True)
            parts = []
            for sheet in wb.worksheets:
                for row in sheet.iter_rows(values_only=True):
                    parts.append(" ".join([str(c) for c in row if c is not None]))
            text = "\n".join(parts)
        except Exception as e:
            raise ValueError(f"解析Excel失败: {e}")
    elif ft == "pdf":
        try:
            import pdfplumber
            with pdfplumber.open(file_path) as pdf:
                text = "\n".join([page.extract_text() or "" for page in pdf.pages])
        except Exception as e:
            raise ValueError(f"解析PDF失败: {e}")
    elif ft == "txt":
        with open(file_path, "r", encoding="utf-8", errors="ignore") as f:
            text = f.read()
    else:
        raise ValueError(f"不支持的文件类型: {ft}")
    return text


def scan_text_for_sensitive(text: str) -> List[dict]:
    """Scan extracted text for sensitive patterns using built-in rules."""
    matches = []
    # ID card
    id_pattern = re.compile(r"(?<!\d)\d{17}[\dXx](?!\d)")
    for m in id_pattern.finditer(text):
        snippet = text[max(0, m.start()-10):min(len(text), m.end()+10)]
        matches.append({"rule_name": "身份证号", "category_code": "CUST_PERSONAL", "level_code": "L4", "snippet": snippet, "position": m.start()})
    # Phone
    phone_pattern = re.compile(r"(?<!\d)1[3-9]\d{9}(?!\d)")
    for m in phone_pattern.finditer(text):
        snippet = text[max(0, m.start()-10):min(len(text), m.end()+10)]
        matches.append({"rule_name": "手机号", "category_code": "CUST_PERSONAL", "level_code": "L4", "snippet": snippet, "position": m.start()})
    # Bank card (simple 16-19 digits)
    bank_pattern = re.compile(r"(?<!\d)\d{16,19}(?!\d)")
    for m in bank_pattern.finditer(text):
        snippet = text[max(0, m.start()-10):min(len(text), m.end()+10)]
        matches.append({"rule_name": "银行卡号", "category_code": "FIN_PAYMENT", "level_code": "L4", "snippet": snippet, "position": m.start()})
    # Amount
    amount_pattern = re.compile(r"(?<!\d)\d{1,3}(,\d{3})*\.\d{2}(?!\d)")
    for m in amount_pattern.finditer(text):
        snippet = text[max(0, m.start()-10):min(len(text), m.end()+10)]
        matches.append({"rule_name": "金额", "category_code": "FIN_PAYMENT", "level_code": "L3", "snippet": snippet, "position": m.start()})
    return matches


def process_unstructured_file(db: Session, file_id: int) -> dict:
    file_obj = db.query(UnstructuredFile).filter(UnstructuredFile.id == file_id).first()
    if not file_obj:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="文件不存在")
    if not file_obj.storage_path:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="文件未上传")

    # Download from MinIO to temp
    tmp_path = f"/tmp/unstructured_{file_id}_{file_obj.original_name}"
    try:
        minio_client.fget_object(settings.MINIO_BUCKET_NAME, file_obj.storage_path, tmp_path)
        text = extract_text_from_file(tmp_path, file_obj.file_type or "")
        file_obj.extracted_text = text[:50000]  # limit storage
        matches = scan_text_for_sensitive(text)
        file_obj.analysis_result = {"matches": matches, "total_chars": len(text)}
        file_obj.status = "processed"
        db.commit()
        return {"success": True, "matches": matches, "total_chars": len(text)}
    except Exception as e:
        file_obj.status = "error"
        db.commit()
        raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=str(e))
    finally:
        if os.path.exists(tmp_path):
            os.remove(tmp_path)