"""模板相关业务逻辑"""
from datetime import datetime
from pathlib import Path
from uuid import uuid4

from fastapi import UploadFile
from sqlalchemy.orm import Session
from ..models.template import Template
from .storage import upload_file


ALLOWED_EXTENSIONS = {".docx"}
MAX_FILE_SIZE = 50 * 1024 * 1024  # 50MB
TEMPLATE_BUCKET = "templates"


def validate_file(file: UploadFile):
    """校验文件格式和大小"""
    if not file.filename:
        raise ValueError("文件名不能为空")

    ext = "." + file.filename.rsplit(".", 1)[-1].lower() if "." in file.filename else ""
    if ext not in ALLOWED_EXTENSIONS:
        raise ValueError(f"不支持的文件格式: {ext}，仅支持 .docx")
    # 读取文件头校验大小
    content = file.file.read()
    file.file.seek(0)
    if len(content) > MAX_FILE_SIZE:
        raise ValueError(f"文件大小超过限制 (50MB)")
    return content


def build_template_file_path(filename: str) -> str:
    """生成模板文件存储路径。"""
    suffix = Path(filename).suffix.lower()
    today = datetime.now().strftime("%Y%m%d")
    return f"{today}/{uuid4().hex}{suffix}"


def store_template_file(file: UploadFile) -> tuple[str, bytes]:
    """校验并保存上传的模板文件，返回存储路径和文件内容。"""
    content = validate_file(file)
    file_path = build_template_file_path(file.filename or "template.docx")
    stored_path = upload_file(TEMPLATE_BUCKET, file_path, content)
    return stored_path, content


def create_template_record(db: Session, name: str, file_path: str, type: str = "report") -> Template:
    """创建模板记录"""
    tmpl = Template(name=name, type=type, original_file_path=file_path)
    db.add(tmpl)
    db.commit()
    db.refresh(tmpl)
    return tmpl