import os
import json
import shutil
import uuid
from fastapi import UploadFile, HTTPException
from config.settings import PDF_SAVE_DIR, JSON_CACHE_DIR
from parser.base_parser import get_file_hash
from parser.ventilation_plan_parser import VentilationPlanParser


def parse_pdf(file: UploadFile) -> dict:
    file_path = f"{PDF_SAVE_DIR}/{uuid.uuid4()}.pdf"
    with open(file_path, "wb") as f:
        f.write(file.file.read())
    hash_id = get_file_hash(file_path)
    new_pdf_path = rename_pdf_by_hash(file_path,hash_id)
    cache_path = f"{JSON_CACHE_DIR}/{hash_id}.json"
    if os.path.exists(cache_path):
        with open(cache_path, "r", encoding="utf-8") as f:
            return json.load(f)
    data = VentilationPlanParser().parse(new_pdf_path)
    with open(cache_path, "w", encoding="utf-8") as f:
        json.dump(data, f, ensure_ascii=False, indent=2)
    return data


def rename_pdf_by_hash(original_pdf_path: str, hash_id: str) -> str:
    """
    根据hash_id重命名PDF文件
    :param original_pdf_path: 原PDF文件路径
    :param hash_id: 生成的唯一hash标识
    :return: 新文件完整路径
    """
    # 拼接新文件名：目录 + hash_id.pdf
    new_file_name = f"{hash_id}.pdf"
    new_pdf_path = os.path.join(PDF_SAVE_DIR, new_file_name)

    # 执行重命名
    shutil.move(original_pdf_path, new_pdf_path)
    return new_pdf_path

def get_latest_file(dir_path: str, suffix: str) -> str:
    """
    获取目录下修改时间最新的指定后缀文件
    :param dir_path: 目标文件夹路径
    :param suffix: 文件后缀，例: .json、.pdf、.txt
    :return: 最新文件完整路径
    """
    # 校验目录是否存在
    if not os.path.isdir(dir_path):
        raise HTTPException(status_code=404, detail="文件夹不存在")

    # 筛选对应后缀文件
    file_list = []
    for file in os.listdir(dir_path):
        file_full_path = os.path.join(dir_path, file)
        if os.path.isfile(file_full_path) and file.lower().endswith(suffix.lower()):
            mtime = os.path.getmtime(file_full_path)
            file_list.append((mtime, file_full_path))

    if not file_list:
        raise HTTPException(status_code=404, detail=f"目录下未找到 {suffix} 格式文件")

    # 按修改时间倒序，取最新文件
    file_list.sort(reverse=True, key=lambda x: x[0])
    return file_list[0][1]