main.py

from fastapi import FastAPI
import markdown
from fastapi import Response
from pydantic import BaseModel
from spellchecker import SpellChecker

app = FastAPI()


@app.get("/")
def hello():
    return {"message": "Hello, World!"}


@app.get("/about")
def about():
    return {"name": "Markdown Notes API", "version": "0.1"}

from fastapi import UploadFile, File, HTTPException
from pathlib import Path

# 笔记存放的目录
NOTES_DIR = Path("notes")
NOTES_DIR.mkdir(exist_ok=True)  # 程序启动时确保目录存在
spell = SpellChecker()  # 初始化拼写检查器


@app.post("/notes")
async def upload_note(file: UploadFile = File(...)):
    """上传一个 markdown 文件并保存。"""
    
    # TODO 1: 校验文件名以 .md 结尾
    # 如果不是 .md, 抛出 HTTPException(status_code=400, detail="...")
    # 提示: file.filename 是上传文件的原始名字
    if not file.filename.endswith(".md"):
        raise HTTPException(status_code=400, detail="Only .md files are allowed")
    
    # TODO 2: 读取上传文件的内容
    # 提示: content = await file.read()  ← 注意 await, 后面会解释
    # 读出来的 content 是 bytes (字节), 不是 str
    content = await file.read()

    # TODO 3: 把内容写到 NOTES_DIR / file.filename
    # 提示: 用 Path 对象的 write_bytes 方法
    save_path = NOTES_DIR / file.filename
    save_path.write_bytes(content)

    
    # TODO 4: 返回一个表示成功的 JSON
    # 例如: {"filename": "xxx.md", "size": 1234, "message": "Uploaded"}
    return {"filename": file.filename, "size": len(content), "message": "Uploaded"}

@app.get("/notes")
async def list_notes():
    """列出所有已保存的笔记。"""
    
    # TODO 1: 遍历 NOTES_DIR 下所有 .md 文件
    # 提示: NOTES_DIR.glob("*.md") 返回一个生成器, 每个元素是 Path 对象
    # 比如: for p in NOTES_DIR.glob("*.md"): print(p.name, p.stat().st_size)

    # TODO 2: 构造每个笔记的信息字典 {"filename": ..., "size": ...}
    # 用列表推导式一行搞定
    notes = [{"filename": p.name, "size": p.stat().st_size} for p in NOTES_DIR.glob("*.md")]
    
    # TODO 3: 返回 {"count": ..., "notes": [...]}
    return {"count": len(notes), "notes": notes}

@app.get("/notes/{filename}/html")
async def render_note_html(filename: str):
    """读取指定笔记, 转成 HTML 返回。"""
    
    # TODO 1: 校验 filename, 防止路径遍历攻击
    # 检查 filename 里不能含 "/", "\\", ".."
    # 如果含, raise HTTPException(400, ...)
    if "/" in filename or "\\" in filename or ".." in filename:
        raise HTTPException(status_code=400, detail="Invalid filename")
    # TODO 2: 拼接完整路径, 并校验它真的在 NOTES_DIR 下
    # file_path = (NOTES_DIR / filename).resolve()
    # 如果 not file_path.is_relative_to(NOTES_DIR.resolve()): 报 400
    file_path = (NOTES_DIR / filename).resolve()
    if not file_path.is_relative_to(NOTES_DIR.resolve()):
        raise HTTPException(status_code=400, detail="Invalid filename") 

    # TODO 3: 检查文件是否存在
    # 不存在 raise HTTPException(404, "Note not found")
    if not file_path.exists():
        raise HTTPException(status_code=404, detail="Note not found")   

    # TODO 4: 读取文件内容 (用 read_text, 指定 encoding="utf-8")
    md_content = file_path.read_text(encoding="utf-8")

    # TODO 5: 转成 HTML
    html = markdown.markdown(md_content)

    # TODO 6: 用 Response 返回, media_type="text/html"
    return Response(content=html, media_type="text/html")

class GrammarCheckRequest(BaseModel):
    text: str


@app.post("/grammar-check")
async def check_grammar(request: GrammarCheckRequest):
    """检查文本拼写, 返回错词和建议。"""
    
    # TODO 1: 把 request.text 拆成词列表
    # 提示: 简单粗暴用 .split() 按空白拆分就行
    words = request.text.split()

    # TODO 2: 用 spell.unknown(words) 找出所有拼错的词
    # 注意返回的是 set, 不是 list
    misspelled = spell.unknown(words)   
    
    # TODO 3: 对每个错词, 构造 {"word": ..., "suggestion": ..., "candidates": ...}
    # 用列表推导式
    # 注意 spell.candidates(word) 返回 set, 需要 list(...) 转一下才能放进 JSON
    # 还要注意 spell.candidates 在某些罕见情况可能返回 None, 加个 if 防御一下
    errors = []
    for word in misspelled:     
        candidates = spell.candidates(word)
        if candidates is None:
            candidates = []
        else:
            candidates = list(candidates)
        suggestion = spell.correction(word)  # 最佳建议
        errors.append({"word": word, "suggestion": suggestion, "candidates": candidates})

    # TODO 4: 返回 {"text": ..., "misspelled_count": ..., "errors": [...]}
    return {"text": request.text, "misspelled_count": len(misspelled), "errors": errors}