from fastapi import FastAPI, UploadFile, File, HTTPException, Form
from fastapi.responses import JSONResponse, FileResponse
from fastapi.staticfiles import StaticFiles
import os, json, uuid, shutil, re
from datetime import datetime

PDF_DIR = "/files"
META = "/files/.metadata.json"

app = FastAPI()

def load_meta():
    if os.path.exists(META):
        with open(META) as f:
            return json.load(f)
    return {}

def save_meta(m):
    with open(META, "w") as f:
        json.dump(m, f, indent=2)

def safe_name(name):
    return re.sub(r'[^\w\-. ]', '_', name)[:200]

@app.get("/api/list")
def list_pdfs():
    meta = load_meta()
    items = []
    for fid, info in meta.items():
        path = os.path.join(PDF_DIR, info["filename"])
        if os.path.exists(path):
            items.append({
                "id": fid,
                "title": info.get("title", info["filename"]),
                "filename": info["filename"],
                "tag": info.get("tag", ""),
                "size": os.path.getsize(path),
                "uploaded": info.get("uploaded", ""),
            })
    items.sort(key=lambda x: x["uploaded"], reverse=True)
    return items

@app.post("/api/upload")
async def upload(file: UploadFile = File(...), title: str = Form(""), tag: str = Form("")):
    if not file.filename.lower().endswith(".pdf"):
        raise HTTPException(400, "PDFs only")
    fid = uuid.uuid4().hex[:12]
    fname = safe_name(file.filename)
    path = os.path.join(PDF_DIR, f"{fid}_{fname}")
    with open(path, "wb") as f:
        shutil.copyfileobj(file.file, f)
    meta = load_meta()
    meta[fid] = {
        "filename": f"{fid}_{fname}",
        "title": title or fname.rsplit(".", 1)[0],
        "tag": tag,
        "uploaded": datetime.utcnow().isoformat(),
    }
    save_meta(meta)
    return {"id": fid}

@app.delete("/api/delete/{fid}")
def delete(fid: str):
    meta = load_meta()
    if fid not in meta:
        raise HTTPException(404)
    path = os.path.join(PDF_DIR, meta[fid]["filename"])
    if os.path.exists(path):
        os.remove(path)
    del meta[fid]
    save_meta(meta)
    return {"ok": True}

@app.get("/view/{fid}")
def view(fid: str):
    meta = load_meta()
    if fid not in meta:
        raise HTTPException(404)
    path = os.path.join(PDF_DIR, meta[fid]["filename"])
    return FileResponse(path, media_type="application/pdf")

@app.patch("/api/update/{fid}")
async def update(fid: str, tag: str = Form(None), title: str = Form(None)):
    meta = load_meta()
    if fid not in meta:
        raise HTTPException(404)
    if tag is not None:
        meta[fid]["tag"] = tag
    if title is not None and title.strip():
        meta[fid]["title"] = title.strip()
    save_meta(meta)
    return {"ok": True}


app.mount("/", StaticFiles(directory="/static", html=True), name="static")