from fastapi import FastAPI, HTTPException, Form
from fastapi.responses import HTMLResponse
import os, json, uuid
from datetime import datetime

DATA = "/data/inventory.json"
app = FastAPI(redirect_slashes=False)

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

def save(d):
    with open(DATA, "w") as f: json.dump(d, f, indent=2)

@app.get("/api/list")
def list_items():
    items = load()
    return sorted(
        [{"id": k, **v} for k, v in items.items()],
        key=lambda x: (x.get("category", ""), x.get("name", "").lower())
    )

@app.post("/api/add")
def add(name: str = Form(""), category: str = Form(""), quantity: str = Form("1"),
        unit: str = Form(""), location: str = Form(""), expires: str = Form(""),
        notes: str = Form("")):
    items = load()
    fid = uuid.uuid4().hex[:12]
    try: qty = float(quantity or 1)
    except: qty = 1
    items[fid] = {
        "name": name, "category": category, "quantity": qty,
        "unit": unit, "location": location, "expires": expires,
        "notes": notes, "added": datetime.utcnow().isoformat()
    }
    save(items)
    return {"id": fid}

@app.patch("/api/update/{fid}")
def update(fid: str, name: str = Form(None), category: str = Form(None),
           quantity: str = Form(None), unit: str = Form(None),
           location: str = Form(None), expires: str = Form(None),
           notes: str = Form(None)):
    items = load()
    if fid not in items: raise HTTPException(404)
    for k, v in {"name": name, "category": category, "unit": unit,
                 "location": location, "expires": expires, "notes": notes}.items():
        if v is not None: items[fid][k] = v
    if quantity is not None:
        try: items[fid]["quantity"] = float(quantity)
        except: pass
    save(items)
    return {"ok": True}

@app.post("/api/adjust/{fid}")
def adjust(fid: str, delta: str = Form(...)):
    items = load()
    if fid not in items: raise HTTPException(404)
    try:
        cur = float(items[fid].get("quantity", 0))
        items[fid]["quantity"] = max(0, cur + float(delta))
    except:
        raise HTTPException(400, "Invalid delta")
    save(items)
    return {"ok": True, "quantity": items[fid]["quantity"]}

@app.delete("/api/delete/{fid}")
def delete(fid: str):
    items = load()
    if fid not in items: raise HTTPException(404)
    del items[fid]
    save(items)
    return {"ok": True}

@app.get("/", response_class=HTMLResponse)
def root():
    with open("/static/index.html") as f:
        return f.read()