from __future__ import annotations

from threading import Lock
from typing import Optional

from fastapi import FastAPI, HTTPException
from prometheus_fastapi_instrumentator import Instrumentator
from pydantic import BaseModel

app = FastAPI(
    title="test-alex-gitops-1",
    description="test-alex-gitops-1",
    version="0.1.0",
)

# Expose /metrics for Prometheus scraping
Instrumentator().instrument(app).expose(app)


# ---------------------------------------------------------------------------
# Domain model
# ---------------------------------------------------------------------------
class ItemRequest(BaseModel):
    name: str
    description: str = ""


class Item(BaseModel):
    id: int
    name: str
    description: str


# ---------------------------------------------------------------------------
# In-memory store (thread-safe)
# ---------------------------------------------------------------------------
_store: dict[int, Item] = {}
_counter = 0
_lock = Lock()


def _next_id() -> int:
    global _counter
    with _lock:
        _counter += 1
        return _counter


# ---------------------------------------------------------------------------
# Routes
# ---------------------------------------------------------------------------
@app.get("/health", tags=["observability"])
def health() -> dict:
    return {"status": "UP"}


@app.get("/api/items", response_model=list[Item], tags=["items"])
def list_items():
    return list(_store.values())


@app.post("/api/items", response_model=Item, status_code=201, tags=["items"])
def create_item(body: ItemRequest):
    item = Item(id=_next_id(), name=body.name, description=body.description)
    _store[item.id] = item
    return item


@app.get("/api/items/{item_id}", response_model=Item, tags=["items"])
def get_item(item_id: int):
    item = _store.get(item_id)
    if item is None:
        raise HTTPException(status_code=404, detail="Item not found")
    return item


@app.put("/api/items/{item_id}", response_model=Item, tags=["items"])
def update_item(item_id: int, body: ItemRequest):
    item = _store.get(item_id)
    if item is None:
        raise HTTPException(status_code=404, detail="Item not found")
    updated = Item(id=item_id, name=body.name, description=body.description)
    _store[item_id] = updated
    return updated


@app.delete("/api/items/{item_id}", tags=["items"])
def delete_item(item_id: int):
    _store.pop(item_id, None)
    return {"deleted": item_id}