"""Locust load-test skeleton for neuronetz-gateway.

Phase 1 provides a *runnable structure* only; Phase 3/5 fill in the real
scenarios that validate SPEC §9 / §12 (100 concurrent users for 5 minutes,
p99 gateway overhead < 25 ms, correct 429 behavior at the limit).

Run (once the gateway is up)::

    NEURONETZ_API_KEY=nz_... \\
        locust -f tests/load/locustfile.py \\
        --host http://localhost:8080

Configuration via environment variables:

* ``NEURONETZ_API_KEY`` - Bearer token to send (placeholder by default).
* ``NEURONETZ_MODEL``   - model name to request (default ``llama3.1:8b``).
"""

from __future__ import annotations

import os

from locust import HttpUser, between, task

API_KEY = os.environ.get("NEURONETZ_API_KEY", "nz_PLACEHOLDER0000replace_me_with_real_key")
MODEL = os.environ.get("NEURONETZ_MODEL", "llama3.1:8b")


# locust resolves to Any under mypy --strict via the pyproject override
# (``ignore_missing_imports = true`` for ``locust.*``), so no per-line ignores
# are needed for the inheritance or decorators here.
class GatewayUser(HttpUser):
    """Simulates a client hitting the OpenAI-compatible chat endpoint."""

    # Realistic think time between requests; tune in Phase 3.
    wait_time = between(1, 3)

    @property
    def _auth_headers(self) -> dict[str, str]:
        return {
            "Authorization": f"Bearer {API_KEY}",
            "Content-Type": "application/json",
        }

    @task(3)
    def chat_completion_non_streaming(self) -> None:
        """Baseline non-streaming chat completion."""
        payload = {
            "model": MODEL,
            "messages": [{"role": "user", "content": "ping"}],
            "stream": False,
        }
        with self.client.post(
            "/v1/chat/completions",
            json=payload,
            headers=self._auth_headers,
            name="/v1/chat/completions",
            catch_response=True,
        ) as resp:
            # Phase 3: assert latency budget + token-accounting headers here.
            if resp.status_code >= 500:
                resp.failure(f"server error: {resp.status_code}")
            else:
                resp.success()

    @task(1)
    def chat_completion_streaming(self) -> None:
        """Streaming chat completion (SSE). Scenario filled in Phase 3."""
        payload = {
            "model": MODEL,
            "messages": [{"role": "user", "content": "stream please"}],
            "stream": True,
        }
        with self.client.post(
            "/v1/chat/completions",
            json=payload,
            headers=self._auth_headers,
            name="/v1/chat/completions [stream]",
            catch_response=True,
        ) as resp:
            if resp.status_code >= 500:
                resp.failure(f"server error: {resp.status_code}")
            else:
                resp.success()