"""Locust load test for DocuVault — D-04, D-05, D-06.

Strategy: self-bootstrapping (Option A) — on_start registers the load-test
user (409 ignored if already exists), then logs in to get an access token.

Run (headless, matches Phase 6 SLA gate):
    locust --headless --users 50 --spawn-rate 10 --run-time 5m \\
           --host http://localhost:8000 \\
           --csv backend/load_tests/results \\
           -f backend/load_tests/locustfile.py

Prerequisites:
    pip install -r backend/requirements-dev.txt
    docker compose up  # backend, postgres, minio must be running

Exit codes (enforced by check_sla listener):
    0 — all SLA thresholds met
    1 — p95 > 200 ms, OR p99 > 500 ms, OR fail_ratio > 1%

Cleanup the load-test user:
    docker compose exec postgres psql -U docuvault -c \\
        "DELETE FROM users WHERE email='loadtest@example.com';"
"""
import os
from io import BytesIO

from locust import HttpUser, between, events, task

TEST_EMAIL = os.environ.get("LOAD_TEST_EMAIL", "loadtest@example.com")
TEST_PASSWORD = os.environ.get("LOAD_TEST_PASSWORD", "Loadtest123!@#")
TEST_HANDLE = "loadtestuser"

# Minimal synthetic PDF — valid enough for the upload parser
_FAKE_PDF = b"%PDF-1.4\n1 0 obj<</Type/Catalog>>endobj\nxref\n0 2\ntrailer<</Size 2>>\n%%EOF"


class DocuVaultUser(HttpUser):
    """Simulated DocuVault end-user exercising all authenticated endpoints.

    Task weights mirror a realistic read-heavy session per D-05:
      5 — list documents  (most common action)
      3 — get single document
      2 — upload a document
      1 — refresh access token
    """

    wait_time = between(0.5, 2.0)
    access_token: str = ""

    def on_start(self) -> None:
        self.client.post(
            "/api/auth/register",
            json={"handle": TEST_HANDLE, "email": TEST_EMAIL, "password": TEST_PASSWORD},
        )
        resp = self.client.post(
            "/api/auth/login",
            json={"email": TEST_EMAIL, "password": TEST_PASSWORD},
            name="POST /api/auth/login",
        )
        if resp.status_code == 200:
            self.access_token = resp.json().get("access_token", "")
        else:
            self.environment.runner.quit()

    def _auth_headers(self) -> dict:
        return {"Authorization": f"Bearer {self.access_token}"}

    @task(5)
    def list_documents(self) -> None:
        self.client.get("/api/documents/", headers=self._auth_headers(), name="GET /api/documents/")

    @task(3)
    def get_document(self) -> None:
        resp = self.client.get(
            "/api/documents/",
            headers=self._auth_headers(),
            name="GET /api/documents/ (for get_document)",
        )
        if resp.status_code == 200:
            docs = resp.json()
            if docs:
                doc_id = docs[0]["id"]
                self.client.get(
                    f"/api/documents/{doc_id}",
                    headers=self._auth_headers(),
                    name="GET /api/documents/{id}",
                )

    @task(2)
    def upload_document(self) -> None:
        # Direct single-step upload to /api/documents/upload (confirmed against documents.py:
        # accepts UploadFile `file` + Form `target_backend` — simpler than the presigned flow).
        self.client.post(
            "/api/documents/upload",
            headers=self._auth_headers(),
            files={"file": ("load_test.pdf", BytesIO(_FAKE_PDF), "application/pdf")},
            data={"target_backend": "minio"},
            name="POST /api/documents/upload",
        )

    @task(1)
    def refresh_token(self) -> None:
        self.client.post(
            "/api/auth/refresh",
            headers=self._auth_headers(),
            name="POST /api/auth/refresh",
        )


@events.quitting.add_listener
def check_sla(environment, **kwargs) -> None:
    """Gate the Locust exit code on D-06 SLA thresholds."""
    stats = environment.runner.stats.total
    p95 = stats.get_response_time_percentile(0.95)
    p99 = stats.get_response_time_percentile(0.99)
    fail_ratio = stats.fail_ratio

    if fail_ratio > 0.01:
        print(f"SLA FAIL: fail_ratio={fail_ratio:.2%} > 1%")
        environment.process_exit_code = 1
    elif p95 > 200:
        print(f"SLA FAIL: p95={p95:.0f}ms > 200ms")
        environment.process_exit_code = 1
    elif p99 > 500:
        print(f"SLA FAIL: p99={p99:.0f}ms > 500ms")
        environment.process_exit_code = 1
    else:
        print(f"SLA PASS: p95={p95:.0f}ms p99={p99:.0f}ms fail_ratio={fail_ratio:.2%}")