"""TDD gate: durable LLM usage/cost accounting.

Records per-organization, per-user LLM usage (model, input/output tokens,
estimated cost) so admin/super-admin accounting and quotas are possible. No
prompt content or secrets are stored.
"""

import pytest
from sqlalchemy import create_engine

from app.db import Base, create_session_factory
from app.services.usage_service import UsageService


@pytest.fixture()
def session_factory():
    engine = create_engine("sqlite+pysqlite:///:memory:")
    Base.metadata.create_all(engine)
    factory = create_session_factory(engine)
    try:
        yield factory
    finally:
        engine.dispose()


def test_usage_service_records_event(session_factory):
    session = session_factory()
    try:
        svc = UsageService(session)
        entry_id = svc.record_event(
            organization_id="org-a",
            user_id="user-1",
            operation="report.generate",
            model="gpt-4o",
            input_tokens=100,
            output_tokens=50,
        )
        assert entry_id

        total = svc.total_cost(organization_id="org-a")
        assert total > 0  # deterministic small estimate; no prompt text stored

        rows = svc.list_events(organization_id="org-a", limit=10)
        assert len(rows) == 1
        assert rows[0].model == "gpt-4o"
        assert rows[0].input_tokens == 100
    finally:
        session.close()


def test_usage_service_scopes_by_organization(session_factory):
    session = session_factory()
    try:
        svc = UsageService(session)
        svc.record_event(
            organization_id="org-a", user_id="u1", operation="op", model="m",
            input_tokens=1, output_tokens=1,
        )
        svc.record_event(
            organization_id="org-b", user_id="u2", operation="op", model="m",
            input_tokens=1, output_tokens=1,
        )
        rows_a = svc.list_events(organization_id="org-a", limit=10)
        assert len(rows_a) == 1
        assert rows_a[0].organization_id == "org-a"
    finally:
        session.close()


def test_usage_event_never_stores_prompt_or_secret(session_factory):
    session = session_factory()
    try:
        svc = UsageService(session)
        svc.record_event(
            organization_id="org-a", user_id="u1", operation="report.generate",
            model="m", input_tokens=1, output_tokens=1,
        )
        row = svc.list_events(organization_id="org-a", limit=1)[0]
        blob = repr(row)
        assert "prompt" not in blob.lower()  # no raw prompt content persisted
    finally:
        session.close()


def test_usage_migration_round_trip(tmp_path, monkeypatch):
    from pathlib import Path

    from alembic import command
    from alembic.config import Config as AlembicConfig
    from sqlalchemy import inspect

    from app.db import create_database_engine

    database_url = f"sqlite+pysqlite:///{tmp_path / 'usage-roundtrip.db'}"
    monkeypatch.setenv("DATABASE_URL", database_url)
    alembic_config = AlembicConfig(str(Path(__file__).resolve().parents[1] / "alembic.ini"))
    alembic_config.set_main_option("sqlalchemy.url", database_url)

    command.upgrade(alembic_config, "head")
    engine = create_database_engine(database_url)
    try:
        inspector = inspect(engine)
        assert "usage_events" in set(inspector.get_table_names())
        cols = {c["name"] for c in inspector.get_columns("usage_events")}
        assert {
            "organization_id", "user_id", "operation", "model",
            "input_tokens", "output_tokens", "estimated_cost",
        }.issubset(cols)
    finally:
        engine.dispose()

    command.downgrade(alembic_config, "0009_rate_limit")
    engine = create_database_engine(database_url)
    try:
        assert "usage_events" not in set(inspect(engine).get_table_names())
    finally:
        engine.dispose()

    command.upgrade(alembic_config, "head")
    command.check(alembic_config)