import pytest
import os
import tempfile
from datetime import datetime, timezone

from agent.cost_guard import CostGuard


@pytest.fixture
async def cost_guard():
    fd, db_path = tempfile.mkstemp(suffix=".db")
    os.close(fd)
    guard = CostGuard(db_path=db_path, daily_limit=10.0, per_task_limit=3.0)
    await guard.initialize()
    yield guard
    await guard.close()
    os.unlink(db_path)


@pytest.mark.asyncio
async def test_record_usage(cost_guard):
    """API 사용량을 기록한다."""
    await cost_guard.record_usage(
        task_id="task-1",
        tokens_input=1000,
        tokens_output=500,
    )
    daily = await cost_guard.get_daily_cost()
    assert daily > 0


@pytest.mark.asyncio
async def test_calculate_cost(cost_guard):
    """토큰에서 비용을 계산한다."""
    cost = cost_guard.calculate_cost(tokens_input=1_000_000, tokens_output=1_000_000)
    # input: $3/MTok + output: $15/MTok = $18
    assert cost == pytest.approx(18.0, rel=0.01)


@pytest.mark.asyncio
async def test_check_daily_limit_ok(cost_guard):
    """일일 한도 내에서 True를 반환한다."""
    result = await cost_guard.check_daily_limit()
    assert result is True


@pytest.mark.asyncio
async def test_check_daily_limit_exceeded(cost_guard):
    """일일 한도 초과 시 False를 반환한다."""
    for i in range(5):
        await cost_guard.record_usage(f"task-{i}", tokens_input=1_000_000, tokens_output=200_000)
    result = await cost_guard.check_daily_limit()
    assert result is False


@pytest.mark.asyncio
async def test_check_task_limit_ok(cost_guard):
    """작업당 한도 내에서 True를 반환한다."""
    await cost_guard.record_usage("task-1", tokens_input=100, tokens_output=50)
    result = await cost_guard.check_task_limit("task-1")
    assert result is True


@pytest.mark.asyncio
async def test_check_task_limit_exceeded(cost_guard):
    """작업당 한도 초과 시 False를 반환한다."""
    await cost_guard.record_usage("task-1", tokens_input=1_000_000, tokens_output=100_000)
    result = await cost_guard.check_task_limit("task-1")
    assert result is False


@pytest.mark.asyncio
async def test_get_task_cost(cost_guard):
    """특정 작업의 누적 비용을 반환한다."""
    await cost_guard.record_usage("task-1", tokens_input=1000, tokens_output=500)
    await cost_guard.record_usage("task-1", tokens_input=2000, tokens_output=1000)
    cost = await cost_guard.get_task_cost("task-1")
    assert cost > 0
    other_cost = await cost_guard.get_task_cost("task-2")
    assert other_cost == 0.0


@pytest.mark.asyncio
async def test_get_daily_summary(cost_guard):
    """일일 요약 정보를 반환한다."""
    await cost_guard.record_usage("task-1", tokens_input=1000, tokens_output=500)
    summary = await cost_guard.get_daily_summary()
    assert "total_cost_usd" in summary
    assert "daily_limit_usd" in summary
    assert "remaining_usd" in summary
    assert summary["record_count"] == 1