import base64
import pytest
from fastapi.testclient import TestClient

from app.main import app

client = TestClient(app)


def test_diagram_json_no_image():
    body = {
        'refrigerant': 'R290',
        'pressure_range': {'min': 0.1, 'max': 10.0},
        'format': 'json',
        'include_isotherms': True,
        'width': 800,
        'height': 600,
        'dpi': 100
    }
    r = client.post('/api/v1/diagrams/ph', json=body)
    assert r.status_code == 200
    j = r.json()
    # image key should not be present for json-only
    assert 'image' not in j
    assert 'data' in j


def test_diagram_png_includes_image():
    body = {
        'refrigerant': 'R290',
        'pressure_range': {'min': 0.1, 'max': 10.0},
        'format': 'png',
        'include_isotherms': True,
        'width': 800,
        'height': 600,
        'dpi': 100
    }
    r = client.post('/api/v1/diagrams/ph', json=body)
    assert r.status_code == 200
    j = r.json()
    assert 'image' in j
    # Validate base64 decodes
    decoded = base64.b64decode(j['image'])
    assert len(decoded) > 10