import sys
import types
from services import email_service


def _install_fake_resend(monkeypatch, raise_error=False):
    fake = types.ModuleType('resend')
    fake.api_key = None
    calls = []

    class _Emails:
        @staticmethod
        def send(payload):
            if raise_error:
                raise RuntimeError('resend api down')
            calls.append(payload)

    fake.Emails = _Emails
    monkeypatch.setitem(sys.modules, 'resend', fake)
    return calls


def test_send_welcome_email_renders_and_sends(monkeypatch):
    calls = _install_fake_resend(monkeypatch)

    result = email_service.send_welcome_email(
        'pm@gadventures.com', 'G Adventures', template_url='https://sheets.google.com/template'
    )

    assert result is True
    assert len(calls) == 1
    assert calls[0]['to'] == 'pm@gadventures.com'
    assert 'G Adventures' in calls[0]['html']
    assert 'template' in calls[0]['html']


def test_send_welcome_email_without_template_url(monkeypatch):
    calls = _install_fake_resend(monkeypatch)
    result = email_service.send_welcome_email('pm@gadventures.com', 'G Adventures')
    assert result is True
    assert len(calls) == 1


def test_send_trial_reminder_email(monkeypatch):
    calls = _install_fake_resend(monkeypatch)

    result = email_service.send_trial_reminder_email('pm@gadventures.com', 'G Adventures', 2, '2026-07-14')

    assert result is True
    assert '2' in calls[0]['subject']
    assert '2026-07-14' in calls[0]['html']


def test_send_price_alert_email_computes_previous_price(monkeypatch):
    calls = _install_fake_resend(monkeypatch)

    result = email_service.send_price_alert_email('pm@gadventures.com', {
        'competitor_name': 'Intrepid Travel', 'trip_name': 'Peru Classic',
        'majority_price_usd': 2190, 'change_amount': -300, 'change_percent': -12,
    })

    assert result is True
    assert 'Intrepid Travel' in calls[0]['subject']
    assert '2490' in calls[0]['html']  # previous = 2190 - (-300)
    assert '2190' in calls[0]['html']


def test_send_new_product_email(monkeypatch):
    calls = _install_fake_resend(monkeypatch)

    result = email_service.send_new_product_email('pm@gadventures.com', {
        'competitor_name': 'Flash Pack', 'trip_name': 'Jordan Desert Explorer',
        'destination': 'Jordan', 'duration_days': 8, 'majority_price_usd': 3200,
    })

    assert result is True
    assert 'Flash Pack' in calls[0]['subject']
    assert 'Jordan Desert Explorer' in calls[0]['html']


def test_send_returns_false_and_logs_on_failure(monkeypatch):
    _install_fake_resend(monkeypatch, raise_error=True)
    result = email_service.send_welcome_email('pm@gadventures.com', 'G Adventures')
    assert result is False