import os
import logging
from jinja2 import Environment, FileSystemLoader, select_autoescape
from repositories.brief_repository import brief_repository

logger = logging.getLogger(__name__)

RESEND_API_KEY = os.getenv('RESEND_API_KEY')
TEMPLATES_DIR = os.path.join(os.path.dirname(__file__), '..', 'templates', 'emails')

# Plain Jinja2 (not flask.render_template) so this service has no
# dependency on an active Flask request/app context — it must also run
# from the n8n-triggered Flask route AND, in principle, from an RQ
# worker process. Autoescaping is mandatory: brief content includes
# scraped third-party trip names which must never be interpreted as
# HTML in the rendered email.
_jinja_env = Environment(
    loader=FileSystemLoader(TEMPLATES_DIR),
    autoescape=select_autoescape(['html'])
)


def send_weekly_brief(tenant_id):
    """
    Renders the weekly intelligence brief as branded HTML and sends it
    via Resend to the tenant admin email.

    Data flow:
      tenant_id → brief_repository.get_weekly_data() (price_history,
      new products, battlecard updates for the past 7 days) →
      brief.html Jinja2 template rendered → Resend API →
      digest_logs record created (sent or failed)
    """
    data = brief_repository.get_weekly_data(tenant_id)
    admin_email = data.get('admin_email')
    if not admin_email:
        logger.error(f'No admin_email on file for tenant {tenant_id} — skipping weekly brief')
        return

    template = _jinja_env.get_template('brief.html')
    html = template.render(**data)

    try:
        # Imported lazily so this module is importable without the
        # `resend` package configured in test environments.
        import resend
        resend.api_key = RESEND_API_KEY
        resend.Emails.send({
            'from': 'Bettersight <brief@bettersight.io>',
            'to': admin_email,
            'subject': f"Bettersight Weekly Brief — Week of {data['week_of']}",
            'html': html,
        })
        brief_repository.log_digest(tenant_id, 'weekly', recipient_email=admin_email, status='sent')
    except Exception as e:
        # A failed email send is a side-effect failure — it must not
        # raise into the n8n workflow that triggered this run.
        logger.error(f'Weekly brief send failed for tenant {tenant_id}: {str(e)}')
        brief_repository.log_digest(tenant_id, 'weekly', recipient_email=admin_email, status='failed')