import os
import logging
from datetime import datetime, timedelta, timezone
from repositories.tenant_repository import tenant_repository

logger = logging.getLogger(__name__)

STRIPE_SECRET_KEY = os.getenv('STRIPE_SECRET_KEY')

TIER_SEATS = {
    'analyse': 5,
    'discover': 8,
    'intelligence': 10,
    'enterprise': 999,  # effectively unlimited
}

TRIAL_PERIODS = {
    'analyse': 14,
    'discover': 21,
    'intelligence': 30,
    'enterprise': 0,
}

ADDITIONAL_SEAT_PRICE = 45  # USD/seat/month — configured as a Stripe add-on price

TIER_PRICE_ENV_VARS = {
    'analyse': 'STRIPE_PRICE_ANALYSE',
    'discover': 'STRIPE_PRICE_DISCOVER',
    'intelligence': 'STRIPE_PRICE_INTELLIGENCE',
    # Enterprise is unlisted — created manually per client, no env var.
}


def _stripe():
    """Lazily imports and configures the stripe SDK — avoids an import-time key requirement."""
    import stripe
    stripe.api_key = STRIPE_SECRET_KEY
    return stripe


def create_portal_session(tenant_id):
    """
    Creates a Stripe customer portal session for self-service billing.

    Data flow:
      tenant_id → PocketBase stripe_customer_id →
      Stripe billing_portal.Session.create → portal URL returned
    """
    tenant = tenant_repository.get_by_id(tenant_id)
    if not tenant or not tenant.get('stripe_customer_id'):
        raise ValueError('Tenant has no Stripe customer on file')

    stripe = _stripe()
    session = stripe.billing_portal.Session.create(
        customer=tenant['stripe_customer_id'],
        return_url='https://app.bettersight.io/account'
    )
    return session.url


def create_upgrade_checkout(tenant_id, target_tier):
    """
    Creates a Stripe checkout session that upgrades a tenant to
    target_tier. Tags the session with tenant_id + target_tier in
    metadata so the webhook handler can distinguish an upgrade
    completion from a brand-new-tenant signup completion.

    Data flow:
      tenant_id + target_tier → STRIPE_PRICE_* env lookup for target_tier →
      Stripe checkout.Session.create (mode=subscription, metadata tagged) →
      checkout URL returned
    """
    price_env_var = TIER_PRICE_ENV_VARS.get(target_tier)
    if not price_env_var or not os.getenv(price_env_var):
        raise ValueError(f'No Stripe price configured for tier: {target_tier}')

    tenant = tenant_repository.get_by_id(tenant_id)
    if not tenant:
        raise ValueError(f'Unknown tenant: {tenant_id}')

    stripe = _stripe()
    session = stripe.checkout.Session.create(
        customer=tenant.get('stripe_customer_id'),
        mode='subscription',
        line_items=[{'price': os.getenv(price_env_var), 'quantity': 1}],
        payment_method_collection='if_required',
        subscription_data={'trial_period_days': TRIAL_PERIODS.get(target_tier, 0)},
        metadata={'tenant_id': tenant_id, 'target_tier': target_tier},
        success_url='https://app.bettersight.io/account?upgrade=success',
        cancel_url='https://app.bettersight.io/account?upgrade=cancelled',
    )
    return session.url


def handle_checkout_completed(event_data):
    """
    Handles checkout.session.completed for both flows:
    - Upgrade flow (metadata.tenant_id present): bumps the existing
      tenant's tier and max_seats.
    - New signup flow (no metadata.tenant_id): out of scope for this
      handler — new-tenant creation from a public checkout flow is not
      part of the Analyse-tier MVP onboarding runbook (CLAUDE.md §32
      onboards the first clients manually); this function only handles
      the upgrade case until self-serve signup is built.

    Data flow:
      Stripe checkout.session.completed event →
      metadata.tenant_id present? →
      yes: tenant tier/max_seats updated, status set to trial/active per
      whether a trial was attached →
      no: logged and ignored (manual onboarding handles new tenants)
    """
    metadata = event_data.get('metadata', {})
    tenant_id = metadata.get('tenant_id')
    target_tier = metadata.get('target_tier')

    if not tenant_id or not target_tier:
        logger.info('checkout.session.completed with no upgrade metadata — ignoring (manual onboarding flow)')
        return

    tenant_repository.update(tenant_id, {
        'tier': target_tier,
        'max_seats': TIER_SEATS.get(target_tier, 5),
        'stripe_subscription_id': event_data.get('subscription'),
        'status': 'trial' if TRIAL_PERIODS.get(target_tier, 0) > 0 else 'active',
        'trial_ends_at': (
            (datetime.now(timezone.utc) + timedelta(days=TRIAL_PERIODS[target_tier])).isoformat()
            if TRIAL_PERIODS.get(target_tier, 0) > 0 else None
        ),
    })


def handle_subscription_updated(event_data, tenant_id):
    """Updates tier/max_seats if the plan changed on an existing subscription."""
    tier = event_data.get('metadata', {}).get('tier')
    updates = {}
    if tier and tier in TIER_SEATS:
        updates['tier'] = tier
        updates['max_seats'] = TIER_SEATS[tier]
    if updates:
        tenant_repository.update(tenant_id, updates)


def handle_subscription_deleted(tenant_id):
    """Marks a tenant inactive on cancellation — seats block at next Apps Script cache expiry (6hrs)."""
    tenant_repository.update(tenant_id, {'status': 'inactive'})