from repositories.tenant_repository import tenant_repository
from repositories.seat_repository import seat_repository

# Both trial and active tenants may use the dashboard and the Apps Script
# export plugin — only 'inactive' (cancelled, or trial expired with no
# card on file) blocks access.
VALID_STATUSES = ['active', 'trial']


def validate_email(email):
    """
    Validates a PM's access to Bettersight via two checks: domain
    registration and seat count.

    Note: CLAUDE.md's earlier §9 draft described a third, sheet_id-binding
    layer, but §15 explicitly removes it for the standalone Apps Script
    model ("validation is email-only... remove the sheet_id binding layer
    — it is redundant and would break the standalone model"). That later,
    more specific instruction is what's implemented here.

    Data flow:
      email →
      domain extraction → tenant lookup by domain (Layer 1) →
      status check (must be trial or active) →
      existing active seat → refresh last_accessed, allow →
      no existing seat → seat count vs tenant.max_seats →
      under limit: register new seat, allow / at limit: reject →
      { valid: bool, tier: str|None, reason: str|None }
    """
    if not email or '@' not in email:
        return {'valid': False, 'reason': 'Invalid email address'}

    domain = email.split('@', 1)[1].lower()

    # Layer 1: domain must belong to a known tenant in good standing
    tenant = tenant_repository.get_by_domain(domain)
    if not tenant:
        return {'valid': False, 'reason': 'Domain not registered'}
    if tenant.get('status') not in VALID_STATUSES:
        return {'valid': False, 'reason': 'Subscription inactive'}

    # Layer 2: existing seat is a fast-path allow with a freshness bump;
    # a new seat must fit within the tenant's purchased seat count
    existing_seat = seat_repository.get_active(tenant['id'], email)
    if existing_seat:
        seat_repository.update_last_accessed(existing_seat['id'])
        return {'valid': True, 'tier': tenant['tier']}

    active_count = seat_repository.count_active(tenant['id'])
    if active_count >= tenant.get('max_seats', 0):
        return {'valid': False, 'reason': 'Seat limit reached'}

    seat_repository.create({
        'tenant_id': tenant['id'],
        'email': email,
        'active': True,
        'added_by': 'self',
    })
    return {'valid': True, 'tier': tenant['tier']}