"""Invoice PDF generation service."""
import asyncio
import hashlib
from datetime import date
from decimal import Decimal
from io import BytesIO
from typing import TYPE_CHECKING
from app.core.utils.currency import format_currency as _fmt_currency
if TYPE_CHECKING:
from app.core.auth.models import Clinic
from .models import Invoice
_LOCALE_BY_LANG = {"es": "es_ES", "en": "en_US"}
class InvoicePDFService:
"""Service for generating invoice PDFs.
Generates professional HTML-based PDFs with clinic branding.
"""
@staticmethod
def _format_address(address: dict | None) -> str:
"""Format address dict as a readable string."""
if not address:
return ""
parts = []
if address.get("street"):
parts.append(address["street"])
city_line = " ".join(filter(None, [address.get("postal_code"), address.get("city")]))
if city_line:
parts.append(city_line)
if address.get("country"):
parts.append(address["country"])
return ", ".join(parts)
@staticmethod
async def generate_pdf(
invoice: Invoice,
clinic: "Clinic",
is_preview: bool = False,
locale: str = "es",
extra_pdf_data: dict | None = None,
total_paid: Decimal | None = None,
balance_due: Decimal | None = None,
) -> bytes:
"""Generate PDF for an invoice.
Args:
invoice: The invoice to generate PDF for
clinic: The clinic for branding
is_preview: If True, adds DRAFT watermark for draft invoices
locale: Language for labels (es/en)
extra_pdf_data: Optional dict produced by a country
``BillingComplianceHook.enhance_pdf_data``. Recognised
keys: ``compliance_qr_png_b64`` (base64 PNG) renders the
QR top-right; ``compliance_qr_label`` (default
``"VERI*FACTU"``); ``legal_notices`` (list[str]) appends
to the legal-notices block.
Returns:
PDF content as bytes
"""
# Generate HTML content. ``total_paid`` / ``balance_due`` are
# computed by callers (billing service) since they are no longer
# stored on Invoice.
html_content = InvoicePDFService._generate_html(
invoice,
clinic,
is_preview,
locale,
extra_pdf_data or {},
total_paid=total_paid or Decimal("0"),
balance_due=balance_due if balance_due is not None else invoice.total,
)
# WeasyPrint is CPU-bound; offload to a thread so the event
# loop keeps serving other requests while it renders.
return await asyncio.to_thread(InvoicePDFService._html_to_pdf, html_content)
@staticmethod
def generate_pdf_hash(pdf_bytes: bytes) -> str:
"""Generate SHA-256 hash of PDF content for signature verification."""
return hashlib.sha256(pdf_bytes).hexdigest()
@staticmethod
def _generate_html(
invoice: Invoice,
clinic: "Clinic",
is_preview: bool,
locale: str,
extra_pdf_data: dict | None = None,
total_paid: Decimal = Decimal("0"),
balance_due: Decimal | None = None,
) -> str:
"""Generate HTML content for the invoice."""
extra = extra_pdf_data or {}
# Localized labels
labels = InvoicePDFService._get_labels(locale)
# Determine if this is a credit note
is_credit_note = invoice.credit_note_for_id is not None
# Format currency from clinic.currency, locale derived from language.
money_locale = _LOCALE_BY_LANG.get(locale, "es_ES")
def format_currency(amount: Decimal) -> str:
return _fmt_currency(amount, clinic.currency, locale=money_locale)
# Build items table rows
items_html = ""
for i, item in enumerate(invoice.items, 1):
tooth_info = ""
if item.tooth_number:
tooth_info = f"#{item.tooth_number}"
if item.surfaces:
tooth_info += f" ({', '.join(item.surfaces)})"
items_html += f"""
| {i} |
{item.description}
{f'
{item.internal_code}' if item.internal_code else ""}
{f'
{tooth_info}' if tooth_info else ""}
|
{item.quantity} |
{format_currency(item.unit_price)} |
{f'{format_currency(item.line_discount)} | ' if item.line_discount else '- | '}
{item.vat_rate}% |
{format_currency(item.line_total)} |
"""
# Status badge
status_label = labels["status"].get(invoice.status, invoice.status)
# Watermark for preview or draft
watermark_style = ""
watermark_html = ""
if is_preview or invoice.status == "draft":
watermark_style = """
.watermark {
position: fixed;
top: 50%;
left: 50%;
transform: translate(-50%, -50%) rotate(-45deg);
font-size: 120px;
color: rgba(200, 200, 200, 0.3);
z-index: 1000;
pointer-events: none;
}
"""
watermark_html = f'{labels["draft"]}
'
# Patient info
patient_name = ""
if invoice.patient:
patient_name = f"{invoice.patient.first_name} {invoice.patient.last_name}"
# Format dates
issue_date = invoice.issue_date.strftime("%d/%m/%Y") if invoice.issue_date else "-"
due_date = invoice.due_date.strftime("%d/%m/%Y") if invoice.due_date else "-"
# Document title
doc_title = labels["credit_note"] if is_credit_note else labels["invoice"]
doc_number = invoice.invoice_number or labels["draft"]
# Credit note reference
credit_note_ref_html = ""
if is_credit_note and invoice.credit_note_for:
ref_number = invoice.credit_note_for.invoice_number or "-"
credit_note_ref_html = f"""
{labels["credit_note_for"]}: {ref_number}
"""
# Compliance QR (e.g. AEAT VERI*FACTU). Country-agnostic block:
# the country compliance hook supplies the base64 PNG via
# ``extra_pdf_data['compliance_qr_png_b64']``. Sized 32 mm and
# placed top-right per AEAT geometry; we render it as a sibling
# of ``.invoice-info`` so it does not push the layout.
qr_b64 = extra.get("compliance_qr_png_b64") or extra.get("verifactu_qr_png_b64")
qr_label = extra.get("compliance_qr_label") or "VERI*FACTU"
qr_block_html = ""
if qr_b64:
qr_block_html = f"""
{qr_label}
"""
# Legal notices appended by compliance hooks (e.g. "Factura
# verificable en VERI*FACTU"). Rendered after the notes section.
legal_notices = extra.get("legal_notices") or []
legal_notices_html = ""
if legal_notices:
items_li = "".join(f"{notice}" for notice in legal_notices)
legal_notices_html = f"""
"""
# Build HTML
html = f"""
{doc_title} {doc_number}
{watermark_html}
{qr_block_html}
{labels["billing_info"]}
{labels["billing_name"]}
{invoice.billing_name}
{
f'
{labels["tax_id"]}
{invoice.billing_tax_id}
'
if invoice.billing_tax_id
else ""
}
{labels["address"]}
{
InvoicePDFService._format_address(invoice.billing_address)
}
{
f'''
{labels["patient"]}
{patient_name}
'''
if patient_name and patient_name != invoice.billing_name
else ""
}
{labels["items"]}
| # |
{labels["description"]} |
{labels["qty"]} |
{labels["unit_price"]} |
{labels["discount"]} |
{labels["vat"]} |
{labels["total"]} |
{items_html}
| {labels["subtotal"]}: |
{format_currency(invoice.subtotal)} |
{
f'''
| {labels["total_discount"]}: |
-{format_currency(invoice.total_discount)} |
'''
if invoice.total_discount
else ""
}
| {labels["tax"]}: |
{format_currency(invoice.total_tax)} |
| {labels["grand_total"]}: |
{format_currency(invoice.total)} |
{
f'''
| {labels["total_paid"]}: |
{format_currency(total_paid)} |
'''
if total_paid > 0
else ""
}
{
f'''
| {labels["balance_due"]}: |
{format_currency(balance_due if balance_due is not None else invoice.total)} |
'''
if (balance_due if balance_due is not None else invoice.total) > 0
else ""
}
{
f'''
{labels["notes"]}
{invoice.public_notes}
'''
if invoice.public_notes
else ""
}
{labels["payment_terms"]}: {invoice.payment_term_days} {
labels["days"]
}
{legal_notices_html}
"""
return html
@staticmethod
def _html_to_pdf(html_content: str) -> bytes:
"""Convert HTML to PDF.
Uses WeasyPrint if available, otherwise returns HTML as fallback.
"""
try:
from weasyprint import HTML
pdf_buffer = BytesIO()
HTML(string=html_content).write_pdf(pdf_buffer)
return pdf_buffer.getvalue()
except ImportError:
# WeasyPrint not installed, return HTML content
# In production, WeasyPrint should be installed
return html_content.encode("utf-8")
@staticmethod
def _get_labels(locale: str) -> dict:
"""Get localized labels for PDF."""
labels_es = {
"invoice": "Factura",
"credit_note": "Factura Rectificativa",
"credit_note_for": "Rectifica a",
"draft": "BORRADOR",
"issue_date": "Fecha emisión",
"due_date": "Fecha vencimiento",
"billing_info": "Datos de Facturación",
"billing_name": "Nombre/Razón social",
"tax_id": "NIF/CIF",
"address": "Dirección",
"patient": "Paciente",
"items": "Conceptos",
"description": "Descripción",
"qty": "Cant.",
"unit_price": "Precio Unit.",
"discount": "Descuento",
"vat": "IVA",
"total": "Total",
"subtotal": "Subtotal",
"total_discount": "Descuento total",
"tax": "IVA",
"grand_total": "TOTAL",
"total_paid": "Total pagado",
"balance_due": "Pendiente",
"notes": "Observaciones",
"payment_terms": "Plazo de pago",
"days": "días",
"generated_by": "Generado por",
"status": {
"draft": "Borrador",
"issued": "Emitida",
"partial": "Pago Parcial",
"paid": "Pagada",
"cancelled": "Cancelada",
"voided": "Anulada",
},
}
labels_en = {
"invoice": "Invoice",
"credit_note": "Credit Note",
"credit_note_for": "Corrects",
"draft": "DRAFT",
"issue_date": "Issue date",
"due_date": "Due date",
"billing_info": "Billing Information",
"billing_name": "Name/Company",
"tax_id": "Tax ID",
"address": "Address",
"patient": "Patient",
"items": "Items",
"description": "Description",
"qty": "Qty",
"unit_price": "Unit Price",
"discount": "Discount",
"vat": "VAT",
"total": "Total",
"subtotal": "Subtotal",
"total_discount": "Total discount",
"tax": "VAT",
"grand_total": "TOTAL",
"total_paid": "Total paid",
"balance_due": "Balance due",
"notes": "Notes",
"payment_terms": "Payment terms",
"days": "days",
"generated_by": "Generated by",
"status": {
"draft": "Draft",
"issued": "Issued",
"partial": "Partial",
"paid": "Paid",
"cancelled": "Cancelled",
"voided": "Voided",
},
}
return labels_es if locale == "es" else labels_en