first commit

modules/account_invoice_watermark/account.py

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+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+from io import BytesIO
+
+from pypdf import PdfReader, PdfWriter
+
+from trytond.pool import Pool, PoolMeta
+from trytond.report import Report
+from trytond.transaction import Transaction
+
+
+class Invoice(metaclass=PoolMeta):
+    __name__ = 'account.invoice'
+
+    @classmethod
+    def _execute(cls, records, header, data, action):
+        pool = Pool()
+        Watermark = pool.get('account.invoice.watermark', type='report')
+        format_, data = super()._execute(records, header, data, action)
+        if format_ == 'pdf':
+            invoice, = records
+            report_id = cls.get_report_id(invoice)
+            if report_id is not None:
+                if invoice.party.lang:
+                    language = invoice.party.lang.code
+                else:
+                    language = Transaction().language
+                with Transaction().set_context(language=language):
+                    _, watermark, _, _ = Watermark.execute([invoice.id], {
+                            'action_id': report_id,
+                            })
+                data = cls.merge(data, watermark)
+        return format_, data
+
+    @classmethod
+    def get_report_id(cls, invoice):
+        pool = Pool()
+        ModelData = pool.get('ir.model.data')
+        if invoice.state == 'paid':
+            return ModelData.get_id(
+                'account_invoice_watermark', 'report_invoice_watermark_paid')
+        elif invoice.state == 'draft':
+            return ModelData.get_id(
+                'account_invoice_watermark', 'report_invoice_watermark_draft')
+
+    @classmethod
+    def merge(cls, invoice, watermark):
+        output = PdfWriter()
+        invoice = PdfReader(BytesIO(invoice))
+        watermark = PdfReader(BytesIO(watermark))
+        watermark = watermark.pages[0]
+        for i in range(len(invoice.pages)):
+            page = invoice.pages[i]
+            page.merge_page(watermark)
+            output.add_page(page)
+        data = BytesIO()
+        output.write(data)
+        return data.getvalue()
+
+
+class InvoiceWatermark(Report):
+    __name__ = 'account.invoice.watermark'