import base64
import io
from unittest.mock import patch

from PIL import Image, ImageDraw

from odoo.exceptions import UserError
from odoo.tests import tagged
from odoo.tests.common import TransactionCase


@tagged('post_install', '-at_install')
class TestInvoiceOcrFlow(TransactionCase):

    def setUp(self):
        super().setUp()
        self.partner = self.env['res.partner'].create({
            'name': 'Test Vendor',
            'supplier_rank': 1,
        })
        self.move = self.env['account.move'].create({
            'move_type': 'in_invoice',
            'partner_id': self.partner.id,
        })

    def test_ocr_state_default(self):
        self.assertEqual(self.move.ocr_state, 'not_requested')

    def test_action_request_ocr_no_attachment_raises(self):
        with self.assertRaises(UserError):
            self.move.action_request_ocr()

    def test_action_request_ocr_with_image(self):
        img = Image.new('RGB', (800, 120), color='white')
        draw = ImageDraw.Draw(img)
        try:
            from PIL import ImageFont
            font = ImageFont.truetype(
                '/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf', 36,
            )
        except Exception:
            font = None
        draw.text((20, 30), "TOTAL $50.00 INV-9999", fill='black', font=font)
        buf = io.BytesIO()
        img.save(buf, format='PNG')

        self.env['ir.attachment'].create({
            'name': 'test_invoice.png',
            'datas': base64.b64encode(buf.getvalue()),
            'res_model': 'account.move',
            'res_id': self.move.id,
            'mimetype': 'image/png',
        })

        # Mock the LLM call to avoid a real API roundtrip.
        with patch(
            'odoo.addons.fusion_accounting_ocr.models.account_move.parse_invoice_fields',
            return_value={
                'vendor_name': None,
                'invoice_number': 'INV-9999',
                'invoice_date': None,
                'due_date': None,
                'currency': None,
                'subtotal': None,
                'tax_total': None,
                'total': 50.0,
                'line_items': [],
            },
        ):
            self.move.action_request_ocr()

        self.assertEqual(self.move.ocr_state, 'done')
        self.assertEqual(self.move.ocr_backend, 'tesseract')
        self.assertGreater(self.move.ocr_confidence, 0)
        self.assertIsNotNone(self.move.ocr_extracted_data)
        # Parsed invoice_number should land on the invoice's ref field.
        self.assertEqual(self.move.ref, 'INV-9999')
        # OCR log row was created.
        self.assertEqual(len(self.move.ocr_log_ids), 1)
        log = self.move.ocr_log_ids
        self.assertEqual(log.backend, 'tesseract')
        self.assertGreater(log.raw_text_length, 0)

    def test_apply_does_not_overwrite_user_entered_ref(self):
        self.move.ref = 'USER-SET-REF'
        img = Image.new('RGB', (400, 80), color='white')
        ImageDraw.Draw(img).text((10, 30), "INV-7777", fill='black')
        buf = io.BytesIO()
        img.save(buf, format='PNG')
        self.env['ir.attachment'].create({
            'name': 't.png',
            'datas': base64.b64encode(buf.getvalue()),
            'res_model': 'account.move',
            'res_id': self.move.id,
            'mimetype': 'image/png',
        })
        with patch(
            'odoo.addons.fusion_accounting_ocr.models.account_move.parse_invoice_fields',
            return_value={
                'vendor_name': None, 'invoice_number': 'INV-7777',
                'invoice_date': None, 'due_date': None, 'currency': None,
                'subtotal': None, 'tax_total': None, 'total': None,
                'line_items': [],
            },
        ):
            self.move.action_request_ocr()

        # User-entered ref must not be overwritten.
        self.assertEqual(self.move.ref, 'USER-SET-REF')

    def test_only_vendor_bills_supported(self):
        customer_invoice = self.env['account.move'].create({
            'move_type': 'out_invoice',
            'partner_id': self.partner.id,
        })
        with self.assertRaises(UserError):
            customer_invoice.action_request_ocr()