"""Tests for sales module: CRUD, contract PDF, GwG logic, vehicle status changes."""

import uuid
from datetime import date
from decimal import Decimal
from unittest.mock import patch, MagicMock

import pytest
import pytest_asyncio
from httpx import AsyncClient
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.sale import Sale
from app.models.vehicle import Vehicle
from app.models.contact import Contact
from app.utils.contract_pdf import build_contract_html
from app.utils.datev import generate_datev_csv, validate_datev_csv, DATEV_HEADERS


@pytest_asyncio.fixture
async def test_vehicle(db_session: AsyncSession) -> Vehicle:
    """Create a test vehicle."""
    vehicle = Vehicle(
        make="Mercedes",
        model="Actros",
        fin="WDB96312345678901",
        year=2020,
        vehicle_type="lkw",
        price=Decimal("45000.00"),
        availability="available",
        condition="used",
    )
    db_session.add(vehicle)
    await db_session.commit()
    await db_session.refresh(vehicle)
    return vehicle


@pytest_asyncio.fixture
async def test_buyer(db_session: AsyncSession) -> Contact:
    """Create a test buyer contact."""
    contact = Contact(
        company_name="Test Buyer GmbH",
        role="kaeufer",
        address_country="DE",
        vat_id="DE123456789",
        address_street="Teststr. 1",
        address_zip="12345",
        address_city="Berlin",
        email="buyer@test.com",
    )
    db_session.add(contact)
    await db_session.commit()
    await db_session.refresh(contact)
    return contact


@pytest_asyncio.fixture
async def test_seller(db_session: AsyncSession) -> Contact:
    """Create a test seller contact."""
    contact = Contact(
        company_name="Test Seller GmbH",
        role="verkaeufer",
        address_country="DE",
        vat_id="DE987654321",
        address_street="Sellerstr. 2",
        address_zip="54321",
        address_city="München",
        email="seller@test.com",
    )
    db_session.add(contact)
    await db_session.commit()
    await db_session.refresh(contact)
    return contact


@pytest_asyncio.fixture
async def test_sale(db_session: AsyncSession, test_vehicle: Vehicle, test_buyer: Contact) -> Sale:
    """Create a test sale."""
    sale = Sale(
        vehicle_id=test_vehicle.id,
        buyer_contact_id=test_buyer.id,
        sale_price=Decimal("45000.00"),
        sale_date=date(2025, 1, 15),
        status="completed",
        is_gwg=False,
    )
    db_session.add(sale)
    await db_session.commit()
    await db_session.refresh(sale)
    return sale


class TestSaleCRUD:
    """Test sale CRUD operations via API."""

    @pytest_asyncio.fixture
    async def setup_data(self, db_session, test_vehicle, test_buyer):
        """Ensure vehicle and buyer exist."""
        return test_vehicle, test_buyer

    async def test_list_sales_empty(self, admin_client: AsyncClient):
        """GET /sales with no sales returns empty list."""
        response = await admin_client.get("/api/v1/sales/")
        assert response.status_code == 200
        data = response.json()
        assert data["items"] == []
        assert data["total"] == 0
        assert data["page"] == 1
        assert data["page_size"] == 20

    async def test_create_sale(self, admin_client: AsyncClient, test_vehicle, test_buyer):
        """POST /sales with valid data returns 201."""
        response = await admin_client.post("/api/v1/sales/", json={
            "vehicle_id": str(test_vehicle.id),
            "buyer_contact_id": str(test_buyer.id),
            "sale_price": "45000.00",
            "sale_date": "2025-01-15",
            "status": "draft",
            "is_gwg": False,
        })
        assert response.status_code == 201
        data = response.json()
        assert data["vehicle_id"] == str(test_vehicle.id)
        assert data["buyer_contact_id"] == str(test_buyer.id)
        assert data["sale_price"] == "45000.00"
        assert data["status"] == "draft"
        assert data["is_gwg"] is False

    async def test_create_sale_without_vehicle_id(self, admin_client: AsyncClient, test_buyer):
        """POST /sales without vehicle_id returns 422."""
        response = await admin_client.post("/api/v1/sales/", json={
            "buyer_contact_id": str(test_buyer.id),
            "sale_price": "45000.00",
        })
        assert response.status_code == 422

    async def test_create_sale_without_buyer_contact_id(self, admin_client: AsyncClient, test_vehicle):
        """POST /sales without buyer_contact_id returns 422."""
        response = await admin_client.post("/api/v1/sales/", json={
            "vehicle_id": str(test_vehicle.id),
            "sale_price": "45000.00",
        })
        assert response.status_code == 422

    async def test_get_sale_by_id(self, admin_client: AsyncClient, test_sale):
        """GET /sales/:id returns sale detail with nested vehicle and contact."""
        response = await admin_client.get(f"/api/v1/sales/{test_sale.id}")
        assert response.status_code == 200
        data = response.json()
        assert data["id"] == str(test_sale.id)
        assert data["vehicle"]["make"] == "Mercedes"
        assert data["buyer"]["company_name"] == "Test Buyer GmbH"

    async def test_get_sale_not_found(self, admin_client: AsyncClient):
        """GET /sales/:nonexistent returns 404."""
        response = await admin_client.get(f"/api/v1/sales/{uuid.uuid4()}")
        assert response.status_code == 404

    async def test_update_sale(self, admin_client: AsyncClient, test_sale):
        """PUT /sales/:id updates sale fields."""
        response = await admin_client.put(f"/api/v1/sales/{test_sale.id}", json={
            "sale_price": "42000.00",
            "status": "completed",
        })
        assert response.status_code == 200
        data = response.json()
        assert data["sale_price"] == "42000.00"
        assert data["status"] == "completed"

    async def test_delete_sale_cancels_and_restores_vehicle(self, admin_client: AsyncClient, test_sale, db_session):
        """DELETE /sales/:id cancels sale and restores vehicle status to 'available'."""
        # First set vehicle to sold (as create_sale would)
        vehicle = await db_session.get(Vehicle, test_sale.vehicle_id)
        vehicle.availability = "sold"
        await db_session.commit()

        response = await admin_client.delete(f"/api/v1/sales/{test_sale.id}")
        assert response.status_code == 200
        data = response.json()
        assert data["status"] == "cancelled"

        # Verify vehicle status restored
        await db_session.refresh(vehicle)
        assert vehicle.availability == "available"

    async def test_list_sales_with_filter(self, admin_client: AsyncClient, test_sale):
        """GET /sales?status=completed filters by status."""
        response = await admin_client.get("/api/v1/sales/?status=completed")
        assert response.status_code == 200
        data = response.json()
        assert data["total"] >= 1
        for item in data["items"]:
            assert item["status"] == "completed"

    async def test_list_sales_with_date_filter(self, admin_client: AsyncClient, test_sale):
        """GET /sales?date_from=2025-01-01&date_to=2025-12-31 filters by date range."""
        response = await admin_client.get("/api/v1/sales/?date_from=2025-01-01&date_to=2025-12-31")
        assert response.status_code == 200
        data = response.json()
        assert data["total"] >= 1


class TestSaleVehicleStatus:
    """Test vehicle status changes on sale create/delete."""

    async def test_create_sale_sets_vehicle_sold(self, admin_client: AsyncClient, test_vehicle, test_buyer, db_session):
        """Creating a sale sets vehicle availability to 'sold'."""
        response = await admin_client.post("/api/v1/sales/", json={
            "vehicle_id": str(test_vehicle.id),
            "buyer_contact_id": str(test_buyer.id),
            "sale_price": "45000.00",
            "sale_date": "2025-01-15",
            "status": "draft",
        })
        assert response.status_code == 201

        # Verify vehicle status
        await db_session.refresh(test_vehicle)
        assert test_vehicle.availability == "sold"

    async def test_cancel_sale_restores_vehicle_available(self, admin_client: AsyncClient, test_sale, db_session):
        """Cancelling a sale restores vehicle availability to 'available'."""
        # Set vehicle to sold first
        vehicle = await db_session.get(Vehicle, test_sale.vehicle_id)
        vehicle.availability = "sold"
        await db_session.commit()

        response = await admin_client.delete(f"/api/v1/sales/{test_sale.id}")
        assert response.status_code == 200

        await db_session.refresh(vehicle)
        assert vehicle.availability == "available"


class TestContractPDF:
    """Test contract PDF generation and GwG logic."""

    async def test_regenerate_contract(self, admin_client: AsyncClient, test_sale):
        """POST /sales/:id/contract regenerates contract PDF."""
        with patch("app.services.sale_service.generate_contract_pdf") as mock_pdf:
            mock_pdf.return_value = "/tmp/contracts/test_contract.pdf"
            response = await admin_client.post(f"/api/v1/sales/{test_sale.id}/contract")
        assert response.status_code == 200
        data = response.json()
        assert data["sale_id"] == str(test_sale.id)
        assert "contract_pdf_path" in data

    async def test_download_contract_not_found(self, admin_client: AsyncClient, test_sale):
        """GET /sales/:id/contract returns 404 if no PDF generated."""
        response = await admin_client.get(f"/api/v1/sales/{test_sale.id}/contract")
        assert response.status_code == 404

    async def test_download_contract_pdf(self, admin_client: AsyncClient, test_sale, db_session):
        """GET /sales/:id/contract returns PDF content."""
        # Create a fake PDF file
        import os
        os.makedirs("/tmp/contracts", exist_ok=True)
        pdf_path = f"/tmp/contracts/contract_{test_sale.id}.pdf"
        with open(pdf_path, "wb") as f:
            f.write(b"%PDF-1.4 fake pdf content")

        test_sale.contract_pdf_path = pdf_path
        db_session.add(test_sale)
        await db_session.commit()

        response = await admin_client.get(f"/api/v1/sales/{test_sale.id}/contract")
        assert response.status_code == 200
        assert response.headers["content-type"] == "application/pdf"

        # Cleanup
        if os.path.exists(pdf_path):
            os.remove(pdf_path)

    def test_gwg_clause_in_contract_html(self, test_sale, test_vehicle, test_buyer):
        """GwG clause appears in contract HTML when is_gwg=true and price <= 800."""
        test_sale.is_gwg = True
        test_sale.sale_price = Decimal("500.00")
        test_sale.vehicle = test_vehicle
        test_sale.buyer = test_buyer

        html = build_contract_html(test_sale)
        assert "Geringwertige Wirtschaftsgüter" in html
        assert "§ 6 Abs. 2 EStG" in html

    def test_gwg_clause_not_in_contract_when_price_too_high(self, test_sale, test_vehicle, test_buyer):
        """GwG clause does NOT appear when price > 800 even if is_gwg=true."""
        test_sale.is_gwg = True
        test_sale.sale_price = Decimal("5000.00")
        test_sale.vehicle = test_vehicle
        test_sale.buyer = test_buyer

        html = build_contract_html(test_sale)
        assert "Geringwertige Wirtschaftsgüter" not in html

    def test_gwg_clause_not_in_contract_when_not_gwg(self, test_sale, test_vehicle, test_buyer):
        """GwG clause does NOT appear when is_gwg=false."""
        test_sale.is_gwg = False
        test_sale.sale_price = Decimal("500.00")
        test_sale.vehicle = test_vehicle
        test_sale.buyer = test_buyer

        html = build_contract_html(test_sale)
        assert "Geringwertige Wirtschaftsgüter" not in html

    def test_contract_html_contains_ust_id_field(self, test_sale, test_vehicle, test_buyer):
        """Contract HTML contains USt-IdNr. field."""
        test_sale.vehicle = test_vehicle
        test_sale.buyer = test_buyer

        html = build_contract_html(test_sale)
        assert "USt-IdNr" in html
        assert "DE123456789" in html


class TestUstIdVerification:
    """Test USt-IdNr. verification endpoint."""

    async def test_verify_ust_id_disabled(self, admin_client: AsyncClient, test_sale):
        """POST /sales/:id/verify-ust-id returns not verified when BZSt API disabled."""
        response = await admin_client.post(f"/api/v1/sales/{test_sale.id}/verify-ust-id")
        assert response.status_code == 200
        data = response.json()
        assert data["verified"] is False
        assert data["message"] == "BZSt API not available"