"""A wvmConnect reads the host's capabilities once, and its domain
capabilities once per emulator, arch, machine and domain type: the create
page's getters parse them some 60 times. An object lives for one request."""

import unittest

from django.conf import settings

if not settings.configured:
    settings.configure(MAC_OUI="52:54:10")

from vrtManager.connection import wvmConnect

CAPABILITIES = """<capabilities><host><cpu><arch>x86_64</arch></cpu></host>
<guest><os_type>hvm</os_type><arch name='x86_64'><emulator>/usr/bin/qemu-kvm</emulator>
<machine>pc-q35-9.0</machine><machine canonical='pc-q35-9.0'>q35</machine><machine canonical='pc-i440fx-9.0'>pc</machine>
<domain type='qemu'/><domain type='kvm'/></arch></guest></capabilities>"""


class FakeConn:
    def __init__(self):
        self.reads = []

    def getCapabilities(self):
        self.reads.append("capabilities")
        return CAPABILITIES

    def getDomainCapabilities(self, emulator, arch, machine, virttype):
        self.reads.append((emulator, arch, machine, virttype))
        return "<domainCapabilities/>"


def connection():
    conn = wvmConnect.__new__(wvmConnect)  # no libvirt connection: only these calls
    conn.wvm = FakeConn()
    return conn


class CapabilitiesOnceTestCase(unittest.TestCase):
    def test_the_capabilities_are_read_once_for_all_getters(self):
        conn = connection()
        for _ in range(2):
            conn.get_emulator("x86_64")
            conn.get_machine_types("x86_64")
            conn.get_hypervisors_domain_types()
            conn.get_cap_xml()
        self.assertEqual(conn.wvm.reads, ["capabilities"])

    def test_domain_capabilities_are_read_once_per_machine(self):
        conn = connection()
        for _ in range(2):
            conn.get_dom_cap_xml("x86_64", "q35")
            conn.get_dom_cap_xml("x86_64", "pc")
            conn.get_dom_cap_xml("x86_64", "unknown")  # falls back to pc
        self.assertEqual(
            conn.wvm.reads,
            ["capabilities", ("/usr/bin/qemu-kvm", "x86_64", "q35", "kvm"), ("/usr/bin/qemu-kvm", "x86_64", "pc", "kvm")],
        )

    def test_two_objects_do_not_share_their_reads(self):
        a, b = connection(), connection()
        a.get_cap_xml()
        b.get_cap_xml()
        self.assertEqual((a.wvm.reads, b.wvm.reads), (["capabilities"], ["capabilities"]))

    def test_a_failed_read_is_not_kept(self):
        conn = connection()
        conn.wvm.getCapabilities = lambda: (_ for _ in ()).throw(RuntimeError("libvirt error"))
        with self.assertRaises(RuntimeError):
            conn.get_cap_xml()
        conn.wvm = FakeConn()
        conn.get_cap_xml()
        self.assertEqual(conn.wvm.reads, ["capabilities"])