"""
Result Proxy
------------

The result proxy wraps the result instance given to each test. It
performs two functions: enabling extended error/failure reporting
and calling plugins.

As each result event is fired, plugins are called with the same event;
however, plugins are called with the nose.case.Test instance that
wraps the actual test. So when a test fails and calls
result.addFailure(self, err), the result proxy calls
addFailure(self.test, err) for each plugin. This allows plugins to
have a single stable interface for all test types, and also to
manipulate the test object itself by setting the `test` attribute of
the nose.case.Test that they receive.
"""
import logging
from nose.config import Config


log = logging.getLogger(__name__)


def proxied_attribute(local_attr, proxied_attr, doc):
    """Create a property that proxies attribute ``proxied_attr`` through
    the local attribute ``local_attr``.
    """
    def fget(self):
        return getattr(getattr(self, local_attr), proxied_attr)
    def fset(self, value):
        setattr(getattr(self, local_attr), proxied_attr, value)
    def fdel(self):
        delattr(getattr(self, local_attr), proxied_attr)
    return property(fget, fset, fdel, doc)


class ResultProxyFactory(object):
    """Factory for result proxies. Generates a ResultProxy bound to each test
    and the result passed to the test.
    """
    def __init__(self, config=None):
        if config is None:
            config = Config()
        self.config = config
        self.__prepared = False
        self.__result = None

    def __call__(self, result, test):
        """Return a ResultProxy for the current test.

        On first call, plugins are given a chance to replace the
        result used for the remaining tests. If a plugin returns a
        value from prepareTestResult, that object will be used as the
        result for all tests.
        """
        if not self.__prepared:
            self.__prepared = True
            plug_result = self.config.plugins.prepareTestResult(result)
            if plug_result is not None:
                self.__result = result = plug_result
        if self.__result is not None:
            result = self.__result
        return ResultProxy(result, test, config=self.config)


class ResultProxy(object):
    """Proxy to TestResults (or other results handler).

    One ResultProxy is created for each nose.case.Test. The result
    proxy calls plugins with the nose.case.Test instance (instead of
    the wrapped test case) as each result call is made. Finally, the
    real result method is called, also with the nose.case.Test
    instance as the test parameter.

    """
    def __init__(self, result, test, config=None):
        if config is None:
            config = Config()
        self.config = config
        self.plugins = config.plugins
        self.result = result
        self.test = test

    def __repr__(self):
        return repr(self.result)

    def _prepareErr(self, err):
        if not isinstance(err[1], Exception):
            # Turn value back into an Exception (required in Python 3.x).
            # Plugins do all sorts of crazy things with exception values.
            try:
                # The actual exception class is needed for failure detail
                # but maybe other plugins?
                value = err[0](err[1])
            except:
                value = Exception(err[1])
            err = (err[0], value, err[2])
        return err

    def assertMyTest(self, test):
        # The test I was called with must be my .test or my
        # .test's .test. or my .test.test's .case

        case = getattr(self.test, 'test', None)
        assert (test is self.test
                or test is case
                or test is getattr(case, '_nose_case', None)), (
                "ResultProxy for %r (%s) was called with test %r (%s)"
                % (self.test, id(self.test), test, id(test)))

    def afterTest(self, test):
        self.assertMyTest(test)
        self.plugins.afterTest(self.test)
        if hasattr(self.result, "afterTest"):
            self.result.afterTest(self.test)

    def beforeTest(self, test):
        self.assertMyTest(test)
        self.plugins.beforeTest(self.test)
        if hasattr(self.result, "beforeTest"):
            self.result.beforeTest(self.test)

    def addError(self, test, err):
        self.assertMyTest(test)
        plugins = self.plugins
        plugin_handled = plugins.handleError(self.test, err)
        if plugin_handled:
            return
        # test.passed is set in result, to account for error classes
        formatted = plugins.formatError(self.test, err)
        if formatted is not None:
            err = formatted
        plugins.addError(self.test, err)
        self.result.addError(self.test, self._prepareErr(err))
        if not self.result.wasSuccessful() and self.config.stopOnError:
            self.shouldStop = True

    def addFailure(self, test, err):
        self.assertMyTest(test)
        plugins = self.plugins
        plugin_handled = plugins.handleFailure(self.test, err)
        if plugin_handled:
            return
        self.test.passed = False
        formatted = plugins.formatFailure(self.test, err)
        if formatted is not None:
            err = formatted
        plugins.addFailure(self.test, err)
        self.result.addFailure(self.test, self._prepareErr(err))
        if self.config.stopOnError:
            self.shouldStop = True

    def addSkip(self, test, reason):
        # 2.7 compat shim
        from nose.plugins.skip import SkipTest
        self.assertMyTest(test)
        plugins = self.plugins
        if not isinstance(reason, Exception):
            # for Python 3.2+
            reason = Exception(reason)
        plugins.addError(self.test, (SkipTest, reason, None))
        self.result.addSkip(self.test, reason)

    def addSuccess(self, test):
        self.assertMyTest(test)
        self.plugins.addSuccess(self.test)
        self.result.addSuccess(self.test)

    def startTest(self, test):
        self.assertMyTest(test)
        self.plugins.startTest(self.test)
        self.result.startTest(self.test)

    def stop(self):
        self.result.stop()

    def stopTest(self, test):
        self.assertMyTest(test)
        self.plugins.stopTest(self.test)
        self.result.stopTest(self.test)

    # proxied attributes
    shouldStop = proxied_attribute('result', 'shouldStop',
                                    """Should the test run stop?""")
    errors = proxied_attribute('result', 'errors',
                               """Tests that raised an exception""")
    failures = proxied_attribute('result', 'failures',
                                 """Tests that failed""")
    testsRun = proxied_attribute('result', 'testsRun',
                                 """Number of tests run""")
