# testing/assertions.py
# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

from __future__ import absolute_import

from . import util as testutil
from sqlalchemy import pool, orm, util
from sqlalchemy.engine import default, url
from sqlalchemy.util import decorator
from sqlalchemy import types as sqltypes, schema
import warnings
import re
from .exclusions import db_spec, _is_excluded
from . import assertsql
from . import config
from .util import fail
import contextlib
from . import mock


def expect_warnings(*messages):
    """Context manager which expects one or more warnings.

    With no arguments, squelches all SAWarnings emitted via
    sqlalchemy.util.warn and sqlalchemy.util.warn_limited.   Otherwise
    pass string expressions that will match selected warnings via regex;
    all non-matching warnings are sent through.

    Note that the test suite sets SAWarning warnings to raise exceptions.

    """
    return _expect_warnings(
        "sqlalchemy.util.deprecations.warnings.warn", messages)


@contextlib.contextmanager
def expect_warnings_on(db, *messages):
    """Context manager which expects one or more warnings on specific
    dialects.

    """
    spec = db_spec(db)

    if isinstance(db, util.string_types) and not spec(config._current):
        yield
    elif not _is_excluded(*db):
        yield
    else:
        with expect_warnings(*messages):
            yield


def emits_warning(*messages):
    """Decorator form of expect_warnings()."""

    @decorator
    def decorate(fn, *args, **kw):
        with expect_warnings(*messages):
            return fn(*args, **kw)

    return decorate


def expect_deprecated(*messages):
    return _expect_warnings(
        "sqlalchemy.util.deprecations.warnings.warn", messages)


def emits_warning_on(db, *messages):
    """Mark a test as emitting a warning on a specific dialect.

    With no arguments, squelches all SAWarning failures.  Or pass one or more
    strings; these will be matched to the root of the warning description by
    warnings.filterwarnings().
    """
    @decorator
    def decorate(fn, *args, **kw):
        with expect_warnings_on(db, *messages):
            return fn(*args, **kw)

    return decorate


def uses_deprecated(*messages):
    """Mark a test as immune from fatal deprecation warnings.

    With no arguments, squelches all SADeprecationWarning failures.
    Or pass one or more strings; these will be matched to the root
    of the warning description by warnings.filterwarnings().

    As a special case, you may pass a function name prefixed with //
    and it will be re-written as needed to match the standard warning
    verbiage emitted by the sqlalchemy.util.deprecated decorator.
    """

    @decorator
    def decorate(fn, *args, **kw):
        with expect_deprecated(*messages):
            return fn(*args, **kw)
    return decorate


@contextlib.contextmanager
def _expect_warnings(to_patch, messages):

    filters = [re.compile(msg, re.I) for msg in messages]

    real_warn = warnings.warn

    def our_warn(msg, exception, *arg, **kw):
        if not filters:
            return

        for filter_ in filters:
            if filter_.match(msg):
                break
        else:
            real_warn(msg, exception, *arg, **kw)

    with mock.patch(to_patch, our_warn):
        yield


def global_cleanup_assertions():
    """Check things that have to be finalized at the end of a test suite.

    Hardcoded at the moment, a modular system can be built here
    to support things like PG prepared transactions, tables all
    dropped, etc.

    """
    _assert_no_stray_pool_connections()

_STRAY_CONNECTION_FAILURES = 0


def _assert_no_stray_pool_connections():
    global _STRAY_CONNECTION_FAILURES

    # lazy gc on cPython means "do nothing."  pool connections
    # shouldn't be in cycles, should go away.
    testutil.lazy_gc()

    # however, once in awhile, on an EC2 machine usually,
    # there's a ref in there.  usually just one.
    if pool._refs:

        # OK, let's be somewhat forgiving.
        _STRAY_CONNECTION_FAILURES += 1

        print("Encountered a stray connection in test cleanup: %s"
              % str(pool._refs))
        # then do a real GC sweep.   We shouldn't even be here
        # so a single sweep should really be doing it, otherwise
        # there's probably a real unreachable cycle somewhere.
        testutil.gc_collect()

    # if we've already had two of these occurrences, or
    # after a hard gc sweep we still have pool._refs?!
    # now we have to raise.
    if pool._refs:
        err = str(pool._refs)

        # but clean out the pool refs collection directly,
        # reset the counter,
        # so the error doesn't at least keep happening.
        pool._refs.clear()
        _STRAY_CONNECTION_FAILURES = 0
        assert False, "Stray connection refused to leave "\
            "after gc.collect(): %s" % err
    elif _STRAY_CONNECTION_FAILURES > 10:
        assert False, "Encountered more than 10 stray connections"
        _STRAY_CONNECTION_FAILURES = 0


def eq_(a, b, msg=None):
    """Assert a == b, with repr messaging on failure."""
    assert a == b, msg or "%r != %r" % (a, b)


def ne_(a, b, msg=None):
    """Assert a != b, with repr messaging on failure."""
    assert a != b, msg or "%r == %r" % (a, b)


def is_(a, b, msg=None):
    """Assert a is b, with repr messaging on failure."""
    assert a is b, msg or "%r is not %r" % (a, b)


def is_not_(a, b, msg=None):
    """Assert a is not b, with repr messaging on failure."""
    assert a is not b, msg or "%r is %r" % (a, b)


def startswith_(a, fragment, msg=None):
    """Assert a.startswith(fragment), with repr messaging on failure."""
    assert a.startswith(fragment), msg or "%r does not start with %r" % (
        a, fragment)


def assert_raises(except_cls, callable_, *args, **kw):
    try:
        callable_(*args, **kw)
        success = False
    except except_cls:
        success = True

    # assert outside the block so it works for AssertionError too !
    assert success, "Callable did not raise an exception"


def assert_raises_message(except_cls, msg, callable_, *args, **kwargs):
    try:
        callable_(*args, **kwargs)
        assert False, "Callable did not raise an exception"
    except except_cls as e:
        assert re.search(
            msg, util.text_type(e), re.UNICODE), "%r !~ %s" % (msg, e)
        print(util.text_type(e).encode('utf-8'))


class AssertsCompiledSQL(object):
    def assert_compile(self, clause, result, params=None,
                       checkparams=None, dialect=None,
                       checkpositional=None,
                       use_default_dialect=False,
                       allow_dialect_select=False,
                       literal_binds=False):
        if use_default_dialect:
            dialect = default.DefaultDialect()
        elif allow_dialect_select:
            dialect = None
        else:
            if dialect is None:
                dialect = getattr(self, '__dialect__', None)

            if dialect is None:
                dialect = config.db.dialect
            elif dialect == 'default':
                dialect = default.DefaultDialect()
            elif isinstance(dialect, util.string_types):
                dialect = url.URL(dialect).get_dialect()()

        kw = {}
        compile_kwargs = {}

        if params is not None:
            kw['column_keys'] = list(params)

        if literal_binds:
            compile_kwargs['literal_binds'] = True

        if isinstance(clause, orm.Query):
            context = clause._compile_context()
            context.statement.use_labels = True
            clause = context.statement

        if compile_kwargs:
            kw['compile_kwargs'] = compile_kwargs

        c = clause.compile(dialect=dialect, **kw)

        param_str = repr(getattr(c, 'params', {}))

        if util.py3k:
            param_str = param_str.encode('utf-8').decode('ascii', 'ignore')
            print(
                ("\nSQL String:\n" +
                 util.text_type(c) +
                 param_str).encode('utf-8'))
        else:
            print(
                "\nSQL String:\n" +
                util.text_type(c).encode('utf-8') +
                param_str)

        cc = re.sub(r'[\n\t]', '', util.text_type(c))

        eq_(cc, result, "%r != %r on dialect %r" % (cc, result, dialect))

        if checkparams is not None:
            eq_(c.construct_params(params), checkparams)
        if checkpositional is not None:
            p = c.construct_params(params)
            eq_(tuple([p[x] for x in c.positiontup]), checkpositional)


class ComparesTables(object):

    def assert_tables_equal(self, table, reflected_table, strict_types=False):
        assert len(table.c) == len(reflected_table.c)
        for c, reflected_c in zip(table.c, reflected_table.c):
            eq_(c.name, reflected_c.name)
            assert reflected_c is reflected_table.c[c.name]
            eq_(c.primary_key, reflected_c.primary_key)
            eq_(c.nullable, reflected_c.nullable)

            if strict_types:
                msg = "Type '%s' doesn't correspond to type '%s'"
                assert isinstance(reflected_c.type, type(c.type)), \
                    msg % (reflected_c.type, c.type)
            else:
                self.assert_types_base(reflected_c, c)

            if isinstance(c.type, sqltypes.String):
                eq_(c.type.length, reflected_c.type.length)

            eq_(
                set([f.column.name for f in c.foreign_keys]),
                set([f.column.name for f in reflected_c.foreign_keys])
            )
            if c.server_default:
                assert isinstance(reflected_c.server_default,
                                  schema.FetchedValue)

        assert len(table.primary_key) == len(reflected_table.primary_key)
        for c in table.primary_key:
            assert reflected_table.primary_key.columns[c.name] is not None

    def assert_types_base(self, c1, c2):
        assert c1.type._compare_type_affinity(c2.type),\
            "On column %r, type '%s' doesn't correspond to type '%s'" % \
            (c1.name, c1.type, c2.type)


class AssertsExecutionResults(object):
    def assert_result(self, result, class_, *objects):
        result = list(result)
        print(repr(result))
        self.assert_list(result, class_, objects)

    def assert_list(self, result, class_, list):
        self.assert_(len(result) == len(list),
                     "result list is not the same size as test list, " +
                     "for class " + class_.__name__)
        for i in range(0, len(list)):
            self.assert_row(class_, result[i], list[i])

    def assert_row(self, class_, rowobj, desc):
        self.assert_(rowobj.__class__ is class_,
                     "item class is not " + repr(class_))
        for key, value in desc.items():
            if isinstance(value, tuple):
                if isinstance(value[1], list):
                    self.assert_list(getattr(rowobj, key), value[0], value[1])
                else:
                    self.assert_row(value[0], getattr(rowobj, key), value[1])
            else:
                self.assert_(getattr(rowobj, key) == value,
                             "attribute %s value %s does not match %s" % (
                             key, getattr(rowobj, key), value))

    def assert_unordered_result(self, result, cls, *expected):
        """As assert_result, but the order of objects is not considered.

        The algorithm is very expensive but not a big deal for the small
        numbers of rows that the test suite manipulates.
        """

        class immutabledict(dict):
            def __hash__(self):
                return id(self)

        found = util.IdentitySet(result)
        expected = set([immutabledict(e) for e in expected])

        for wrong in util.itertools_filterfalse(lambda o:
                                                isinstance(o, cls), found):
            fail('Unexpected type "%s", expected "%s"' % (
                type(wrong).__name__, cls.__name__))

        if len(found) != len(expected):
            fail('Unexpected object count "%s", expected "%s"' % (
                len(found), len(expected)))

        NOVALUE = object()

        def _compare_item(obj, spec):
            for key, value in spec.items():
                if isinstance(value, tuple):
                    try:
                        self.assert_unordered_result(
                            getattr(obj, key), value[0], *value[1])
                    except AssertionError:
                        return False
                else:
                    if getattr(obj, key, NOVALUE) != value:
                        return False
            return True

        for expected_item in expected:
            for found_item in found:
                if _compare_item(found_item, expected_item):
                    found.remove(found_item)
                    break
            else:
                fail(
                    "Expected %s instance with attributes %s not found." % (
                        cls.__name__, repr(expected_item)))
        return True

    def assert_sql_execution(self, db, callable_, *rules):
        assertsql.asserter.add_rules(rules)
        try:
            callable_()
            assertsql.asserter.statement_complete()
        finally:
            assertsql.asserter.clear_rules()

    def assert_sql(self, db, callable_, list_, with_sequences=None):
        if (with_sequences is not None and
                config.db.dialect.supports_sequences):
            rules = with_sequences
        else:
            rules = list_

        newrules = []
        for rule in rules:
            if isinstance(rule, dict):
                newrule = assertsql.AllOf(*[
                    assertsql.ExactSQL(k, v) for k, v in rule.items()
                ])
            else:
                newrule = assertsql.ExactSQL(*rule)
            newrules.append(newrule)

        self.assert_sql_execution(db, callable_, *newrules)

    def assert_sql_count(self, db, callable_, count):
        self.assert_sql_execution(
            db, callable_, assertsql.CountStatements(count))

    @contextlib.contextmanager
    def assert_execution(self, *rules):
        assertsql.asserter.add_rules(rules)
        try:
            yield
            assertsql.asserter.statement_complete()
        finally:
            assertsql.asserter.clear_rules()

    def assert_statement_count(self, count):
        return self.assert_execution(assertsql.CountStatements(count))