
from ..engine.default import DefaultDialect
from .. import util
import re


class AssertRule(object):

    def process_execute(self, clauseelement, *multiparams, **params):
        pass

    def process_cursor_execute(self, statement, parameters, context,
                               executemany):
        pass

    def is_consumed(self):
        """Return True if this rule has been consumed, False if not.

        Should raise an AssertionError if this rule's condition has
        definitely failed.

        """

        raise NotImplementedError()

    def rule_passed(self):
        """Return True if the last test of this rule passed, False if
        failed, None if no test was applied."""

        raise NotImplementedError()

    def consume_final(self):
        """Return True if this rule has been consumed.

        Should raise an AssertionError if this rule's condition has not
        been consumed or has failed.

        """

        if self._result is None:
            assert False, 'Rule has not been consumed'
        return self.is_consumed()


class SQLMatchRule(AssertRule):
    def __init__(self):
        self._result = None
        self._errmsg = ""

    def rule_passed(self):
        return self._result

    def is_consumed(self):
        if self._result is None:
            return False

        assert self._result, self._errmsg

        return True


class ExactSQL(SQLMatchRule):

    def __init__(self, sql, params=None):
        SQLMatchRule.__init__(self)
        self.sql = sql
        self.params = params

    def process_cursor_execute(self, statement, parameters, context,
                               executemany):
        if not context:
            return
        _received_statement = \
            _process_engine_statement(context.unicode_statement,
                context)
        _received_parameters = context.compiled_parameters

        # TODO: remove this step once all unit tests are migrated, as
        # ExactSQL should really be *exact* SQL

        sql = _process_assertion_statement(self.sql, context)
        equivalent = _received_statement == sql
        if self.params:
            if util.callable(self.params):
                params = self.params(context)
            else:
                params = self.params
            if not isinstance(params, list):
                params = [params]
            equivalent = equivalent and params \
                == context.compiled_parameters
        else:
            params = {}
        self._result = equivalent
        if not self._result:
            self._errmsg = \
                'Testing for exact statement %r exact params %r, '\
                'received %r with params %r' % (sql, params,
                    _received_statement, _received_parameters)


class RegexSQL(SQLMatchRule):

    def __init__(self, regex, params=None):
        SQLMatchRule.__init__(self)
        self.regex = re.compile(regex)
        self.orig_regex = regex
        self.params = params

    def process_cursor_execute(self, statement, parameters, context,
                               executemany):
        if not context:
            return
        _received_statement = \
            _process_engine_statement(context.unicode_statement,
                context)
        _received_parameters = context.compiled_parameters
        equivalent = bool(self.regex.match(_received_statement))
        if self.params:
            if util.callable(self.params):
                params = self.params(context)
            else:
                params = self.params
            if not isinstance(params, list):
                params = [params]

            # do a positive compare only

            for param, received in zip(params, _received_parameters):
                for k, v in param.items():
                    if k not in received or received[k] != v:
                        equivalent = False
                        break
        else:
            params = {}
        self._result = equivalent
        if not self._result:
            self._errmsg = \
                'Testing for regex %r partial params %r, received %r '\
                'with params %r' % (self.orig_regex, params,
                                    _received_statement,
                                    _received_parameters)


class CompiledSQL(SQLMatchRule):

    def __init__(self, statement, params=None):
        SQLMatchRule.__init__(self)
        self.statement = statement
        self.params = params

    def process_cursor_execute(self, statement, parameters, context,
                               executemany):
        if not context:
            return
        from sqlalchemy.schema import _DDLCompiles
        _received_parameters = list(context.compiled_parameters)

        # recompile from the context, using the default dialect

        if isinstance(context.compiled.statement, _DDLCompiles):
            compiled = \
                context.compiled.statement.compile(dialect=DefaultDialect())
        else:
            compiled = \
                context.compiled.statement.compile(dialect=DefaultDialect(),
                column_keys=context.compiled.column_keys)
        _received_statement = re.sub(r'[\n\t]', '', str(compiled))
        equivalent = self.statement == _received_statement
        if self.params:
            if util.callable(self.params):
                params = self.params(context)
            else:
                params = self.params
            if not isinstance(params, list):
                params = [params]
            else:
                params = list(params)
            all_params = list(params)
            all_received = list(_received_parameters)
            while params:
                param = dict(params.pop(0))
                for k, v in context.compiled.params.items():
                    param.setdefault(k, v)
                if param not in _received_parameters:
                    equivalent = False
                    break
                else:
                    _received_parameters.remove(param)
            if _received_parameters:
                equivalent = False
        else:
            params = {}
            all_params = {}
            all_received = []
        self._result = equivalent
        if not self._result:
            print('Testing for compiled statement %r partial params '\
                '%r, received %r with params %r' % (self.statement,
                    all_params, _received_statement, all_received))
            self._errmsg = \
                'Testing for compiled statement %r partial params %r, '\
                'received %r with params %r' % (self.statement,
                    all_params, _received_statement, all_received)


            # print self._errmsg

class CountStatements(AssertRule):

    def __init__(self, count):
        self.count = count
        self._statement_count = 0

    def process_execute(self, clauseelement, *multiparams, **params):
        self._statement_count += 1

    def process_cursor_execute(self, statement, parameters, context,
                               executemany):
        pass

    def is_consumed(self):
        return False

    def consume_final(self):
        assert self.count == self._statement_count, \
            'desired statement count %d does not match %d' \
            % (self.count, self._statement_count)
        return True


class AllOf(AssertRule):

    def __init__(self, *rules):
        self.rules = set(rules)

    def process_execute(self, clauseelement, *multiparams, **params):
        for rule in self.rules:
            rule.process_execute(clauseelement, *multiparams, **params)

    def process_cursor_execute(self, statement, parameters, context,
                               executemany):
        for rule in self.rules:
            rule.process_cursor_execute(statement, parameters, context,
                    executemany)

    def is_consumed(self):
        if not self.rules:
            return True
        for rule in list(self.rules):
            if rule.rule_passed():  # a rule passed, move on
                self.rules.remove(rule)
                return len(self.rules) == 0
        assert False, 'No assertion rules were satisfied for statement'

    def consume_final(self):
        return len(self.rules) == 0


def _process_engine_statement(query, context):
    if util.jython:

        # oracle+zxjdbc passes a PyStatement when returning into

        query = str(query)
    if context.engine.name == 'mssql' \
        and query.endswith('; select scope_identity()'):
        query = query[:-25]
    query = re.sub(r'\n', '', query)
    return query


def _process_assertion_statement(query, context):
    paramstyle = context.dialect.paramstyle
    if paramstyle == 'named':
        pass
    elif paramstyle == 'pyformat':
        query = re.sub(r':([\w_]+)', r"%(\1)s", query)
    else:
        # positional params
        repl = None
        if paramstyle == 'qmark':
            repl = "?"
        elif paramstyle == 'format':
            repl = r"%s"
        elif paramstyle == 'numeric':
            repl = None
        query = re.sub(r':([\w_]+)', repl, query)

    return query


class SQLAssert(object):

    rules = None

    def add_rules(self, rules):
        self.rules = list(rules)

    def statement_complete(self):
        for rule in self.rules:
            if not rule.consume_final():
                assert False, \
                    'All statements are complete, but pending '\
                    'assertion rules remain'

    def clear_rules(self):
        del self.rules

    def execute(self, conn, clauseelement, multiparams, params, result):
        if self.rules is not None:
            if not self.rules:
                assert False, \
                    'All rules have been exhausted, but further '\
                    'statements remain'
            rule = self.rules[0]
            rule.process_execute(clauseelement, *multiparams, **params)
            if rule.is_consumed():
                self.rules.pop(0)

    def cursor_execute(self, conn, cursor, statement, parameters,
                       context, executemany):
        if self.rules:
            rule = self.rules[0]
            rule.process_cursor_execute(statement, parameters, context,
                    executemany)

asserter = SQLAssert()
