from pytest import raises
import sqlalchemy as sa
from sqlalchemy.dialects import postgresql
from sqlalchemy_utils.types import TSVectorType
from sqlalchemy_utils.expressions import (
    explain,
    explain_analyze,
    tsvector_match,
    tsvector_concat,
    to_tsquery,
    plainto_tsquery
)
from tests import TestCase


class ExpressionTestCase(TestCase):
    dns = 'postgres://postgres@localhost/sqlalchemy_utils_test'

    def create_models(self):
        class Article(self.Base):
            __tablename__ = 'article'
            id = sa.Column(sa.Integer, primary_key=True)
            name = sa.Column(sa.Unicode(255))
            content = sa.Column(sa.UnicodeText)
            search_vector = sa.Column(TSVectorType)
            search_vector2 = sa.Column(TSVectorType)

        self.Article = Article

    def assert_startswith(self, query, query_part):
        assert str(
            query.compile(dialect=postgresql.dialect())
        ).startswith(query_part)
        # Check that query executes properly
        self.session.execute(query)


class TestExplain(ExpressionTestCase):
    def test_render_explain(self):
        self.assert_startswith(
            explain(self.session.query(self.Article)),
            'EXPLAIN SELECT'
        )

    def test_render_explain_with_analyze(self):
        self.assert_startswith(
            explain(self.session.query(self.Article), analyze=True),
            'EXPLAIN (ANALYZE true) SELECT'
        )

    def test_with_string_as_stmt_param(self):
        self.assert_startswith(
            explain('SELECT 1 FROM article'),
            'EXPLAIN SELECT'
        )

    def test_format(self):
        self.assert_startswith(
            explain('SELECT 1 FROM article', format='json'),
            'EXPLAIN (FORMAT json) SELECT'
        )

    def test_timing(self):
        self.assert_startswith(
            explain('SELECT 1 FROM article', analyze=True, timing=False),
            'EXPLAIN (ANALYZE true, TIMING false) SELECT'
        )

    def test_verbose(self):
        self.assert_startswith(
            explain('SELECT 1 FROM article', verbose=True),
            'EXPLAIN (VERBOSE true) SELECT'
        )

    def test_buffers(self):
        self.assert_startswith(
            explain('SELECT 1 FROM article', analyze=True, buffers=True),
            'EXPLAIN (ANALYZE true, BUFFERS true) SELECT'
        )

    def test_costs(self):
        self.assert_startswith(
            explain('SELECT 1 FROM article', costs=False),
            'EXPLAIN (COSTS false) SELECT'
        )


class TestExplainAnalyze(ExpressionTestCase):
    def test_render_explain_analyze(self):
        assert str(
            explain_analyze(self.session.query(self.Article))
            .compile(
                dialect=postgresql.dialect()
            )
        ).startswith('EXPLAIN (ANALYZE true) SELECT')


class TestMatchTSVector(ExpressionTestCase):
    def test_raises_exception_if_less_than_2_parameters_given(self):
        with raises(Exception):
            str(
                tsvector_match(
                    self.Article.search_vector,
                )
            )

    def test_supports_postgres(self):
        assert str(tsvector_match(
            self.Article.search_vector,
            to_tsquery('something'),
        )) == '(article.search_vector) @@ to_tsquery(:to_tsquery_1)'


class TestToTSQuery(ExpressionTestCase):
    def test_requires_atleast_one_parameter(self):
        with raises(Exception):
            str(to_tsquery())

    def test_supports_postgres(self):
        assert str(to_tsquery('something')) == 'to_tsquery(:to_tsquery_1)'


class TestPlainToTSQuery(ExpressionTestCase):
    def test_requires_atleast_one_parameter(self):
        with raises(Exception):
            str(plainto_tsquery())

    def test_supports_postgres(self):
        assert str(plainto_tsquery('s')) == (
            'plainto_tsquery(:plainto_tsquery_1)'
        )


class TestConcatTSVector(ExpressionTestCase):
    def test_concatenate_search_vectors(self):
        assert str(tsvector_match(
            tsvector_concat(
                self.Article.search_vector,
                self.Article.search_vector2
            ),
            to_tsquery('finnish', 'something'),
        )) == (
            '(article.search_vector || article.search_vector2) '
            '@@ to_tsquery(:to_tsquery_1, :to_tsquery_2)'
        )