// Copyright 2016 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package executor_test

import (
	. "github.com/pingcap/check"
	"github.com/pingcap/tidb/context"
	"github.com/pingcap/tidb/sessionctx/variable"
	"github.com/pingcap/tidb/sessionctx/varsutil"
	"github.com/pingcap/tidb/util/testkit"
	"github.com/pingcap/tidb/util/testleak"
)

func (s *testSuite) TestSetVar(c *C) {
	defer testleak.AfterTest(c)()
	tk := testkit.NewTestKit(c, s.store)
	testSQL := "SET @a = 1;"
	tk.MustExec(testSQL)

	testSQL = `SET @a = "1";`
	tk.MustExec(testSQL)

	testSQL = "SET @a = null;"
	tk.MustExec(testSQL)

	testSQL = "SET @@global.autocommit = 1;"
	tk.MustExec(testSQL)

	// TODO: this test case should returns error.
	// testSQL = "SET @@global.autocommit = null;"
	// _, err := tk.Exec(testSQL)
	// c.Assert(err, NotNil)

	testSQL = "SET @@autocommit = 1;"
	tk.MustExec(testSQL)

	testSQL = "SET @@autocommit = null;"
	_, err := tk.Exec(testSQL)
	c.Assert(err, NotNil)

	errTestSql := "SET @@date_format = 1;"
	_, err = tk.Exec(errTestSql)
	c.Assert(err, NotNil)

	errTestSql = "SET @@rewriter_enabled = 1;"
	_, err = tk.Exec(errTestSql)
	c.Assert(err, NotNil)

	errTestSql = "SET xxx = abcd;"
	_, err = tk.Exec(errTestSql)
	c.Assert(err, NotNil)

	errTestSql = "SET @@global.a = 1;"
	_, err = tk.Exec(errTestSql)
	c.Assert(err, NotNil)

	errTestSql = "SET @@global.timestamp = 1;"
	_, err = tk.Exec(errTestSql)
	c.Assert(err, NotNil)

	// For issue 998
	testSQL = "SET @issue998a=1, @issue998b=5;"
	tk.MustExec(testSQL)
	tk.MustQuery(`select @issue998a, @issue998b;`).Check(testkit.Rows("1 5"))
	testSQL = "SET @@autocommit=0, @issue998a=2;"
	tk.MustExec(testSQL)
	tk.MustQuery(`select @issue998a, @@autocommit;`).Check(testkit.Rows("2 0"))
	testSQL = "SET @@global.autocommit=1, @issue998b=6;"
	tk.MustExec(testSQL)
	tk.MustQuery(`select @issue998b, @@global.autocommit;`).Check(testkit.Rows("6 1"))

	// Set default
	// {ScopeGlobal | ScopeSession, "low_priority_updates", "OFF"},
	// For global var
	tk.MustQuery(`select @@global.low_priority_updates;`).Check(testkit.Rows("OFF"))
	tk.MustExec(`set @@global.low_priority_updates="ON";`)
	tk.MustQuery(`select @@global.low_priority_updates;`).Check(testkit.Rows("ON"))
	tk.MustExec(`set @@global.low_priority_updates=DEFAULT;`) // It will be set to compiled-in default value.
	tk.MustQuery(`select @@global.low_priority_updates;`).Check(testkit.Rows("OFF"))
	// For session
	tk.MustQuery(`select @@session.low_priority_updates;`).Check(testkit.Rows("OFF"))
	tk.MustExec(`set @@global.low_priority_updates="ON";`)
	tk.MustExec(`set @@session.low_priority_updates=DEFAULT;`) // It will be set to global var value.
	tk.MustQuery(`select @@session.low_priority_updates;`).Check(testkit.Rows("ON"))

	// For mysql jdbc driver issue.
	tk.MustQuery(`select @@session.tx_read_only;`).Check(testkit.Rows("0"))

	// Test session variable states.
	vars := tk.Se.(context.Context).GetSessionVars()
	tk.Se.CommitTxn()
	tk.MustExec("set @@autocommit = 1")
	c.Assert(vars.InTxn(), IsFalse)
	c.Assert(vars.IsAutocommit(), IsTrue)
	tk.MustExec("set @@autocommit = 0")
	c.Assert(vars.IsAutocommit(), IsFalse)

	tk.MustExec("set @@sql_mode = 'strict_trans_tables'")
	c.Assert(vars.StrictSQLMode, IsTrue)
	tk.MustExec("set @@sql_mode = ''")
	c.Assert(vars.StrictSQLMode, IsFalse)

	tk.MustExec("set names utf8")
	charset, collation := vars.GetCharsetInfo()
	c.Assert(charset, Equals, "utf8")
	c.Assert(collation, Equals, "utf8_general_ci")

	tk.MustExec("set @@character_set_results = NULL")

	c.Assert(vars.SkipConstraintCheck, IsFalse)
	tk.MustExec("set @@tidb_skip_constraint_check = '1'")
	c.Assert(vars.SkipConstraintCheck, IsTrue)
	tk.MustExec("set @@tidb_skip_constraint_check = '0'")
	c.Assert(vars.SkipConstraintCheck, IsFalse)
}

func (s *testSuite) TestSetCharset(c *C) {
	defer testleak.AfterTest(c)()
	tk := testkit.NewTestKit(c, s.store)
	tk.MustExec(`SET NAMES latin1`)

	ctx := tk.Se.(context.Context)
	sessionVars := ctx.GetSessionVars()
	for _, v := range variable.SetNamesVariables {
		sVar, err := varsutil.GetSessionSystemVar(sessionVars, v)
		c.Assert(err, IsNil)
		c.Assert(sVar != "utf8", IsTrue)
	}
	tk.MustExec(`SET NAMES utf8`)
	for _, v := range variable.SetNamesVariables {
		sVar, err := varsutil.GetSessionSystemVar(sessionVars, v)
		c.Assert(err, IsNil)
		c.Assert(sVar, Equals, "utf8")
	}
	sVar, err := varsutil.GetSessionSystemVar(sessionVars, variable.CollationConnection)
	c.Assert(err, IsNil)
	c.Assert(sVar, Equals, "utf8_general_ci")

	// Issue 1523
	tk.MustExec(`SET NAMES binary`)
}