// Copyright 2017 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 expression

import (
	"time"

	. "github.com/pingcap/check"
	"github.com/pingcap/errors"
	"github.com/pingcap/parser/ast"
	"github.com/pingcap/parser/mysql"
	"github.com/pingcap/tidb/types"
	"github.com/pingcap/tidb/types/json"
	"github.com/pingcap/tidb/util/chunk"
	"github.com/pingcap/tidb/util/testleak"
)

func (s *testEvaluatorSuite) TestCompareFunctionWithRefine(c *C) {
	defer testleak.AfterTest(c)()
	tblInfo := newTestTableBuilder("").add("a", mysql.TypeLong).build()
	tests := []struct {
		exprStr string
		result  string
	}{
		{"a < '1.0'", "lt(a, 1)"},
		{"a <= '1.0'", "le(a, 1)"},
		{"a > '1'", "gt(a, 1)"},
		{"a >= '1'", "ge(a, 1)"},
		{"a = '1'", "eq(a, 1)"},
		{"a <=> '1'", "nulleq(a, 1)"},
		{"a != '1'", "ne(a, 1)"},
		{"a < '1.1'", "lt(a, 2)"},
		{"a <= '1.1'", "le(a, 1)"},
		{"a > 1.1", "gt(a, 1)"},
		{"a >= '1.1'", "ge(a, 2)"},
		{"a = '1.1'", "0"},
		{"a <=> '1.1'", "0"},
		{"a != '1.1'", "ne(cast(a), 1.1)"},
		{"'1' < a", "lt(1, a)"},
		{"'1' <= a", "le(1, a)"},
		{"'1' > a", "gt(1, a)"},
		{"'1' >= a", "ge(1, a)"},
		{"'1' = a", "eq(1, a)"},
		{"'1' <=> a", "nulleq(1, a)"},
		{"'1' != a", "ne(1, a)"},
		{"'1.1' < a", "lt(1, a)"},
		{"'1.1' <= a", "le(2, a)"},
		{"'1.1' > a", "gt(2, a)"},
		{"'1.1' >= a", "ge(1, a)"},
		{"'1.1' = a", "0"},
		{"'1.1' <=> a", "0"},
		{"'1.1' != a", "ne(1.1, cast(a))"},
		{"'123456789123456711111189' = a", "0"},
		{"123456789123456789.12345 = a", "0"},
		// This cast can not be eliminated,
		// since converting "aaaa" to an int will cause DataTruncate error.
		{"'aaaa'=a", "eq(cast(aaaa), cast(a))"},
	}

	for _, t := range tests {
		f, err := ParseSimpleExprWithTableInfo(s.ctx, t.exprStr, tblInfo)
		c.Assert(err, IsNil)
		c.Assert(f.String(), Equals, t.result)
	}
}

func (s *testEvaluatorSuite) TestCompare(c *C) {
	defer testleak.AfterTest(c)()

	intVal, uintVal, realVal, stringVal, decimalVal := 1, uint64(1), 1.1, "123", types.NewDecFromFloatForTest(123.123)
	timeVal := types.Time{Time: types.FromGoTime(time.Now()), Fsp: 6, Type: mysql.TypeDatetime}
	durationVal := types.Duration{Duration: time.Duration(12*time.Hour + 1*time.Minute + 1*time.Second)}
	jsonVal := json.CreateBinary("123")
	// test cases for generating function signatures.
	tests := []struct {
		arg0     interface{}
		arg1     interface{}
		funcName string
		tp       byte
		expected int64
	}{
		{intVal, intVal, ast.LT, mysql.TypeLonglong, 0},
		{stringVal, stringVal, ast.LT, mysql.TypeVarString, 0},
		{intVal, decimalVal, ast.LT, mysql.TypeNewDecimal, 1},
		{realVal, decimalVal, ast.LT, mysql.TypeDouble, 1},
		{durationVal, durationVal, ast.LT, mysql.TypeDuration, 0},
		{realVal, realVal, ast.LT, mysql.TypeDouble, 0},
		{intVal, intVal, ast.NullEQ, mysql.TypeLonglong, 1},
		{decimalVal, decimalVal, ast.LE, mysql.TypeNewDecimal, 1},
		{decimalVal, decimalVal, ast.GT, mysql.TypeNewDecimal, 0},
		{decimalVal, decimalVal, ast.GE, mysql.TypeNewDecimal, 1},
		{decimalVal, decimalVal, ast.NE, mysql.TypeNewDecimal, 0},
		{decimalVal, decimalVal, ast.EQ, mysql.TypeNewDecimal, 1},
		{decimalVal, decimalVal, ast.NullEQ, mysql.TypeNewDecimal, 1},
		{durationVal, durationVal, ast.LE, mysql.TypeDuration, 1},
		{durationVal, durationVal, ast.GT, mysql.TypeDuration, 0},
		{durationVal, durationVal, ast.GE, mysql.TypeDuration, 1},
		{durationVal, durationVal, ast.EQ, mysql.TypeDuration, 1},
		{durationVal, durationVal, ast.NE, mysql.TypeDuration, 0},
		{durationVal, durationVal, ast.NullEQ, mysql.TypeDuration, 1},
		{nil, nil, ast.NullEQ, mysql.TypeNull, 1},
		{nil, intVal, ast.NullEQ, mysql.TypeDouble, 0},
		{uintVal, intVal, ast.NullEQ, mysql.TypeLonglong, 1},
		{uintVal, intVal, ast.EQ, mysql.TypeLonglong, 1},
		{intVal, uintVal, ast.NullEQ, mysql.TypeLonglong, 1},
		{intVal, uintVal, ast.EQ, mysql.TypeLonglong, 1},
		{timeVal, timeVal, ast.LT, mysql.TypeDatetime, 0},
		{timeVal, timeVal, ast.LE, mysql.TypeDatetime, 1},
		{timeVal, timeVal, ast.GT, mysql.TypeDatetime, 0},
		{timeVal, timeVal, ast.GE, mysql.TypeDatetime, 1},
		{timeVal, timeVal, ast.EQ, mysql.TypeDatetime, 1},
		{timeVal, timeVal, ast.NE, mysql.TypeDatetime, 0},
		{timeVal, timeVal, ast.NullEQ, mysql.TypeDatetime, 1},
		{jsonVal, jsonVal, ast.LT, mysql.TypeJSON, 0},
		{jsonVal, jsonVal, ast.LE, mysql.TypeJSON, 1},
		{jsonVal, jsonVal, ast.GT, mysql.TypeJSON, 0},
		{jsonVal, jsonVal, ast.GE, mysql.TypeJSON, 1},
		{jsonVal, jsonVal, ast.NE, mysql.TypeJSON, 0},
		{jsonVal, jsonVal, ast.EQ, mysql.TypeJSON, 1},
		{jsonVal, jsonVal, ast.NullEQ, mysql.TypeJSON, 1},
	}

	for _, t := range tests {
		bf, err := funcs[t.funcName].getFunction(s.ctx, s.primitiveValsToConstants([]interface{}{t.arg0, t.arg1}))
		c.Assert(err, IsNil)
		args := bf.getArgs()
		c.Assert(args[0].GetType().Tp, Equals, t.tp)
		c.Assert(args[1].GetType().Tp, Equals, t.tp)
		res, isNil, err := bf.evalInt(chunk.Row{})
		c.Assert(err, IsNil)
		c.Assert(isNil, IsFalse)
		c.Assert(res, Equals, t.expected)
	}

	// test <non-const decimal expression> <cmp> <const string expression>
	decimalCol, stringCon := &Column{RetType: types.NewFieldType(mysql.TypeNewDecimal)}, &Constant{RetType: types.NewFieldType(mysql.TypeVarchar)}
	bf, err := funcs[ast.LT].getFunction(s.ctx, []Expression{decimalCol, stringCon})
	c.Assert(err, IsNil)
	args := bf.getArgs()
	c.Assert(args[0].GetType().Tp, Equals, mysql.TypeNewDecimal)
	c.Assert(args[1].GetType().Tp, Equals, mysql.TypeNewDecimal)

	// test <time column> <cmp> <non-time const>
	timeCol := &Column{RetType: types.NewFieldType(mysql.TypeDatetime)}
	bf, err = funcs[ast.LT].getFunction(s.ctx, []Expression{timeCol, stringCon})
	c.Assert(err, IsNil)
	args = bf.getArgs()
	c.Assert(args[0].GetType().Tp, Equals, mysql.TypeDatetime)
	c.Assert(args[1].GetType().Tp, Equals, mysql.TypeDatetime)
}

func (s *testEvaluatorSuite) TestCoalesce(c *C) {
	defer testleak.AfterTest(c)()

	cases := []struct {
		args     []interface{}
		expected interface{}
		isNil    bool
		getErr   bool
	}{
		{[]interface{}{nil}, nil, true, false},
		{[]interface{}{nil, nil}, nil, true, false},
		{[]interface{}{nil, nil, nil}, nil, true, false},
		{[]interface{}{nil, 1}, int64(1), false, false},
		{[]interface{}{nil, 1.1}, float64(1.1), false, false},
		{[]interface{}{1, 1.1}, float64(1), false, false},
		{[]interface{}{nil, types.NewDecFromFloatForTest(123.456)}, types.NewDecFromFloatForTest(123.456), false, false},
		{[]interface{}{1, types.NewDecFromFloatForTest(123.456)}, types.NewDecFromInt(1), false, false},
		{[]interface{}{nil, duration}, duration, false, false},
		{[]interface{}{nil, tm, nil}, tm, false, false},
		{[]interface{}{nil, dt, nil}, dt, false, false},
		{[]interface{}{tm, dt}, tm, false, false},
	}

	for _, t := range cases {
		f, err := newFunctionForTest(s.ctx, ast.Coalesce, s.primitiveValsToConstants(t.args)...)
		c.Assert(err, IsNil)

		d, err := f.Eval(chunk.Row{})

		if t.getErr {
			c.Assert(err, NotNil)
		} else {
			c.Assert(err, IsNil)
			if t.isNil {
				c.Assert(d.Kind(), Equals, types.KindNull)
			} else {
				c.Assert(d.GetValue(), DeepEquals, t.expected)
			}
		}
	}

	_, err := funcs[ast.Length].getFunction(s.ctx, []Expression{Zero})
	c.Assert(err, IsNil)
}

func (s *testEvaluatorSuite) TestIntervalFunc(c *C) {
	defer testleak.AfterTest(c)()
	sc := s.ctx.GetSessionVars().StmtCtx
	origin := sc.IgnoreTruncate
	sc.IgnoreTruncate = true
	defer func() {
		sc.IgnoreTruncate = origin
	}()

	for _, t := range []struct {
		args []types.Datum
		ret  int64
	}{
		{types.MakeDatums(nil, 1, 2), -1},
		{types.MakeDatums(1, 2, 3), 0},
		{types.MakeDatums(2, 1, 3), 1},
		{types.MakeDatums(3, 1, 2), 2},
		{types.MakeDatums(0, "b", "1", "2"), 1},
		{types.MakeDatums("a", "b", "1", "2"), 1},
		{types.MakeDatums(23, 1, 23, 23, 23, 30, 44, 200), 4},
		{types.MakeDatums(23, 1.7, 15.3, 23.1, 30, 44, 200), 2},
		{types.MakeDatums(9007199254740992, 9007199254740993), 0},
		{types.MakeDatums(uint64(9223372036854775808), uint64(9223372036854775809)), 0},
		{types.MakeDatums(9223372036854775807, uint64(9223372036854775808)), 0},
		{types.MakeDatums(-9223372036854775807, uint64(9223372036854775808)), 0},
		{types.MakeDatums(uint64(9223372036854775806), 9223372036854775807), 0},
		{types.MakeDatums(uint64(9223372036854775806), -9223372036854775807), 1},
		{types.MakeDatums("9007199254740991", "9007199254740992"), 0},

		// tests for appropriate precision loss
		{types.MakeDatums(9007199254740992, "9007199254740993"), 1},
		{types.MakeDatums("9007199254740992", 9007199254740993), 1},
		{types.MakeDatums("9007199254740992", "9007199254740993"), 1},
	} {
		fc := funcs[ast.Interval]
		f, err := fc.getFunction(s.ctx, s.datumsToConstants(t.args))
		c.Assert(err, IsNil)
		v, err := evalBuiltinFunc(f, chunk.Row{})
		c.Assert(err, IsNil)
		c.Assert(v.GetInt64(), Equals, t.ret)
	}
}

func (s *testEvaluatorSuite) TestGreatestLeastFuncs(c *C) {
	defer testleak.AfterTest(c)()

	sc := s.ctx.GetSessionVars().StmtCtx
	originIgnoreTruncate := sc.IgnoreTruncate
	sc.IgnoreTruncate = true
	defer func() {
		sc.IgnoreTruncate = originIgnoreTruncate
	}()

	for _, t := range []struct {
		args             []interface{}
		expectedGreatest interface{}
		expectedLeast    interface{}
		isNil            bool
		getErr           bool
	}{
		{
			[]interface{}{1, 2, 3, 4},
			int64(4), int64(1), false, false,
		},
		{
			[]interface{}{"a", "b", "c"},
			"c", "a", false, false,
		},
		{
			[]interface{}{"123a", "b", "c", 12},
			float64(123), float64(0), false, false,
		},
		{
			[]interface{}{tm, "123"},
			curTimeString, "123", false, false,
		},
		{
			[]interface{}{tm, 123},
			curTimeInt, int64(123), false, false,
		},
		{
			[]interface{}{duration, "123"},
			"12:59:59", "123", false, false,
		},
		{
			[]interface{}{"123", nil, "123"},
			nil, nil, true, false,
		},
		{
			[]interface{}{errors.New("must error"), 123},
			nil, nil, false, true,
		},
	} {
		f0, err := newFunctionForTest(s.ctx, ast.Greatest, s.primitiveValsToConstants(t.args)...)
		c.Assert(err, IsNil)
		d, err := f0.Eval(chunk.Row{})
		if t.getErr {
			c.Assert(err, NotNil)
		} else {
			c.Assert(err, IsNil)
			if t.isNil {
				c.Assert(d.Kind(), Equals, types.KindNull)
			} else {
				c.Assert(d.GetValue(), DeepEquals, t.expectedGreatest)
			}
		}

		f1, err := newFunctionForTest(s.ctx, ast.Least, s.primitiveValsToConstants(t.args)...)
		c.Assert(err, IsNil)
		d, err = f1.Eval(chunk.Row{})
		if t.getErr {
			c.Assert(err, NotNil)
		} else {
			c.Assert(err, IsNil)
			if t.isNil {
				c.Assert(d.Kind(), Equals, types.KindNull)
			} else {
				c.Assert(d.GetValue(), DeepEquals, t.expectedLeast)
			}
		}
	}
	_, err := funcs[ast.Greatest].getFunction(s.ctx, []Expression{Zero, One})
	c.Assert(err, IsNil)
	_, err = funcs[ast.Least].getFunction(s.ctx, []Expression{Zero, One})
	c.Assert(err, IsNil)
}
