// 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

import (
	. "github.com/pingcap/check"
	"github.com/pingcap/tidb/ast"
	"github.com/pingcap/tidb/expression"
	"github.com/pingcap/tidb/kv"
	"github.com/pingcap/tidb/model"
	"github.com/pingcap/tidb/mysql"
	"github.com/pingcap/tidb/tablecodec"
	"github.com/pingcap/tidb/util"
	"github.com/pingcap/tidb/util/mock"
	"github.com/pingcap/tidb/util/types"
)

var _ = Suite(&testExecSuite{})

type testExecSuite struct {
}

type handleRange struct {
	start int64
	end   int64
}

func getExpectedRanges(tid int64, hrs []*handleRange) []kv.KeyRange {
	krs := make([]kv.KeyRange, 0, len(hrs))
	for _, hr := range hrs {
		startKey := tablecodec.EncodeRowKeyWithHandle(tid, hr.start)
		endKey := tablecodec.EncodeRowKeyWithHandle(tid, hr.end)
		krs = append(krs, kv.KeyRange{StartKey: startKey, EndKey: endKey})
	}
	return krs
}

func (s *testExecSuite) TestMergeHandles(c *C) {
	handles := []int64{0, 2, 3, 4, 5, 10, 11, 100}

	// Build expected key ranges.
	hrs := make([]*handleRange, 0, len(handles))
	hrs = append(hrs, &handleRange{start: 0, end: 1})
	hrs = append(hrs, &handleRange{start: 2, end: 6})
	hrs = append(hrs, &handleRange{start: 10, end: 12})
	hrs = append(hrs, &handleRange{start: 100, end: 101})
	expectedKrs := getExpectedRanges(1, hrs)

	// Build key ranges.
	krs := tableHandlesToKVRanges(1, handles)

	// Compare key ranges and expected key ranges.
	c.Assert(len(krs), Equals, len(expectedKrs))
	for i, kr := range krs {
		ekr := expectedKrs[i]
		c.Assert(kr.StartKey, DeepEquals, ekr.StartKey)
		c.Assert(kr.EndKey, DeepEquals, ekr.EndKey)
	}
}

// mockSessionManager is a mocked session manager which is used for test.
type mockSessionManager struct {
	PS []util.ProcessInfo
}

// ShowProcessList implements the SessionManager.ShowProcessList interface.
func (msm *mockSessionManager) ShowProcessList() []util.ProcessInfo {
	return msm.PS
}

// Kill implements the SessionManager.Kill interface.
func (msm *mockSessionManager) Kill(cid uint64, query bool) {

}

func (s *testExecSuite) TestShowProcessList(c *C) {
	// Compose schema.
	names := []string{"Id", "User", "Host", "db", "Command", "Time", "State", "Info"}
	ftypes := []byte{mysql.TypeLonglong, mysql.TypeVarchar, mysql.TypeVarchar,
		mysql.TypeVarchar, mysql.TypeVarchar, mysql.TypeLong, mysql.TypeVarchar, mysql.TypeString}
	schema := buildSchema(names, ftypes)

	// Compose a mocked session manager.
	ps := make([]util.ProcessInfo, 0, 1)
	pi := util.ProcessInfo{
		ID:      0,
		User:    "test",
		Host:    "127.0.0.1",
		DB:      "test",
		Command: "select * from t",
		State:   1,
		Info:    "",
	}
	ps = append(ps, pi)
	sm := &mockSessionManager{
		PS: ps,
	}
	ctx := mock.NewContext()
	ctx.SetSessionManager(sm)

	// Compose executor.
	e := &ShowExec{
		baseExecutor: newBaseExecutor(schema, ctx),
		Tp:           ast.ShowProcessList,
	}

	// Run test and check results.
	for _, p := range ps {
		r, err := e.Next()
		c.Assert(err, IsNil)
		c.Assert(r, NotNil)
		c.Assert(r[0].GetUint64(), Equals, p.ID)
	}
	r, err := e.Next()
	c.Assert(err, IsNil)
	c.Assert(r, IsNil)
}

func buildSchema(names []string, ftypes []byte) *expression.Schema {
	schema := expression.NewSchema(make([]*expression.Column, 0, len(names))...)
	for i := range names {
		col := &expression.Column{
			ColName: model.NewCIStr(names[i]),
		}
		// User varchar as the default return column type.
		tp := mysql.TypeVarchar
		if len(ftypes) != 0 && ftypes[0] != mysql.TypeUnspecified {
			tp = ftypes[0]
		}
		fieldType := types.NewFieldType(tp)
		fieldType.Flen, fieldType.Decimal = mysql.GetDefaultFieldLengthAndDecimal(tp)
		fieldType.Charset, fieldType.Collate = types.DefaultCharsetForType(tp)
		col.RetType = fieldType
		schema.Append(col)
	}
	return schema
}