// Copyright 2023 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package testutil

import (
	"github.com/pingcap/tidb/pkg/meta/model"
	"github.com/pingcap/tidb/pkg/parser/mysql"
	"github.com/pingcap/tidb/pkg/statistics"
	"github.com/pingcap/tidb/pkg/types"
)

// NewMockStatisticsTable creates a mock statistics table with given columns and indices.
// each column and index consumes 4 bytes memory
func NewMockStatisticsTable(columns int, indices int, withCMS, withTopN, withHist bool) *statistics.Table {
	t := &statistics.Table{HistColl: *statistics.NewHistColl(0, false, 0, 0, 0, 0)}
	for i := 1; i <= columns; i++ {
		var (
			cms  *statistics.CMSketch
			topn *statistics.TopN
			hist statistics.Histogram
		)
		if withCMS {
			cms = statistics.NewCMSketch(1, 1)
		}
		if withTopN {
			topn = statistics.NewTopN(1)
			topn.AppendTopN([]byte{}, 1)
		}
		if withHist {
			hist = *statistics.NewHistogram(0, 10, 0, 0, types.NewFieldType(mysql.TypeBlob), 1, 0)
		}
		t.SetCol(int64(i), &statistics.Column{
			Info:              &model.ColumnInfo{ID: int64(i)},
			StatsLoadedStatus: statistics.NewStatsFullLoadStatus(),
			CMSketch:          cms,
			TopN:              topn,
			Histogram:         hist,
		})
	}
	for i := 1; i <= indices; i++ {
		var (
			cms  *statistics.CMSketch
			topn *statistics.TopN
			hist statistics.Histogram
		)
		if withCMS {
			cms = statistics.NewCMSketch(1, 1)
		}
		if withTopN {
			topn = statistics.NewTopN(1)
			topn.AppendTopN([]byte{}, 1)
		}
		if withHist {
			hist = *statistics.NewHistogram(0, 10, 0, 0, types.NewFieldType(mysql.TypeBlob), 1, 0)
		}
		t.SetIdx(int64(i), &statistics.Index{
			Info:              &model.IndexInfo{ID: int64(i)},
			StatsLoadedStatus: statistics.NewStatsFullLoadStatus(),
			CMSketch:          cms,
			TopN:              topn,
			Histogram:         hist,
		})
	}
	return t
}

// MockTableAppendColumn appends a column to the table.
func MockTableAppendColumn(t *statistics.Table) {
	index := int64(t.ColNum() + 1)
	t.SetCol(index, &statistics.Column{
		Info:     &model.ColumnInfo{ID: index},
		CMSketch: statistics.NewCMSketch(1, 1),
	})
}

// MockTableAppendIndex appends an index to the table.
func MockTableAppendIndex(t *statistics.Table) {
	index := int64(t.IdxNum() + 1)
	t.SetIdx(index, &statistics.Index{
		Info:     &model.IndexInfo{ID: index},
		CMSketch: statistics.NewCMSketch(1, 1),
	})
}