// Copyright 2018 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 statistics_test

import (
	"fmt"

	. "github.com/pingcap/check"
	"github.com/pingcap/parser/model"
	"github.com/pingcap/tidb/statistics"
	"github.com/pingcap/tidb/util/testkit"
)

func (s *testStatsSuite) TestConversion(c *C) {
	defer cleanEnv(c, s.store, s.do)
	tk := testkit.NewTestKit(c, s.store)
	tk.MustExec("use test")

	tk.MustExec("create table t (a int, b int)")
	tk.MustExec("create index c on t(a,b)")
	tk.MustExec("insert into t(a,b) values (3, 1),(2, 1),(1, 10)")
	tk.MustExec("analyze table t")
	tk.MustExec("insert into t(a,b) values (1, 1),(3, 1),(5, 10)")
	is := s.do.InfoSchema()
	h := s.do.StatsHandle()
	h.DumpStatsDeltaToKV(statistics.DumpAll)
	h.Update(is)

	tableInfo, err := is.TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
	c.Assert(err, IsNil)
	jsonTbl, err := h.DumpStatsToJSON("test", tableInfo.Meta())
	c.Assert(err, IsNil)
	loadTbl, err := statistics.TableStatsFromJSON(tableInfo.Meta(), tableInfo.Meta().ID, jsonTbl)
	c.Assert(err, IsNil)

	tbl := h.GetTableStats(tableInfo.Meta())
	assertTableEqual(c, loadTbl, tbl)

	err = h.LoadStatsFromJSON(is, jsonTbl)
	c.Assert(err, IsNil)
	loadTblInStorage := h.GetTableStats(tableInfo.Meta())
	assertTableEqual(c, loadTblInStorage, tbl)
}

func (s *testStatsSuite) TestDumpPartitions(c *C) {
	defer cleanEnv(c, s.store, s.do)
	tk := testkit.NewTestKit(c, s.store)
	tk.MustExec("use test")
	tk.MustExec("drop table if exists t")
	createTable := `CREATE TABLE t (a int, b int, primary key(a), index idx(b))
PARTITION BY RANGE ( a ) (
		PARTITION p0 VALUES LESS THAN (6),
		PARTITION p1 VALUES LESS THAN (11),
		PARTITION p2 VALUES LESS THAN (16),
		PARTITION p3 VALUES LESS THAN (21)
)`
	tk.MustExec(createTable)
	for i := 1; i < 21; i++ {
		tk.MustExec(fmt.Sprintf(`insert into t values (%d, %d)`, i, i))
	}
	tk.MustExec("analyze table t")
	is := s.do.InfoSchema()
	h := s.do.StatsHandle()
	h.Update(is)

	table, err := is.TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
	c.Assert(err, IsNil)
	tableInfo := table.Meta()
	jsonTbl, err := h.DumpStatsToJSON("test", tableInfo)
	c.Assert(err, IsNil)
	pi := tableInfo.GetPartitionInfo()
	originTables := make([]*statistics.Table, 0, len(pi.Definitions))
	for _, def := range pi.Definitions {
		originTables = append(originTables, h.GetPartitionStats(tableInfo, def.ID))
	}

	tk.MustExec("delete from mysql.stats_meta")
	tk.MustExec("delete from mysql.stats_histograms")
	tk.MustExec("delete from mysql.stats_buckets")
	h.Clear()

	err = h.LoadStatsFromJSON(s.do.InfoSchema(), jsonTbl)
	c.Assert(err, IsNil)
	for i, def := range pi.Definitions {
		t := h.GetPartitionStats(tableInfo, def.ID)
		assertTableEqual(c, originTables[i], t)
	}
}

func (s *testStatsSuite) TestDumpAlteredTable(c *C) {
	defer cleanEnv(c, s.store, s.do)
	tk := testkit.NewTestKit(c, s.store)
	tk.MustExec("use test")
	tk.MustExec("drop table if exists t")
	h := s.do.StatsHandle()
	oriLease := h.Lease
	h.Lease = 1
	defer func() { h.Lease = oriLease }()
	tk.MustExec("create table t(a int, b int)")
	tk.MustExec("analyze table t")
	tk.MustExec("alter table t drop column a")
	table, err := s.do.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
	c.Assert(err, IsNil)
	_, err = h.DumpStatsToJSON("test", table.Meta())
	c.Assert(err, IsNil)
}