// Copyright 2024 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 exec

import (
	"time"

	"github.com/pingcap/tidb/pkg/metrics"
	"github.com/pingcap/tidb/pkg/parser/ast"
	"github.com/pingcap/tidb/pkg/sessionctx"
	"github.com/pingcap/tidb/pkg/statistics"
	statslogutil "github.com/pingcap/tidb/pkg/statistics/handle/logutil"
	statstypes "github.com/pingcap/tidb/pkg/statistics/handle/types"
	statsutil "github.com/pingcap/tidb/pkg/statistics/handle/util"
	"github.com/pingcap/tidb/pkg/util/chunk"
	"github.com/pingcap/tidb/pkg/util/sqlescape"
	"github.com/pingcap/tidb/pkg/util/sqlexec"
	"go.uber.org/zap"
)

var execOptionForAnalyze = map[int]sqlexec.OptionFuncAlias{
	statistics.Version0: sqlexec.ExecOptionAnalyzeVer1,
	statistics.Version1: sqlexec.ExecOptionAnalyzeVer1,
	statistics.Version2: sqlexec.ExecOptionAnalyzeVer2,
}

// AutoAnalyze executes the auto analyze task.
func AutoAnalyze(
	sctx sessionctx.Context,
	statsHandle statstypes.StatsHandle,
	sysProcTracker sessionctx.SysProcTracker,
	statsVer int,
	sql string,
	params ...any,
) {
	startTime := time.Now()
	_, _, err := execAnalyzeStmt(sctx, statsHandle, sysProcTracker, statsVer, sql, params...)
	dur := time.Since(startTime)
	metrics.AutoAnalyzeHistogram.Observe(dur.Seconds())
	if err != nil {
		escaped, err1 := sqlescape.EscapeSQL(sql, params...)
		if err1 != nil {
			escaped = ""
		}
		statslogutil.StatsLogger().Error(
			"auto analyze failed",
			zap.String("sql", escaped),
			zap.Duration("cost_time", dur),
			zap.Error(err),
		)
		metrics.AutoAnalyzeCounter.WithLabelValues("failed").Inc()
	} else {
		metrics.AutoAnalyzeCounter.WithLabelValues("succ").Inc()
	}
}

func execAnalyzeStmt(
	sctx sessionctx.Context,
	statsHandle statstypes.StatsHandle,
	sysProcTracker sessionctx.SysProcTracker,
	statsVer int,
	sql string,
	params ...any,
) ([]chunk.Row, []*ast.ResultField, error) {
	pruneMode := sctx.GetSessionVars().PartitionPruneMode.Load()
	analyzeSnapshot := sctx.GetSessionVars().EnableAnalyzeSnapshot
	optFuncs := []sqlexec.OptionFuncAlias{
		execOptionForAnalyze[statsVer],
		sqlexec.GetAnalyzeSnapshotOption(analyzeSnapshot),
		sqlexec.GetPartitionPruneModeOption(pruneMode),
		sqlexec.ExecOptionUseCurSession,
		sqlexec.ExecOptionWithSysProcTrack(statsHandle.AutoAnalyzeProcID(), sysProcTracker.Track, sysProcTracker.UnTrack),
	}
	return statsutil.ExecWithOpts(sctx, optFuncs, sql, params...)
}