// 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 plannersession

import (
	"github.com/pingcap/tidb/pkg/expression/exprctx"
	"github.com/pingcap/tidb/pkg/planner/planctx"
	"github.com/pingcap/tidb/pkg/sessionctx"
	"github.com/pingcap/tidb/pkg/sessiontxn"
	"github.com/pingcap/tidb/pkg/util/intest"
)

var _ planctx.PlanContext = struct {
	sessionctx.Context
	*PlanCtxExtended
}{}

// PlanCtxExtended provides extended method for session context to implement `PlanContext`
type PlanCtxExtended struct {
	sctx                   sessionctx.Context
	nullRejectCheckExprCtx *exprctx.NullRejectCheckExprContext
	readonlyUserVars       map[string]struct{}
}

// NewPlanCtxExtended creates a new PlanCtxExtended.
func NewPlanCtxExtended(sctx sessionctx.Context) *PlanCtxExtended {
	return &PlanCtxExtended{
		sctx:                   sctx,
		nullRejectCheckExprCtx: exprctx.WithNullRejectCheck(sctx.GetExprCtx()),
	}
}

// GetNullRejectCheckExprCtx returns a context with null rejected check
func (ctx *PlanCtxExtended) GetNullRejectCheckExprCtx() exprctx.ExprContext {
	intest.AssertFunc(func() bool {
		// assert `sctx.GetExprCtx()` should keep the same to avoid some unexpected behavior.
		return ctx.nullRejectCheckExprCtx.ExprContext == ctx.sctx.GetExprCtx()
	})
	return ctx.nullRejectCheckExprCtx
}

// AdviseTxnWarmup advises the txn to warm up.
func (ctx *PlanCtxExtended) AdviseTxnWarmup() error {
	return sessiontxn.GetTxnManager(ctx.sctx).AdviseWarmup()
}

// SetReadonlyUserVarMap sets the readonly user variable map.
func (ctx *PlanCtxExtended) SetReadonlyUserVarMap(readonlyUserVars map[string]struct{}) {
	ctx.readonlyUserVars = readonlyUserVars
}

// GetReadonlyUserVarMap gets the readonly user variable map.
func (ctx *PlanCtxExtended) GetReadonlyUserVarMap() map[string]struct{} {
	return ctx.readonlyUserVars
}

// Reset resets the local
func (ctx *PlanCtxExtended) Reset() {
	ctx.readonlyUserVars = nil
}