/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 at

import (
	"context"
	"fmt"

	"github.com/mitchellh/copystructure"
	"github.com/pkg/errors"
	"github.com/seata/seata-go/pkg/datasource/sql/parser"
	"github.com/seata/seata-go/pkg/datasource/sql/undo"
	"github.com/seata/seata-go/pkg/tm"

	"github.com/seata/seata-go/pkg/datasource/sql/exec"
	"github.com/seata/seata-go/pkg/datasource/sql/types"
)

type ATExecutor struct {
	hooks []exec.SQLHook
	ex    exec.SQLExecutor
}

func (e *ATExecutor) Interceptors(hooks []exec.SQLHook) {
	e.hooks = hooks
}

func (e *ATExecutor) ExecWithNamedValue(ctx context.Context, execCtx *types.ExecContext, f exec.CallbackWithNamedValue) (types.ExecResult, error) {
	for _, hook := range e.hooks {
		hook.Before(ctx, execCtx)
	}

	var (
		beforeImages []*types.RecordImage
		afterImages  []*types.RecordImage
		result       types.ExecResult
		err          error
	)

	beforeImages, err = e.beforeImage(ctx, execCtx)
	if err != nil {
		return nil, err
	}
	if beforeImages != nil {
		beforeImagesTmp, err := copystructure.Copy(beforeImages)
		if err != nil {
			return nil, err
		}
		newBeforeImages, ok := beforeImagesTmp.([]*types.RecordImage)
		if !ok {
			return nil, errors.New("copy beforeImages failed")
		}
		execCtx.TxCtx.RoundImages.AppendBeofreImages(newBeforeImages)
	}

	defer func() {
		for _, hook := range e.hooks {
			hook.After(ctx, execCtx)
		}
	}()

	if e.ex != nil {
		result, err = e.ex.ExecWithNamedValue(ctx, execCtx, f)
	} else {
		result, err = f(ctx, execCtx.Query, execCtx.NamedValues)
	}

	if err != nil {
		return nil, err
	}

	afterImages, err = e.afterImage(ctx, execCtx, beforeImages)
	if err != nil {
		return nil, err
	}
	if afterImages != nil {
		execCtx.TxCtx.RoundImages.AppendAfterImages(afterImages)
	}

	return result, err
}

func (e *ATExecutor) prepareUndoLog(ctx context.Context, execCtx *types.ExecContext) error {
	if execCtx.TxCtx.RoundImages.IsEmpty() {
		return nil
	}

	if execCtx.ParseContext.UpdateStmt != nil {
		if !execCtx.TxCtx.RoundImages.IsBeforeAfterSizeEq() {
			return fmt.Errorf("Before image size is not equaled to after image size, probably because you updated the primary keys.")
		}
	}
	undoLogManager, err := undo.GetUndoLogManager(execCtx.DBType)
	if err != nil {
		return err
	}
	return undoLogManager.FlushUndoLog(execCtx.TxCtx, execCtx.Conn)
}

func (e *ATExecutor) ExecWithValue(ctx context.Context, execCtx *types.ExecContext, f exec.CallbackWithValue) (types.ExecResult, error) {
	for _, hook := range e.hooks {
		hook.Before(ctx, execCtx)
	}

	var (
		beforeImages []*types.RecordImage
		afterImages  []*types.RecordImage
		result       types.ExecResult
		err          error
	)

	beforeImages, err = e.beforeImage(ctx, execCtx)
	if err != nil {
		return nil, err
	}
	if beforeImages != nil {
		execCtx.TxCtx.RoundImages.AppendBeofreImages(beforeImages)
	}

	defer func() {
		for _, hook := range e.hooks {
			hook.After(ctx, execCtx)
		}
	}()

	if e.ex != nil {
		result, err = e.ex.ExecWithValue(ctx, execCtx, f)
	} else {
		result, err = f(ctx, execCtx.Query, execCtx.Values)
	}
	if err != nil {
		return nil, err
	}

	afterImages, err = e.afterImage(ctx, execCtx, beforeImages)
	if err != nil {
		return nil, err
	}
	if afterImages != nil {
		execCtx.TxCtx.RoundImages.AppendAfterImages(afterImages)
	}

	return result, err
}

func (e *ATExecutor) beforeImage(ctx context.Context, execCtx *types.ExecContext) ([]*types.RecordImage, error) {
	if !tm.IsGlobalTx(ctx) {
		return nil, nil
	}

	pc, err := parser.DoParser(execCtx.Query)
	if err != nil {
		return nil, err
	}
	if !pc.HasValidStmt() {
		return nil, nil
	}
	execCtx.ParseContext = pc

	builder := undo.GetUndologBuilder(pc.ExecutorType)
	if builder == nil {
		return nil, nil
	}
	return builder.BeforeImage(ctx, execCtx)
}

// After
func (e *ATExecutor) afterImage(ctx context.Context, execCtx *types.ExecContext, beforeImages []*types.RecordImage) ([]*types.RecordImage, error) {
	if !tm.IsGlobalTx(ctx) {
		return nil, nil
	}
	pc, err := parser.DoParser(execCtx.Query)
	if err != nil {
		return nil, err
	}
	if !pc.HasValidStmt() {
		return nil, nil
	}
	execCtx.ParseContext = pc
	builder := undo.GetUndologBuilder(pc.ExecutorType)
	if builder == nil {
		return nil, nil
	}
	return builder.AfterImage(ctx, execCtx, beforeImages)
}