func ReviewTableSchema()

in webv2/table/review_table_schema.go [53:182]
102 lines of code
28 McCabe index (conditional complexity)

func ReviewTableSchema(w http.ResponseWriter, r *http.Request) {
	reqBody, err := ioutil.ReadAll(r.Body)
	if err != nil {
		http.Error(w, fmt.Sprintf("Body Read Error : %v", err), http.StatusInternalServerError)
		return
	}
	var t updateTable

	tableId := r.FormValue("table")

	err = json.Unmarshal(reqBody, &t)
	if err != nil {
		http.Error(w, fmt.Sprintf("Request Body parse error : %v", err), http.StatusBadRequest)
		return
	}

	sessionState := session.GetSessionState()
	sessionState.Conv.ConvLock.Lock()
	defer sessionState.Conv.ConvLock.Unlock()

	var conv *internal.Conv

	convByte, err := json.Marshal(sessionState.Conv)
	if err != nil {
		http.Error(w, fmt.Sprintf("conversion object parse error : %v", err), http.StatusInternalServerError)
		return
	}
	if err := json.Unmarshal(convByte, &conv); err != nil {
		http.Error(w, fmt.Sprintf("conversion object parse error : %v", err), http.StatusInternalServerError)
		return
	}

	conv.UsedNames = internal.ComputeUsedNames(conv)

	interleaveTableSchema := []InterleaveTableSchema{}

	for colId, v := range t.UpdateCols {

		if v.Add {
			addColumn(tableId, colId, conv)
		}

		if v.Removed {
			RemoveColumn(tableId, colId, conv)
		}

		if v.Rename != "" && v.Rename != conv.SpSchema[tableId].ColDefs[colId].Name {

			for _, c := range conv.SpSchema[tableId].ColDefs {
				if strings.EqualFold(c.Name, v.Rename) {
					http.Error(w, fmt.Sprintf("Multiple columns with similar name cannot exist for column : %v", v.Rename), http.StatusBadRequest)
					return
				}
			}
			oldName := conv.SpSchema[tableId].ColDefs[colId].Name
			// Using a regular expression to match the exact column name
			re := regexp.MustCompile(`\b` + regexp.QuoteMeta(oldName) + `\b`)

			for i := range conv.SpSchema[tableId].CheckConstraints {
				originalString := conv.SpSchema[tableId].CheckConstraints[i].Expr
				updatedValue := re.ReplaceAllString(originalString, v.Rename)
				conv.SpSchema[tableId].CheckConstraints[i].Expr = updatedValue
			}

			interleaveTableSchema = reviewRenameColumn(v.Rename, tableId, colId, conv, interleaveTableSchema)

		}

		_, found := conv.SrcSchema[tableId].ColDefs[colId]
		if v.ToType != "" && found {

			typeChange, err := utilities.IsTypeChanged(v.ToType, tableId, colId, conv)
			if err != nil {
				http.Error(w, err.Error(), http.StatusBadRequest)
				return
			}

			if typeChange {

				interleaveTableSchema, err = ReviewColumnType(v.ToType, tableId, colId, conv, interleaveTableSchema, w)
				if err != nil {
					return
				}
			}
		}

		if v.NotNull != "" {
			UpdateNotNull(v.NotNull, tableId, colId, conv)
		}

		if v.MaxColLength != "" {
			var colMaxLength int64
			if strings.ToLower(v.MaxColLength) == "max" {
				colMaxLength = ddl.MaxLength
			} else {
				colMaxLength, _ = strconv.ParseInt(v.MaxColLength, 10, 64)
			}
			if conv.SpSchema[tableId].ColDefs[colId].T.Len != colMaxLength {
				interleaveTableSchema = ReviewColumnSize(colMaxLength, tableId, colId, conv, interleaveTableSchema)
			}
		}

		if !v.Removed && !v.Add && v.Rename == "" {
			sequences := UpdateAutoGenCol(v.AutoGen, tableId, colId, conv)
			conv.SpSequences = sequences
			UpdateDefaultValue(v.DefaultValue, tableId, colId, conv)
		}
	}

	ddl := GetSpannerTableDDL(conv.SpSchema[tableId], conv.SpDialect, sessionState.Driver)

	interleaveTableSchema = trimRedundantInterleaveTableSchema(interleaveTableSchema)
	// update interleaveTableSchema by filling the missing fields.
	interleaveTableSchema = updateInterleaveTableSchema(conv, interleaveTableSchema)

	resp := ReviewTableSchemaResponse{
		DDL:     ddl,
		Changes: interleaveTableSchema,
	}

	sessionMetaData := session.GetSessionState().SessionMetadata
	if sessionMetaData.DatabaseName == "" || sessionMetaData.DatabaseType == "" || sessionMetaData.SessionName == "" {
		sessionMetaData.DatabaseName = sessionState.DbName
		sessionMetaData.DatabaseType = sessionState.Driver
		sessionMetaData.SessionName = "NewSession"
	}
	session.GetSessionState().SessionMetadata = sessionMetaData
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(resp)
}