使用R Shiny中的动态输入构建线性回归

I am trying to build a simple shiny app using a linear regression that allows the user to select both the independent and dependent variables that are used in the lm() function and eventually plot out a few charts as well. I am currently stuck on passing the inputs to the lm() function on the server side of shiny and being able to print out the summary of the regression. Can anyone assist me in where my logic/code is going wrong. Below is the codeI am trying to build a simple shiny app using a