How to recognize a swing direction

I am writing an indicator which gives an alert when there appears some certain candle pattern near an S/R level. It needs to recognize the swing direction in which it approaches the S/R level. Recognizing the swing direction in the indicator is a bit difficult for me. Would you give me some advice on it? Thanks in advance.

You are tackling a toughie. I have tried something like that myself and was only partly successful. I guess the first thing we need to know to help you is how are you defining S/R. Do you input these levels to the indicator or is there some logic in the indicator for this?

My suggestion is to get familiar with Fractals. They will give you the recent high or low swings. That may sound simple, but it isn't so you need to be very familiar to discuss this further. The other suggestion is to look at an MTF (Multi TF) Fractal indicator - a search should find one.

I define the S/R manually and draw horizontal lines on the chart. The indicator will search the lines.
I am now considering the zigzag indicator to define the swing but it seems not ideal. I will try to use fractals.
Thanks a lot for the info.

Defining the S/R levels for the EA is definitely the best thing to do. Sounds to me like you are on the right track. I have worked with Fractals and wondered if I should use ZigZag but never took the time to examine the benefits of ZigZag. Perhaps someone with experience with both can comment.

Turning points IMO are too finite to use as simple S/R.

I just define S/R 'zones' by calculating the 'bar density'--number of bars at a certain price point--in a given range of bars.