app.py

def to_md(content):
    is_inside_code_block = False
    output_spans = []
    for i in range(len(content)):
        if content[i]=="\n" and not is_inside_code_block:
            if len(output_spans)>0 and output_spans[-1].endswith("```"):
                output_spans.append("\n")
            else:
                output_spans.append("<br>")
        elif content[i]=="`":
            output_spans.append(content[i])
            if len(output_spans)>=3 and all([output_spans[j]=="`" for j in [-3,-2,-1]]):
                is_inside_code_block = not is_inside_code_block
                output_spans = output_spans[:-3]
                if is_inside_code_block:
                    if len(output_spans)==0:
                        output_spans.append("```")
                    elif output_spans[-1]=="<br>":
                        output_spans[-1] = "\n"
                        output_spans.append("```")
                    elif output_spans[-1].endswith("\n"):
                        output_spans.append("```")
                    else:
                        output_spans.append("\n```")
                    
                    if i+1<len(content) and content[i+1]!="\n":
                        output_spans.append("\n")
                else:
                    if output_spans[-1].endswith("\n"):
                        output_spans.append("```")
                    else:
                        output_spans.append("\n```")
                    
                    if i+1<len(content) and content[i+1]!="\n":
                        output_spans.append("\n")
        else:
            output_spans.append(content[i])
    return "".join(output_spans)