import os
from flask import Flask, Response
import threading
from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer

# --------------  VARIABLES   --------------
html_file_path = r"PATH"
host = "0.0.0.0"
port = 80
is_oe11 = True  # if using OE11 set it to True, for OE12 set it to False (encoding)
scroll_pixels = 100
scroll_interval = 3  # seconds
bottom_wait_time = 3  # seconds
top_wait_time = 3  # seconds
# -------------- END VARIABLES --------------

app = Flask(__name__)
file_change_event = threading.Event()


class FileChangeHandler(FileSystemEventHandler):
    def on_modified(self, event):
        if event.src_path == html_file_path:
            file_change_event.set()


@app.route("/_file_change")
def file_change_stream():
    def stream():
        while True:
            file_change_event.wait()
            yield "data: reload\n\n"
            file_change_event.clear()

    return Response(stream(), content_type="text/event-stream")


@app.route("/")
def serve_html():
    with open(html_file_path, "r", encoding=("cp1252" if is_oe11 else "utf-8")) as file:
        content = file.read()
    content += f"""
    <style>
        html {{
            scroll-behavior: smooth;
        }}
    </style>
<script>
        let scrollAmount = {scroll_pixels};
        let scrollInterval = {scroll_interval} * 1000;
        let bottomWaitTime = {bottom_wait_time} * 1000;
        let topWaitTime = {top_wait_time} * 1000;
        let scrollPos = 0;
        let scrollingDown = true;

        function autoScroll() {{
            if (scrollingDown) {{
                window.scrollBy(0, scrollAmount);
                scrollPos += scrollAmount;
                if ((window.innerHeight + window.scrollY) >= document.body.offsetHeight) {{
                    scrollingDown = false;
                    setTimeout(reloadPage, bottomWaitTime);
                    return;
                }}
            }} else {{
                window.scrollTo(0, 0);
                scrollPos = 0;
                scrollingDown = true;
                setTimeout(autoScroll, topWaitTime);
                return;
            }}
            setTimeout(autoScroll, scrollInterval);
        }}

        function reloadPage() {{
            window.scrollTo(0, 0);
            setTimeout(() => {{
                location.reload();
            }}, 100);
        }}

        window.onload = function() {{
            window.scrollTo(0, 0);
            if (document.body.scrollHeight <= window.innerHeight) {{
                const eventSource = new EventSource('/_file_change');
                eventSource.onmessage = function() {{
                    location.reload();
                }};
            }} else {{
                setTimeout(autoScroll, topWaitTime);
            }}
        }};
    </script>
    """
    return content


if __name__ == "__main__":
    event_handler = FileChangeHandler()
    observer = Observer()
    observer.schedule(
        event_handler, path=os.path.dirname(html_file_path), recursive=False
    )
    observer.start()
    try:
        app.run(host=host, port=port)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()