#!/usr/bin/env python3
"""Dev server for Molly Cool.

Plain http.server caches ES modules hard enough that you edit a file,
reload, and still run the old code — which costs more debugging time
than it has any right to. This just turns caching off.
"""
import sys
from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer


import re

VERSIONED = re.compile(r"^/v\d+/")


class NoCache(SimpleHTTPRequestHandler):
    def translate_path(self, path):
        # /v1234567/src/main.js  ->  /src/main.js
        #
        # index.html imports the entry under a fresh /v<timestamp>/ prefix each
        # load, so every relative import inside the graph resolves to a URL the
        # browser has never seen. No-cache headers alone don't do it: browsers
        # cache the *parsed* module by URL, so an edited file can keep running
        # its old code until the URL itself changes.
        return super().translate_path(VERSIONED.sub("/", path))

    def end_headers(self):
        self.send_header("Cache-Control", "no-store, no-cache, must-revalidate, max-age=0")
        self.send_header("Pragma", "no-cache")
        self.send_header("Expires", "0")
        super().end_headers()

    def log_message(self, fmt, *args):
        pass  # quiet


if __name__ == "__main__":
    port = int(sys.argv[1]) if len(sys.argv) > 1 else 5178
    print(f"molly cool -> http://localhost:{port}")
    ThreadingHTTPServer(("", port), NoCache).serve_forever()