from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.request import Request, urlopen
from urllib.error import URLError, HTTPError
import re

TARGET_URL = "https://m.slrclub.com/l/free"

class ProxyHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        requested_path = self.path
        if requested_path == "/" or requested_path == "":
            requested_path = "/l/free"

        target_url = f"https://m.slrclub.com{requested_path}"

        try:
            req = Request(
                target_url,
                headers={
                    "User-Agent": "Mozilla/5.0 (compatible; Python crawler/1.0)",
                    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
                },
            )
            with urlopen(req, timeout=15) as response:
                content_type = response.headers.get_content_type()
                charset = response.headers.get_content_charset(failobj="utf-8")
                raw_html = response.read().decode(charset, errors="replace")

            # Rewrite relative links to use this local proxy.
            if "<head" in raw_html.lower():
                host = self.headers.get("Host", f"localhost:{self.server.server_port}")
                raw_html = re.sub(
                    r"(<head[^>]*>)",
                    rf"\1<base href=\"http://{host}/\" />",
                    raw_html,
                    count=1,
                    flags=re.IGNORECASE,
                )

            self.send_response(200)
            self.send_header("Content-Type", f"{content_type}; charset={charset}")
            self.end_headers()
            self.wfile.write(raw_html.encode(charset, errors="replace"))

        except HTTPError as e:
            self.send_response(e.code)
            self.send_header("Content-Type", "text/plain; charset=utf-8")
            self.end_headers()
            self.wfile.write(f"HTTP Error: {e.code} {e.reason}".encode("utf-8"))
        except URLError as e:
            self.send_response(502)
            self.send_header("Content-Type", "text/plain; charset=utf-8")
            self.end_headers()
            self.wfile.write(f"Failed to fetch target page: {e.reason}".encode("utf-8"))
        except Exception as e:
            self.send_response(500)
            self.send_header("Content-Type", "text/plain; charset=utf-8")
            self.end_headers()
            self.wfile.write(f"Server error: {e}".encode("utf-8"))


def run(server_class=HTTPServer, handler_class=ProxyHandler, port=8000):
    server_address = ("", port)
    try:
        httpd = server_class(server_address, handler_class)
    except OSError as exc:
        if exc.errno == 98:
            raise SystemExit(f"Port {port} is already in use. Run with a different port using --port.") from exc
        raise
    print(f"Serving crawler homepage at http://localhost:{port}/")
    httpd.serve_forever()


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser(description="Proxy crawler for https://m.slrclub.com/l/free")
    parser.add_argument("--port", type=int, default=8000, help="Port to listen on")
    args = parser.parse_args()
    run(port=args.port)