#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Simple CMS
#
# Copyright (C) 2011-2024 Michael Büsch <m@bues.ch>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import sys, os, fcntl, socket, time, pathlib, argparse

def get_backsock(rundir):
    notify_socket = os.getenv("NOTIFY_SOCKET")
    if notify_socket:
        listen_fds = os.getenv("LISTEN_FDS")
        if not listen_fds:
            raise ValueError("env: LISTEN_FDS not set.")
        listen_fds = int(listen_fds, 10)
        if listen_fds <= 0 or listen_fds > 1:
            raise ValueError("env: Invalid LISTEN_FDS.")

        with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as sdsock:
            sdsock.connect(notify_socket)
            fd = 3
            for i in range(fd, fd + listen_fds):
                fcntl.fcntl(i, fcntl.F_SETFD, fcntl.FD_CLOEXEC)
            backsock = socket.fromfd(fd, socket.AF_UNIX, socket.SOCK_STREAM)
            sdsock.sendall(b"READY=1")
        return backsock
    else:
        backsock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        backsock.bind(str(rundir / "cms-backd.sock"))
        backsock.listen()
        return backsock

def run_backd(backsock, rundir):
    debug = False
    while True:
        try:
            conn, addr = backsock.accept()
            if debug:
                startStamp = time.monotonic()
            msg = recv_message(conn, MAGIC_BACK)
        except Exception as e:
            print(f"cms-backd: Receive failed: {e}", file=sys.stderr)
            time.sleep(0.1)
            continue

        status = 200 # Ok
        reply_body = b""
        reply_mime = ""
        extra_headers = []
        cms = CMS(domain="", rundir=rundir, debug=debug)
        try:
            if isinstance(msg, MsgGet):
                cms.domain = msg.host
                protocol = "https" if msg.https else "http"
                reply_body, reply_mime = cms.get(msg.path, msg.query, protocol)

                if "html" in reply_mime:
                    extra_headers.append("Cache-Control: max-age=10")
                elif reply_mime.startswith("image/"):
                    extra_headers.append("Cache-Control: max-age=3600")
                elif reply_mime.startswith("text/css"):
                    extra_headers.append("Cache-Control: max-age=600")
            elif isinstance(msg, MsgPost):
                cms.domain = msg.host
                protocol = "https" if msg.https else "http"
                reply_body, reply_mime = cms.post(msg.path, msg.query, msg.body, msg.body_mime, protocol)

                extra_headers.append("Cache-Control: no-cache")
            else:
                raise RuntimeError("Received invalid message.")
        except CMSException as e:
            status = e.httpStatusCode
            reply_body, reply_mime, extra_headers = cms.getErrorPage(e, protocol)
            extra_headers.append("Cache-Control: no-store")

        if debug:
            delta = time.monotonic() - startStamp
            us = round(delta * 1e6)
            extra_headers.append(f"X-CMS-Py-Walltime: {us} us")

        reply = MsgReply(
            status=status,
            body=reply_body,
            mime=reply_mime,
            extra_headers=extra_headers,
        )
        reply_data = reply.pack()
        try:
            conn.sendall(reply_data)
        except Exception as e:
            print(f"cms-backd: Failed to send reply: {e}", file=sys.stderr)
            continue

if __name__ == "__main__":
    p = argparse.ArgumentParser()
    p.add_argument("--rundir", type=pathlib.Path,
                   default=pathlib.Path("/run"))
    p.add_argument("--pythonpath", type=pathlib.Path,
                   default=pathlib.Path("/opt/cms/lib/python3/site-packages"))
    p.add_argument("--no-cython", action="store_true")
    args = p.parse_args()

    sys.path.insert(0, str(args.pythonpath))
    imported = False
    if not args.no_cython:
        try:
            from cms_cython.socket import *
            from cms_cython import CMS, CMSException
            imported = True
        except ImportError as e:
            print("cms-backd: Failed to import cms_cython:", e, file=sys.stderr)
    if not imported:
        from cms.socket import *
        from cms import CMS, CMSException

    backsock = get_backsock(args.rundir)
    run_backd(backsock, args.rundir)

# vim: ts=4 sw=4 expandtab