# sb-builder - ssh and virsh transport
# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

"""The only code that talks to the VM: ssh to sbb-remote, and local virsh."""

import json
import os
import shlex

from PyQt6.QtCore import QObject, QProcess, QStandardPaths

DOWN = "ssh: connection failed"
MISSING = "sbb-remote is not installed on the VM"


def parse(rc, out, err):
    """Map one sbb-remote call to (data, error)."""
    if rc == 255:
        return None, DOWN
    if rc == 127:
        return None, MISSING
    try:
        data = json.loads(out)
    except ValueError:
        return None, err.decode(errors="replace").strip() or f"exit {rc}"
    if rc != 0 or "error" in data:
        return None, data.get("error", f"exit {rc}")
    return data, None


class Remote(QObject):
    def __init__(self, cfg, parent=None):
        super().__init__(parent)
        self.cfg = cfg  # shared dict, updated in place on config reload
        run = QStandardPaths.writableLocation(QStandardPaths.StandardLocation.RuntimeLocation)
        self.control = os.path.join(run or "/tmp", "sbb-%C")

    def ssh_args(self, *args):
        r = self.cfg["remote"]
        # ssh joins its args into a remote shell command: quote every one
        return ["-o", "ControlMaster=auto", "-o", f"ControlPath={self.control}",
                "-o", "ControlPersist=10m", "-o", "BatchMode=yes", "-o", "ConnectTimeout=5",
                *r["ssh_options"], r["target"], "sbb-remote", *map(shlex.quote, args)]

    def call(self, cb, *args):
        """Run sbb-remote <args>, then cb(data, error)."""
        self._run("ssh", self.ssh_args(*args), lambda rc, out, err: cb(*parse(rc, out, err)))

    def virsh(self, cb, *args):
        """Run local virsh against the configured libvirt URI, then cb(rc, text)."""
        argv = ["-c", self.cfg["vm"]["libvirt_uri"], *args]
        self._run("virsh", argv,
                  lambda rc, out, err: cb(rc, (out or err).decode(errors="replace").strip()))

    def follow(self, jid, offset):
        """Start job-follow; the caller wires readyReadStandardOutput and finished."""
        p = QProcess(self)
        p.start("ssh", self.ssh_args("job-follow", jid, str(offset)))
        return p

    def _run(self, prog, argv, cb):
        p = QProcess(self)

        def done(rc, _status=None):
            cb(rc, bytes(p.readAllStandardOutput()), bytes(p.readAllStandardError()))
            p.deleteLater()

        p.finished.connect(done)
        p.errorOccurred.connect(
            lambda e: e == QProcess.ProcessError.FailedToStart and done(-1))
        p.start(prog, argv)