office: --new creates the Paperclip project, --remote adopts a folder on another machine

bin/office

@@ -2,12 +2,19 @@
 """Open a folder as a project: adopt it, remember it, build its pages.
 
     bin/office <folder> [--project <id|urlKey|name>] [--session NAME] [--dry]
-    bin/office .        # the folder you are in
+    bin/office .                          # the folder you are in
+    bin/office <folder> --new "Name"      # create the Paperclip project too
+    bin/office --remote <ssh-host> <folder> --project "Name"   # the folder is on another machine
 
-Adopting writes one file, <folder>/.harness/harness.toml, and nothing else. An
-existing folder is never overwritten: what is already there stays, and only the
-missing file is written. Paperclip's project record is read, never created —
-bin/office adopts a project that exists, it does not invent one.
+Adopting writes <folder>/.harness/ (the project file, check.sh, NOTES.md) and
+nothing else. An existing file is never overwritten. With --new, Paperclip gets
+a project for the folder, with the per-task worktree policy set; without it,
+--project adopts a project that already exists.
+
+A session is created on the daemon of the machine that runs this command, and
+the panes run on that machine. A program cannot move your client to the new
+session: TUIOS refuses that from a pane. Switch with TUIOS's session switcher,
+or `tuios attach --host <machine> <session>`.
 
 The machine is remembered, so the flag is stated once. Running the same command
 on a machine that is not the recorded one is refused rather than silently
@@ -16,6 +23,7 @@ producing a second copy of the same project.
 
 import json
 import os
+import shlex
 import subprocess
 import sys
 
@@ -27,21 +35,34 @@ import tuios  # noqa: E402
 
 
 def parse(argv):
-    opts = {"folder": ".", "project": "", "session": "", "dry": "--dry" in argv,
-            "host": "", "no_switch": "--no-switch" in argv, "new": ""}
-    for i, a in enumerate(argv):
-        if a == "--new" and i + 1 < len(argv):
-            opts["new"] = argv[i + 1]
-    args = [a for a in argv if not a.startswith("--")]
-    if args:
-        opts["folder"] = args[0]
-    for i, a in enumerate(argv):
-        if a == "--project" and i + 1 < len(argv):
-            opts["project"] = argv[i + 1]
-        if a == "--session" and i + 1 < len(argv):
-            opts["session"] = argv[i + 1]
-        if a == "--host" and i + 1 < len(argv):
-            opts["host"] = argv[i + 1]
+    """Read the flags, then take what is left as the folder.
+
+    A flag's value is not a folder. The first version of this treated the value
+    of --remote as the folder, which is exactly the kind of bug that only shows
+    up when someone uses the flag.
+    """
+    opts = {"folder": ".", "project": "", "session": "", "dry": False,
+            "host": "", "no_switch": False, "new": "", "remote": ""}
+    positional = []
+    i = 0
+    while i < len(argv):
+        a = argv[i]
+        if a in ("--project", "--session", "--host", "--new", "--remote"):
+            if i + 1 < len(argv):
+                opts[a[2:]] = argv[i + 1]
+                i += 2
+                continue
+            i += 1
+            continue
+        if a == "--dry":
+            opts["dry"] = True
+        elif a == "--no-switch":
+            opts["no_switch"] = True
+        elif not a.startswith("-"):
+            positional.append(a)
+        i += 1
+    if positional:
+        opts["folder"] = positional[0]
     return opts
 
 
@@ -145,6 +166,34 @@ exit 0
     return written
 
 
+
+def run_on_remote(host, folder, opts):
+    """Adopt a folder that lives on another machine, from where you are sitting.
+
+    The session has to be made by the daemon that will hold the panes, and the
+    panes have to run on the machine that owns the folder. So the work is done
+    over ssh on that machine, and only the last step — showing the session — is
+    the client's own business.
+    """
+    here = os.path.dirname(os.path.abspath(__file__))
+    inner = [os.path.join(here, "office"), folder, "--no-switch"]
+    for flag, value in (("--project", opts["project"]), ("--session", opts["session"]), ("--new", opts["new"])):
+        if value:
+            inner += [flag, value]
+    if opts["dry"]:
+        inner.append("--dry")
+    cmd = " ".join(shlex.quote(a) for a in inner)
+    h.say("on %s: %s" % (host, cmd))
+    out = subprocess.run(["ssh", "-o", "StrictHostKeyChecking=accept-new", host, cmd],
+                         capture_output=True, text=True, timeout=600)
+    sys.stdout.write(out.stdout)
+    if out.returncode != 0:
+        raise h.Refused(3, "the other machine refused: %s" % (out.stderr or out.stdout).strip()[:300])
+    h.say("")
+    h.say("switch to it:  tuios attach --host %s %s" % (host, opts["session"] or os.path.basename(folder)))
+    return 0
+
+
 def main():
     opts = parse(sys.argv[1:])
     folder = os.path.abspath(os.path.expanduser(opts["folder"]))
@@ -168,6 +217,9 @@ def main():
     # so one command takes a person from a folder to a working layout. TUIOS has
     # the verb for exactly this; asking the person to run `tuios new` first was
     # the step everyone forgot.
+    if opts["remote"]:
+        return run_on_remote(opts["remote"], folder, opts)
+
     if opts["dry"]:
         h.say("would create a Paperclip project %r for %s" % (opts["new"] or opts["project"], folder))
         h.say("would write %s" % os.path.join(folder, ".harness", "harness.toml"))