#!/usr/bin/env python3
"""The agent and its supervisor must mean the same thing by "here".

    python3 tests/test_vm_working_directory.py

WHY

A Windows session was asked to write a PowerShell script, test it, and
keep it. It did all three, perfectly, and the session was reported as a
failure.

The agent's `run` inherited whatever directory the guest agent happened to
start in - on Windows, `C:\\Windows\\system32`. So `Set-Content
Get-SystemInfo.ps1`, `Get-Content .\\Get-SystemInfo.ps1` and
`powershell .\\Get-SystemInfo.ps1` all agreed with each other and all
passed. The supervisor then re-ran the verification from the PROJECT
folder, because that is the only place work survives, and found nothing
there. The model read the failure, worked out what had happened, and spent
a second whole session redoing it - roughly four minutes of machine time
to move a file.

Two rules come out of that, and this file holds both:

  1. There is ONE definition of where a command runs, and both sides call
     it. Two copies of this logic is exactly how they came to disagree.
  2. It is the project folder, because that is the only thing that
     outlives the machine. A file written anywhere else is deleted with
     the disk.
"""

import ast
import os
import sys

HERE = os.path.dirname(os.path.abspath(__file__))
VMD = os.path.join(HERE, "..", "vm", "vmd")
sys.path.insert(0, VMD)

FAILS: list[str] = []


def check(label: str, condition: bool, detail: str = "") -> None:
    if condition:
        print(f"ok    {label}")
    else:
        FAILS.append(label)
        print(f"FAIL  {label}\n      {detail}")


import verify  # noqa: E402


class FakeSession:
    def __init__(self, os_name, share):
        self.os_name = os_name
        self.share = share


# --- the prelude itself --------------------------------------------------
linux = verify.working_directory_prelude(FakeSession("ubuntu", "/Pool/vmprojects/x"))
windows = verify.working_directory_prelude(FakeSession("windows", "/Pool/vmprojects/x"))

check("a Linux command starts in the project folder", "/mnt/project" in linux, linux)
check("a Windows command starts in the project folder", "Z:\\" in windows, windows)
check("the Windows prelude is PowerShell, not shell",
      "Set-Location" in windows and "||" not in windows,
      "PowerShell has no ||; this exact mistake reported correct work as a claim")
check("the Linux prelude is shell", "cd " in linux)
check("neither prelude can fail the command it prefixes",
      "SilentlyContinue" in windows and "2>/dev/null" in linux,
      "a missing share must not turn every command into an error")

# With no project folder there is nowhere to keep anything, but a command
# still has to run somewhere predictable.
check("a session with no project folder still lands somewhere definite",
      "C:\\" in verify.working_directory_prelude(FakeSession("windows", None))
      and "/root" in verify.working_directory_prelude(FakeSession("ubuntu", None)))

# --- and both sides use it -----------------------------------------------
vmd_src = open(os.path.join(VMD, "vmd.py"), encoding="utf-8").read()
verify_src = open(os.path.join(VMD, "verify.py"), encoding="utf-8").read()

tree = ast.parse(vmd_src)
run_verb = next(n for n in ast.walk(tree)
                if isinstance(n, ast.FunctionDef) and n.name == "v_run")
run_src = ast.get_source_segment(vmd_src, run_verb) or ""
check("the agent's own run is given the prelude",
      "working_directory_prelude" in run_src,
      "this is the half that was missing, and it cost a whole extra session")
check("the supervisor's re-run is given the same prelude",
      "working_directory_prelude" in verify_src)

# One definition, not two. The duplicate is how they drifted apart.
check("the directory is decided in exactly one place",
      verify_src.count('Set-Location -LiteralPath') == 1
      and vmd_src.count("Set-Location") == 0,
      "a second copy is how the agent and the supervisor came to disagree")

print()
if FAILS:
    print(f"FAILED {len(FAILS)}")
    raise SystemExit(1)
print("the agent and its supervisor start in the same place, and it is the one that survives")