Always run in a project virtual environment

start.bat

@@ -1,35 +1,106 @@
 @echo off
-setlocal
+setlocal enabledelayedexpansion
 
 cd /d "%~dp0"
 
+if "%SOLIXAUTO_HOME%"=="" (
+    set "DATA_DIR=%USERPROFILE%\solix-automation"
+) else (
+    set "DATA_DIR=%SOLIXAUTO_HOME%"
+)
+set "VENV_DIR=%DATA_DIR%\venv"
+set "VENV_PYTHON=%VENV_DIR%\Scripts\python.exe"
+
 echo.
 echo ==============================================================
-echo  Anker SOLIX to Shelly automation - setup
+echo  Anker SOLIX to Shelly automation
 echo ==============================================================
 echo.
 
-set PYTHON=
-
-for %%P in (py python) do (
-    if not defined PYTHON (
-        where %%P >nul 2>&1 && set PYTHON=%%P
+if exist "%VENV_PYTHON%" (
+    "%VENV_PYTHON%" -c "import anker_solix_api.api, yaml, aiohttp" >nul 2>&1
+    if not errorlevel 1 (
+        echo Using: %VENV_PYTHON%
+        echo.
+        "%VENV_PYTHON%" "%~dp0solixauto.py" setup
+        goto :end
     )
 )
 
-if not defined PYTHON (
-    echo No Python found on PATH.
-    echo Install Python 3.12 or newer from https://www.python.org/downloads/
+set "BASE="
+for %%P in (py python) do (
+    if not defined BASE (
+        where %%P >nul 2>&1 && set "BASE=%%P"
+    )
+)
+
+if not defined BASE (
+    echo Python 3.12 or newer is required and was not found on PATH.
+    echo Install it from https://www.python.org/downloads/
     echo Tick "Add python.exe to PATH" during installation, then run this again.
     echo.
     pause
     exit /b 1
 )
 
-echo Using: %PYTHON%
+where git >nul 2>&1
+if errorlevel 1 (
+    echo Git is required to fetch the Anker library, and was not found.
+    echo Install it from https://git-scm.com/download/win
+    echo.
+    pause
+    exit /b 1
+)
+
+echo This project runs in its own Python environment, so that installing or
+echo removing packages elsewhere on this machine cannot break your automation.
 echo.
+echo It will be created at:
+echo     %VENV_DIR%
+echo.
+set /p REPLY="Set it up now? [Y/n]: "
+if /i "%REPLY%"=="n" (
+    echo Nothing was changed.
+    goto :end
+)
 
-%PYTHON% "%~dp0solixauto.py" setup
+echo.
+echo Creating the environment...
+if not exist "%DATA_DIR%" mkdir "%DATA_DIR%"
+if exist "%VENV_DIR%" rmdir /s /q "%VENV_DIR%"
 
+%BASE% -m venv "%VENV_DIR%"
+if not exist "%VENV_PYTHON%" (
+    echo Could not create a virtual environment at %VENV_DIR%
+    pause
+    exit /b 1
+)
+
+echo Installing packages. This takes a minute.
+echo.
+"%VENV_PYTHON%" -m pip install --upgrade pip --quiet
+"%VENV_PYTHON%" -m pip install -r "%~dp0requirements.txt" --quiet
+"%VENV_PYTHON%" -m pip install "git+https://github.com/thomluther/anker-solix-api.git" --quiet
+"%VENV_PYTHON%" -m pip install aiofiles cryptography paho-mqtt --quiet
+
+"%VENV_PYTHON%" -c "import anker_solix_api.api" >nul 2>&1
+if errorlevel 1 (
+    echo.
+    echo The install finished but the Anker library still will not import.
+    echo Run this to see the error:
+    echo     "%VENV_PYTHON%" -c "import anker_solix_api.api"
+    pause
+    exit /b 1
+)
+
+echo.
+echo Environment ready.
+echo.
+echo From now on, run commands with:
+echo     "%VENV_PYTHON%" solixauto.py ^<command^>
+echo.
+"%VENV_PYTHON%" "%~dp0solixauto.py" setup
+
+:end
 echo.
 pause