FROM microsoft/windowsservercore

SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop';"]

ENV PYTHON_VERSION %%PLACEHOLDER%%
ENV PYTHON_RELEASE %%PLACEHOLDER%%

# if this is called "PIP_VERSION", pip explodes with "ValueError: invalid truth value '<VERSION>'"
ENV PYTHON_PIP_VERSION %%PLACEHOLDER%%

RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
	Write-Host ('Downloading {0} ...' -f $url); \
	(New-Object System.Net.WebClient).DownloadFile($url, 'python.exe'); \
	\
	Write-Host 'Installing ...'; \
# https://docs.python.org/3.5/using/windows.html#installing-without-ui
	Start-Process python.exe -Wait \
		-ArgumentList @( \
			'/quiet', \
			'InstallAllUsers=1', \
			'TargetDir=C:\Python', \
			'PrependPath=1', \
			'Shortcuts=0', \
			'Include_doc=0', \
			'Include_test=0' \
		); \
	\
# the installer updated PATH, so we should refresh our local value
	$env:PATH = [Environment]::GetEnvironmentVariable('PATH', [EnvironmentVariableTarget]::Machine); \
	\
	Write-Host 'Verifying install ...'; \
	Write-Host '  python --version'; python --version; \
	\
	Write-Host 'Removing ...'; \
	Remove-Item python.exe -Force; \
	\
	$pipInstall = ('pip=={0}' -f $env:PYTHON_PIP_VERSION); \
	Write-Host ('Installing {0} ...' -f $pipInstall); \
# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
# https://github.com/docker-library/python/pull/143#issuecomment-241032683
	pip install --no-cache-dir --upgrade --force-reinstall $pipInstall; \
	\
	Write-Host 'Verifying pip install ...'; \
	pip --version; \
	\
	Write-Host 'Complete.';

CMD ["python"]