chore: extract dependencies.bat from windows.bat (#910)

The logic to install dependencies on Windows now separately lives in
`scripts/windows/dependencies.bat`, similarly to what we've been done
with other operating systems.

Signed-off-by: Juan Cruz Viotti <jviotti@openmailbox.org>

scripts/build/windows.bat

@@ -74,13 +74,6 @@ if %ERRORLEVEL% neq 0 (
   exit /b 1
 )
 
-:: Check that bower is installed.
-where bower >nul 2>nul
-if %ERRORLEVEL% neq 0 (
-  echo Dependency missing: bower 1>&2
-  exit /b 1
-)
-
 :: Check that makensis is installed.
 where makensis >nul 2>nul
 if %ERRORLEVEL% neq 0 (
@@ -158,28 +151,12 @@ for /f %%i in (' "node -v" ') do (
 
 set package_name=Etcher-%etcher_version%-win32-%arch%
 
-:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-:: Configure NPM to build native addons for Electron correctly
-:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-
-:: We require Visual Studio 2013 specifically since newer versions
-:: lack command line build tools such as `lib.exe` and `cl.exe`.
-set GYP_MSVS_VERSION=2013
-
-set npm_config_disturl=https://atom.io/download/atom-shell
-set npm_config_runtime=electron
-set npm_config_target=%electron_version%
-set npm_config_arch=%electron_arch%
-set HOME=%homedrive%%homepath%\.electron-gyp
-
 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
 :: Install dependencies
 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
 
 if not "%command%"=="package" (
-  call rimraf node_modules bower_components
-  call npm install --build-from-source
-  call bower install --production
+  call scripts\windows\dependencies.bat -r %arch% -v %electron_version% -t electron
 )
 
 if "%command%"=="install" (

scripts/windows/dependencies.bat

@@ -0,0 +1,118 @@
+@echo off
+setlocal EnableDelayedExpansion
+
+:ParameterLoop
+if x%1 equ x goto :ParameterDone
+set parameter=%1
+if %parameter:~0,1% equ - goto CheckParameter
+:Usage
+echo Usage: %0
+echo.
+echo Options
+echo.
+echo     -r ^<architecture^>
+echo     -v ^<target version^>
+echo     -t ^<target platform (node^|electron)^>
+echo     -f force install
+echo     -p production install
+exit /b 1
+:NextParameter
+shift /1
+goto ParameterLoop
+:CheckParameter
+if "%1" equ "-r" goto ARGV_R
+if "%1" equ "-v" goto ARGV_V
+if "%1" equ "-t" goto ARGV_T
+if "%1" equ "-f" goto ARGV_F
+if "%1" equ "-p" goto ARGV_P
+goto Usage
+:ARGV_R
+  shift /1
+  set argv_architecture=%1
+  goto NextParameter
+:ARGV_V
+  shift /1
+  set argv_target_version=%1
+  goto NextParameter
+:ARGV_T
+  shift /1
+  set argv_target_platform=%1
+  goto NextParameter
+:ARGV_F
+  shift /1
+  set argv_force=true
+  goto NextParameter
+:ARGV_P
+  shift /1
+  set argv_production=true
+  goto NextParameter
+:ParameterDone
+if not defined argv_architecture (goto Usage)
+if not defined argv_target_version (goto Usage)
+if not defined argv_target_platform (goto Usage)
+
+:: Check that rimraf is installed.
+:: We make use of this command line tool to clear
+:: saved dependencies since doing so with `del`
+:: might return errors due to long paths.
+where rimraf >nul 2>nul
+if %ERRORLEVEL% neq 0 (
+  echo Dependency missing: rimraf 1>&2
+  exit /b 1
+)
+
+:: Check that npm is installed.
+where npm >nul 2>nul
+if %ERRORLEVEL% neq 0 (
+  echo Dependency missing: npm 1>&2
+  exit /b 1
+)
+
+:: Check that bower is installed.
+where bower >nul 2>nul
+if %ERRORLEVEL% neq 0 (
+  echo Dependency missing: bower 1>&2
+  exit /b 1
+)
+
+:: Check that python is installed.
+where python >nul 2>nul
+if %ERRORLEVEL% neq 0 (
+  echo Dependency missing: python 1>&2
+  exit /b 1
+)
+
+:: We require Visual Studio 2013 specifically since newer versions
+:: lack command line build tools such as `lib.exe` and `cl.exe`.
+set GYP_MSVS_VERSION=2013
+
+if "%argv_target_platform%"=="electron" (
+  set npm_config_disturl=https://atom.io/download/atom-shell
+  set npm_config_runtime=electron
+)
+
+set npm_config_target=%argv_target_version%
+
+if "%argv_architecture%"=="x86" (
+  set npm_config_arch=ia32
+) else (
+  set npm_config_arch=%electron_arch%
+)
+
+set npm_install_opts=--build-from-source
+
+if "%argv_force%"=="true" (
+  set npm_install_opts=%npm_install_opts% --force
+)
+
+if "%argv_production%"=="true" (
+  set npm_install_opts=%npm_install_opts% --production
+)
+
+call rimraf node_modules
+call npm install %npm_install_opts%
+
+if "%argv_target_platform%"=="electron" (
+  call rimraf bower_components
+  call bower install --production
+)