#!/usr/bin/ruby
# This script installs to /usr/local only. To install elsewhere you can just
# untar https://github.com/mxcl/homebrew/tarball/master anywhere you like or
# change the value of HOMEBREW_PREFIX.
HOMEBREW_PREFIX = '/usr/local'

module Tty extend self
  def blue; bold 34; end
  def white; bold 39; end
  def red; underline 31; end
  def reset; escape 0; end
  def bold n; escape "1;#{n}" end
  def underline n; escape "4;#{n}" end
  def escape n; "\033[#{n}m" if STDOUT.tty? end
end

class Array
  def shell_s
    cp = dup
    first = cp.shift
    cp.map{ |arg| arg.gsub " ", "\\ " }.unshift(first) * " "
  end
end

def ohai *args
  puts "#{Tty.blue}==>#{Tty.white} #{args.shell_s}#{Tty.reset}"
end

def warn warning
  puts "#{Tty.red}Warning#{Tty.reset}: #{warning.chomp}"
end
 
def system *args
  abort "Failed during: #{args.shell_s}" unless Kernel.system *args
end

def sudo *args
  args = if args.length > 1
    args.unshift "/usr/bin/sudo"
  else
    "/usr/bin/sudo #{args.first}"
  end
  ohai *args
  system *args
end

def getc  # NOTE only tested on OS X
  system "/bin/stty raw -echo"
  if RUBY_VERSION >= '1.8.7'
    STDIN.getbyte
  else
    STDIN.getc
  end
ensure
  system "/bin/stty -raw echo"
end

def wait_for_user
  puts
  puts "Press ENTER to continue or any other key to abort"
  c = getc
  # we test for \r and \n because some stuff does \r instead
  abort unless c == 13 or c == 10
end

def macos_version
  @macos_version ||= /(10\.\d+)(\.\d+)?/.match(`/usr/bin/sw_vers -productVersion`).captures.first.to_f
end

def git
  @git ||= if ENV['GIT'] and File.executable? ENV['GIT']
    ENV['GIT']
  elsif Kernel.system '/usr/bin/which -s git'
    'git'
  else
    s = `xcrun -find git 2>/dev/null`.chomp
    s if $? and not s.empty?
  end
end

# The block form of Dir.chdir fails later if Dir.CWD doesn't exist which I
# guess is fair enough. Also sudo prints a warning message for no good reason
Dir.chdir "/usr"

####################################################################### script
abort "MacOS too old, see: https://gist.github.com/1144389" if macos_version < 10.5
abort "Don't run this as root!" if Process.uid == 0
abort <<-EOABORT unless `groups`.split.include? "admin"
This script requires the user #{ENV['USER']} to be an Administrator. If this
sucks for you then you can install Homebrew in your home directory or however
you please; please refer to our homepage. If you still want to use this script
set your user to be an Administrator in System Preferences or `su' to a
non-root user with Administrator privileges.
EOABORT
abort <<-EOABORT unless Dir["#{HOMEBREW_PREFIX}/.git/*"].empty?
It appears Homebrew is already installed. If your intent is to reinstall you
should do the following before running this installer again:
    rm -rf #{HOMEBREW_PREFIX}/Cellar #{HOMEBREW_PREFIX}/.git && brew cleanup
EOABORT
# Tests will fail if the prefix exists, but we don't have execution
# permissions. Abort in this case.
abort <<-EOABORT if File.directory? HOMEBREW_PREFIX and not File.executable? HOMEBREW_PREFIX
The Homeprew prefix, #{HOMEBREW_PREFIX}, exists but is not searchable. If this is
not intentional, please restore the default permissions and try running the
installer again:
    sudo chmod 755 #{HOMEBREW_PREFIX}
EOABORT

ohai "This script will install:"
puts "#{HOMEBREW_PREFIX}/bin/brew"
puts "#{HOMEBREW_PREFIX}/Library/..."
puts "#{HOMEBREW_PREFIX}/share/man/man1/brew.1"

chmods = %w( . bin etc include lib lib/pkgconfig Library sbin share var var/log share/locale share/man
             share/man/man1 share/man/man2 share/man/man3 share/man/man4
             share/man/man5 share/man/man6 share/man/man7 share/man/man8
             share/info share/doc share/aclocal ).
            map{ |d| "#{HOMEBREW_PREFIX}/#{d}" }.
            select{ |d| File.directory? d and (not File.readable? d or not File.writable? d or not File.executable? d) }
chgrps = chmods.reject{ |d| File.stat(d).grpowned? }

unless chmods.empty?
  ohai "The following directories will be made group writable:"
  puts *chmods
end
unless chgrps.empty?
  ohai "The following directories will have their group set to #{Tty.underline 39}admin#{Tty.reset}:"
  puts *chgrps
end

wait_for_user if STDIN.tty?

if File.directory? HOMEBREW_PREFIX
  sudo "/bin/chmod", "g+rwx", *chmods unless chmods.empty?
  sudo "/usr/bin/chgrp", "admin", *chgrps unless chgrps.empty?
else
  sudo "/bin/mkdir #{HOMEBREW_PREFIX}"
  sudo "/bin/chmod g+rwx #{HOMEBREW_PREFIX}"
  # the group is set to wheel by default for some reason
  sudo "/usr/bin/chgrp admin #{HOMEBREW_PREFIX}"
end

ohai "Downloading and Installing Homebrew..."
Dir.chdir HOMEBREW_PREFIX do
  if git
    # we do it in four steps to avoid merge errors when reinstalling
    system git, "init", "-q"
    system git, "remote", "add", "origin", "https://github.com/mxcl/homebrew"

    args = git, "fetch", "origin", "master:refs/remotes/origin/master", "-n"
    args << "--depth=1" if ARGV.include? "--fast"
    system *args

    system git, "reset", "--hard", "origin/master"
  else
    # -m to stop tar erroring out if it can't modify the mtime for root owned directories
    # pipefail to cause the exit status from curl to propogate if it fails
    # we use -k because OS X curl has a bunch of bad SSL certificates
    # you may want to remove the -k flag from your fork!
    system "/bin/bash -o pipefail -c '/usr/bin/curl -skSfL https://github.com/mxcl/homebrew/tarball/master | /usr/bin/tar xz -m --strip 1'"
  end
end

warn "#{HOMEBREW_PREFIX}/bin is not in your PATH." unless ENV['PATH'].split(':').include? "#{HOMEBREW_PREFIX}/bin"

if macos_version < 10.7
  warn "Now install Xcode: https://developer.apple.com/xcode/" unless File.exist? "/usr/bin/cc"
else
  `/usr/bin/cc --version 2> /dev/null` =~ %r{tags/Apple/clang-(\d+)}
  version = $1.to_i
  warn %{Install the "Command Line Tools for Xcode": http://connect.apple.com} if version < 421
end

ohai "Installation successful!"
puts "You should run `brew doctor' *before* you install anything."
puts "Now type: brew help"