Base init implementation for generating from an xcode project.

lib/cocoapods/command/init.rb

+require 'xcodeproj'
+
 module Pod
   class Command
     class Init < Command
-      self.summary = 'Create a Podfile'
 
+      self.summary = 'Generate a Podfile for the current directory.'
       self.description = <<-DESC
-        Creates a Podfile for the current directory if none currently exists.
+        Creates a Podfile for the current directory if none currently exists. If
+        an Xcode project file is specified or if there is only a single project
+        file in the current directory, targets will be automatically generated
+        based on targets defined in the project.
       DESC
+      self.arguments = '[XCODEPROJ]'
+
+      def initialize(argv)
+        @podfile_path = Pathname.pwd + "Podfile"
+        @project_path = argv.shift_argument
+        @project_paths = Pathname.pwd.children.select { |pn| pn.extname == '.xcodeproj' }
+        super
+      end
+
+      def validate!
+        super
+        help! "Existing Podfile found in directory" if File.file? @podfile_path
+        unless @project_path
+          help! "No xcode project found, please specify one" unless @project_paths.length > 0
+          help! "Multiple xcode projects found, please specify one" unless @project_paths.length == 1
+          @project_path = @project_paths.first
+        end
+        help! "Xcode project at #{@project_path} does not exist" unless File.exist? @project_path
+        @xcode_project = Xcodeproj::Project.new(@project_path)
+      end
 
       def run
-        (Pathname.pwd + "Podfile").open('w') { |f| f << '' }
+        @podfile_path.open('w') { |f| f << podfile_template(@xcode_project) }
+      end
+
+      def podfile_template(project)
+        platforms = project.targets.map { |t| t.platform_name }.uniq
+        if platforms.length == 1
+          podfile = <<-PLATFORM
+platform #{platforms.first}
+PLATFORM
+        else
+          podfile = <<-PLATFORM
+# Uncomment this line to define the platform for your project
+platform :ios, "6.0"
+PLATFORM
+        end
+        for target in project.targets
+          podfile << target_module(target)
+        end
+        podfile
+      end
+
+      def target_module(target, define_platform = true)
+        platform = "platform #{target.platform_name}" if define_platform
+        return <<-TARGET
+target :#{target.name} do
+  #{platform}
+end
+TARGET
       end
     end
   end