require "rjb"
require "core/project"

module Buildr
  
  # Base module for all things Java.
  module Java

    # Options accepted by #java and other methods here.
    JAVA_OPTIONS = [ :verbose, :classpath, :name, :java_args ]
    # Classpath dependencies available when running JUnit.
    JUNIT_REQUIRES = [ "junit:junit:jar:3.8.1", "jmock:jmock:jar:1.1.0" ]

    # Returned by Java#rjb, you can use this object to set the RJB classpath, specify blocks to be invoked
    # after loading RJB, and load RJB itself.
    #
    # RJB can be loaded exactly once, and once loaded, you cannot change its classpath. Of course you can
    # call libraries that manage their own classpath, but the lazy way is to just tell RJB of all the
    # classpath dependencies you need in advance, before loading it.
    #
    # For that reason, you should not load RJB until the moment you need it. You can call #load or call
    # Java#rjb with a block. For the same reason, you may need to specify code to execute when loading
    # (see #onload).
    class RjbWrapper

      include Singleton

      def initialize() #:nodoc:
        @classpath = []
        @onload = []
        onload do
          Rjb.load(artifacts(classpath).each { |task| task.invoke if task.respond_to?(:invoke) }.
            map(&:to_s).join(File::PATH_SEPARATOR))
        end
      end

      # The classpath used when loading RJB.
      attr_accessor :classpath

      # :call-seq:
      #   onload { ... }
      #
      # Adds a block to call when loading RJB and returns self.
      #
      # You can only load RJB once, and you may need to do some tasks after the initial load.
      # For example, the Ant module requires Antwrap which can only be loaded after RJB.
      def onload(&block)
        @onload << block
        self
      end

      # :call-seq:
      #   load()
      #
      # Loads RJB. You can also call Java#ejb with a block to get the same effect.
      def load()
        @onload.each(&:call)
        @onload.clear
      end

      def method_missing(sym, *args, &block) #:nodoc:
        Rjb.send sym, *args, &block
      end
    end

    class << self

      # :call-seq:
      #   version() => string
      #
      # Returns the version number of the JVM.
      #
      # For example:
      #   puts Java.version
      #   => 1.5.0_10
      def version()
        @version ||= `#{path_to_bin("java")} -version 2>&1`.scan(/java version "(.*)"/)[0][0]
      end

      # :call-seq:
      #   tools_jar() => path
      #
      # Returns a path to tools.jar.
      def tools_jar()
        unless @tools
          home = ENV["JAVA_HOME"] || File.dirname(File.dirname(`which java`.split.first))
          tools = File.join(home, "lib/tools.jar")
          @tools = tools if File.exist?(tools)
        end
        @tools
      end

      # :call-seq:
      #   java(class, *args, options?)
      #
      # Runs Java with the specified arguments.
      #
      # The last argument may be a Hash with additional options:
      # * :classpath -- One or more file names, tasks or artifact specifications.
      #   These are all expanded into artifacts, and all tasks are invoked.
      # * :java_args -- Any additional arguments to pass (e.g. -hotspot, -xms)
      # * :name -- Shows this name, otherwise shows the first argument (the class name).
      # * :verbose -- If true, prints the command and all its argument.
      def java(*args)
        options = Hash === args.last ? args.pop : {}
        options[:verbose] ||= Rake.application.options.trace || false
        fu_check_options options, *JAVA_OPTIONS

        name = options[:name] || "java #{args.first}"
        cmd_args = []
        classpath = classpath_from(options)
        cmd_args << "-cp" << classpath.join(File::PATH_SEPARATOR) unless classpath.empty?
        cmd_args += options[:java_args].flatten if options[:java_args]
        cmd_args += args.flatten.compact
        cmd_args << { :verbose=>options[:verbose] }
        unless Rake.application.options.dryrun
          puts "Running #{name}" if verbose
          sh(path_to_bin("java"), *cmd_args) { |ok, res| fail "Failed to execute #{name}, see errors above" unless ok }
        end
      end

      # :call-seq:
      #   apt(*files, options)
      #
      # Runs Apt with the specified arguments.
      #
      # The last argument may be a Hash with additional options:
      # * :compile -- If true, compile source files to class files.
      # * :source -- Specifies source compatibility with a given JVM release.
      # * :output -- Directory where to place the generated source files, or the
      #   generated class files when compiling.
      # * :classpath -- One or more file names, tasks or artifact specifications.
      #   These are all expanded into artifacts, and all tasks are invoked.
      # * :verbose -- If true, prints the command and all its argument and also runs
      #   Apt in verbose mode (the default is -nowarn).
      def apt(*args)
        options = Hash === args.last ? args.pop : {}
        options[:verbose] ||= Rake.application.options.trace || false
        fu_check_options options, :verbose, :compile, :source, :output, :classpath

        files = args.flatten.map(&:to_s).
          collect { |arg| File.directory?(arg) ? FileList["#{arg}/**/*.java"] : arg }.flatten
        args = [ options[:verbose] ? "-verbose" : "-nowarn" ]
        if options[:compile]
          args << "-d" << options[:output].to_s
        else
          args << "-nocompile" << "-s" << options[:output].to_s
        end
        args << "-source" << options[:source] if options[:source]
        classpath = classpath_from(options)
        args << "-cp" << classpath.join(File::PATH_SEPARATOR) unless classpath.empty?
        args += files
        args << { :verbose=>options[:verbose] }
        unless Rake.application.options.dryrun
          puts "Running apt" if verbose
          sh(path_to_bin("apt"), *args) { |ok, res| fail "Failed to execute apt, see errors above" unless ok }
        end
      end

      # :call-seq:
      #   javac(*files, options)
      #
      # Runs Javac with the specified arguments.
      #
      # The last argument may be a Hash with additional options:
      # * :output -- Target directory for all compiled class files.
      # * :classpath -- One or more file names, tasks or artifact specifications.
      #   These are all expanded into artifacts, and all tasks are invoked.
      # * :sourcepath -- Additional source paths to use.
      # * :javac_args -- Any additional arguments to pass (e.g. -extdirs, -encoding)
      # * :name -- Shows this name, otherwise shows the working directory.
      # * :verbose -- If true, prints the command and all its argument.
      def javac(*args)
        options = Hash === args.last ? args.pop : {}
        options[:verbose] ||= Rake.application.options.trace || false
        fu_check_options options, :verbose, :classpath, :sourcepath, :output, :javac_args, :name

        files = args.flatten.each { |f| f.invoke if f.respond_to?(:invoke) }.map(&:to_s).
          collect { |arg| File.directory?(arg) ? FileList["#{arg}/**/*.java"] : arg }.flatten
        name = options[:name] || Dir.pwd

        cmd_args = []
        classpath = classpath_from(options)
        #classpath += options[:output] if options[:output]
        cmd_args << "-cp" << classpath.join(File::PATH_SEPARATOR) unless classpath.empty?
        cmd_args << "-sourcepath" << options[:sourcepath].join(File::PATH_SEPARATOR) if options[:sourcepath]
        cmd_args << "-d" << options[:output].to_s if options[:output]
        cmd_args += options[:javac_args].flatten if options[:javac_args]
        cmd_args += files
        cmd_args << { :verbose=>options[:verbose] }
        unless Rake.application.options.dryrun
          puts "Compiling #{files.size} source files in #{name}" if verbose
          sh(path_to_bin("javac"), *cmd_args) { |ok, res| fail "Failed to compile, see errors above" unless ok }
        end
      end

      # :call-seq:
      #   junit(*classes, options) => [ passed, failed ]
      #
      # Runs JUnit test cases from the specified classes. Returns an array with two lists,
      # one containing the names of all classes that passes, the other containing the names
      # of all classes that failed.
      #
      # The last argument may be a Hash with additional options:
      # * :classpath -- One or more file names, tasks or artifact specifications.
      #   These are all expanded into artifacts, and all tasks are invoked.
      # * :verbose -- If true, prints the command and all its argument.
      def junit(*args)
        options = Hash === args.last ? args.pop : {}
        options[:verbose] ||= Rake.application.options.trace || false
        fu_check_options options, :verbose, :classpath

        classpath = classpath_from(options) + junit_artifacts
        tests = args.flatten
        failed = tests.inject([]) do |failed, test|
          begin
            java "junit.textui.TestRunner", test, :classpath=>classpath, :name=>"tests in #{test}", :verbose=>options[:verbose]
            failed
          rescue
            failed << test
          end
        end
        [ tests - failed, failed ]
      end

      # :call-seq:
      #   rjb() => RjbWrapper
      #   rjb() { ... }
      #
      # This method can be used in two ways. Without a block, returns the RjbWrapper
      # object which you can use to configure the RJB classpath or call other RJB methods.
      # With a block, loads RJB and yields to the block, returning its result.
      #
      # For example:
      #   Java.rjb.classpath += REQUIRES
      #   Java.rjb.onload { require "antwrap" }
      #   . . .
      #
      #  def execute(name, options)
      #    options = options.merge(:name=>name, :base_dir=>Dir.pwd, :declarative=>true)
      #    Java.rjb { AntProject.new(options) }
      #  end
      def rjb()
        if block_given?
          RjbWrapper.instance.load
          yield
        else
          RjbWrapper.instance
        end
      end

      # :call-seq:
      #   path_to_bin(cmd?) => path
      #
      # Returns the path to the specified Java command (with no argument to java itself).
      # Uses JAVA_HOME if set, otherwise assumes the command is accessible from the path.
      def path_to_bin(name = "java")
        ENV["JAVA_HOME"] ? File.join(ENV["JAVA_HOME"], "bin", name) : name
      end

  protected

      # :call-seq:
      #    classpath_from(options) => files
      #
      # Extracts the classpath from the options, expands it by calling artifacts, invokes
      # each of the artifacts and returns an array of paths.
      def classpath_from(options)
        classpath = (options[:classpath] || []).collect
        artifacts(classpath).each { |t| t.invoke if t.respond_to?(:invoke) }.map(&:to_s)
      end

      # :call-seq:
      #    junit_artifacts() => files
      #
      # Returns the JUnit artifacts as paths, after downloading and installing them (if necessary).
      def junit_artifacts()
        @junit_artifacts ||= artifacts(JUNIT_REQUIRES).each { |task| task.invoke }.map(&:to_s)
      end

    end

    # See Java#java.
    def java(*args)
      Java.java(*args)
    end

    # :call-seq:
    #   apt(*sources) => task
    #
    # Returns a task that will use Java#apt to generate source files in target/generated/apt,
    # from all the source directories passed as arguments. Uses the compile.sources list if
    # on arguments supplied.
    #
    # For example:
    #
    def apt(*sources)
      sources = compile.sources if sources.empty?
      file(path_to("target/generated/apt")=>sources) do |task|
        Java.apt(sources.map(&:to_s) - [task.name], :output=>task.name,
          :classpath=>compile.classpath, :source=>compile.options.source)
      end
    end

  end

  class Project
    include Java
  end
end