# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with this
# work for additional information regarding copyright ownership.  The ASF
# licenses this file to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
# License for the specific language governing permissions and limitations under
# the License.


require 'buildr/core/project'
require 'buildr/packaging'


module Buildr
  module Eclipse #:nodoc:

    include Extension

    first_time do
      # Global task "eclipse" generates artifacts for all projects.
      desc 'Generate Eclipse artifacts for all projects'
      Project.local_task 'eclipse'=>'artifacts'
    end

    before_define do |project|
      project.recursive_task('eclipse')
    end

    after_define do |project|
      eclipse = project.task('eclipse')

      # Check if project has scala facet
      scala = project.compile.language == :scala

      # Only for projects that we support
      supported_languages = [:java, :scala]
      supported_packaging = %w(jar war rar mar aar)
      if (supported_languages.include?(project.compile.language) ||
          supported_languages.include?(project.test.compile.language) ||
          project.packages.detect { |pkg| supported_packaging.include?(pkg.type.to_s) })
        eclipse.enhance [ file(project.path_to('.classpath')), file(project.path_to('.project')) ]

        # The only thing we need to look for is a change in the Buildfile.
        file(project.path_to('.classpath')=>Buildr.application.buildfile) do |task|
          info "Writing #{task.name}"

          m2repo = Buildr::Repositories.instance.local

          File.open(task.name, 'w') do |file|
            classpathentry = ClasspathEntryWriter.new project, file
            classpathentry.write do
              # Note: Use the test classpath since Eclipse compiles both "main" and "test" classes using the same classpath
              cp = project.test.compile.dependencies.map(&:to_s) - [ project.compile.target.to_s, project.resources.target.to_s ]
              cp = cp.uniq

              # Convert classpath elements into applicable Project objects
              cp.collect! { |path| Buildr.projects.detect { |prj| prj.packages.detect { |pkg| pkg.to_s == path } } || path }

              # project_libs: artifacts created by other projects
              project_libs, others = cp.partition { |path| path.is_a?(Project) }

              # Separate artifacts from Maven2 repository
              m2_libs, others = others.partition { |path| path.to_s.index(m2repo) == 0 }

              # Generated: classpath elements in the project are assumed to be generated
              generated, libs = others.partition { |path| path.to_s.index(project.path_to.to_s) == 0 }

              classpathentry.src project.compile.sources + generated
              classpathentry.src project.resources

              if project.test.compile.target
                classpathentry.src project.test.compile
                classpathentry.src project.test.resources
              end

              # Classpath elements from other projects
              classpathentry.src_projects project_libs

              classpathentry.output project.compile.target if project.compile.target
              classpathentry.lib libs
              classpathentry.var m2_libs, 'M2_REPO', m2repo

              classpathentry.con 'ch.epfl.lamp.sdt.launching.SCALA_CONTAINER' if scala
              classpathentry.con 'org.eclipse.jdt.launching.JRE_CONTAINER'
            end
          end
        end

        # The only thing we need to look for is a change in the Buildfile.
        file(project.path_to('.project')=>Buildr.application.buildfile) do |task|
          info "Writing #{task.name}"
          File.open(task.name, 'w') do |file|
            xml = Builder::XmlMarkup.new(:target=>file, :indent=>2)
            xml.projectDescription do
              xml.name project.id
              xml.projects
              xml.buildSpec do
                if scala
                  xml.buildCommand do
                    xml.name 'ch.epfl.lamp.sdt.core.scalabuilder'
                  end
                else
                  xml.buildCommand do
                    xml.name 'org.eclipse.jdt.core.javabuilder'
                  end
                end
              end
              xml.natures do
                xml.nature 'ch.epfl.lamp.sdt.core.scalanature' if scala
                xml.nature 'org.eclipse.jdt.core.javanature'
              end
            end
          end
        end
      end

    end

    # Writes 'classpathentry' tags in an xml file.
    # It converts tasks to paths.
    # It converts absolute paths to relative paths.
    # It ignores duplicate directories.
    class ClasspathEntryWriter
      def initialize project, target
        @project = project
        @xml = Builder::XmlMarkup.new(:target=>target, :indent=>2)
        @excludes = [ '**/.svn/', '**/CVS/' ].join('|')
        @paths_written = []
      end
      
      def write &block
        @xml.classpath &block
      end
      
      def con path
        @xml.classpathentry :kind=>'con', :path=>path
      end

      def lib libs
        libs.map(&:to_s).sort.uniq.each do |path|
          @xml.classpathentry :kind=>'lib', :path=>path
        end
      end

      # Write a classpathentry of kind 'src'.
      # Accept an array of absolute paths or a task.
      def src arg
        if [:sources, :target].all? { |message| arg.respond_to?(message) }
          src_from_task arg
        else
          src_from_absolute_paths arg
        end
      end

      # Write a classpathentry of kind 'src' for dependent projects.
      # Accept an array of projects.
      def src_projects project_libs
        project_libs.map(&:id).sort.uniq.each do |project_id|
          @xml.classpathentry :kind=>'src', :combineaccessrules=>'false', :path=>"/#{project_id}"
        end
      end
      
      def output target
        @xml.classpathentry :kind=>'output', :path=>relative(target)
      end

      # Write a classpathentry of kind 'var' (variable) for a library in a local repo.
      # * +libs+ is an array of library paths.
      # * +var_name+ is a variable name as defined in Eclipse (e.g., 'M2_REPO').
      # * +var_value+ is the value of this variable (e.g., '/home/me/.m2').
      # E.g., <tt>var([lib1, lib2], 'M2_REPO', '/home/me/.m2/repo')</tt>
      def var libs, var_name, var_value
        libs.each do |lib_path|
          lib_artifact = file(lib_path)
          source_path = lib_artifact.sources_artifact.to_s
          relative_lib_path = lib_path.sub(var_value, var_name)
          relative_source_path = source_path.sub(var_value, var_name)
          @xml.classpathentry :kind=>'var', :path=>relative_lib_path, :sourcepath=>relative_source_path
        end
      end
              
      private

      # Find a path relative to the project's root directory.
      def relative path
        path or raise "Invalid path '#{path.inspect}'"
        msg = [:to_path, :to_str, :to_s].find { |msg| path.respond_to? msg }
        path = path.__send__(msg)
        Util.relative_path(File.expand_path(path), @project.path_to)
      end

      def src_from_task task
        src_from_absolute_paths task.sources, task.target
      end

      def src_from_absolute_paths absolute_paths, output=nil
        relative_paths = absolute_paths.map { |src| relative(src) }
        relative_paths.sort.uniq.each do |path|
          unless @paths_written.include?(path)
            attributes = { :kind=>'src', :path=>path, :excluding=>@excludes }
            attributes[:output] = relative(output) if output
            @xml.classpathentry attributes
            @paths_written << path
          end
        end
      end
    end

  end
end # module Buildr


class Buildr::Project
  include Buildr::Eclipse
end