# 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.

module OSGi #:nodoc:

  # A bundle is an OSGi artifact represented by a jar file or a folder.
  # It contains a manifest file with specific OSGi headers.
  #
  class Bundle

    #Keys used in the MANIFEST.MF file
    B_NAME = "Bundle-SymbolicName"
    B_REQUIRE = "Require-Bundle"
    B_IMPORT_PKG = "Import-Package"
    B_EXPORT_PKG = "Export-Package"
    B_FRAGMENT_HOST = "Fragment-Host"
    B_VERSION = "Bundle-Version"
    B_DEP_VERSION = "bundle-version"
    B_RESOLUTION = "resolution"
    B_LAZY_START = "Bundle-ActivationPolicy"
    B_OLD_LAZY_START = "Eclipse-LazyStart"
    
    # Creates itself by loading from the manifest file passed to it as a hash
    # Finds the name and version, and populates a list of dependencies.
    def self.fromManifest(manifest, jarFile) 
      if manifest.first[B_NAME].nil?
        warn "Could not find the name of the bundle represented by #{jarFile}"
        return nil
      end
      
      #see http://aspsp.blogspot.com/2008/01/wheressystembundlejarfilecont.html for the system.bundle trick.
      #key.strip: sometimes there is a space between the comma and the name of the bundle.
      #Add the required bundles:
      bundles = []
      manifest.first[B_REQUIRE].each_pair {|key, value| bundles << Bundle.new(key.strip, value[B_DEP_VERSION], {:optional => value[B_RESOLUTION] == "optional"}) unless "system.bundle" == key} unless manifest.first[B_REQUIRE].nil?
      exports = []
      manifest.first[B_EXPORT_PKG].each_pair {|key, value| exports << BundlePackage.new(key.strip, value["version"])} unless manifest.first[B_EXPORT_PKG].nil?
      
      #Parse the version
      version = manifest.first[B_VERSION].nil? ? nil : manifest.first[B_VERSION].keys.first
      
      #Read the imports
      imports = []
      manifest.first[B_IMPORT_PKG].each_pair {|key, value| imports << BundlePackage.new(key.strip, value["version"], :is_export => false, :optional => value[B_RESOLUTION] == "optional")} unless manifest.first[B_IMPORT_PKG].nil?
      
      #Read the imported packages
      
      bundle = Bundle.new(manifest.first[B_NAME].keys.first, version, {:file => jarFile, :bundles => bundles, :imports => imports, :exported_packages => exports})
      if !manifest.first[B_LAZY_START].nil? 
        # We look for the value of BundleActivationPolicy: lazy or nothing usually. 
        # lazy may be spelled Lazy too apparently, so we downcase the string in case.
        bundle.lazy_start = "lazy" == manifest.first[B_LAZY_START].keys.first.strip.downcase
      else
        bundle.lazy_start = "true" == manifest.first[B_OLD_LAZY_START].keys.first.strip unless manifest.first[B_OLD_LAZY_START].nil?
      end
      if (bundle.lazy_start)
        bundle.start_level = 4
      else
        bundle.start_level = 1
      end
      
      bundle.fragment = Bundle.new(manifest.first[B_FRAGMENT_HOST].keys.first.strip, 
        manifest.first[B_FRAGMENT_HOST].values.first[B_DEP_VERSION]) unless (manifest.first[B_FRAGMENT_HOST].nil?)
      return bundle
    end

    

    # Attributes of a bundle, derived from its manifest
    # The name is always the symbolic name
    # The version is either the exact version of the bundle or the range in which the bundle would be accepted.
    # The file is the location of the bundle on the disk
    # The optional tag is present on bundles resolved as dependencies, marked as optional.
    # The start level is deduced from the bundles.info file. Default is 1.
    # The lazy start is found in the bundles.info file
    # group is the artifact group used for Maven. By default it is set to OSGI_GROUP_ID.
    # fragment is a Bundle object that represents the fragment host of this bundle (which means this bundle is a fragment if this field is not null).
    # exported_packages is an array of strings representing the packages exported by the bundle.
    # imports is an array of BundlePackage objects representing the packages imported by the bundle.
    attr_accessor :name, :version, :bundles, :file, :optional, :start_level, :lazy_start, :group, :fragment, :exported_packages, :imports

    alias :id :name

    def initialize(name, version, args = {:file => nil, :bundles=>[], :imports => [], :optional => false}) #:nodoc:
      @name = name
      @version = VersionRange.parse(version) || (version.nil? ? nil : Version.new(version))
      @bundles = args[:bundles] || []
      @imports = args[:imports] || []
      @exported_packages = args[:exported_packages] || []
      @file = args[:file]
      @optional = args[:optional]
      @start_level = 4
      @type = "jar" #it's always a jar, even if it is a directory: we will jar it for Maven.
      @group = GroupMatcher.instance.group(name)
    end

    
    #
    # Resolves the matching artifacts.
    #
    def resolve_matching_artifacts
      
      return OSGi.registry.resolved_containers.collect {|i| 
        i.find(:name => name, :version => version)
      }.flatten.compact.collect{|b| b.dup }
    end

    # Returns true if the bundle is an OSGi fragment.
    #
    def fragment?
      !fragment.nil?
    end

    def to_s #:nodoc:
       "#{name}:#{id}"
    end

    def to_yaml(opts = {}) #:nodoc:
      to_s.to_yaml(opts)
    end

    def <=>(other) #:nodoc:
      if other.is_a?(Bundle)
       return to_s <=> other.to_s
      else
        return to_s <=> other
      end
    end

    # Resolve a bundle from itself, by finding the appropriate bundle in the OSGi containers.
    # Returns self or the project it represents if a project is found to be self.
    #
    def resolve(bundles = resolve_matching_artifacts)
      bundle = case bundles.size
      when 0 then nil
      when 1 then bundles.first
      else
        BundleResolvingStrategies.send(OSGi.options.bundle_resolving_strategy, bundles)
      end
      if bundle.nil?
        warn "Could not resolve bundle for #{self.to_s}" 
        return nil
      end
      
      osgi = self.dup
      osgi.name = bundle.name
      osgi.version = bundle.version
      osgi.bundles = bundle.bundles
      osgi.file = bundle.file
      osgi.optional = bundle.optional
      osgi.start_level = bundle.start_level
      osgi.group = bundle.group

      osgi
    end

    # Finds the fragments associated with this bundle.
    #
    def fragments
      OSGi.registry.resolved_containers.collect {|i| 
        i.find_fragments(:host => name).select{|f|
          if f.fragment.version.is_a? VersionRange
            f.fragment.version.in_range(version)
          elsif f.fragment.version.nil?
            true
          else
            f.fragment.version == version 
          end
          }
        }.flatten.compact.collect{|b| b.dup }
      end
      
    # Compares with another bundle and returns true if the name and version match.  
    def ==(other) #:nodoc:
      return false unless other.is_a?(Bundle)
      name == other.name && version == other.version    
    end
    
    alias :eql? ==
    
    # Important for maps.
    # We absolutely want to avoid having to resolve several times the same bundle
    #
    def hash
      return to_s.hash
    end

  end
end