require 'autobuild/config'
require 'autobuild/exceptions'

# This class is the base class for objects that are used to get the source from
# various RCS into the package source directory. A list of patches to apply
# after the import can be given in the +:patches+ option.
class Autobuild::Importer
    # Creates a new Importer object. The options known to Importer are:
    # [:patches] a list of patch to apply after import
    #
    # More options are specific to each importer type.
    def initialize(options); @options = options end

    def patches
	@options[:patches] ||= []
    end

    # Performs the import of +package+
    def import(package)
        srcdir = package.srcdir
        if File.directory?(srcdir)
            if Autobuild.do_update
                update(package)
                patch(package)
            else
                puts "Not updating #{package.name}"
                return
            end

        elsif File.exists?(srcdir)
            raise ConfigException, "#{srcdir} exists but is not a directory"
        else
            begin
                checkout(package)
                patch(package)
            rescue Autobuild::Exception
                FileUtils.rm_rf package.srcdir
                raise
            end
        end
    end

    private
    
    # We assume that package.srcdir already exists (checkout is supposed to
    # have been called)
    def patchlist(package)
        "#{package.srcdir}/patches-autobuild-stamp"
    end

    def call_patch(package, reverse, file)
        patch = Autobuild.tool('patch')
        Dir.chdir(package.srcdir) {
            Subprocess.run(package.name, :patch, patch, '-p0', (reverse ? '-R' : nil), "<#{file}")
        }
    end

    def apply(package, path);   call_patch(package, false, path) end
    def unapply(package, path); call_patch(package, true, path)   end

    def patch(package)
        # Get the list of already applied patches
        patches_file = patchlist(package)
        cur_patches =   if !File.exists?(patches_file) then []
                        else
                            File.open(patches_file) do |f| 
                                f.readlines.collect { |path| path.rstrip } 
                            end
                        end

        # Do not be smart, remove all already applied patches
        # and then apply the new ones
        begin
            while p = cur_patches.pop
                unapply(package, p) 
            end

            patches.to_a.each do |p| 
                apply(package, p) 
                cur_patches << p
	    end
        ensure
            File.open(patchlist(package), 'w+') do |f|
                f.write(cur_patches.join("\n"))
            end
        end
    end
end