require 'repertoire/media/exceptions/unknown_media'
require 'repertoire/media/exceptions/program_not_found'
require 'repertoire/extensions/uri'
require 'repertoire/compat'

require 'fileutils'

module Repertoire
  class Media

    #
    # Returns the Hash of all registered Media types.
    #
    def Media.types
      @types ||= {}
    end

    #
    # Returns +true+ if a Media type was registered for the specified
    # _scheme_, returns +false+ otherwise.
    #
    def Media.supported?(scheme)
      Media.types.has_key?(scheme.to_s)
    end

    #
    # Get the Media type that was registered for the specified _scheme_.
    #
    def Media.get(scheme)
      unless Media.supported?(scheme)
        raise(UnknownMedia,"media type #{scheme.dump} is unsupported",caller)
      end

      return Media.types[scheme]
    end

    #
    # Get the Media type that was registered for the scheme of the
    # specified _uri_.
    #
    def Media.get_for_uri(uri)
      Media.get(URI.parse(uri).scheme)
    end

    #
    # Attempts to determine the correct Media type for the specified _path_.
    #
    def Media.guess(path)
      path = File.expand_path(path)

      Media.types.values.uniq.each do |media|
        if media.respond_to?(:is_repo?)
          return media if media.is_repo?(path)
        end
      end

      raise(UnknownMedia,"the media type for #{path.dump} is unknown",caller)
    end

    #
    # Checkout the repository at the specified _uri_ and the given _path_.
    #
    def Media.checkout(uri,path=nil)
      if path
        path = File.expand_path(path)
      else
        path = URI.repo_name(uri)
      end

      return Media.get_for_uri(uri).checkout(uri,path)
    end

    #
    # Update the repository at the specified _path_ and the given _uri_.
    # If _uri_ is not given Repertoire will attempt to guess the media
    # type of the repository, see Media.guess.
    #
    def Media.update(path,uri=nil)
      path = File.expand_path(path)

      if uri.nil?
        media = Media.guess(path)
      else
        media = Media.get_for_uri(uri)
      end

      return media.update(path,uri)
    end

    #
    # Delete the repository at the specified _path_.
    #
    def Media.delete(path)
      FileUtils.rm_r(path.to_s,:force => true, :secure => true)
    end

    protected

    #
    # Register a Media type for the specified _schemes_.
    #
    #   uses_schemes 'cvs'
    #
    #   uses_schemes 'svn', 'svn+ssh'
    #
    def self.uses_schemes(*schemes)
      schemes.each do |scheme|
        Media.types[scheme.to_s] = self
      end
    end

    #
    # Runs the command specified by _program_ and the given _args_.
    # If _program_ cannot be found on the system, a ProgramNotFound
    # exception will be raised.
    #
    #   sh('ls','-la','/')
    #
    def self.sh(program,*args)
      program = program.to_s

      program_path = Compat.find_program(program)
      unless program_path
        raise(ProgramNotFound,"the program #{program.dump} was not found",caller)
      end

      # stringify the args
      args = args.map { |arg| arg.to_s }

      return system(program_path,*args)
    end

  end
end