require 'veewee/definition'
require 'veewee/templates'
require 'veewee/template'

module Veewee
  class Definitions

    attr_accessor :env

    def initialize(env)
      @env=env
      return self
    end

    def [](name)
      begin
        definition=Veewee::Definition.load(name,env)
        return definition
      rescue Veewee::DefinitionNotExist
        return nil
      end
    end

    # Fetch all definitions
    def each(&block)
      definitions=Hash.new

      env.logger.debug("[Definition] Searching #{env.definition_dir} for definitions:")
      subdirs=Dir.glob("#{env.definition_dir}/*")

      subdirs.each do |sub|
        name=File.basename(sub)
        env.logger.debug("[Definition] possible definition '#{name}' found")
        begin
          definitions[name]=Veewee::Definition.load(name,env)
        rescue Veewee::DefinitionError => ex
          env.logger.debug("[Definition] failed to load definition from directory '#{name}' #{ex}")
        end
      end

      if definitions.length==0
        env.logger.debug("[Definition] no definitions found") 
      end

      definitions.each(&block)
    end

    # This function 'defines'/'clones'/'instantiates a template:
    # It copies from a template dir with template_name
    #           to a new definition dir with definition_name
    #
    # Options are : :force => true to overwrite an existing definition
    #
    # Returns definition object


    def define(definition_name,template_name,options = {})

      # Default is not to overwrite
      options = {'force' => false}.merge(options)

      env.logger.debug("Forceflag : #{options['force']}")

      # Check if template exists
      template=env.templates[template_name]
      if template.nil?
        env.logger.fatal("Template '#{template_name}' does not exist")
        raise Veewee::TemplateError, "Template '#{template_name}' does not exist"
      else
        env.logger.debug("Template '#{template_name}' exists")
      end

      create_definition_dir_if_needed

      # Check if definition does not exist
      definition=env.definitions[definition_name]
      unless definition.nil?
        env.logger.debug("Definition '#{definition_name}' exists")
        if options['force']==true
          self.undefine(definition_name,options)
        else
           raise Veewee::DefinitionError,"Definition #{definition_name} already exists and no force option was given"
        end
      end

      env.logger.debug("Creating definition #{definition_name} in directory '#{env.definition_dir}' ")
      dst_dir="#{File.join(env.definition_dir,definition_name)}"
      FileUtils.mkdir(dst_dir)
      env.logger.debug("Definition Directory '#{File.join(env.definition_dir,definition_name)}' succesfuly created")

      # Start copying/cloning the directory of the template to the definition directory
      begin
        env.logger.debug("Starting copy '#{template.path}' to '#{dst_dir}'")
        FileUtils.cp_r(template.path+"/.",dst_dir)
        env.logger.debug("Copy '#{template.path}' to '#{dst_dir}' succesfull")
      rescue Exception => ex
        env.logger.fatal("Copy '#{template.path}' to #{dst_dir}' failed: #{ex}")
        raise Veewee::Error , "Copy '#{template.path}' to #{dst_dir}' failed: #{ex}"
      end

      definition=env.definitions[definition_name]
      return definition
    end


    # This function undefines/removes the definition by removing the directoy with definition_name
    # under env.definition_dir
    def undefine(definition_name,options = {})
      definition=env.definitions[definition_name]
      unless definition.nil?

        #TODO: Needs to be more defensive!!
        env.logger.debug("[Undefine] About to remove '#{definition.path} for '#{definition_name}'")
        begin
          if File.exists?(File.join(definition.path,"definition.rb"))
            FileUtils.rm_rf(definition.path)
          else
            env.logger.fatal("Aborting delete: The directory definition.path does not contain a definition.rb file")
            raise Veewee::DefinitionError,"Aborting delete: The directory definition.path does not contain a definition.rb file"
          end
        rescue Exception => ex
          env.logger.fatal("Removing '#{definition.path} for '#{definition_name}' failed: #{ex}")
          raise Veewee::Error, "Removing '#{definition.path }for '#{definition_name}' failed: #{ex}"
        end
        env.logger.debug("Removing '#{definition.path} for '#{definition_name}' succesful")
      else
        raise Veewee::DefinitionError,"Definition '#{definition_name}' does not exist"
      end
    end

    def create_definition_dir_if_needed
      # Check if definition_dir already exists
      unless File.exists?(env.definition_dir)
        env.logger.debug("Creating definition base directory '#{env.definition_dir}' ")
        FileUtils.mkdir(env.definition_dir)
        env.logger.debug("Definition base directory '#{env.definition_dir}' succesfuly created")
      end

      if File.writable?(env.definition_dir)
        env.logger.debug("DefinitionDir '#{env.definition_dir}' is writable")
        if File.exists?("#{env.definition_dir}")
          env.logger.debug("DefinitionDir '#{env.definition_dir}' already exists")
        else
          env.logger.debug("DefinitionDir '#{env.definition_dir}' does not exist, creating it")
          FileUtils.mkdir(definition_dir)
          env.logger.debug("DefinitionDir '#{env.definition_dir}' succesfuly created")
        end
      else
        env.logger.fatal("DefinitionDir '#{definition_dir}' is not writable")
        raise Veewee::Error, "DefinitionDir '#{definition_dir}' is not writable"
      end
    end


  end
end