#
# == MasterView Admin Controller
# 
# The MasterviewController is a Rails controller that you can enable
# in your Rails application to provide administrative operations
# for the MasterView template engine.
# 
# To enable or disable the admin controller, use the
# MasterView::Configuration setting +enable_admin_pages+
# to enable or disable its availability in your
# config/masterview/settngs.rb or a suitable environment
# settings file, according to your intended usage:
# 
#   config.enable_admin_pages = true
# 
# When enabled, the MasterView admin controller is accessable
# in your application at the address:
# 
#    http://yourapp.foo/masterview
# 
# The controller places its stylesheets in a +masterview+ subdirectory 
# in your rails stylesheets directory (app/stylesheets/masterview).
# 
# The MasterView admin controller is primarily a developer facility; 
# it is not generally appropriate for end-users of your rails application.
# If you enable this facility in your production environment,
# you should consider restricting access to authorized users.
#
#--
# ISSUE: we need to work through scenario of how mv admin controller fits
# into overall scheme of one's rails application.  How/when would developer
# integrate stylesheets and layout into their overal app look?
# How/when would access restriction actually be hooked up?
# Standard technique is to do something along the lines of using
# a before_filter which invokes things like :check_authentication 
# and :check_authorization services in the app framework
# (or, say, predicate can_access? or has_permission? or...].
# But... this whole area of user authentication and authorization 
# has no specific conventions in the Rails ecosystem yet,
# so we really can't make any assumptions yet about any particular
# approach that MasterviewController itself could hook into.
# We'll have to leave this as an exercise for the user and give
# them tips on how to make it happen.
# [DJL 17-Jun-2006]
#++
# 


class MasterviewController < ApplicationController

  before_filter :check_authorization, :except => [ :access_not_allowed ]

  ENABLE_ADMIN_LAYOUT = false #:nodoc:  #UNDER CONSTRUCTION - fine idea, but doesn't work yet [DJL 03-Jun-2006]

  # Describe the MasterView configuration option settings
  def configuration
    if ENABLE_ADMIN_LAYOUT
      smart_render_with_layout('masterview/admin/configuration', 'masterview_admin')
    else
      #ugly, but keep this version
      aint_got_no_layout_backstop = '<div style="padding-top: 6px;">(back to <a href=".">Admin home</a>)</div>'
      config_html = MasterView::Info.to_html( :postscript => aint_got_no_layout_backstop )
      render :text => config_html
    end
  end
  
  def index
    redirect_to :action => :list
  end

  # List the templates in the application and their status.
  # Provide operations to force rebuild (reparse and regenerate) 
  # of specific templates or all templates and
  # create utility to ...mumble...
  # 
  def list
    template_specs, content_hash = MasterView::TemplateSpec.scan
    @template_specs_sorted = template_specs.sort
    smart_render 'masterview/admin/list'
  end

  def features
    smart_render 'masterview/admin/features'
  end

  # Rebuild all templates in the application.
  # Invoked from the main masterview admin page.
  def rebuild_all
    files_rebuilt = []
    MasterView::TemplateSpec.scan do |template_spec, content_hash|
      if template_spec.status == MasterView::TemplateSpec::Status::ImportsOutdated &&
         template_spec.rebuild_template(content_hash, :write_to_file => true)
            files_rebuilt << template_spec.path
      end
    end
    unless files_rebuilt.empty?
      flash[:notice] = files_rebuilt.join(', ')+' were updated'
    end
    redirect_to :action => :list
  end

  # Rebuild a specific template.
  # Invoked from the main masterview admin page.
  def rebuild
    path = params[:id]
    template_specs, content_hash = MasterView::TemplateSpec.scan
    template_spec = template_specs[path]
    raise 'Template '+path+' not found' unless template_spec
    if template_spec.rebuild_template(content_hash, :write_to_file => true)
      flash[:notice] = 'File '+path+' updated'
    else
      flash[:notice] = 'Identical content - no update needed for '+path
    end
    redirect_to :action => :list
  end

  # Create a new, empty template.
  # Invoked from the main masterview admin page.
  def create
    if @request.post?
      action_to_create = params[:action_name]
      src_file = params[:id]

      empty_file_path = find_path('app/views/masterview/admin/empty.rhtml')
      empty_insert_erb = File.readlines(empty_file_path).join

      dst_file = MasterView::TemplateSpec.create_empty_shell_for_action(src_file, action_to_create, empty_insert_erb, :write_to_file => true)
      flash[:notice] = dst_file+' was created'
      redirect_to :action => :list
    else
      smart_render 'masterview/admin/create'
    end
  end

  # View the generated rhtml
  def view_rhtml
    raise "View RHTML is disabled. Edit your config/masterview/settings.rb (or config/masterview/environments/xxxx.rb) file and set config.enable_view_rhtml = true. Restart application for change to take effect." unless MasterView::EnableMasterViewAdminViewRHTML
    @rhtml_file = params[:id]
    raise "RHTML file not specified" unless @rhtml_file
    f = MasterView::IOMgr.erb.path(@rhtml_file)
    raise "RHTML file ("+@rhtml_file+") not found. Maybe automatic parsing is disabled. You may invoke parsing manually by using rake mv:parse" unless f.exist?
    @rhtml_content = f.read
    smart_render 'masterview/admin/view_rhtml'
  end

  def access_not_allowed #:nodoc:
    render :text => '<p>We\'re sorry, but the page you have requested is only available to authorized users.</p>', 
            :status => 500
  end

  protected

  # Default implementation of authorization check
  # to restrict access to administrative services
  def allow_access?
    # a more general solution might look something like:
    # current_user && user_has_perm?('mv-admin')
    # backstop: only allow for developer testing on local machine
    local_request?
  end

  # Check that the current user has authorization to access admin operations
  def check_authorization
    if ! allow_access?
      redirect_to :action => :access_not_allowed
    end
  end

  private 

  # checks app path first for views and files, then falls back to files in MV
  def find_path(path)
    local_path = File.join(RAILS_ROOT, path)
    mv_path = File.join(File.dirname(__FILE__), '../..', path)
    working_path = (File.exist?(local_path)) ? local_path : mv_path
  end

  # render local template file if exists otherwise render file from mv
  def smart_render(short_path)
    local_path = File.join(RAILS_ROOT, 'app/views', short_path)+'.rhtml'
    if File.exist?(local_path)
      render :template => short_path
    else
      mv_path = File.join(File.dirname(__FILE__), '../../app/views', short_path)+'.rhtml'
      MasterView::Log.debug { 'mv_path='+mv_path }
      render :file => mv_path
    end
  end

  # render local template file if exists otherwise render file from mv
  def smart_render_with_layout(short_path, layout) #:nodoc:  #UNDER CONSTRUCTION
    #DOESN'T WORK YET - we get the right path, but need a way into template rendering
    # (usual path through rails bolts in assumption of app/views rel path)
    # [DJL 03-Jul-2006]
    local_path = File.join(RAILS_ROOT, 'app/views', short_path)+'.rhtml'
    if File.exist?(local_path)
      render :template => short_path, :layout => smart_layout_path(layout)
    else
      mv_path = File.join(File.dirname(__FILE__), '../../app/views', short_path)+'.rhtml'
      MasterView::Log.debug { 'mv_path='+mv_path }
      render :file => mv_path, :layout => smart_layout_path(layout)
    end
  end

  def smart_layout_path(short_path)  #:nodoc:  #UNDER CONSTRUCTION
    local_path = File.join(RAILS_ROOT, 'app/views/layouts', short_path)+'.rhtml'
    if File.exist?(local_path)
      short_path
    else
      mv_layouts_dir_path = File.expand_path( File.join(File.dirname(__FILE__), '../../app/views/layouts') )
      mv_path = File.join(mv_layouts_dir_path, short_path)+'.rhtml'
      if File.exist?(mv_path)
        MasterView::Log.debug { 'admin layout mv_path='+mv_path }
      else
        MasterView::Log.error { '***BAD ADMIN PAGE LAYOUT REF: mv_path='+mv_path }
      end
      mv_path
    end
  end

end