# 1. create the role "references" first
::xo::db::sql::acs_rel_type create_role -role references

# 2. create the role type "CrossReferences"
::xo::db::sql::acs_rel_type create_type \
    -rel_type CrossReference  \
    -pretty_name "A cross reference for ::demo::Notes"  \
    -pretty_plural "Cross references for ::demo::Notes"\
    -table_name cross_references -id_column cross_reference_id \
    -package_name CrossReference  \
    -object_type_one content_item  \
    -min_n_rels_one 0  \
    -max_n_rels_one "" \
    -object_type_two content_item  \
    -role_two references \
    -min_n_rels_two 0  \
    -max_n_rels_two ""

# 3. drop the role type

::xo::db::sql::acs_rel_type drop_type -rel_type CrossReference

# 1. provide context resolver

::demo::Package initialize -ad_doc {

  Referencing a note

  @author Stefan Sobernig
  @cvs-id $Id$
  
}

# 2. create two ::demo::Note objects to be associated

set referent [::demo::Note new_persistent_object \
		  -name my_referent \
		  -title "The referring note" \
		  -text "Some text (see references)" \
		  -number 1 \
		  -package_id $package_id \
		  -set parent_id [$package_id folder_id]]
set referee [::demo::Note new_persistent_object \
		 -name my_referee \
		 -title "The referred note" \
		 -text "Some text (see backlinks)" \
		 -number 2 \
		 -package_id $package_id \
		 -set parent_id [$package_id folder_id]]

# 3. establish the association (role assignment)
# Beware the subtle difference between establishing
# a relationship type (role type) between:
# a) two revision of a content item ("::demo::Note" as object_type restriction in acs_rel_type + revision_id for acs_rel->new())
# b) two content items ("content_item" as as object_type restriction in acs_rel_type + revision_id for acs_rel->new())

set rel_id [::xo::db::sql::acs_rel new \
    -rel_type CrossReference \
    -object_id_one [$referent item_id] \
    -object_id_two [$referee item_id]]

# 4. delete association (role assignment)

::xo::db::sql::acs_rel delete -rel_id $rel_id

ad_returnredirect "."

#
# 1. provide context resolver
#

::demo::Package initialize -ad_doc {

  Getting cross-references for a note

  @author Stefan Sobernig
  @cvs-id $Id$
  
}

#
# 2. resolve referent
#

set referent_id [::xo::db::CrClass lookup -name "my_referent"]

#
# 3. formulate an instance_select_query on ::demo::Note that
# is constraint to the referenced notes from a particular one.
# this needs a nested select statement as refinement. 
#

if {$referent_id != 0} {
  # found an so-named item
  set sql_statement [::demo::Note instance_select_query \
			 -folder_id [$package_id folder_id] \
			 -where_clause "ci.item_id IN ((select object_id_two from acs_rels rels where rels.object_id_one = $referent_id))"] 

  #
  # 4. 
  #
  db_foreach select_references $sql_statement {
    # the following variables will be initialised (from the
    # instance_select_query default select header): item_id, name,
    # publish_status, object_type
    
    # ...
  }
}

ad_return "."

::demo::Package initialize -ad_doc {

  permission checks

  @param object_id 

} -parameter {
  {-object_id:integer}
}

#
# 1. require authentication
#

auth::require_login

#
# We need to verify the current user's privileges
#

#
# 1. legacy style
#

permission::permission_p \
    -party_id  [::xo::cc user_id] \
    -object_id $object_id \
    -privilege delete

#
# 2. XOTcl Core style
#

::xo::cc permission -object_id $object_id -privilege write

#
# add the -with_categories switch to
# the Generic::Form instantiation
#
# this will render a multiple-select box
# and take care of persisting category
# settings ...
#

::Generic::Form create form1 -volatile \
    -data $item \
    -fields {
      {item_id:key}
      {name:text {label Name}}
      {number:text {label Number}}
      {text:richtext(richtext),nospell,optional {label Content} {options {editor xinha}}}
      {description:text(textarea),nospell,optional {label Description} {html {cols 60 rows 2}}}
    } -with_categories true

#
# 1. provide context resolver
#

::demo::Package initialize -ad_doc {

  Getting categorized notes

  @author Stefan Sobernig
  @cvs-id $Id$
  
} -parameter {
 {-category_id:required}
}


#
# 2. formulate an instance_select_query on ::demo::Note that
# is constraint to those assigned a particular category_id.
#
 set sql_statement [::demo::Note instance_select_query \
			 -folder_id [$package_id folder_id] \
			 -from_clause ", category_object_map com"
			 -where_clause "com.object_id = ci.item_id and
				        com.category_id = $category_id"] 


#
# 3. 
#
db_foreach select_references $sql_statement {
    # the following variables will be initialised (from the
    # instance_select_query default select header): item_id, name,
    # publish_status, object_type
    
    # ...
  }
}

ad_return "."