# Copyright 2002 Katipo Communications
#
# This file is part of Koha.
#
# Koha is free software; you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# Koha is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along with
# Koha; if not, write to the Free Software Foundation, Inc., 59 Temple Place,
# Suite 330, Boston, MA  02111-1307 USA

# $Id$
package C4::Context;
use strict;
use DBI;
use C4::Boolean;
use XML::Simple;
use vars qw($VERSION $AUTOLOAD),
	qw($context),
	qw(@context_stack);

$VERSION = do { my @v = '$Revision$' =~ /\d+/g;
		shift(@v) . "." . join("_", map {sprintf "%03d", $_ } @v); };

=head1 NAME

C4::Context - Maintain and manipulate the context of a Koha script

=head1 SYNOPSIS

  use C4::Context;

  use C4::Context("/path/to/koha.xml");

  $config_value = C4::Context->config("config_variable");
  $db_handle = C4::Context->dbh;
  $stopwordhash = C4::Context->stopwords;

=head1 DESCRIPTION

When a Koha script runs, it makes use of a certain number of things:
configuration settings in F</etc/koha.xml>, a connection to the Koha
databases, and so forth. These things make up the I<context> in which
the script runs.

This module takes care of setting up the context for a script:
figuring out which configuration file to load, and loading it, opening
a connection to the right database, and so forth.

Most scripts will only use one context. They can simply have

  use C4::Context;

at the top.

Other scripts may need to use several contexts. For instance, if a
library has two databases, one for a certain collection, and the other
for everything else, it might be necessary for a script to use two
different contexts to search both databases. Such scripts should use
the C<&set_context> and C<&restore_context> functions, below.

By default, C4::Context reads the configuration from
F</etc/koha.xml>. This may be overridden by setting the C<$KOHA_CONF>
environment variable to the pathname of a configuration file to use.

=head1 METHODS

=over 2

=cut

#'
# In addition to what is said in the POD above, a Context object is a
# reference-to-hash with the following fields:
#
# config
#	A reference-to-hash whose keys and values are the
#	configuration variables and values specified in the config
#	file (/etc/koha.xml).
# dbh
#	A handle to the appropriate database for this context.
# dbh_stack
#	Used by &set_dbh and &restore_dbh to hold other database
#	handles for this context.
# Zconn
# 	A connection object for the Zebra server

use constant CONFIG_FNAME => "/etc/koha.xml";
				# Default config file, if none is specified

$context = undef;		# Initially, no context is set
@context_stack = ();		# Initially, no saved contexts

# read_config_file
# Reads the specified Koha config file. Returns a reference-to-hash
# whose keys are the configuration variables, and whose values are the
# configuration values (duh).
# Returns undef in case of error.
#
# Revision History:
# 2004-08-10 A. Tarallo: Added code that checks if a variable is already
# assigned and prints a message, otherwise create a new entry in the hash to
# be returned. 
# Also added code that complaints if finds a line that isn't a variable 
# assignmet and skips the line.
# Added a quick hack that makes the translation between the db_schema
# and the DBI driver for that schema.
#
sub read_config_file
{
	my $fname = shift;	# Config file to read

	my $retval = {};	# Return value: ref-to-hash holding the
				# configuration

my $koha = XMLin($fname, keyattr => ['id'],forcearray => ['listen']);

	return $koha;
}

# db_scheme2dbi
# Translates the full text name of a database into de appropiate dbi name
# 
sub db_scheme2dbi
{
	my $name = shift;

	for ($name) {
# FIXME - Should have other databases. 
		if (/mysql/i) { return("mysql"); }
		if (/Postgres|Pg|PostgresSQL/) { return("Pg"); }
		if (/oracle/i) { return("Oracle"); }
	}
	return undef; 		# Just in case
}

sub import
{
	my $package = shift;
	my $conf_fname = shift;		# Config file name
	my $context;

	# Create a new context from the given config file name, if
	# any, then set it as the current context.
	$context = new C4::Context($conf_fname);
	return undef if !defined($context);
	$context->set_context;
}

=item new

  $context = new C4::Context;
  $context = new C4::Context("/path/to/koha.xml");

Allocates a new context. Initializes the context from the specified
file, which defaults to either the file given by the C<$KOHA_CONF>
environment variable, or F</etc/koha.xml>.

C<&new> does not set this context as the new default context; for
that, use C<&set_context>.

=cut

#'
# Revision History:
# 2004-08-10 A. Tarallo: Added check if the conf file is not empty
sub new
{
	my $class = shift;
	my $conf_fname = shift;		# Config file to load
	my $self = {};

	# check that the specified config file exists and is not empty
	undef $conf_fname unless 
	    (defined $conf_fname && -e $conf_fname && -s $conf_fname);
	# Figure out a good config file to load if none was specified.
	if (!defined($conf_fname))
	{
		# If the $KOHA_CONF environment variable is set, use
		# that. Otherwise, use the built-in default.
		$conf_fname = $ENV{"KOHA_CONF"} || CONFIG_FNAME;
	}
		# Load the desired config file.
	$self = read_config_file($conf_fname);
	$self->{"config_file"} = $conf_fname;


	
	warn "read_config_file($conf_fname) returned undef" if !defined($self->{"config"});
	return undef if !defined($self->{"config"});

	$self->{"dbh"} = undef;		# Database handle
	$self->{"Zconn"} = undef;	# Zebra Connection
	$self->{"Zconnauth"} = undef;	# Zebra Connection for updating
	$self->{"stopwords"} = undef; # stopwords list
	$self->{"marcfromkohafield"} = undef; # the hash with relations between koha table fields and MARC field/subfield
	$self->{"attrfromkohafield"} = undef; # the hash with relations between koha table fields and Bib1-attributes
	$self->{"userenv"} = undef;		# User env
	$self->{"activeuser"} = undef;		# current active user

	bless $self, $class;
	return $self;
}

=item set_context

  $context = new C4::Context;
  $context->set_context();
or
  set_context C4::Context $context;

  ...
  restore_context C4::Context;

In some cases, it might be necessary for a script to use multiple
contexts. C<&set_context> saves the current context on a stack, then
sets the context to C<$context>, which will be used in future
operations. To restore the previous context, use C<&restore_context>.

=cut

#'
sub set_context
{
	my $self = shift;
	my $new_context;	# The context to set

	# Figure out whether this is a class or instance method call.
	#
	# We're going to make the assumption that control got here
	# through valid means, i.e., that the caller used an instance
	# or class method call, and that control got here through the
	# usual inheritance mechanisms. The caller can, of course,
	# break this assumption by playing silly buggers, but that's
	# harder to do than doing it properly, and harder to check
	# for.
	if (ref($self) eq "")
	{
		# Class method. The new context is the next argument.
		$new_context = shift;
	} else {
		# Instance method. The new context is $self.
		$new_context = $self;
	}

	# Save the old context, if any, on the stack
	push @context_stack, $context if defined($context);

	# Set the new context
	$context = $new_context;
}

=item restore_context

  &restore_context;

Restores the context set by C<&set_context>.

=cut

#'
sub restore_context
{
	my $self = shift;

	if ($#context_stack < 0)
	{
		# Stack underflow.
		die "Context stack underflow";
	}

	# Pop the old context and set it.
	$context = pop @context_stack;

	# FIXME - Should this return something, like maybe the context
	# that was current when this was called?
}

=item config

  $value = C4::Context->config("config_variable");

  $value = C4::Context->config_variable;

Returns the value of a variable specified in the configuration file
from which the current context was created.

The second form is more compact, but of course may conflict with
method names. If there is a configuration variable called "new", then
C<C4::Config-E<gt>new> will not return it.

=cut

#'
sub config
{
	my $self = shift;
	my $var = shift;		# The config variable to return

	return undef if !defined($context->{"config"});
			# Presumably $self->{config} might be
			# undefined if the config file given to &new
			# didn't exist, and the caller didn't bother
			# to check the return value.

	# Return the value of the requested config variable
	return $context->{"config"}->{$var};
}
=item zebraconfig
$serverdir=C4::Context->zebraconfig("biblioserver")->{directory};

returns the zebra server specific details for different zebra servers
similar to C4:Context->config
=cut

sub zebraconfig
{
	my $self = shift;
	my $var = shift;		# The config variable to return

	return undef if !defined($context->{"server"});
	# Return the value of the requested config variable
	return $context->{"server"}->{$var};
}
=item preference

  $sys_preference = C4::Context->preference("some_variable");

Looks up the value of the given system preference in the
systempreferences table of the Koha database, and returns it. If the
variable is not set, or in case of error, returns the undefined value.

=cut

#'
# FIXME - The preferences aren't likely to change over the lifetime of
# the script (and things might break if they did change), so perhaps
# this function should cache the results it finds.
sub preference
{
	my $self = shift;
	my $var = shift;		# The system preference to return
	my $retval;			# Return value
	my $dbh = C4::Context->dbh;	# Database handle
	my $sth;			# Database query handle

	# Look up systempreferences.variable==$var
	$retval = $dbh->selectrow_array(<<EOT);
		SELECT	value
		FROM	systempreferences
		WHERE	variable='$var'
		LIMIT	1
EOT
	return $retval;
}

sub boolean_preference ($) {
	my $self = shift;
	my $var = shift;		# The system preference to return
	my $it = preference($self, $var);
	return defined($it)? C4::Boolean::true_p($it): undef;
}

# AUTOLOAD
# This implements C4::Config->foo, and simply returns
# C4::Context->config("foo"), as described in the documentation for
# &config, above.

# FIXME - Perhaps this should be extended to check &config first, and
# then &preference if that fails. OTOH, AUTOLOAD could lead to crappy
# code, so it'd probably be best to delete it altogether so as not to
# encourage people to use it.
sub AUTOLOAD
{
	my $self = shift;

	$AUTOLOAD =~ s/.*:://;		# Chop off the package name,
					# leaving only the function name.
	return $self->config($AUTOLOAD);
}

=item Zconn

$Zconn = C4::Context->Zconn
$Zconnauth = C4::Context->Zconnauth
Returns a connection to the Zebra database for the current
context. If no connection has yet been made, this method 
creates one and connects.

=cut

sub Zconn {
        my $self = shift;
my $server=shift;
my $syntax=shift;
	my $Zconn;
	$context->{"Zconn"} = &new_Zconn($server,$syntax);
	return $context->{"Zconn"};
  
}

sub Zconnauth {
        my $self = shift;
my $server=shift;
my $syntax=shift;
	my $Zconnauth;
##We destroy each connection made so create a new one	
		$context->{"Zconnauth"} = &new_Zconnauth($server,$syntax);
		return $context->{"Zconnauth"};
		
}



=item new_Zconn

Internal helper function. creates a new database connection from
the data given in the current context and returns it.

=cut

sub new_Zconn {
use ZOOM;
my $server=shift;
my $syntax=shift;
$syntax="xml" unless $syntax;
my $Zconn;
my ($tcp,$host,$port)=split /:/,$context->{"listen"}->{$server}->{"content"};
my $o = new ZOOM::Options();
$o->option(async => 1);
$o->option(preferredRecordSyntax => $syntax); ## Authorities use marc while biblioserver is xml
$o->option(databaseName=>$context->{"config"}->{$server});
#$o->option(proxy=>$context->{"config"}->{"proxy"});## if proxyserver provided will route searches to proxy
my $o2= new ZOOM::Options();

 $Zconn=create ZOOM::Connection($o);
	$Zconn->connect($context->{"config"}->{"hostname"},$port);
	
	return $Zconn;
}

## Zebra handler with write permission
sub new_Zconnauth {
use ZOOM;
my $server=shift;
my $syntax=shift;
$syntax="xml" unless $syntax;
my $Zconnauth;
my ($tcp,$host,$port)=split /:/,$context->{"listen"}->{$server}->{"content"};
my $o = new ZOOM::Options();
#$o->option(async => 1);
$o->option(preferredRecordSyntax => $syntax);
$o->option(user=>$context->{"config"}->{"zebrauser"});
$o->option(password=>$context->{"config"}->{"zebrapass"});
$o->option(databaseName=>$context->{"config"}->{$server});
 $o->option(charset=>"UTF8");
 $Zconnauth=create ZOOM::Connection($o);
$Zconnauth->connect($context->config("hostname"),$port);
return $Zconnauth;
}


# _new_dbh
# Internal helper function (not a method!). This creates a new
# database connection from the data given in the current context, and
# returns it.
sub _new_dbh
{
	##correct name for db_schme		
	my $db_driver;
	if ($context->config("db_scheme")){
	$db_driver=db_scheme2dbi($context->config("db_scheme"));
	}else{
	$db_driver="mysql";
	}

	my $db_name   = $context->config("database");
	my $db_host   = $context->config("hostname");
	my $db_user   = $context->config("user");
	my $db_passwd = $context->config("pass");
	my $dbh= DBI->connect("DBI:$db_driver:$db_name:$db_host",
			    $db_user, $db_passwd);
	# Koha 3.0 is utf-8, so force utf8 communication between mySQL and koha, whatever the mysql default config.
	# this is better than modifying my.cnf (and forcing all communications to be in utf8)
	$dbh->do("set NAMES 'utf8'");
	return $dbh;
}

=item dbh

  $dbh = C4::Context->dbh;

Returns a database handle connected to the Koha database for the
current context. If no connection has yet been made, this method
creates one, and connects to the database.

This database handle is cached for future use: if you call
C<C4::Context-E<gt>dbh> twice, you will get the same handle both
times. If you need a second database handle, use C<&new_dbh> and
possibly C<&set_dbh>.

=cut

#'
sub dbh
{
	my $self = shift;
	my $sth;

	if (defined($context->{"dbh"})) {
	    $sth=$context->{"dbh"}->prepare("select 1");
	    return $context->{"dbh"} if (defined($sth->execute));
	}

	# No database handle or it died . Create one.
	$context->{"dbh"} = &_new_dbh();

	return $context->{"dbh"};
}

=item new_dbh

  $dbh = C4::Context->new_dbh;

Creates a new connection to the Koha database for the current context,
and returns the database handle (a C<DBI::db> object).

The handle is not saved anywhere: this method is strictly a
convenience function; the point is that it knows which database to
connect to so that the caller doesn't have to know.

=cut

#'
sub new_dbh
{
	my $self = shift;

	return &_new_dbh();
}

=item set_dbh

  $my_dbh = C4::Connect->new_dbh;
  C4::Connect->set_dbh($my_dbh);
  ...
  C4::Connect->restore_dbh;

C<&set_dbh> and C<&restore_dbh> work in a manner analogous to
C<&set_context> and C<&restore_context>.

C<&set_dbh> saves the current database handle on a stack, then sets
the current database handle to C<$my_dbh>.

C<$my_dbh> is assumed to be a good database handle.

=cut

#'
sub set_dbh
{
	my $self = shift;
	my $new_dbh = shift;

	# Save the current database handle on the handle stack.
	# We assume that $new_dbh is all good: if the caller wants to
	# screw himself by passing an invalid handle, that's fine by
	# us.
	push @{$context->{"dbh_stack"}}, $context->{"dbh"};
	$context->{"dbh"} = $new_dbh;
}

=item restore_dbh

  C4::Context->restore_dbh;

Restores the database handle saved by an earlier call to
C<C4::Context-E<gt>set_dbh>.

=cut

#'
sub restore_dbh
{
	my $self = shift;

	if ($#{$context->{"dbh_stack"}} < 0)
	{
		# Stack underflow
		die "DBH stack underflow";
	}

	# Pop the old database handle and set it.
	$context->{"dbh"} = pop @{$context->{"dbh_stack"}};

	# FIXME - If it is determined that restore_context should
	# return something, then this function should, too.
}

=item marcfromkohafield

  $dbh = C4::Context->marcfromkohafield;

Returns a hash with marcfromkohafield.

This hash is cached for future use: if you call
C<C4::Context-E<gt>marcfromkohafield> twice, you will get the same hash without real DB access

=cut

#'
sub marcfromkohafield
{
	my $retval = {};

	# If the hash already exists, return it.
	return $context->{"marcfromkohafield"} if defined($context->{"marcfromkohafield"});

	# No hash. Create one.
	$context->{"marcfromkohafield"} = &_new_marcfromkohafield();

	return $context->{"marcfromkohafield"};
}


# _new_marcfromkohafield
# Internal helper function (not a method!). 
sub _new_marcfromkohafield
{
	my $dbh = C4::Context->dbh;
	my $marcfromkohafield;
	my $sth = $dbh->prepare("select marctokoha,tagfield,tagsubfield,recordtype from koha_attr where tagfield is not null  ");
	$sth->execute;
	while (my ($kohafield,$tagfield,$tagsubfield,$recordtype) = $sth->fetchrow) {
		my $retval = {};
		$marcfromkohafield->{$recordtype}->{$kohafield} = [$tagfield,$tagsubfield];
	}
	
	return $marcfromkohafield;
}


#item attrfromkohafield
#To use as a hash of koha to z3950 attributes
sub _new_attrfromkohafield
{
	my $dbh = C4::Context->dbh;
	my $attrfromkohafield;
	my $sth2 = $dbh->prepare("select marctokoha,attr from koha_attr" );
	$sth2->execute;
	while (my ($marctokoha,$attr) = $sth2->fetchrow) {
		my $retval = {};
		$attrfromkohafield->{$marctokoha} = $attr;
	}
	return $attrfromkohafield;
}
sub attrfromkohafield
{
	my $retval = {};

	# If the hash already exists, return it.
	return $context->{"attrfromkohafield"} if defined($context->{"attrfromkohafield"});

	# No hash. Create one.
	$context->{"attrfromkohafield"} = &_new_attrfromkohafield();

	return $context->{"attrfromkohafield"};
}
=item stopwords

  $dbh = C4::Context->stopwords;

Returns a hash with stopwords.

This hash is cached for future use: if you call
C<C4::Context-E<gt>stopwords> twice, you will get the same hash without real DB access

=cut

#'
sub stopwords
{
	my $retval = {};

	# If the hash already exists, return it.
	return $context->{"stopwords"} if defined($context->{"stopwords"});

	# No hash. Create one.
	$context->{"stopwords"} = &_new_stopwords();

	return $context->{"stopwords"};
}

# _new_stopwords
# Internal helper function (not a method!). This creates a new
# hash with stopwords
sub _new_stopwords
{
	my $dbh = C4::Context->dbh;
	my $stopwordlist;
	my $sth = $dbh->prepare("select word from stopwords");
	$sth->execute;
	while (my $stopword = $sth->fetchrow_array) {
		my $retval = {};
		$stopwordlist->{$stopword} = uc($stopword);
	}
	$stopwordlist->{A} = "A" unless $stopwordlist;
	return $stopwordlist;
}

=item userenv

  C4::Context->userenv;

Builds a hash for user environment variables.

This hash shall be cached for future use: if you call
C<C4::Context-E<gt>userenv> twice, you will get the same hash without real DB access

set_userenv is called in Auth.pm

=cut

#'
sub userenv
{
	my $var = $context->{"activeuser"};
	return $context->{"userenv"}->{$var} if (defined $context->{"userenv"}->{$var});
	return 0;
	warn "NO CONTEXT for $var";
}

=item set_userenv

  C4::Context->set_userenv($usernum, $userid, $usercnum, $userfirstname, $usersurname, $userbranch, $userflags, $emailaddress);

Informs a hash for user environment variables.

This hash shall be cached for future use: if you call
C<C4::Context-E<gt>userenv> twice, you will get the same hash without real DB access

set_userenv is called in Auth.pm

=cut
#'
sub set_userenv{
	my ($usernum, $userid, $usercnum, $userfirstname, $usersurname, $userbranch, $branchname, $userflags, $emailaddress,$branchprinter)= @_;
	my $var=$context->{"activeuser"};
	my $cell = {
		"number"     => $usernum,
		"id"         => $userid,
		"cardnumber" => $usercnum,
#		"firstname"  => $userfirstname,
#		"surname"    => $usersurname,
#possibly a law problem
		"branch"     => $userbranch,
		"branchname" => $branchname,
		"flags"      => $userflags,
		"emailaddress"	=> $emailaddress,
		"branchprinter" => $branchprinter,
	};
	$context->{userenv}->{$var} = $cell;
	return $cell;
}

=item _new_userenv

  C4::Context->_new_userenv($session);

Builds a hash for user environment variables.

This hash shall be cached for future use: if you call
C<C4::Context-E<gt>userenv> twice, you will get the same hash without real DB access

_new_userenv is called in Auth.pm

=cut

#'
sub _new_userenv
{
	shift;
	my ($sessionID)= @_;
 	$context->{"activeuser"}=$sessionID;
}

=item _unset_userenv

  C4::Context->_unset_userenv;

Destroys the hash for activeuser user environment variables.

=cut
#'

sub _unset_userenv
{
	my ($sessionID)= @_;
	undef $context->{"activeuser"} if ($context->{"activeuser"} eq $sessionID);
}



1;
__END__

=back

=head1 ENVIRONMENT

=over 4

=item C<KOHA_CONF>

Specifies the configuration file to read.

=back

=head1 SEE ALSO

DBI(3)

=head1 AUTHOR

Andrew Arensburger <arensb at ooblick dot com>

=cut
# $Log$
# Revision 1.46  2006/09/06 16:21:03  tgarip1957
# Clean up before final commits
#
# Revision 1.43  2006/08/10 12:49:37  toins
# sync with dev_week.
#
# Revision 1.42  2006/07/04 14:36:51  toins
# Head & rel_2_2 merged
#
# Revision 1.41  2006/05/20 14:36:09  tgarip1957
# Typo error. Missing '>'
#
# Revision 1.40  2006/05/20 14:28:02  tgarip1957
# Adding support to read zebra database name from config files
#
# Revision 1.39  2006/05/19 09:52:54  alaurin
# committing new feature ip and printer management
# adding two fields in branches table (branchip,branchprinter)
#
# branchip : if the library enter an ip or ip range any librarian that connect from computer in this ip range will be temporarly affected to the corresponding branch .
#
# branchprinter : the library  can select a default printer for a branch
#
# Revision 1.38  2006/05/14 00:22:31  tgarip1957
# Adding support for getting details of different zebra servers
#
# Revision 1.37  2006/05/13 19:51:39  tgarip1957
# Now reads koha.xml rather than koha.conf.
# koha.xml contains both the koha configuration and zebraserver configuration.
# Zebra connection is modified to allow connection to authority zebra as well.
# It will break head if koha.conf is not replaced with koha.xml
#
# Revision 1.36  2006/05/09 13:28:08  tipaul
# adding the branchname and the librarian name in every page :
# - modified userenv to add branchname
# - modifier menus.inc to have the librarian name & userenv displayed on every page. they are in a librarian_information div.
#
# Revision 1.35  2006/04/13 08:40:11  plg
# bug fixed: typo on Zconnauth name
#
# Revision 1.34  2006/04/10 21:40:23  tgarip1957
# A new handler defined for zebra Zconnauth with read/write permission. Zconnauth should only be called in biblio.pm where write operations are. Use of this handler will break things unless koha.conf contains new variables:
# zebradb=localhost
# zebraport=<your port>
# zebrauser=<username>
# zebrapass=<password>
#
# The zebra.cfg file should read:
# perm.anonymous:r
# perm.username:rw
# passw.c:<yourpasswordfile>
#
# Password file should be prepared with Apaches htpasswd utility in encrypted mode and should exist in a folder zebra.cfg can read
#
# Revision 1.33  2006/03/15 11:21:56  plg
# bug fixed: utf-8 data where not displayed correctly in screens. Supposing
# your data are truely utf-8 encoded in your database, they should be
# correctly displayed. "set names 'UTF8'" on mysql connection (C4/Context.pm)
# is mandatory and "binmode" to utf8 (C4/Interface/CGI/Output.pm) seemed to
# converted data twice, so it was removed.
#
# Revision 1.32  2006/03/03 17:25:01  hdl
# Bug fixing : a line missed a comment sign.
#
# Revision 1.31  2006/03/03 16:45:36  kados
# Remove the search that tests the Zconn -- warning, still no fault
# tollerance
#
# Revision 1.30  2006/02/22 00:56:59  kados
# First go at a connection object for Zebra. You can now get a
# connection object by doing:
#
# my $Zconn = C4::Context->Zconn;
#
# My initial tests indicate that as soon as your funcion ends
# (ie, when you're done doing something) the connection will be
# closed automatically. There may be some other way to make the
# connection more stateful, I'm not sure...
#
# Local Variables:
# tab-width: 4
# End: