package Anvil::Tools::Account;
# 
# This module contains methods used to handle user accounts, logging in and out.
# 

use strict;
use warnings;
use Digest::SHA qw(sha256_base64 sha384_base64 sha512_base64);
use Scalar::Util qw(weaken isweak);

our $VERSION  = "3.0.0";
my $THIS_FILE = "Account.pm";

### Methods;
# encrypt_password
# read_details
# validate_password


=pod

=encoding utf8

=head1 NAME

Anvil::Tools::Account

Provides all methods related to user management and log in/out features.

=head1 SYNOPSIS

 use Anvil::Tools;

 # Get a common object handle on all Anvil::Tools modules.
 my $anvil = Anvil::Tools->new();
 
 # Access to methods using '$anvil->Account->X'. 

=head1 METHODS

Methods in the core module;

=cut

sub new
{
	my $class = shift;
	my $self  = {};
	
	bless $self, $class;
	
	return ($self);
}

# Get a handle on the Anvil::Tools object. I know that technically that is a sibling module, but it makes more
# sense in this case to think of it as a parent.
sub parent
{
	my $self   = shift;
	my $parent = shift;
	
	$self->{HANDLE}{TOOLS} = $parent if $parent;
	
	# Defend against memory leads. See Scalar::Util'.
	if (not isweak($self->{HANDLE}{TOOLS}))
	{
		weaken($self->{HANDLE}{TOOLS});;
	}
	
	return ($self->{HANDLE}{TOOLS});
}


#############################################################################################################
# Public methods                                                                                            #
#############################################################################################################

=head2 encrypt_password

This takes a string (a new password from a user), generates a salt, appends the salt to the string and hashes that using C<< sys::password::algorithm >>, the re-hashes the string C<< sys::password::hash_count >> times. The default algorithm is 'sha512' and the default rehashing count is '500,000' times. 

This method returns a hash reference with the following keys;

* user_password_hash: The final encrypted hash.
* user_salt:          The salt created (or used) to generate the hash.
* user_algorithm:     The algorithm used to compute the hash.
* user_hash_count:    The number of re-encryptions of the initial hash.

If anything goes wrong, all four keys will have empty strings.

Parameters

=head3 password (required)

This is the password (string) to encrypt.

=cut
sub encrypt_password
{
	my $self      = shift;
	my $parameter = shift;
	my $anvil     = $self->parent;
	my $debug     = defined $parameter->{debug} ? $parameter->{debug} : 3;
	
	my $user_password_hash = defined $parameter->{password} ? $parameter->{password} : "";
	my $user_hash_count    = $anvil->data->{sys}{password}{hash_count} =~ /^\d+$/ ? $anvil->data->{sys}{password}{hash_count} : 500000;
	my $user_algorithm     = $anvil->data->{sys}{password}{algorithm}             ? $anvil->data->{sys}{password}{algorithm}  : "sha512";
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		password => $anvil->Log->secure ? $user_password_hash : "--",
	}});
	
	# We'll fill these out below if we succeed.
	my $answer = {
		user_password_hash => "",
		user_salt          => "",
		user_hash_count    => "",
		user_algorithm     => "",
	};
	
	# Make sure we got a string
	if (not $user_password_hash)
	{
		$anvil->Log->entry({source => $THIS_FILE, line => __LINE__, level => 0, priority => "err", key => "log_0020", variables => { method => "Account->encrypt_password()", parameter => "password" }});
		return($answer);
	}
	
	# Generate a salt.
	my $user_salt = $anvil->Get->_salt;
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_salt => $user_salt }});
	
	### TODO: Look at using/support bcrypt as the default algorithm. Needed RPMs are already in the el7 AN!Repo.
	# We support sha256, sha384 and sha512, possible new ones later.
	if ($user_algorithm eq "sha256" )
	{
		$user_password_hash = sha256_base64($user_password_hash.$user_salt);
		$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_password_hash => $user_password_hash }});
		
		if ($user_hash_count > 0)
		{
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_hash_count => $user_hash_count }});
			for (1..$user_hash_count)
			{
				$user_password_hash = sha256_base64($user_password_hash);
			}
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_password_hash => $user_password_hash }});
		}
	}
	elsif ($user_algorithm eq "sha384" )
	{
		$user_password_hash = sha384_base64($user_password_hash.$user_salt);
		$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_password_hash => $user_password_hash }});
		
		if ($user_hash_count > 0)
		{
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_hash_count => $user_hash_count }});
			for (1..$user_hash_count)
			{
				$user_password_hash = sha384_base64($user_password_hash);
			}
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_password_hash => $user_password_hash }});
		}
	}
	elsif ($user_algorithm eq "sha512" )
	{
		$user_password_hash = sha512_base64($user_password_hash.$user_salt);
		$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_password_hash => $user_password_hash }});
		
		if ($user_hash_count > 0)
		{
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_hash_count => $user_hash_count }});
			for (1..$user_hash_count)
			{
				$user_password_hash = sha512_base64($user_password_hash);
			}
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_password_hash => $user_password_hash }});
		}
	}
	else
	{
		# Bash algorith. 
		$anvil->Log->entry({source => $THIS_FILE, line => __LINE__, level => 0, priority => "err", key => "log_0171", variables => { user_algorithm => $user_algorithm }});
		return($answer);
	}
	
	$answer = {
		user_password_hash => $user_password_hash,
		user_salt          => $user_salt,
		user_hash_count    => $user_hash_count,
		user_algorithm     => $user_algorithm,
	};
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		'answer->user_password_hash' => $answer->{user_password_hash}, 
		'answer->user_salt'          => $answer->{user_salt}, 
		'answer->user_hash_count'    => $answer->{user_hash_count}, 
		'answer->user_algorithm'     => $answer->{user_algorithm}, 
		
	}});
	
	return($answer);
}

=head2 read_details

This method takes a user name and, if the user is found, reads in the details and sets C<< sys::user::<column names> >>. If the user is found, C<< 1 >> is returned. If not, C<< 0 >> is returned.

Parameters;

=head3 user_name (required)

This is the user name being searched for. It is case sensitive.

=cut
sub read_details
{
	my $self      = shift;
	my $parameter = shift;
	my $anvil     = $self->parent;
	my $debug     = defined $parameter->{debug} ? $parameter->{debug} : 3;
	
	my $user_name = defined $parameter->{user_name} ? $parameter->{user_name} : "";
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_name => $user_name }});
	
	my $query = "
SELECT 
    user_uuid,
    user_password_hash, 
    user_salt, 
    user_algorithm, 
    user_hash_count, 
    user_language, 
    user_is_admin, 
    user_is_experienced, 
    user_is_trusted 
FROM 
    users 
WHERE 
    user_name = ".$anvil->data->{sys}{use_db_fh}->quote($user_name)." 
;";
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { query => $query }});
	
	my $results = $anvil->Database->query({query => $query, source => $THIS_FILE, line => __LINE__});
	my $count   = @{$results};
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		results => $results, 
		count   => $count, 
	}});
	if (not $count)
	{
		# User doesn't exist.
		return(0);
	}
	my $user_uuid           = $results->[0]->[0];
	my $user_password_hash  = $results->[0]->[1];
	my $user_salt           = $results->[0]->[2];
	my $user_algorithm      = $results->[0]->[3];
	my $user_hash_count     = $results->[0]->[4];
	my $user_language       = $results->[0]->[5];
	my $user_is_admin       = $results->[0]->[6];
	my $user_is_experienced = $results->[0]->[7];
	my $user_is_trusted     = $results->[0]->[8];
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		user_uuid           => $user_uuid, 
		user_password_hash  => $user_password_hash,
		user_salt           => $user_salt,
		user_algorithm      => $user_algorithm,
		user_hash_count     => $user_hash_count,
		user_language       => $user_language,
		user_is_admin       => $user_is_admin,
		user_is_experienced => $user_is_experienced,
		user_is_trusted     => $user_is_trusted,
	}});
			
	$anvil->data->{sys}{user}{user_name}           = $user_name;
	$anvil->data->{sys}{user}{user_uuid}           = $user_uuid;
	$anvil->data->{sys}{user}{user_password_hash}  = $user_password_hash,
	$anvil->data->{sys}{user}{user_salt}           = $user_salt,
	$anvil->data->{sys}{user}{user_algorithm}      = $user_algorithm,
	$anvil->data->{sys}{user}{user_hash_count}     = $user_hash_count,
	$anvil->data->{sys}{user}{user_language}       = $user_language,
	$anvil->data->{sys}{user}{user_is_admin}       = $user_is_admin,
	$anvil->data->{sys}{user}{user_is_experienced} = $user_is_experienced,
	$anvil->data->{sys}{user}{user_is_trusted}     = $user_is_trusted,
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		'sys::user::user_name'           => $anvil->data->{sys}{user}{user_name}, 
		'sys::user::user_uuid'           => $anvil->data->{sys}{user}{user_uuid}, 
		'sys::user::user_password_hash'  => $anvil->data->{sys}{user}{user_password_hash}, 
		'sys::user::user_salt'           => $anvil->data->{sys}{user}{user_salt}, 
		'sys::user::user_algorithm'      => $anvil->data->{sys}{user}{user_algorithm}, 
		'sys::user::user_hash_count'     => $anvil->data->{sys}{user}{user_hash_count}, 
		'sys::user::user_language'       => $anvil->data->{sys}{user}{user_language}, 
		'sys::user::user_is_admin'       => $anvil->data->{sys}{user}{user_is_admin}, 
		'sys::user::user_is_experienced' => $anvil->data->{sys}{user}{user_is_experienced}, 
		'sys::user::user_is_trusted'     => $anvil->data->{sys}{user}{user_is_trusted}, 
	}});
	
	return(1);
}

=head2 validate_password

This method takes a user name and password and checks to see if the password matches.

If the password is wrong, or if the user isn't found, C<< 0 >> is returned. If the password matches, C<< 1 >> is returned.

Parameters;

=head3 password (required)

This is the password to test.

=head3 user (required)

This is the user whose password we're testing.

=cut
sub validate_password
{
	my $self      = shift;
	my $parameter = shift;
	my $anvil     = $self->parent;
	my $debug     = defined $parameter->{debug} ? $parameter->{debug} : 3;
	
	my $password  = defined $parameter->{password} ? $parameter->{password} : "";
	my $user      = defined $parameter->{user}     ? $parameter->{user}     : "";
	my $valid     = 0;
	my $hash      = "";
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		password => $anvil->Log->secure ? $password : "--",
		user     => $user, 
	}});
	
	if (not $password)
	{
		$anvil->Log->entry({source => $THIS_FILE, line => __LINE__, level => 0, priority => "err", key => "log_0020", variables => { method => "Account->validate_password()", parameter => "password" }});
		return($valid);
	}
	if (not $user)
	{
		$anvil->Log->entry({source => $THIS_FILE, line => __LINE__, level => 0, priority => "err", key => "log_0020", variables => { method => "Account->validate_password()", parameter => "user" }});
		return($valid);
	}
	
	my $query = "
SELECT 
    user_password_hash, 
    user_salt, 
    user_algorithm, 
    user_hash_count 
FROM 
    users 
WHERE 
    user_name = ".$anvil->data->{sys}{use_db_fh}->quote($user)." 
;";
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { query => $query }});
	
	my $results = $anvil->Database->query({query => $query, source => $THIS_FILE, line => __LINE__});
	my $count   = @{$results};
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		results => $results, 
		count   => $count, 
	}});
	
	if (not $count)
	{
		# User not found.
		$anvil->Log->entry({source => $THIS_FILE, line => __LINE__, level => 0, priority => "err", key => "log_0172", variables => { user => $user }});
		return($valid);
	}
	
	my $user_password_hash = $results->[0]->[0];
	my $user_salt          = $results->[0]->[1];
	my $user_algorithm     = $results->[0]->[2];
	my $user_hash_count    = $results->[0]->[3];
	$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { 
		user_password_hash => $user_password_hash,
		user_salt          => $user_salt,
		user_algorithm     => $user_algorithm,
		user_hash_count    => $user_hash_count,
	}});
	
	if ($user_algorithm eq "sha256" )
	{
		$hash = sha256_base64($password.$user_salt);
		$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { hash => $hash }});
		
		if ($user_hash_count > 0)
		{
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_hash_count => $user_hash_count }});
			for (1..$user_hash_count)
			{
				$hash = sha256_base64($hash);
			}
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { hash => $hash }});
		}
	}
	elsif ($user_algorithm eq "sha384" )
	{
		$hash = sha384_base64($password.$user_salt);
		$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { hash => $hash }});
		
		if ($user_hash_count > 0)
		{
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_hash_count => $user_hash_count }});
			for (1..$user_hash_count)
			{
				$hash = sha384_base64($hash);
			}
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { hash => $hash }});
		}
	}
	elsif ($user_algorithm eq "sha512" )
	{
		$hash = sha512_base64($password.$user_salt);
		$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { hash => $hash }});
		
		if ($user_hash_count > 0)
		{
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { user_hash_count => $user_hash_count }});
			for (1..$user_hash_count)
			{
				$hash = sha512_base64($hash);
			}
			$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { hash => $hash }});
		}
	}
	else
	{
		# Bad algorith. 
		$anvil->Log->entry({source => $THIS_FILE, line => __LINE__, level => 0, priority => "err", key => "log_0173", variables => { user_algorithm => $user_algorithm }});
		return($valid);
	}
	
	# Test.
	if ($hash eq $user_password_hash)
	{
		# Good password.
		$valid = 1;
		$anvil->Log->variables({source => $THIS_FILE, line => __LINE__, level => $debug, list => { valid => $valid }});
	}
	
	return($valid);
}

1;