<?php
class Ledger extends AppModel {

  var $name = 'Ledger';
  var $validate = array(
    'id' => array('numeric'),
    'name' => array('notempty'),
  );

  var $belongsTo = array(
    'Account',
    'PriorLedger' => array('className' => 'Ledger'),
    'Close',
  );

  var $hasMany = array(
    'LedgerEntry' => array(
      'foreignKey' => false,

      // conditions will be used when JOINing tables
      // (such as find with LinkableBehavior)
      'conditions' => array('OR' =>
			    array('LedgerEntry.debit_ledger_id = %{MODEL_ALIAS}.id',
				  'LedgerEntry.credit_ledger_id = %{MODEL_ALIAS}.id')),

      // finderQuery will be used when tables are put
      // together across several querys, not with JOIN.
      // (such as find with ContainableBehavior)
      'finderQuery' => 'SELECT `LedgerEntry`.*
                         FROM pmgr_ledger_entries AS `LedgerEntry`
                         WHERE LedgerEntry.debit_ledger_id = ({$__cakeID__$})
                            OR LedgerEntry.credit_ledger_id = ({$__cakeID__$})',

      'counterQuery' => ''
    ),
    'DebitLedgerEntry' => array(
      'className' => 'LedgerEntry',
      'foreignKey' => 'debit_ledger_id',
      'dependent' => false,
    ),
    'CreditLedgerEntry' => array(
      'className' => 'LedgerEntry',
      'foreignKey' => 'credit_ledger_id',
      'dependent' => false,
    ),
  );


  /**************************************************************************
   **************************************************************************
   **************************************************************************
   * function: closeLedger
   *  - Closes the current ledger, and returns a fresh one
   */
  function closeLedger($id, $close_id) {
    $this->recursive = -1;

    $stamp = date('Y-m-d G:i:s');
    $this->id = $id;
    $this->read();
    $this->data['Ledger']['close_id'] = $close_id;
    $this->save($this->data, false);

    $stats = $this->stats($id);

    $this->read();
    $this->data['Ledger']['id'] = null;
    $this->data['Ledger']['close_id'] = null;
    $this->data['Ledger']['prior_ledger_id'] = $id;
    $this->data['Ledger']['comment'] = null;
    ++$this->data['Ledger']['sequence'];
    $this->id = null;
    $this->save($this->data, false);
    //pr($this->data);

    if ($stats['balance'] == 0)
      return $this->id;

    $this->read();
    $ftype = $this->Account->fundamentalType($this->data['Ledger']['account_id']);
    $otype = $this->Account->fundamentalOpposite($ftype);

    // Create a transaction for balance transfer
    $transaction = new Transaction();
    $transaction->create();
    if (!$transaction->save(array(), false)) {
      return null;
    }

    // Create an entry to carry the balance forward
    $carry_entry_data = array
      ($ftype.'_ledger_id' => $this->id,
       $otype.'_ledger_id' => $id,
       'transaction_id' => $transaction->id,
       'amount' => $stats['balance'],
       'comment' => "Ledger Balance Forward",
       );

    $carry_entry = new LedgerEntry();
    $carry_entry->create();
    if (!$carry_entry->save($carry_entry_data, false)) {
      return null;
    }

    return $this->id;
    }


  /**************************************************************************
   **************************************************************************
   **************************************************************************
   * function: findLedgerEntries
   *  - Returns an array of ledger entries that belong to a given
   *    ledger. There is extra work done... see the LedgerEntry model.
   */
  function findLedgerEntries($id, $account_type = null, $cond = null, $link = null) {
/*     pr(array('function' => 'Ledger::findLedgerEntries', */
/* 	     'args' => compact('id', 'account_type', 'cond', 'link'), */
/* 	     )); */

    if (!isset($account_type)) {
      $ledger = $this->find('first', array
			    ('contain' => array
			     ('Account' => array
			      ('fields' => array('type'),
			       ),
			      ),
			     'fields' => array(),
			     'conditions' => array(array('Ledger.id' => $id)),
			     ));
      $account_type = $ledger['Account']['type'];
    }

    // If the requested entries are limited by date, we must calculate
    // a balance forward, or the resulting balance will be thrown off.
    //
    // REVISIT <AP>: This obviously is more general than date.
    //               As such, it will not work (or, only work if the
    //               condition only manages to exclude the first parts
    //               of the ledger, nothing in the middle or at the
    //               end. For now, I'll just create an 'other' entry,
    //               not necessarily a balance forward.

    $bf = array();
    if (0 && isset($cond)) {
      //$date = '<NOT IMPLEMENTED>';
      $stats = $this->stats($id, array('NOT' => array($cond)));
      $bf = array(array(array('debit' => $stats['debits'],
			      'credit' => $stats['credits'],
			      'balance' => $stats['balance']),

			'LedgerEntry' => array('id' => null,
					       //'comment' => "Balance Forward from $date"),
					       'comment' => "-- SUMMARY OF EXCLUDED ENTRIES --"),

			'Transaction' => array('id' => null,
					       //'stamp' => $date,
					       'stamp' => null,
					       'comment' => null),
			));
    }

    $entries = $this->LedgerEntry->findInLedgerContext($id, $account_type, $cond, $link);
/*     pr(array('function' => 'Ledger::findLedgerEntries', */
/* 	     'args' => compact('id', 'account_type', 'cond', 'link'), */
/* 	     'vars' => compact('ledger'), */
/* 	     'return' => compact('entries'), */
/* 	     )); */
    return $entries;
  }


  /**************************************************************************
   **************************************************************************
   **************************************************************************
   * function: stats
   *  - Returns summary data from the requested ledger.
   */
  function stats($id, $cond = null) {
    if (!isset($cond))
      $cond = array();
    $cond[] = array('Ledger.id' => $id);

    $stats = $this->find
      ('first', array
       ('link' =>
	array(// Models
	      'Account' => array('fields' => array()),
	      //'LedgerEntry' => array('fields' => array()),
	      'LedgerEntry' =>
	      array('fields' => array(),
		    'Transaction' => array('fields' => array('stamp')),
		    ),
	      ),
	'fields' =>
	array("SUM(IF(LedgerEntry.debit_ledger_id  = Ledger.id,
                      LedgerEntry.amount, NULL)) AS debits",
	      "SUM(IF(LedgerEntry.credit_ledger_id = Ledger.id,
                      LedgerEntry.amount, NULL)) AS credits",
	      "SUM(IF(Account.type IN ('ASSET', 'EXPENSE'),
                      IF(LedgerEntry.debit_ledger_id  = Ledger.id, 1, -1),
                      IF(LedgerEntry.credit_ledger_id = Ledger.id, 1, -1)
                      ) * IF(LedgerEntry.amount, LedgerEntry.amount, 0)
                   ) AS balance",
	      "COUNT(LedgerEntry.id) AS entries"),
	'conditions' => $cond,
	'group' => 'Ledger.id',
	));

    // The fields are all tucked into the [0] index,
    // and the rest of the array is useless (empty).
    return $stats[0];
  }

}
?>