<?php
class Ledger extends AppModel {

  var $belongsTo = array(
    'Account',
    'PriorLedger' => array('className' => 'Ledger'),
    'Close',
  );

  var $hasMany = array(
    'Entry',

    'DoubleEntry' => array(
      'foreignKey' => false,

      // conditions will be used when JOINing tables
      // (such as find with LinkableBehavior)
      'conditions' => array('OR' =>
			    array('DoubleEntry.debit_ledger_id = %{MODEL_ALIAS}.id',
				  'DoubleEntry.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 `DoubleEntry`.*
                         FROM pmgr_double_entries AS `DoubleEntry`
                         WHERE DoubleEntry.debit_ledger_id = ({$__cakeID__$})
                            OR DoubleEntry.credit_ledger_id = ({$__cakeID__$})',

      'counterQuery' => ''
    ),
  );


  /**************************************************************************
   **************************************************************************
   **************************************************************************
   * function: accountID
   *  - Returns the account ID for the given ledger
   */
  function accountID($id) {
    $this->cacheQueries = true;
    $item = $this->find('first', array
			('contain' => 'Account.id',
			 'conditions' => array('Ledger.id' => $id),
			 ));
    $this->cacheQueries = false;
    return $item['Account']['id'];
  }


  /**************************************************************************
   **************************************************************************
   **************************************************************************
   * function: currentLedgerID
   *  - Returns the current ledger ID of the account for the given ledger.
   */
  function currentLedgerID($id) {
    return $this->Account->currentLedgerID($this->accountID($id));
  }


  /**************************************************************************
   **************************************************************************
   **************************************************************************
   * 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 DoubleEntry();
    $carry_entry->create();
    if (!$carry_entry->save($carry_entry_data, false)) {
      return null;
    }

    return $this->id;
    }


  function debitCreditFields($id, $sum = false, $entry_name = 'Entry', $double_name = 'DoubleEntry') {
    $ftype = strtoupper($this->Account->fundamentalType($this->accountID($id)));

    $fields = array
      (
       ($sum ? 'SUM(' : '') .
       "IF({$entry_name}.crdr  = 'DEBIT',  {$double_name}.amount, NULL)" .
       ($sum ? ')' : '') . ' AS debit' . ($sum ? 's' : ''),

       ($sum ? 'SUM(' : '') .
       "IF({$entry_name}.crdr  = 'CREDIT', {$double_name}.amount, NULL)" .
       ($sum ? ')' : '') . ' AS credit' . ($sum ? 's' : ''),

       ($sum ? 'SUM(' : '') .
       "IF({$entry_name}.crdr = '$ftype', 1, -1) * {$double_name}.amount" .
       // IF({$double_name}.amount, {$double_name}.amount, 0)" .
       ($sum ? ')' : '') . ' AS balance',
       );

    if ($sum)
      $fields[] = "COUNT({$entry_name}.id) AS entries";

    return $fields;
  }

  /**************************************************************************
   **************************************************************************
   **************************************************************************
   * function: ledgerEntries
   *  - Returns an array of ledger entries that belong to a given
   *    ledger. There is extra work done to establish debit/credit
   */
  function ledgerEntries($ids, $cond = null, $link = null) {
    if (empty($ids))
      return null;

/*     $id = (is_array($ids) ? $ids[0] : $ids); */
/*     $ftype = strtoupper($this->Account->fundamentalType($this->accountID($id))); */

    $entries = $this->Entry->find
      ('all', array
       ('contain' => array('DoubleEntry' => array('fields' => array('amount'))),
	'fields' => array_merge(array("Entry.*"),
				$this->debitCreditFields(is_array($ids) ? $ids[0] : $ids)),
/* 			  "IF(Entry.crdr = 'CREDIT', DoubleEntry.amount, NULL) AS credit", */
/* 			  "IF(Entry.crdr = 'DEBIT',  DoubleEntry.amount, NULL) AS debit", */
/* 			  "IF(Entry.crdr = '$ftype', 1, -1) * DoubleEntry.amount AS balance", */

	'conditions' => array('Entry.ledger_id' => $ids),
	));

    pr(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()),
	      'Entry' => array
	      ('DoubleEntry' =>
	       array('fields' => array(),
		     'Transaction' => array('fields' => array('stamp')),
		     ),
	       ),
	      ),
	'fields' => $this->debitCreditFields($id, true),
	'conditions' => $cond,
	'group' => 'Ledger.id',
	));

    // The fields are all tucked into the [0] index,
    // and the rest of the array is useless (empty).
    $stats = $stats[0];

    // Make sure we have a non-null balance
    if (!isset($stats['balance']))
      $stats['balance'] = 0;

    return $stats;
  }

}
?>