<?php defined('SYSPATH') or die('No direct access allowed.');

/**
 * This class provides invoice capabilities.
 *
 * @package    OSB
 * @subpackage Invoice
 * @category   Models
 * @author     Deon George
 * @copyright  (c) 2010 Open Source Billing
 * @license    http://dev.osbill.net/license.html
 */
class Model_Invoice extends ORMOSB {
	protected $_belongs_to = array(
		'account'=>array()
	);
	protected $_has_many = array(
		'invoice_item'=>array('far_key'=>'id'),
		'invoice_item_tax'=>array('through'=>'invoice_item'),
		'service'=>array('through'=>'invoice_item'),
		'payment'=>array('through'=>'payment_item'),
		'payment_item'=>array('far_key'=>'id'),
	);

	protected $_sorting = array(
		'id'=>'DESC',
	);

	protected $_display_filters = array(
		'date_orig'=>array(
			array('Config::date',array(':value')),
		),
		'due_date'=>array(
			array('Config::date',array(':value')),
		),
		'billed_amt'=>array(
			array('Currency::display',array(':value')),
		),
		'credit_amt'=>array(
			array('Currency::display',array(':value')),
		),
		'status'=>array(
			array('StaticList_YesNo::display',array(':value')),
		),
		'total_amt'=>array(
			array('Currency::display',array(':value')),
		),
	);

	// Items belonging to an invoice
	private $invoice_items = array();

	/**
	 * Display the Invoice Number
	 */
	public function id() {
		return sprintf('%06s',$this->id);
	}

	/**
	 * Display the Invoice Reference Number
	 */
	public function refnum() {
		return sprintf('%s-%06s',$this->account->accnum(),$this->id);
	}

	/**
	 * Display the amount due
	 */
	public function due($format=FALSE) {
		// If the invoice is active calculate the due amount
		$result = $this->status ? round($this->total()-$this->payments_total(),2) : 0;

		return $format ? Currency::display($result) : $result;
	}

	/**
	 * Return a list of invoice items for this invoice.
	 */
	public function items() {
		// If we havent been changed, we'll load the records from the DB.
		if ($this->loaded() AND ! $this->_changed)
			return $this->invoice_item->order_by('service_id,item_type,module_id')->find_all()->as_array();
		else
			return $this->invoice_items;
	}

	/**
	 * Return the subtotal of all items
	 */
	public function subtotal($format=FALSE) {
		$result = 0;

		// @todo This rounding should be a system config.
		foreach ($this->items() as $ito)
			$result += round($ito->subtotal(),2);

		return $format ? Currency::display($result) : $result;
	}

	public function discount($format=FALSE) {
		$result = 0;

		// @todo This rounding should be a system config.
		foreach ($this->items() as $ito)
			$result += round($ito->discount_amt,2);

		return $format ? Currency::display($result) : $result;
	}

	public function tax($format=FALSE) {
		$result = 0;

		// @todo This rounding should be a system config.
		foreach ($this->items() as $ito)
			$result += round($ito->tax(),2);

		return $format ? Currency::display($result) : $result;
	}

	/**
	 * Return the total of all items
	 */
	public function total($format=FALSE) {
		$result = 0;

		// @todo This rounding should be a system config.
		foreach ($this->items() as $ito)
			$result += round($ito->total(),2);

		// Reduce by any credits
		$result -= round($this->credit_amt,2);

		return $format ? Currency::display($result) : $result;
	}

	public function payments() {
		return ($this->loaded() AND ! $this->_changed) ? $this->payment_item->find_all() : NULL;
	}

	public function payments_total($format=FALSE) {
		$result = 0;

		foreach ($this->payments() as $po)
			$result += $po->alloc_amt;

		return $format ? Currency::display($result) : $result;
	}

	/**
	 * Get a list of services on an invoice
	 *
	 * We use this to list details by service on an invoice.
	 */
	public function items_services(array $items=array()) {
		$result = array();
		if (! $items)
			$items = $this->items();

		foreach ($items as $ito)
			if ($ito->service_id AND empty($result[$ito->service_id])) 
				$result[$ito->service_id] = $ito->service;

		return $result;
	}

	/**
	 * Return all invoice items for a service optionally by recurring schedule
 	 */
	public function items_service($sid,$rs=NULL) {
		$result = array();
		$items = $this->items();

		Sort::MAsort($items,'item_type');
		foreach ($items as $ito)
			if ($ito->service_id == $sid AND (is_null($rs) OR $ito->recurring_schedule == $rs))
				array_push($result,$ito);

		return $result;
	}

	/**
	 * Return a list of periods and services
	 *
	 * This is so that we can list items summarised by billing period
	 */
	public function items_service_periods() {
		$result = array();

		$c = array();
		foreach ($this->items() as $ito)
			if ($ito->service_id) {
				// If we have already covered a service with no recurring_schedule
				if (! $ito->recurring_schedule AND in_array($ito->service_id,$c))
					continue;

				array_push($c,$ito->service_id);

				$result[$ito->recurring_schedule][] = $ito;
			}

		return $result;
	}

	/**
	 * Summarise the items on an invoice
	 *
	 * We summaries based on product.
	 */
	public function items_summary() {
		$result = array();

		foreach ($this->items() as $ito) {
			// We conly summaries item_type=0
			if (! $ito->item_type == 0)
				continue;

			$t = $ito->product_id;

			if (! isset($result[$t])) {
				$result[$t]['quantity'] = 0;
				$result[$t]['subtotal'] = 0;
			}

			$result[$t]['quantity'] += $ito->quantity;
			$result[$t]['subtotal'] += $ito->subtotal();
		}

		return $result;
	}

	/**
	 * Calculate the total for items for a service
	 */
	public function items_service_total($sid) {
		$total = 0;

		foreach ($this->items_service($sid) as $ito)
			$total += $ito->total();

		return $total;
	}

	/**
	 * Calculate the tax of items for a service
	 */
	public function items_service_tax($sid) {
		$total = 0;

		foreach ($this->items_service($sid) as $ito)
			$total += $ito->tax();

		return $total;
	}

	/**
	 * Calculate the discounts of items for a service
	 */
	public function items_service_discount($sid) {
		$total = 0;

		foreach ($this->items_service($sid) as $ito)
			$total += $ito->discount();

		return $total;
	}

	/**
	 * Return a list of taxes used on this invoice
	 * @todo Move some of this to invoice_item_tax.
	 */
	public function tax_summary() {
		$summary = array();

		foreach ($this->items() as $ito) {
			foreach ($ito->invoice_item_tax->find_all() as $item_tax) {
				if (! isset($summary[$item_tax->tax_id]))
					$summary[$item_tax->tax_id] = $item_tax->amount;
				else
					$summary[$item_tax->tax_id] += $item_tax->amount;
			}
		}

		// @todo This should be removed eventually
		if (! $summary)
			$summary[1] = $this->tax();

		return $summary;
	}

	/**
	 * Add an item to an invoice
	 */
	public function add_item() {
		if ($this->loaded() and ! $this->invoice_items)
			throw new Kohana_Exception('Need to load invoice_items?');

		$c = count($this->invoice_items);

		$this->invoice_items[$c] = ORM::factory('invoice_item');

		return $this->invoice_items[$c];
	}

	public function min_due($date) {
		// @todo This should be configurable;
		return ($date < time()) ? time() : $date;
	}

	public function save(Validation $validation = NULL) {
		// Our items will be clobbered once we save the object, so we need to save it here.
		$items = $this->items();

		// Save the invoice
		parent::save($validation);

		// Need to save the associated items and their taxes
		if ($this->saved()) {
			foreach ($items as $iio) {
				$iio->invoice_id = $this->id;

				if (! $iio->check()) {
					// @todo Mark invoice as cancelled and write a memo, then...
					throw new Kohana_Exception('Problem saving invoice_item for invoice :invoice - Failed check()',array(':invoice'=>$invoice->id));
				}

				$iio->save();

				if (! $iio->saved()) {
					// @todo Mark invoice as cancelled and write a memo, then...
					throw new Kohana_Exception('Problem saving invoice_item for invoice :invoice - Failed save()',array(':invoice'=>$invoice->id));
				}

				// @todo Need to save tax information
				// @todo Need to save discount information
			}

		} else
			throw new Kohana_Exception('Couldnt save invoice for some reason?');
	}

	/**
	 * Check the reminder value
	 */
	public function remind($key) {
		if (! $this->loaded())
			return NULL;

		if (! trim($this->reminders))
			return FALSE;

		if (! preg_match('/^a:/',$this->reminders))
			throw new Kohana_Exception('Reminder is not an array? (:reminder)',array(':remind',$this->reminders));

		$remind = unserialize($this->reminders);

		if (isset($remind[$key]))
			return (is_array($remind[$key])) ? end($remind[$key]) : $remind[$key];
		else
			return FALSE;
	}

	public function set_remind($key,$value,$add=FALSE) {
		if (! $this->loaded())
			throw new Kohana_Exception('Cant call :method when a record not loaded.',array(':method',__METHOD__));

		if (! trim($this->reminders)) {
			$remind = array();

		} else {
			if (! preg_match('/^a:/',$this->reminders))
				throw new Kohana_Exception('Reminder is not an array? (:reminder)',array(':remind',$this->reminders));

			$remind = unserialize($this->reminders);
		}

		// If our value is null, we'll remove it.
		if (is_null($value) AND isset($remind[$key]))
			unset($remind[$key]);
		elseif ($add)
			$remind[$key][] = $value;
		else
			$remind[$key] = $value;

		$this->reminders = serialize($remind);
		$this->save();
		return $this->saved();
	}

	/** LIST FUNCTIONS **/

	private function _list_due() {
		static $result = array();

		if (! $result)
			foreach (ORM::factory('invoice')->where('status','=',1)->find_all() as $io)
				if ($io->due())
					array_push($result,$io);

		return $result;
	}

	/**
	 * Identify all the invoices that are due
	 */
	public function list_overdue($time=NULL) {
		$result = array();

		if (is_null($time))
			$time = time();

		foreach ($this->_list_due() as $io)
			if ($io->due_date <= $time)
				array_push($result,$io);

		return $result;
	}

	/**
	 * Return a list of invoices that are over their due date with/without auto billing
	 */
	public function list_overdue_billing($time=NULL,$billing=FALSE) {
		$return = array();

		foreach ($this->list_overdue($time) as $io) {
			$i = FALSE;
			foreach ($io->service->find_all() as $so)
				if (($billing AND $so->account_billing_id) OR (! $billing AND ! $so->account_billing_id)) {
					array_push($return,$io);

					break;
				}
		}

		return $return;
	}

	/**
	 * Return a list of invoices that are due, excluding overdue.
	 */
	public function list_due($time=NULL) {
		$result = array();

		foreach ($this->_list_due() as $io)
			if ($io->due_date > time())
				if (is_null($time))
					array_push($result,$io);
				elseif ($this->due_date <= $time)
					array_push($result,$io);

		return $result;
	}
}
?>