<?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 {
	private $invoice_items = array();

	protected $_belongs_to = array(
		'account'=>array()
	);
	protected $_has_many = array(
		'invoice_item'=>array('far_key'=>'id'),
		'invoice_item_tax'=>array(),
		'service'=>array('through'=>'invoice_item'),
		'payment'=>array('through'=>'payment_item'),
	);

	/**
	 * @var array Filters to render values properly
	 */
	protected $_filters = array(
		// @todo This rounding should be a global configuration
		'total_amt'=>array('round'=>array('2')),
	);

	protected $_callbacks = array(
		'id'=>array('get_next_id'),
		'total_amt'=>array('calc_total'),
		'tax_amt'=>array('calc_tax'),
	);

	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')),
		),
	);

	/**
	 * 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_amt-$this->credit_amt-$this->billed_amt,Kohana::config('config.currency_format')) : 0;

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

	/**
	 * Return a list of invoice items for this invoice.
	 *
	 * We only return the items, if the invoice hasnt been changed.
	 */
	public function items() {
		return ($this->loaded() AND ! $this->_changed) ? $this->invoice_item->order_by('service_id,item_type,module_id')->find_all() : NULL;
	}

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

		foreach ($this->items() as $ito)
			$result += $ito->subtotal();

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

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

		foreach ($this->items() as $ito)
			$result += $ito->tax_amt;

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

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

		foreach ($this->items() as $ito)
			$result += $ito->total();

		// Reduce by any credits
		$result -= $this->credit_amt;

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

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

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

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

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

	/**
	 * Return a list of our main invoice items (item_id=0)
	 */
	public function items_main() {
		return ($this->loaded() AND ! $this->_changed) ? $this->invoice_item->where('item_type','=',0)->find_all() : NULL;
	}

	/**
	 * Return a list of our sub invoice items (item_id!=0)
	 *
	 * @param sid int Service ID
	 */
	public function items_sub($sid) {
		return ($this->loaded() AND ! $this->_changed) ? $this->invoice_item->where('service_id','=',$sid)->and_where('item_type','<>',0)->find_all() : NULL;
	}

	/**
	 * Summarise the items on an invoice
	 */
	public function items_summary() {
		$result = array();

		foreach ($this->items_main() as $ito) {
			$unique = TRUE;

			$t = $ito->product->summary();
			if (! isset($result[$t])) {
				$result[$t]['quantity'] = 0;
				$result[$t]['subtotal'] = 0;
			}

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

		return $result;
	}

	/**
	 * Find all the invoice items relating to a service
	 *
	 * @param int Service ID
	 */
	private function items_service($sid) {
		return $this->invoice_item->where('service_id','=',$sid)->find_all();
	}

	/**
	 * 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_amt;

		return $total;
	}

	/**
	 * Return a list of items based on a sort criteria
	 */
	public function sorted_service_items($index) {
		$summary = array();

		foreach ($this->items() as $ito) {
			$key = $ito->service->$index;

			if (! isset($summary[$key]['items'])) {
				$summary[$key]['items'] = array();
				$summary[$key]['total'] = 0;
			}

			// Only record items with item_type=0
			if ($ito->item_type == 0)
				array_push($summary[$key]['items'],$ito);

			$summary[$key]['total'] += $ito->total();
		}

		return $summary;
	}

	/**
	 * Return a list of taxes used on this invoice
	 */
	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;
			}
		}

		return $summary;
	}

	/**
	 * Add an item to an invoice
	 */
	public function add_item() {
		$c = count($this->invoice_items);

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

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

	public function save(Validation $validation = NULL) {
		// Save the invoice
		parent::save($validation);

		// Need to save the associated items and their taxes
		if ($this->saved()) {
			$tax_amt = 0;
			$discount_amt = 0;

			foreach ($this->items() as $invoice_item) {
				$invoice_item->invoice_id = $this->id;

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

				$invoice_item->save();

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

		echo Kohana::debug(array('saved'=>$this));
	}

	public function calc_total(Validate $array, $field) {
		$array[$field] = 0;

		// @todo Rounding here should come from a global config
		foreach ($this->invoice_items as $ito)
			$array[$field] += round($ito->price_base+$ito->price_setup,2);

		$this->_changed[$field] = $field;
	}

	public function calc_tax(Validate $array, $field) {
		$array[$field] = 0;

		// @todo Rounding here should come from a global config
		// @todo tax should be evaluated per item
		// @todo tax parameters should come from user session
		foreach ($this->invoice_items as $ito)
			$array[$field] += round(Tax::total(61,NULL,$ito->price_base+$ito->price_setup),2);

		$this->_changed[$field] = $field;
	}
}
?>