<?php
/**
 * TPriorityMap, TPriorityMapIterator classes
 *
 * @author Brad Anderson <javalizard@mac.com>
 * @link https://github.com/pradosoft/prado
 * @license https://github.com/pradosoft/prado/blob/master/LICENSE
 */

namespace Prado\Collections;

use Prado\TPropertyValue;
use Prado\Exceptions\TInvalidOperationException;
use Prado\Exceptions\TInvalidDataTypeException;

/**
 * TPriorityMap class
 *
 * TPriorityMap implements a collection that takes key-value pairs with
 * a priority to allow key-value pairs to be ordered.  This ordering is
 * important when flattening the map. When flattening the map, if some
 * key-value pairs are required to be before or after others, use this
 * class to keep order to your map.
 *
 * You can access, add or remove an item with a key by using
 * {@link itemAt}, {@link add}, and {@link remove}.  These functions
 * can optionally take a priority parameter to allow access to specific
 * priorities.  TPriorityMap is functionally backward compatible
 * with {@link TMap}.
 *
 * To get the number of the items in the map, use {@link getCount}.
 * TPriorityMap can also be used like a regular array as follows,
 * <code>
 * $map[$key]=$value; // add a key-value pair
 * unset($map[$key]); // remove the value with the specified key
 * if(isset($map[$key])) // if the map contains the key
 * foreach($map as $key=>$value) // traverse the items in the map
 * $n=count($map);  // returns the number of items in the map
 * </code>
 * Using standard array access method like these will always use
 * the default priority.
 *
 * An item that doesn't specify a priority will receive the default
 * priority.  The default priority is set during the instantiation
 * of a new TPriorityMap. If no custom default priority is specified,
 * the standard default priority of 10 is used.
 *
 * Priorities with significant digits below precision will be rounded.
 *
 * A priority may also be a numeric with decimals.  This is set
 * during the instantiation of a new TPriorityMap.
 * The default is 8 decimal places for a priority.  If a negative number
 * is used, rounding occurs into the integer space rather than in
 * the decimal space.  See {@link round}.
 *
 * @author Brad Anderson <javalizard@mac.com>
 * @since 3.2a
 * @method void dyAddItem(mixed $key, mixed $value)
 * @method void dyRemoveItem(mixed $key, mixed $value)
 * @method mixed dyNoItem(mixed $returnValue, mixed $key)
 */
class TPriorityMap extends TMap
{
	/**
	 * @var bool indicates if the _d is currently ordered.
	 */
	private $_o = false;
	/**
	 * @var null|array cached flattened internal data storage
	 */
	private $_fd;
	/**
	 * @var int number of items contain within the map
	 */
	private $_c = 0;
	/**
	 * @var numeric the default priority of items without specified priorities
	 */
	private $_dp = 10;
	/**
	 * @var int the precision of the numeric priorities within this priority list.
	 */
	private $_p = 8;

	/**
	 * Constructor.
	 * Initializes the array with an array or an iterable object.
	 * @param null|array|TPriorityMap|\Traversable $data the intial data. Default is null, meaning no initialization.
	 * @param bool $readOnly whether the list is read-only
	 * @param numeric $defaultPriority the default priority of items without specified priorities.
	 * @param int $precision the precision of the numeric priorities
	 * @throws TInvalidDataTypeException If data is not null and neither an array nor an iterator.
	 */
	public function __construct($data = null, $readOnly = false, $defaultPriority = 10, $precision = 8)
	{
		parent::__construct();
		if ($data !== null) {
			$this->copyFrom($data);
		}
		$this->setReadOnly($readOnly);
		$this->setPrecision($precision);
		$this->setDefaultPriority($defaultPriority);
	}

	/**
	 * @return numeric gets the default priority of inserted items without a specified priority
	 */
	public function getDefaultPriority()
	{
		return $this->_dp;
	}

	/**
	 * This must be called internally or when instantiated.
	 * @param numeric $value sets the default priority of inserted items without a specified priority
	 */
	protected function setDefaultPriority($value)
	{
		$this->_dp = (string) round(TPropertyValue::ensureFloat($value), $this->_p);
	}

	/**
	 * @return int The precision of numeric priorities, defaults to 8
	 */
	public function getPrecision()
	{
		return $this->_p;
	}

	/**
	 * This must be called internally or when instantiated.
	 * @param int $value The precision of numeric priorities.
	 */
	protected function setPrecision($value)
	{
		$this->_p = TPropertyValue::ensureInteger($value);
	}

	/**
	 * Returns an iterator for traversing the items in the map.
	 * This method is required by the interface \IteratorAggregate.
	 * @return \Iterator an iterator for traversing the items in the map.
	 */
	#[\ReturnTypeWillChange]
	public function getIterator()
	{
		return new \ArrayIterator($this->flattenPriorities());
	}


	/**
	 * Orders the priority list internally.
	 */
	protected function sortPriorities()
	{
		if (!$this->_o) {
			ksort($this->_d, SORT_NUMERIC);
			$this->_o = true;
		}
	}

	/**
	 * This flattens the priority map into a flat array [0,...,n-1]
	 * @return array array of items in the list in priority and index order
	 */
	protected function flattenPriorities()
	{
		if (is_array($this->_fd)) {
			return $this->_fd;
		}

		$this->sortPriorities();
		$this->_fd = [];
		foreach ($this->_d as $priority => $itemsatpriority) {
			$this->_fd = array_merge($this->_fd, $itemsatpriority);
		}
		return $this->_fd;
	}

	/**
	 * @return int the number of items in the map
	 */
	public function getCount()
	{
		return $this->_c;
	}

	/**
	 * Gets the number of items at a priority within the map.
	 * @param null|numeric $priority optional priority at which to count items.  if no parameter,
	 * it will be set to the default {@link getDefaultPriority}
	 * @return false|int the number of items in the map at the specified priority
	 */
	public function getPriorityCount($priority = null)
	{
		if ($priority === null) {
			$priority = $this->getDefaultPriority();
		}
		$priority = (string) round(TPropertyValue::ensureFloat($priority), $this->_p);

		if (!isset($this->_d[$priority]) || !is_array($this->_d[$priority])) {
			return false;
		}
		return count($this->_d[$priority]);
	}

	/**
	 * This returns a list of the priorities within this map, ordered lowest to highest.
	 * @return array the array of priority numerics in decreasing priority order
	 */
	public function getPriorities()
	{
		$this->sortPriorities();
		return array_keys($this->_d);
	}

	/**
	 * Returns the keys within the map ordered through the priority of each key-value pair
	 * @return array the key list
	 */
	public function getKeys()
	{
		return array_keys($this->flattenPriorities());
	}

	/**
	 * Returns the item with the specified key.  If a priority is specified, only items
	 * within that specific priority will be selected
	 * @param mixed $key the key
	 * @param mixed $priority the priority.  null is the default priority, false is any priority,
	 * and numeric is a specific priority.  default: false, any priority.
	 * @return mixed the element at the offset, null if no element is found at the offset
	 */
	public function itemAt($key, $priority = false)
	{
		if ($priority === false) {
			$map = $this->flattenPriorities();
			return $map[$key] ?? $this->dyNoItem(null, $key);
		} else {
			if ($priority === null) {
				$priority = $this->getDefaultPriority();
			}
			$priority = (string) round(TPropertyValue::ensureFloat($priority), $this->_p);
			return (isset($this->_d[$priority]) && isset($this->_d[$priority][$key])) ? $this->_d[$priority][$key] : $this->dyNoItem(null, $key);
		}
	}

	/**
	 * This changes an item's priority.  Specify the item and the new priority.
	 * This method is exactly the same as {@link offsetGet}.
	 * @param mixed $key the key
	 * @param null|numeric $priority the priority.  default: null, filled in with the default priority numeric.
	 * @return numeric old priority of the item
	 */
	public function setPriorityAt($key, $priority = null)
	{
		if ($priority === null) {
			$priority = $this->getDefaultPriority();
		}
		$priority = (string) round(TPropertyValue::ensureFloat($priority), $this->_p);

		$oldpriority = $this->priorityAt($key);
		if ($oldpriority !== false && $oldpriority != $priority) {
			$value = $this->remove($key, $oldpriority);
			$this->add($key, $value, $priority);
		}
		return $oldpriority;
	}

	/**
	 * Gets all the items at a specific priority.
	 * @param null|numeric $priority priority of the items to get.  Defaults to null, filled in with the default priority, if left blank.
	 * @return array all items at priority in index order, null if there are no items at that priority
	 */
	public function itemsAtPriority($priority = null)
	{
		if ($priority === null) {
			$priority = $this->getDefaultPriority();
		}
		$priority = (string) round(TPropertyValue::ensureFloat($priority), $this->_p);

		return $this->_d[$priority] ?? null;
	}

	/**
	 * Returns the priority of a particular item within the map.  This searches the map for the item.
	 * @param mixed $item item to look for within the map
	 * @return false|numeric priority of the item in the map
	 */
	public function priorityOf($item)
	{
		$this->sortPriorities();
		foreach ($this->_d as $priority => $items) {
			if (($index = array_search($item, $items, true)) !== false) {
				return $priority;
			}
		}
		return false;
	}

	/**
	 * Retutrns the priority of an item at a particular flattened index.
	 * @param int $key index of the item within the map
	 * @return false|numeric priority of the item in the map
	 */
	public function priorityAt($key)
	{
		$this->sortPriorities();
		foreach ($this->_d as $priority => $items) {
			if (array_key_exists($key, $items)) {
				return $priority;
			}
		}
		return false;
	}

	/**
	 * Adds an item into the map.  A third parameter may be used to set the priority
	 * of the item within the map.  Priority is primarily used during when flattening
	 * the map into an array where order may be and important factor of the key-value
	 * pairs within the array.
	 * Note, if the specified key already exists, the old value will be overwritten.
	 * No duplicate keys are allowed regardless of priority.
	 * @param mixed $key
	 * @param mixed $value
	 * @param null|numeric $priority default: null, filled in with default priority
	 * @throws TInvalidOperationException if the map is read-only
	 * @return numeric priority at which the pair was added
	 */
	public function add($key, $value, $priority = null)
	{
		if ($priority === null) {
			if ($value instanceof IPriorityItem) {
				$priority = $value->getPriority();
			}
			$priority = is_numeric($priority) ? $priority : $this->getDefaultPriority();
		}
		$priority = (string) round(TPropertyValue::ensureFloat($priority), $this->_p);

		if (!$this->_r) {
			foreach ($this->_d as $innerpriority => $items) {
				if (array_key_exists($key, $items)) {
					unset($this->_d[$innerpriority][$key]);
					$this->_c--;
					if (count($this->_d[$innerpriority]) === 0) {
						unset($this->_d[$innerpriority]);
					}
				}
			}
			if (!isset($this->_d[$priority])) {
				$this->_d[$priority] = [$key => $value];
				$this->_o = false;
			} else {
				$this->_d[$priority][$key] = $value;
			}
			$this->_c++;
			$this->_fd = null;
			$this->dyAddItem($key, $value);
		} else {
			throw new TInvalidOperationException('map_readonly', get_class($this));
		}
		return $priority;
	}

	/**
	 * Removes an item from the map by its key. If no priority, or false, is specified
	 * then priority is irrelevant. If null is used as a parameter for priority, then
	 * the priority will be the default priority.  If a priority is specified, or
	 * the default priority is specified, only key-value pairs in that priority
	 * will be affected.
	 * @param mixed $key the key of the item to be removed
	 * @param null|false|numeric $priority priority.  False is any priority, null is the
	 * default priority, and numeric is a specific priority
	 * @throws TInvalidOperationException if the map is read-only
	 * @return mixed the removed value, null if no such key exists.
	 */
	public function remove($key, $priority = false)
	{
		if (!$this->_r) {
			if ($priority === null) {
				$priority = $this->getDefaultPriority();
			}

			if ($priority === false) {
				$this->sortPriorities();
				foreach ($this->_d as $priority => $items) {
					if (array_key_exists($key, $items)) {
						$value = $this->_d[$priority][$key];
						unset($this->_d[$priority][$key]);
						$this->_c--;
						if (count($this->_d[$priority]) === 0) {
							unset($this->_d[$priority]);
							$this->_o = false;
						}
						$this->_fd = null;
						$this->dyRemoveItem($key, $value);
						return $value;
					}
				}
				return null;
			} else {
				$priority = (string) round(TPropertyValue::ensureFloat($priority), $this->_p);
				if (isset($this->_d[$priority]) && (isset($this->_d[$priority][$key]) || array_key_exists($key, $this->_d[$priority]))) {
					$value = $this->_d[$priority][$key];
					unset($this->_d[$priority][$key]);
					$this->_c--;
					if (count($this->_d[$priority]) === 0) {
						unset($this->_d[$priority]);
						$this->_o = false;
					}
					$this->_fd = null;
					$this->dyRemoveItem($key, $value);
					return $value;
				} else {
					return null;
				}
			}
		} else {
			throw new TInvalidOperationException('map_readonly', get_class($this));
		}
	}

	/**
	 * Removes all items in the map.  {@link remove} is called on all items.
	 */
	public function clear()
	{
		foreach ($this->_d as $priority => $items) {
			foreach (array_keys($items) as $key) {
				$this->remove($key);
			}
		}
	}

	/**
	 * @param mixed $key the key
	 * @return bool whether the map contains an item with the specified key
	 */
	public function contains($key)
	{
		$map = $this->flattenPriorities();
		return isset($map[$key]) || array_key_exists($key, $map);
	}

	/**
	 * When the map is flattened into an array, the priorities are taken into
	 * account and elements of the map are ordered in the array according to
	 * their priority.
	 * @return array the list of items in array
	 */
	public function toArray()
	{
		return $this->flattenPriorities();
	}

	/**
	 * Combines the map elements which have a priority below the parameter value
	 * @param numeric $priority the cut-off priority.  All items of priority less than this are returned.
	 * @param bool $inclusive whether or not the input cut-off priority is inclusive.  Default: false, not inclusive.
	 * @return array the array of priorities keys with values of arrays of items that are below a specified priority.
	 *  The priorities are sorted so important priorities, lower numerics, are first.
	 */
	public function toArrayBelowPriority($priority, $inclusive = false)
	{
		$this->sortPriorities();
		$items = [];
		foreach ($this->_d as $itemspriority => $itemsatpriority) {
			if ((!$inclusive && $itemspriority >= $priority) || $itemspriority > $priority) {
				break;
			}
			$items = array_merge($items, $itemsatpriority);
		}
		return $items;
	}

	/**
	 * Combines the map elements which have a priority above the parameter value
	 * @param numeric $priority the cut-off priority.  All items of priority greater than this are returned.
	 * @param bool $inclusive whether or not the input cut-off priority is inclusive.  Default: true, inclusive.
	 * @return array the array of priorities keys with values of arrays of items that are above a specified priority.
	 *  The priorities are sorted so important priorities, lower numerics, are first.
	 */
	public function toArrayAbovePriority($priority, $inclusive = true)
	{
		$this->sortPriorities();
		$items = [];
		foreach ($this->_d as $itemspriority => $itemsatpriority) {
			if ((!$inclusive && $itemspriority <= $priority) || $itemspriority < $priority) {
				continue;
			}
			$items = array_merge($items, $itemsatpriority);
		}
		return $items;
	}

	/**
	 * Copies iterable data into the map.
	 * Note, existing data in the map will be cleared first.
	 * @param array|TPriorityMap|\Traversable $data the data to be copied from, must be an array, object implementing
	 * @throws TInvalidDataTypeException If data is neither an array nor an iterator.
	 */
	public function copyFrom($data)
	{
		if ($data instanceof TPriorityMap) {
			if ($this->getCount() > 0) {
				$this->clear();
			}
			foreach ($data->getPriorities() as $priority) {
				foreach ($data->itemsAtPriority($priority) as $key => $value) {
					$this->add($key, $value, $priority);
				}
			}
		} elseif (is_array($data) || $data instanceof \Traversable) {
			if ($this->getCount() > 0) {
				$this->clear();
			}
			foreach ($data as $key => $value) {
				$this->add($key, $value);
			}
		} elseif ($data !== null) {
			throw new TInvalidDataTypeException('map_data_not_iterable');
		}
	}

	/**
	 * Merges iterable data into the map.
	 * Existing data in the map will be kept and overwritten if the keys are the same.
	 * @param array|TPriorityMap|\Traversable $data the data to be merged with, must be an array,
	 * object implementing Traversable, or a TPriorityMap
	 * @throws TInvalidDataTypeException If data is neither an array nor an iterator.
	 */
	public function mergeWith($data)
	{
		if ($data instanceof TPriorityMap) {
			foreach ($data->getPriorities() as $priority) {
				foreach ($data->itemsAtPriority($priority) as $key => $value) {
					$this->add($key, $value, $priority);
				}
			}
		} elseif (is_array($data) || $data instanceof \Traversable) {
			foreach ($data as $key => $value) {
				$this->add($key, $value);
			}
		} elseif ($data !== null) {
			throw new TInvalidDataTypeException('map_data_not_iterable');
		}
	}
}