<?php

namespace TablePress\PhpOffice\PhpSpreadsheet\Collection;

use Generator;
use TablePress\PhpOffice\PhpSpreadsheet\Cell\Cell;
use TablePress\PhpOffice\PhpSpreadsheet\Cell\Coordinate;
use TablePress\PhpOffice\PhpSpreadsheet\Exception as PhpSpreadsheetException;
use TablePress\PhpOffice\PhpSpreadsheet\Settings;
use TablePress\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
use TablePress\Psr\SimpleCache\CacheInterface;

class Cells
{
	protected const MAX_COLUMN_ID = 16384;

	/**
	 * @var CacheInterface
	 */
	private $cache;

	/**
	 * Parent worksheet.
	 *
	 * @var null|Worksheet
	 */
	private $parent;

	/**
	 * The currently active Cell.
	 *
	 * @var null|Cell
	 */
	private $currentCell;

	/**
	 * Coordinate of the currently active Cell.
	 *
	 * @var null|string
	 */
	private $currentCoordinate;

	/**
	 * Flag indicating whether the currently active Cell requires saving.
	 *
	 * @var bool
	 */
	private $currentCellIsDirty = false;

	/**
	 * An index of existing cells. int pointer to the coordinate (0-base-indexed row * 16,384 + 1-base indexed column)
	 *    indexed by their coordinate.
	 *
	 * @var int[]
	 */
	private $index = [];

	/**
	 * Prefix used to uniquely identify cache data for this worksheet.
	 *
	 * @var string
	 */
	private $cachePrefix;

	/**
	 * Initialise this new cell collection.
	 *
	 * @param Worksheet $parent The worksheet for this cell collection
	 */
	public function __construct(Worksheet $parent, CacheInterface $cache)
	{
		// Set our parent worksheet.
		// This is maintained here to facilitate re-attaching it to Cell objects when
		// they are woken from a serialized state
		$this->parent = $parent;
		$this->cache = $cache;
		$this->cachePrefix = $this->getUniqueID();
	}

	/**
	 * Return the parent worksheet for this cell collection.
	 *
	 * @return null|Worksheet
	 */
	public function getParent()
	{
		return $this->parent;
	}

	/**
	 * Whether the collection holds a cell for the given coordinate.
	 *
	 * @param string $cellCoordinate Coordinate of the cell to check
	 */
	public function has($cellCoordinate): bool
	{
		return ($cellCoordinate === $this->currentCoordinate) || isset($this->index[$cellCoordinate]);
	}

	/**
	 * Add or update a cell in the collection.
	 *
	 * @param Cell $cell Cell to update
	 */
	public function update(Cell $cell): Cell
	{
		return $this->add($cell->getCoordinate(), $cell);
	}

	/**
	 * Delete a cell in cache identified by coordinate.
	 *
	 * @param string $cellCoordinate Coordinate of the cell to delete
	 */
	public function delete($cellCoordinate): void
	{
		if ($cellCoordinate === $this->currentCoordinate && $this->currentCell !== null) {
			$this->currentCell->detach();
			$this->currentCoordinate = null;
			$this->currentCell = null;
			$this->currentCellIsDirty = false;
		}

		unset($this->index[$cellCoordinate]);

		// Delete the entry from cache
		$this->cache->delete($this->cachePrefix . $cellCoordinate);
	}

	/**
	 * Get a list of all cell coordinates currently held in the collection.
	 *
	 * @return string[]
	 */
	public function getCoordinates()
	{
		return array_keys($this->index);
	}

	/**
	 * Get a sorted list of all cell coordinates currently held in the collection by row and column.
	 *
	 * @return string[]
	 */
	public function getSortedCoordinates()
	{
		asort($this->index);

		return array_keys($this->index);
	}

	/**
	 * Return the cell coordinate of the currently active cell object.
	 *
	 * @return null|string
	 */
	public function getCurrentCoordinate()
	{
		return $this->currentCoordinate;
	}

	/**
	 * Return the column coordinate of the currently active cell object.
	 */
	public function getCurrentColumn(): string
	{
		$column = 0;
		$row = '';
		sscanf($this->currentCoordinate ?? '', '%[A-Z]%d', $column, $row);

		return (string) $column;
	}

	/**
	 * Return the row coordinate of the currently active cell object.
	 */
	public function getCurrentRow(): int
	{
		$column = 0;
		$row = '';
		sscanf($this->currentCoordinate ?? '', '%[A-Z]%d', $column, $row);

		return (int) $row;
	}

	/**
	 * Get highest worksheet column and highest row that have cell records.
	 *
	 * @return array Highest column name and highest row number
	 */
	public function getHighestRowAndColumn()
	{
		// Lookup highest column and highest row
		$maxRow = $maxColumn = 1;
		foreach ($this->index as $coordinate) {
			$row = (int) floor($coordinate / self::MAX_COLUMN_ID) + 1;
			$maxRow = ($maxRow > $row) ? $maxRow : $row;
			$column = $coordinate % self::MAX_COLUMN_ID;
			$maxColumn = ($maxColumn > $column) ? $maxColumn : $column;
		}

		return [
			'row' => $maxRow,
			'column' => Coordinate::stringFromColumnIndex($maxColumn),
		];
	}

	/**
	 * Get highest worksheet column.
	 *
	 * @param null|int|string $row Return the highest column for the specified row,
	 *                    or the highest column of any row if no row number is passed
	 *
	 * @return string Highest column name
	 */
	public function getHighestColumn($row = null)
	{
		if ($row === null) {
			return $this->getHighestRowAndColumn()['column'];
		}

		$row = (int) $row;
		if ($row <= 0) {
			throw new PhpSpreadsheetException('Row number must be a positive integer');
		}

		$maxColumn = 1;
		$toRow = $row * self::MAX_COLUMN_ID;
		$fromRow = --$row * self::MAX_COLUMN_ID;
		foreach ($this->index as $coordinate) {
			if ($coordinate < $fromRow || $coordinate >= $toRow) {
				continue;
			}
			$column = $coordinate % self::MAX_COLUMN_ID;
			$maxColumn = $maxColumn > $column ? $maxColumn : $column;
		}

		return Coordinate::stringFromColumnIndex($maxColumn);
	}

	/**
	 * Get highest worksheet row.
	 *
	 * @param null|string $column Return the highest row for the specified column,
	 *                       or the highest row of any column if no column letter is passed
	 *
	 * @return int Highest row number
	 */
	public function getHighestRow($column = null)
	{
		if ($column === null) {
			return $this->getHighestRowAndColumn()['row'];
		}

		$maxRow = 1;
		$columnIndex = Coordinate::columnIndexFromString($column);
		foreach ($this->index as $coordinate) {
			if ($coordinate % self::MAX_COLUMN_ID !== $columnIndex) {
				continue;
			}
			$row = (int) floor($coordinate / self::MAX_COLUMN_ID) + 1;
			$maxRow = ($maxRow > $row) ? $maxRow : $row;
		}

		return $maxRow;
	}

	/**
	 * Generate a unique ID for cache referencing.
	 *
	 * @return string Unique Reference
	 */
	private function getUniqueID()
	{
		$cacheType = Settings::getCache();

		return ($cacheType instanceof Memory\SimpleCache1 || $cacheType instanceof Memory\SimpleCache3)
			? random_bytes(7) . ':'
			: uniqid('phpspreadsheet.', true) . '.';
	}

	/**
	 * Clone the cell collection.
	 *
	 * @return self
	 */
	public function cloneCellCollection(Worksheet $worksheet)
	{
		$this->storeCurrentCell();
		$newCollection = clone $this;

		$newCollection->parent = $worksheet;
		$newCollection->cachePrefix = $newCollection->getUniqueID();

		foreach ($this->index as $key => $value) {
			$newCollection->index[$key] = $value;
			$stored = $newCollection->cache->set(
				$newCollection->cachePrefix . $key,
				clone $this->cache->get($this->cachePrefix . $key)
			);
			if ($stored === false) {
				$this->destructIfNeeded($newCollection, 'Failed to copy cells in cache');
			}
		}

		return $newCollection;
	}

	/**
	 * Remove a row, deleting all cells in that row.
	 *
	 * @param int|string $row Row number to remove
	 */
	public function removeRow($row): void
	{
		$this->storeCurrentCell();
		$row = (int) $row;
		if ($row <= 0) {
			throw new PhpSpreadsheetException('Row number must be a positive integer');
		}

		$toRow = $row * self::MAX_COLUMN_ID;
		$fromRow = --$row * self::MAX_COLUMN_ID;
		foreach ($this->index as $coordinate) {
			if ($coordinate >= $fromRow && $coordinate < $toRow) {
				$row = (int) floor($coordinate / self::MAX_COLUMN_ID) + 1;
				$column = Coordinate::stringFromColumnIndex($coordinate % self::MAX_COLUMN_ID);
				$this->delete("{$column}{$row}");
			}
		}
	}

	/**
	 * Remove a column, deleting all cells in that column.
	 *
	 * @param string $column Column ID to remove
	 */
	public function removeColumn($column): void
	{
		$this->storeCurrentCell();

		$columnIndex = Coordinate::columnIndexFromString($column);
		foreach ($this->index as $coordinate) {
			if ($coordinate % self::MAX_COLUMN_ID === $columnIndex) {
				$row = (int) floor($coordinate / self::MAX_COLUMN_ID) + 1;
				$column = Coordinate::stringFromColumnIndex($coordinate % self::MAX_COLUMN_ID);
				$this->delete("{$column}{$row}");
			}
		}
	}

	/**
	 * Store cell data in cache for the current cell object if it's "dirty",
	 * and the 'nullify' the current cell object.
	 */
	private function storeCurrentCell(): void
	{
		if ($this->currentCellIsDirty && isset($this->currentCoordinate, $this->currentCell)) {
			$this->currentCell->/** @scrutinizer ignore-call */ detach();

			$stored = $this->cache->set($this->cachePrefix . $this->currentCoordinate, $this->currentCell);
			if ($stored === false) {
				$this->destructIfNeeded($this, "Failed to store cell {$this->currentCoordinate} in cache");
			}
			$this->currentCellIsDirty = false;
		}

		$this->currentCoordinate = null;
		$this->currentCell = null;
	}

	private function destructIfNeeded(self $cells, string $message): void
	{
		$cells->__destruct();

		throw new PhpSpreadsheetException($message);
	}

	/**
	 * Add or update a cell identified by its coordinate into the collection.
	 *
	 * @param string $cellCoordinate Coordinate of the cell to update
	 * @param Cell $cell Cell to update
	 *
	 * @return Cell
	 */
	public function add($cellCoordinate, Cell $cell)
	{
		if ($cellCoordinate !== $this->currentCoordinate) {
			$this->storeCurrentCell();
		}
		$column = 0;
		$row = '';
		sscanf($cellCoordinate, '%[A-Z]%d', $column, $row);
		$this->index[$cellCoordinate] = (--$row * self::MAX_COLUMN_ID) + Coordinate::columnIndexFromString((string) $column);

		$this->currentCoordinate = $cellCoordinate;
		$this->currentCell = $cell;
		$this->currentCellIsDirty = true;

		return $cell;
	}

	/**
	 * Get cell at a specific coordinate.
	 *
	 * @param string $cellCoordinate Coordinate of the cell
	 *
	 * @return null|Cell Cell that was found, or null if not found
	 */
	public function get($cellCoordinate)
	{
		if ($cellCoordinate === $this->currentCoordinate) {
			return $this->currentCell;
		}
		$this->storeCurrentCell();

		// Return null if requested entry doesn't exist in collection
		if ($this->has($cellCoordinate) === false) {
			return null;
		}

		// Check if the entry that has been requested actually exists in the cache
		$cell = $this->cache->get($this->cachePrefix . $cellCoordinate);
		if ($cell === null) {
			throw new PhpSpreadsheetException("Cell entry {$cellCoordinate} no longer exists in cache. This probably means that the cache was cleared by someone else.");
		}

		// Set current entry to the requested entry
		$this->currentCoordinate = $cellCoordinate;
		$this->currentCell = $cell;
		// Re-attach this as the cell's parent
		$this->currentCell->attach($this);

		// Return requested entry
		return $this->currentCell;
	}

	/**
	 * Clear the cell collection and disconnect from our parent.
	 */
	public function unsetWorksheetCells(): void
	{
		if ($this->currentCell !== null) {
			$this->currentCell->detach();
			$this->currentCell = null;
			$this->currentCoordinate = null;
		}

		// Flush the cache
		$this->__destruct();

		$this->index = [];

		// detach ourself from the worksheet, so that it can then delete this object successfully
		$this->parent = null;
	}

	/**
	 * Destroy this cell collection.
	 */
	public function __destruct()
	{
		$this->cache->deleteMultiple($this->getAllCacheKeys());
	}

	/**
	 * Returns all known cache keys.
	 *
	 * @return Generator|string[]
	 */
	private function getAllCacheKeys()
	{
		foreach ($this->index as $coordinate => $value) {
			yield $this->cachePrefix . $coordinate;
		}
	}
}
