<?php

namespace Box\Spout\Reader\ODS;

use Box\Spout\Common\Exception\IOException;
use Box\Spout\Reader\Exception\XMLProcessingException;
use Box\Spout\Reader\IteratorInterface;
use Box\Spout\Reader\ODS\Helper\SettingsHelper;
use Box\Spout\Reader\Wrapper\XMLReader;

/**
 * Class SheetIterator
 * Iterate over ODS sheet.
 *
 * @package Box\Spout\Reader\ODS
 */
class SheetIterator implements IteratorInterface {

	const CONTENT_XML_FILE_PATH = 'content.xml';

	/** Definition of XML nodes name and attribute used to parse sheet data */
	const XML_NODE_TABLE           = 'table:table';
	const XML_ATTRIBUTE_TABLE_NAME = 'table:name';

	/** @var string $filePath Path of the file to be read */
	protected $filePath;

	/** @var \Box\Spout\Reader\ODS\ReaderOptions Reader's current options */
	protected $options;

	/** @var XMLReader The XMLReader object that will help read sheet's XML data */
	protected $xmlReader;

	/** @var \Box\Spout\Common\Escaper\ODS Used to unescape XML data */
	protected $escaper;

	/** @var bool Whether there are still at least a sheet to be read */
	protected $hasFoundSheet;

	/** @var int The index of the sheet being read (zero-based) */
	protected $currentSheetIndex;

	/** @var string The name of the sheet that was defined as active */
	protected $activeSheetName;

	/**
	 * @param string $filePath Path of the file to be read
	 * @param \Box\Spout\Reader\ODS\ReaderOptions $options Reader's current options
	 * @throws \Box\Spout\Reader\Exception\NoSheetsFoundException If there are no sheets in the file
	 */
	public function __construct( $filePath, $options ) {
		$this->filePath  = $filePath;
		$this->options   = $options;
		$this->xmlReader = new XMLReader();

		/** @noinspection PhpUnnecessaryFullyQualifiedNameInspection */
		$this->escaper = \Box\Spout\Common\Escaper\ODS::getInstance();

		$settingsHelper        = new SettingsHelper();
		$this->activeSheetName = $settingsHelper->getActiveSheetName( $filePath );
	}

	/**
	 * Rewind the Iterator to the first element
	 * @link http://php.net/manual/en/iterator.rewind.php
	 *
	 * @return void
	 * @throws \Box\Spout\Common\Exception\IOException If unable to open the XML file containing sheets' data
	 */
	public function rewind() {
		$this->xmlReader->close();

		if ( $this->xmlReader->openFileInZip( $this->filePath, self::CONTENT_XML_FILE_PATH ) === false ) {
			$contentXmlFilePath = $this->filePath . '#' . self::CONTENT_XML_FILE_PATH;
			throw new IOException( "Could not open \"{$contentXmlFilePath}\"." );
		}

		try {
			$this->hasFoundSheet = $this->xmlReader->readUntilNodeFound( self::XML_NODE_TABLE );
		} catch ( XMLProcessingException $exception ) {
			throw new IOException( "The content.xml file is invalid and cannot be read. [{$exception->getMessage()}]" );
		}

		$this->currentSheetIndex = 0;
	}

	/**
	 * Checks if current position is valid
	 * @link http://php.net/manual/en/iterator.valid.php
	 *
	 * @return bool
	 */
	public function valid() {
		return $this->hasFoundSheet;
	}

	/**
	 * Move forward to next element
	 * @link http://php.net/manual/en/iterator.next.php
	 *
	 * @return void
	 */
	public function next() {
		$this->hasFoundSheet = $this->xmlReader->readUntilNodeFound( self::XML_NODE_TABLE );

		if ( $this->hasFoundSheet ) {
			$this->currentSheetIndex++;
		}
	}

	/**
	 * Return the current element
	 * @link http://php.net/manual/en/iterator.current.php
	 *
	 * @return \Box\Spout\Reader\ODS\Sheet
	 */
	public function current() {
		 $escapedSheetName = $this->xmlReader->getAttribute( self::XML_ATTRIBUTE_TABLE_NAME );
		$sheetName         = $this->escaper->unescape( $escapedSheetName );
		$isActiveSheet     = $this->isActiveSheet( $sheetName, $this->currentSheetIndex, $this->activeSheetName );

		return new Sheet( $this->xmlReader, $this->currentSheetIndex, $sheetName, $isActiveSheet, $this->options );
	}

	/**
	 * Returns whether the current sheet was defined as the active one
	 *
	 * @param string $sheetName Name of the current sheet
	 * @param int $sheetIndex Index of the current sheet
	 * @param string|null Name of the sheet that was defined as active or NULL if none defined
	 * @return bool Whether the current sheet was defined as the active one
	 */
	private function isActiveSheet( $sheetName, $sheetIndex, $activeSheetName ) {
		// The given sheet is active if its name matches the defined active sheet's name
		// or if no information about the active sheet was found, it defaults to the first sheet.
		return (
			( $activeSheetName === null && $sheetIndex === 0 ) ||
			( $activeSheetName === $sheetName )
		);
	}

	/**
	 * Return the key of the current element
	 * @link http://php.net/manual/en/iterator.key.php
	 *
	 * @return int
	 */
	public function key() {
		 return $this->currentSheetIndex + 1;
	}

	/**
	 * Cleans up what was created to iterate over the object.
	 *
	 * @return void
	 */
	public function end() {
		 $this->xmlReader->close();
	}
}