<?php

class InvalidParameterException extends Exception
{
}

abstract class Parameters
{
	public $aData = null;

	public function __construct()
	{
		$this->aData = null;
	}

	public function Get($sCode, $default = '')
	{
		if (array_key_exists($sCode, $this->aData)) {
			return $this->aData[$sCode];
		}
		return $default;
	}

	/**
	 * @return array Allow to update config using {@see Config::UpdateFromParams()}
	 */
	public function GetParamForConfigArray()
	{
		$aDBParams = $this->Get('database');
		$aParamValues = [
			'mode' => $this->Get('mode'),
			'db_server' => $aDBParams['server'],
			'db_user' => $aDBParams['user'],
			'db_pwd' => $aDBParams['pwd'],
			'db_name' => $aDBParams['name'],
			'new_db_name' => $aDBParams['name'],
			'db_prefix' => $aDBParams['prefix'],
			'db_tls_enabled' => $aDBParams['db_tls_enabled'],
			'db_tls_ca' => $aDBParams['db_tls_ca'],
			'application_path' => $this->Get('url', ''),
			'language' => $this->Get('language', ''),
			'graphviz_path' => $this->Get('graphviz_path', ''),
			'source_dir' => $this->Get('source_dir', ''),
		];

		return $aParamValues;
	}

	public function Set($sCode, $value)
	{
		$this->aData[$sCode] = $value;
	}

	public function ToXML(DOMNode $oRoot, $data = null, $sNodeName = null)
	{
		if ($data === null) {
			$data = $this->aData;
		}

		if (is_array($data)) {
			if ($oRoot instanceof DOMDocument) {
				$oNode = $oRoot->createElement($sNodeName);
			} else {
				$oNode = $oRoot->ownerDocument->createElement($sNodeName);
			}
			$oRoot->appendChild($oNode);

			$aKeys = array_keys($data);
			$bNumericKeys = true;
			foreach ($aKeys as $subkey) {
				if (((int)$subkey) !== $subkey) {
					$bNumericKeys = false;
					break;
				}
			}
			if ($bNumericKeys) {
				$oNode->setAttribute("type", "array");
				foreach ($data as $key => $value) {
					$this->ToXML($oNode, $value, 'item');
				}
			} else {
				foreach ($data as $key => $value) {
					$this->ToXML($oNode, $value, $key);
				}
			}
		} else {
			$oNode = $oRoot->ownerDocument->createElement($sNodeName);
			$oRoot->appendChild($oNode);
			$oTextNode = $oRoot->ownerDocument->createTextNode($data);
			$oNode->appendChild($oTextNode);
		}
		return $oNode;
	}
}

class PHPParameters extends Parameters
{
	public function LoadFromHash($aData)
	{
		$this->aData = $aData;
	}

	public function LoadFromFile($sParametersFile)
	{
		if ($this->aData == null) {
			require_once($sParametersFile);
			$this->aData = $ITOP_PARAMS; // Defined in the file loaded just above
		}
	}
}

class XMLParameters extends Parameters
{
	/** @var array */
	public $aData;
	protected $sParametersFile;

	public function __construct($sParametersFile)
	{
		parent::__construct();
		$this->LoadFromFile($sParametersFile);
	}

	public function LoadFromFile($sParametersFile)
	{
		$this->sParametersFile = $sParametersFile;
		if ($this->aData == null) {
			libxml_use_internal_errors(true);
			$oXML = @simplexml_load_file($this->sParametersFile);
			if (!$oXML) {
				$aMessage = [];
				foreach (libxml_get_errors() as $oError) {
					$aMessage[] = "(line: {$oError->line}) ".$oError->message; // Beware: $oError->columns sometimes returns wrong (misleading) value
				}
				libxml_clear_errors();
				throw new InvalidParameterException("Invalid Parameters file '{$this->sParametersFile}': ".implode(' ', $aMessage));
			}

			$this->aData = [];
			foreach ($oXML as $key => $oElement) {
				$this->aData[(string)$key] = $this->ReadElement($oElement);
			}
		}
	}

	protected function ReadElement(SimpleXMLElement $oElement)
	{
		$sDefaultNodeType = (count($oElement->children()) > 0) ? 'hash' : 'string';
		$sNodeType = $this->GetAttribute('type', $oElement, $sDefaultNodeType);
		switch ($sNodeType) {
			case 'array':
				$value = [];
				// Treat the current element as zero based array, child tag names are NOT meaningful
				$sFirstTagName = null;
				foreach ($oElement->children() as $oChildElement) {
					if ($sFirstTagName == null) {
						$sFirstTagName = $oChildElement->getName();
					} elseif ($sFirstTagName != $oChildElement->getName()) {
						throw new InvalidParameterException("Invalid Parameters file '{$this->sParametersFile}': mixed tags ('$sFirstTagName' and '".$oChildElement->getName()."') inside array '".$oElement->getName()."'");
					}
					$val = $this->ReadElement($oChildElement);
					$value[] = $val;
				}
				break;

			case 'hash':
				$value = [];
				// Treat the current element as a hash, child tag names are keys
				foreach ($oElement->children() as $oChildElement) {
					if (array_key_exists($oChildElement->getName(), $value)) {
						throw new InvalidParameterException("Invalid Parameters file '{$this->sParametersFile}': duplicate tags '".$oChildElement->getName()."' inside hash '".$oElement->getName()."'");
					}
					$val = $this->ReadElement($oChildElement);
					$value[$oChildElement->getName()] = $val;
				}
				break;

			case 'int':
			case 'integer':
				$value = (int)$oElement;
				break;

			case 'string':
			default:
				$value = (string)$oElement;
		}
		return $value;
	}

	protected function GetAttribute($sAttName, $oElement, $sDefaultValue)
	{
		$sRet = $sDefaultValue;

		foreach ($oElement->attributes() as $sKey => $oChildElement) {
			if ((string)$sKey == $sAttName) {
				$sRet = (string)$oChildElement;
				break;
			}
		}
		return $sRet;
	}

}