<?php

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014-2019 British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author     CodeIgniter Dev Team
 * @copyright  2014-2019 British Columbia Institute of Technology (https://bcit.ca/)
 * @license    https://opensource.org/licenses/MIT	MIT License
 * @link       https://codeigniter.com
 * @since      Version 4.0.0
 * @filesource
 */

namespace CodeIgniter\HTTP;

use CodeIgniter\HTTP\Exceptions\HTTPException;

/**
 * An HTTP message
 */
class Message
{

	/**
	 * List of all HTTP request headers.
	 *
	 * @var array
	 */
	protected $headers = [];

	/**
	 * Holds a map of lower-case header names
	 * and their normal-case key as it is in $headers.
	 * Used for case-insensitive header access.
	 *
	 * @var array
	 */
	protected $headerMap = [];

	/**
	 * Protocol version
	 *
	 * @var string
	 */
	protected $protocolVersion;

	/**
	 * List of valid protocol versions
	 *
	 * @var array
	 */
	protected $validProtocolVersions = [
		'1.0',
		'1.1',
		'2',
	];

	/**
	 * Message body
	 *
	 * @var string
	 */
	protected $body;

	//--------------------------------------------------------------------
	//--------------------------------------------------------------------
	// Body
	//--------------------------------------------------------------------

	/**
	 * Returns the Message's body.
	 *
	 * @return mixed
	 */
	public function getBody()
	{
		return $this->body;
	}

	//--------------------------------------------------------------------

	/**
	 * Sets the body of the current message.
	 *
	 * @param $data
	 *
	 * @return Message|Response
	 */
	public function setBody($data)
	{
		$this->body = $data;

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Appends data to the body of the current message.
	 *
	 * @param $data
	 *
	 * @return Message|Response
	 */
	public function appendBody($data)
	{
		$this->body .= (string) $data;

		return $this;
	}

	//--------------------------------------------------------------------
	//--------------------------------------------------------------------
	// Headers
	//--------------------------------------------------------------------

	/**
	 * Populates the $headers array with any headers the getServer knows about.
	 */
	public function populateHeaders()
	{
		$contentType = $_SERVER['CONTENT_TYPE'] ?? getenv('CONTENT_TYPE');
		if (! empty($contentType))
		{
			$this->setHeader('Content-Type', $contentType);
		}
		unset($contentType);

		foreach ($_SERVER as $key => $val)
		{
			if (sscanf($key, 'HTTP_%s', $header) === 1)
			{
				// take SOME_HEADER and turn it into Some-Header
				$header = str_replace('_', ' ', strtolower($header));
				$header = str_replace(' ', '-', ucwords($header));

				$this->setHeader($header, $_SERVER[$key]);

				// Add us to the header map so we can find them case-insensitively
				$this->headerMap[strtolower($header)] = $header;
			}
		}
	}

	//--------------------------------------------------------------------

	/**
	 * Returns an array containing all headers.
	 *
	 * @return array        An array of the request headers
	 */
	public function getHeaders(): array
	{
		// If no headers are defined, but the user is
		// requesting it, then it's likely they want
		// it to be populated so do that...
		if (empty($this->headers))
		{
			$this->populateHeaders();
		}

		return $this->headers;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns a single header object. If multiple headers with the same
	 * name exist, then will return an array of header objects.
	 *
	 * @param string $name
	 *
	 * @return array|\CodeIgniter\HTTP\Header
	 */
	public function getHeader(string $name)
	{
		$orig_name = $this->getHeaderName($name);

		if (! isset($this->headers[$orig_name]))
		{
			return null;
		}

		return $this->headers[$orig_name];
	}

	//--------------------------------------------------------------------

	/**
	 * Determines whether a header exists.
	 *
	 * @param string $name
	 *
	 * @return boolean
	 */
	public function hasHeader(string $name): bool
	{
		$orig_name = $this->getHeaderName($name);

		return isset($this->headers[$orig_name]);
	}

	//--------------------------------------------------------------------

	/**
	 * Retrieves a comma-separated string of the values for a single header.
	 *
	 * This method returns all of the header values of the given
	 * case-insensitive header name as a string concatenated together using
	 * a comma.
	 *
	 * NOTE: Not all header values may be appropriately represented using
	 * comma concatenation. For such headers, use getHeader() instead
	 * and supply your own delimiter when concatenating.
	 *
	 * @param string $name
	 *
	 * @return string
	 */
	public function getHeaderLine(string $name): string
	{
		$orig_name = $this->getHeaderName($name);

		if (! array_key_exists($orig_name, $this->headers))
		{
			return '';
		}

		return $this->headers[$orig_name]->getValueLine();
	}

	//--------------------------------------------------------------------

	/**
	 * Sets a header and it's value.
	 *
	 * @param string            $name
	 * @param array|null|string $value
	 *
	 * @return Message|Response
	 */
	public function setHeader(string $name, $value)
	{
		$origName = $this->getHeaderName($name);
		
		if (isset($this->headers[$origName]) && is_array($this->headers[$origName]))
		{
			$this->appendHeader($origName, $value);
		}
		else
		{
			$this->headers[$origName] = new Header($origName, $value);
			$this->headerMap[strtolower($origName)] = $origName;
		}

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Removes a header from the list of headers we track.
	 *
	 * @param string $name
	 *
	 * @return Message
	 */
	public function removeHeader(string $name)
	{
		$orig_name = $this->getHeaderName($name);

		unset($this->headers[$orig_name]);
		unset($this->headerMap[strtolower($name)]);

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Adds an additional header value to any headers that accept
	 * multiple values (i.e. are an array or implement ArrayAccess)
	 *
	 * @param string $name
	 * @param string $value
	 *
	 * @return Message
	 */
	public function appendHeader(string $name, string $value)
	{
		$orig_name = $this->getHeaderName($name);

		$this->headers[$orig_name]->appendValue($value);

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Adds an additional header value to any headers that accept
	 * multiple values (i.e. are an array or implement ArrayAccess)
	 *
	 * @param string $name
	 * @param string $value
	 *
	 * @return Message
	 */
	public function prependHeader(string $name, string $value)
	{
		$orig_name = $this->getHeaderName($name);

		$this->headers[$orig_name]->prependValue($value);

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the HTTP Protocol Version.
	 *
	 * @return string
	 */
	public function getProtocolVersion(): string
	{
		return $this->protocolVersion ?? '1.1';
	}

	//--------------------------------------------------------------------

	/**
	 * Sets the HTTP protocol version.
	 *
	 * @param string $version
	 *
	 * @return Message
	 */
	public function setProtocolVersion(string $version)
	{
		if (! is_numeric($version))
		{
			$version = substr($version, strpos($version, '/') + 1);
		}

		if (! in_array($version, $this->validProtocolVersions))
		{
			throw HTTPException::forInvalidHTTPProtocol(implode(', ', $this->validProtocolVersions));
		}

		$this->protocolVersion = $version;

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Takes a header name in any case, and returns the
	 * normal-case version of the header.
	 *
	 * @param string $name
	 *
	 * @return string
	 */
	protected function getHeaderName(string $name): string
	{
		$lower_name = strtolower($name);

		return $this->headerMap[$lower_name] ?? $name;
	}

	//--------------------------------------------------------------------
}