<?php

/*
 *  Copyright (c) 2010-2013 Tinyboard Development Group
 */

use Vichan\Context;
use Vichan\Functions\{Hide, Net};

defined('TINYBOARD') or exit;

// create a hash/salt pair for validate logins
function mkhash(string $username, ?string $password, mixed $salt = false): array|string {
	global $config;

	if (!$salt) {
		// Create some salt for the hash.
		$salt = \bin2hex(\random_bytes(15)); // 20 characters.
		$generated_salt = true;
	} else {
		$generated_salt = false;
	}

	// generate hash (method is not important as long as it's strong)
	$hash = \substr(
		Hide\secure_hash(
			$username . $config['cookies']['salt'] . Hide\secure_hash(
				$username . $password . $salt . (
					$config['mod']['lock_ip'] ? $_SERVER['REMOTE_ADDR'] : ''
				), true
			) . Hide\secure_hash($config['password_crypt_version'], true), // Log out users being logged in with older password encryption schema
			false
		),
		0,
		40
	);

	if ($generated_salt) {
		return [ $hash, $salt ];
	} else {
		return $hash;
	}
}

function crypt_password(string $password): array {
	global $config;
	// `salt` database field is reused as a version value. We don't want it to be 0.
	$version = $config['password_crypt_version'] ? $config['password_crypt_version'] : 1;
	$pre_hash = \hash('tiger160,3', $password, false); // Note that it's truncated to 72 in the next line.
	$r = \password_hash($pre_hash, \PASSWORD_BCRYPT, [ 'cost' => 12 ]);
	if ($r === false) {
		throw new \RuntimeException("Could not hash password");
	}

	return [ $version, $r ];
}

function test_password(string $db_hash, string|int $version, string $input_password): bool {
	$version = (int)$version;
	if ($version < 2) {
		$ok = \hash_equals($db_hash, \crypt($input_password, $db_hash));
	} else {
		$pre_hash = \hash('tiger160,3', $input_password, false);
		$ok = \password_verify($pre_hash, $db_hash);
	}
	return $ok;
}

function login(string $username, string $password): array|false {
	global $mod;

	$query = prepare("SELECT `id`, `type`, `boards`, `password`, `version` FROM ``mods`` WHERE BINARY `username` = :username");
	$query->bindValue(':username', $username);
	$query->execute();

	if ($user = $query->fetch(PDO::FETCH_ASSOC)) {
		$ok = test_password($user['password'], $user['version'], $password);

		if ($ok) {
			if ((int)$user['version'] < 2) {
				// It's time to upgrade the password hashing method!
				list ($user['version'], $user['password']) = crypt_password($password);
				$query = prepare("UPDATE ``mods`` SET `password` = :password, `version` = :version WHERE `id` = :id");
				$query->bindValue(':password', $user['password']);
				$query->bindValue(':version', $user['version']);
				$query->bindValue(':id', $user['id']);
				$query->execute();
			}

			return $mod = [
				'id' => $user['id'],
				'type' => $user['type'],
				'username' => $username,
				'hash' => mkhash($username, $user['password']),
				'boards' => explode(',', $user['boards'])
			];
		}
	}

	return false;
}

function setCookies(): void {
	global $mod, $config;
	if (!$mod) {
		error('setCookies() was called for a non-moderator!');
	}

	$is_https = Net\is_connection_https();

	setcookie($config['cookies']['mod'],
			$mod['username'] . // username
			':' .
			$mod['hash'][0] . // password
			':' .
			$mod['hash'][1], // salt
		time() + $config['cookies']['expire'], $config['cookies']['jail'] ? $config['cookies']['path'] : '/', null, $is_https, $config['cookies']['httponly']);
}

function destroyCookies(): void {
	global $config;
	$is_https = Net\is_connection_https();
	// Delete the cookies
	setcookie($config['cookies']['mod'], 'deleted', time() - $config['cookies']['expire'], $config['cookies']['jail']?$config['cookies']['path'] : '/', null, $is_https, true);
}

function modLog(string $action, ?string $_board = null): void {
	global $mod, $board, $config;
	$query = prepare("INSERT INTO ``modlogs`` VALUES (:id, :ip, :board, :time, :text)");
	$query->bindValue(':id', (isset($mod['id']) ? $mod['id'] : -1), PDO::PARAM_INT);
	$query->bindValue(':ip', $_SERVER['REMOTE_ADDR']);
	$query->bindValue(':time', time(), PDO::PARAM_INT);
	$query->bindValue(':text', $action);
	if (isset($_board))
		$query->bindValue(':board', $_board);
	elseif (isset($board))
		$query->bindValue(':board', $board['uri']);
	else
		$query->bindValue(':board', null, PDO::PARAM_NULL);
	$query->execute() or error(db_error($query));

	if ($config['syslog']) {
		_syslog(LOG_INFO, '[mod/' . $mod['username'] . ']: ' . $action);
	}
}

function create_pm_header(): mixed {
	global $mod, $config;

	if ($config['cache']['enabled'] && ($header = cache::get('pm_unread_' . $mod['id'])) != false) {
		if ($header === true) {
			return false;
		}

		return $header;
	}

	$query = prepare("SELECT `id` FROM ``pms`` WHERE `to` = :id AND `unread` = 1");
	$query->bindValue(':id', $mod['id'], PDO::PARAM_INT);
	$query->execute() or error(db_error($query));

	if ($pm = $query->fetch(PDO::FETCH_ASSOC)) {
		$header = [ 'id' => $pm['id'], 'waiting' => $query->rowCount() - 1 ];
	} else {
		$header = true;
	}

	if ($config['cache']['enabled']) {
		cache::set('pm_unread_' . $mod['id'], $header);
	}

	if ($header === true) {
		return false;
	}

	return $header;
}

function make_secure_link_token(string $uri): string {
	global $mod, $config;
	return substr(sha1($config['cookies']['salt'] . '-' . $uri . '-' . $mod['id']), 0, 8);
}

function check_login(Context $ctx, bool $prompt = false): void {
	global $config, $mod;

	// Validate session
	if (isset($_COOKIE[$config['cookies']['mod']])) {
		// Should be username:hash:salt
		$cookie = explode(':', $_COOKIE[$config['cookies']['mod']]);
		if (count($cookie) != 3) {
			// Malformed cookies
			destroyCookies();
			if ($prompt) {
				mod_login($ctx);
			}
			exit;
		}

		$query = prepare("SELECT `id`, `type`, `boards`, `password` FROM ``mods`` WHERE `username` = :username");
		$query->bindValue(':username', $cookie[0]);
		$query->execute() or error(db_error($query));
		$user = $query->fetch(PDO::FETCH_ASSOC);

		// validate password hash
		if ($cookie[1] !== mkhash($cookie[0], $user['password'], $cookie[2])) {
			// Malformed cookies
			destroyCookies();
			if ($prompt) {
				mod_login($ctx);
			}
			exit;
		}

		$mod = array(
			'id' => (int)$user['id'],
			'type' => (int)$user['type'],
			'username' => $cookie[0],
			'boards' => explode(',', $user['boards'])
		);
	}
}