<?php
/* Icinga Web 2 | (c) 2015 Icinga Development Team | GPLv2+ */

namespace Icinga\Forms\Navigation;

use InvalidArgumentException;
use Icinga\Application\Config;
use Icinga\Application\Logger;
use Icinga\Application\Icinga;
use Icinga\Authentication\Auth;
use Icinga\Data\ConfigObject;
use Icinga\Exception\IcingaException;
use Icinga\Exception\NotFoundError;
use Icinga\Exception\ProgrammingError;
use Icinga\Forms\ConfigForm;
use Icinga\User;
use Icinga\Util\StringHelper;
use Icinga\Web\Form;

/**
 * Form for managing navigation items
 */
class NavigationConfigForm extends ConfigForm
{
    /**
     * The class namespace where to locate navigation type forms
     *
     * @var string
     */
    const FORM_NS = 'Forms\\Navigation';

    /**
     * The secondary configuration to write
     *
     * This is always the reduced configuration and is only written to
     * disk once the main configuration has been successfully written.
     *
     * @var Config
     */
    protected $secondaryConfig;

    /**
     * The navigation item to load when displaying the form for the first time
     *
     * @var string
     */
    protected $itemToLoad;

    /**
     * The user for whom to manage navigation items
     *
     * @var User
     */
    protected $user;

    /**
     * The user's navigation configuration
     *
     * @var Config
     */
    protected $userConfig;

    /**
     * The shared navigation configuration
     *
     * @var Config
     */
    protected $shareConfig;

    /**
     * The available navigation item types
     *
     * @var array
     */
    protected $itemTypes;

    private $defaultUrl;

    /**
     * Initialize this form
     */
    public function init()
    {
        $this->setName('form_config_navigation');
        $this->setSubmitLabel($this->translate('Save Changes'));
    }

    /**
     * Set the user for whom to manage navigation items
     *
     * @param   User    $user
     *
     * @return  $this
     */
    public function setUser(User $user)
    {
        $this->user = $user;
        return $this;
    }

    /**
     * Return the user for whom to manage navigation items
     *
     * @return  User
     */
    public function getUser()
    {
        return $this->user;
    }

    /**
     * Set the user's navigation configuration
     *
     * @param   Config  $config
     *
     * @return  $this
     */
    public function setUserConfig(Config $config)
    {
        $config->getConfigObject()->setKeyColumn('name');
        $this->userConfig = $config;
        return $this;
    }

    /**
     * Return the user's navigation configuration
     *
     * @param   string  $type
     *
     * @return  Config
     */
    public function getUserConfig($type = null)
    {
        if ($this->userConfig === null || $type !== null) {
            if ($type === null) {
                throw new ProgrammingError('You need to pass a type if no user configuration is set');
            }

            $this->setUserConfig(Config::navigation($type, $this->getUser()->getUsername()));
        }

        return $this->userConfig;
    }

    /**
     * Set the shared navigation configuration
     *
     * @param   Config  $config
     *
     * @return  $this
     */
    public function setShareConfig(Config $config)
    {
        $config->getConfigObject()->setKeyColumn('name');
        $this->shareConfig = $config;
        return $this;
    }

    /**
     * Return the shared navigation configuration
     *
     * @param   string  $type
     *
     * @return  Config
     */
    public function getShareConfig($type = null)
    {
        if ($this->shareConfig === null) {
            if ($type === null) {
                throw new ProgrammingError('You need to pass a type if no share configuration is set');
            }

            $this->setShareConfig(Config::navigation($type));
        }

        return $this->shareConfig;
    }

    /**
     * Set the available navigation item types
     *
     * @param   array   $itemTypes
     *
     * @return  $this
     */
    public function setItemTypes(array $itemTypes)
    {
        $this->itemTypes = $itemTypes;
        return $this;
    }

    /**
     * Return the available navigation item types
     *
     * @return  array
     */
    public function getItemTypes()
    {
        return $this->itemTypes ?: array();
    }

    /**
     * Return a list of available parent items for the given type of navigation item
     *
     * @param   string  $type
     * @param   string  $owner
     *
     * @return  array
     */
    public function listAvailableParents($type, $owner = null)
    {
        $children = $this->itemToLoad ? $this->getFlattenedChildren($this->itemToLoad) : array();

        $names = array();
        foreach ($this->getShareConfig($type) as $sectionName => $sectionConfig) {
            if ((string) $sectionName !== $this->itemToLoad
                && $sectionConfig->owner === ($owner ?: $this->getUser()->getUsername())
                && ! in_array($sectionName, $children, true)
            ) {
                $names[] = $sectionName;
            }
        }

        foreach ($this->getUserConfig($type) as $sectionName => $sectionConfig) {
            if ((string) $sectionName !== $this->itemToLoad
                && ! in_array($sectionName, $children, true)
            ) {
                $names[] = $sectionName;
            }
        }

        return $names;
    }

    /**
     * Recursively return all children of the given navigation item
     *
     * @param   string  $name
     *
     * @return  array
     */
    protected function getFlattenedChildren($name)
    {
        $config = $this->getConfigForItem($name);
        if ($config === null) {
            return array();
        }

        $children = array();
        foreach ($config->toArray() as $sectionName => $sectionConfig) {
            if (isset($sectionConfig['parent']) && $sectionConfig['parent'] === $name) {
                $children[] = $sectionName;
                $children = array_merge($children, $this->getFlattenedChildren($sectionName));
            }
        }

        return $children;
    }

    /**
     * Populate the form with the given navigation item's config
     *
     * @param   string  $name
     *
     * @return  $this
     *
     * @throws  NotFoundError   In case no navigation item with the given name is found
     */
    public function load($name)
    {
        if ($this->getConfigForItem($name) === null) {
            throw new NotFoundError('No navigation item called "%s" found', $name);
        }

        $this->itemToLoad = $name;
        return $this;
    }

    /**
     * Add a new navigation item
     *
     * The navigation item to add is identified by the array-key `name'.
     *
     * @param   array   $data
     *
     * @return  $this
     *
     * @throws  InvalidArgumentException    In case $data does not contain a navigation item name or type
     * @throws  IcingaException             In case a navigation item with the same name already exists
     */
    public function add(array $data)
    {
        if (! isset($data['name'])) {
            throw new InvalidArgumentException('Key \'name\' missing');
        } elseif (! isset($data['type'])) {
            throw new InvalidArgumentException('Key \'type\' missing');
        }

        $shared = false;
        $config = $this->getUserConfig($data['type']);
        if ((isset($data['users']) && $data['users']) || (isset($data['groups']) && $data['groups'])) {
            if ($this->getUser()->can('user/share/navigation')) {
                $data['owner'] = $this->getUser()->getUsername();
                $config = $this->getShareConfig($data['type']);
                $shared = true;
            } else {
                unset($data['users']);
                unset($data['groups']);
            }
        } elseif (isset($data['parent']) && $data['parent'] && $this->hasBeenShared($data['parent'], $data['type'])) {
            $data['owner'] = $this->getUser()->getUsername();
            $config = $this->getShareConfig($data['type']);
            $shared = true;
        }

        $itemName = $data['name'];
        $exists = $config->hasSection($itemName);
        if (! $exists) {
            if ($shared) {
                $exists = $this->getUserConfig($data['type'])->hasSection($itemName);
            } else {
                $exists = (bool) $this->getShareConfig($data['type'])
                    ->select()
                    ->where('name', $itemName)
                    ->where('owner', $this->getUser()->getUsername())
                    ->count();
            }
        }

        if ($exists) {
            throw new IcingaException(
                $this->translate('A navigation item with the name "%s" does already exist'),
                $itemName
            );
        }

        unset($data['name']);
        $config->setSection($itemName, $data);
        $this->setIniConfig($config);
        return $this;
    }

    /**
     * Edit a navigation item
     *
     * @param   string  $name
     * @param   array   $data
     *
     * @return  $this
     *
     * @throws  NotFoundError       In case no navigation item with the given name is found
     * @throws  IcingaException     In case a navigation item with the same name already exists
     */
    public function edit($name, array $data)
    {
        $config = $this->getConfigForItem($name);
        if ($config === null) {
            throw new NotFoundError('No navigation item called "%s" found', $name);
        } else {
            $itemConfig = $config->getSection($name);
        }

        $shared = false;
        if ($this->hasBeenShared($name)) {
            if (isset($data['parent']) && $data['parent']
                ? ! $this->hasBeenShared($data['parent'])
                : ((! isset($data['users']) || ! $data['users']) && (! isset($data['groups']) || ! $data['groups']))
            ) {
                // It is shared but shouldn't anymore
                $config = $this->unshare($name, isset($data['parent']) ? $data['parent'] : null);
            }
        } elseif ((isset($data['users']) && $data['users']) || (isset($data['groups']) && $data['groups'])) {
            if ($this->getUser()->can('user/share/navigation')) {
                // It is not shared yet but should be
                $this->secondaryConfig = $config;
                $config = $this->getShareConfig();
                $data['owner'] = $this->getUser()->getUsername();
                $shared = true;
            } else {
                unset($data['users']);
                unset($data['groups']);
            }
        } elseif (isset($data['parent']) && $data['parent'] && $this->hasBeenShared($data['parent'])) {
            // Its parent is shared so should it itself
            $this->secondaryConfig = $config;
            $config = $this->getShareConfig();
            $data['owner'] = $this->getUser()->getUsername();
            $shared = true;
        }

        $oldName = null;
        if (isset($data['name'])) {
            if ($data['name'] !== $name) {
                $oldName = $name;
                $name = $data['name'];

                $exists = $config->hasSection($name);
                if (! $exists) {
                    $ownerName = $itemConfig->owner ?: $this->getUser()->getUsername();
                    if ($shared || $this->hasBeenShared($oldName)) {
                        if ($ownerName === $this->getUser()->getUsername()) {
                            $exists = $this->getUserConfig()->hasSection($name);
                        } else {
                            $exists = Config::navigation($itemConfig->type, $ownerName)->hasSection($name);
                        }
                    } else {
                        $exists = (bool) $this->getShareConfig()
                            ->select()
                            ->where('name', $name)
                            ->where('owner', $ownerName)
                            ->count();
                    }
                }

                if ($exists) {
                    throw new IcingaException(
                        $this->translate('A navigation item with the name "%s" does already exist'),
                        $name
                    );
                }
            }

            unset($data['name']);
        }

        $itemConfig->merge($data);

        if ($shared) {
            // Share all descendant children
            foreach ($this->getFlattenedChildren($oldName ?: $name) as $child) {
                $childConfig = $this->secondaryConfig->getSection($child);
                $this->secondaryConfig->removeSection($child);
                $childConfig->owner = $this->getUser()->getUsername();
                $config->setSection($child, $childConfig);
            }
        }

        if ($oldName) {
            // Update the parent name on all direct children
            foreach ($config as $sectionConfig) {
                if ($sectionConfig->parent === $oldName) {
                    $sectionConfig->parent = $name;
                }
            }

            $config->removeSection($oldName);
        }

        if ($this->secondaryConfig !== null) {
            $this->secondaryConfig->removeSection($oldName ?: $name);
        }

        $config->setSection($name, $itemConfig);
        $this->setIniConfig($config);
        return $this;
    }

    /**
     * Remove a navigation item
     *
     * @param   string  $name
     *
     * @return  ConfigObject        The navigation item's config
     *
     * @throws  NotFoundError       In case no navigation item with the given name is found
     * @throws  IcingaException     In case the navigation item has still children
     */
    public function delete($name)
    {
        $config = $this->getConfigForItem($name);
        if ($config === null) {
            throw new NotFoundError('No navigation item called "%s" found', $name);
        }

        $children = $this->getFlattenedChildren($name);
        if (! empty($children)) {
            throw new IcingaException(
                $this->translate(
                    'Unable to delete navigation item "%s". There'
                    . ' are other items dependent from it: %s'
                ),
                $name,
                join(', ', $children)
            );
        }

        $section = $config->getSection($name);
        $config->removeSection($name);
        $this->setIniConfig($config);
        return $section;
    }

    /**
     * Unshare the given navigation item
     *
     * @param   string  $name
     * @param   string  $parent
     *
     * @return  Config              The new config of the given navigation item
     *
     * @throws  NotFoundError       In case no navigation item with the given name is found
     * @throws  IcingaException     In case the navigation item has a parent assigned to it
     */
    public function unshare($name, $parent = null)
    {
        $config = $this->getShareConfig();
        if (! $config->hasSection($name)) {
            throw new NotFoundError('No navigation item called "%s" found', $name);
        }

        $itemConfig = $config->getSection($name);
        if ($parent === null) {
            $parent = $itemConfig->parent;
        }

        if ($parent && $this->hasBeenShared($parent)) {
            throw new IcingaException(
                $this->translate(
                    'Unable to unshare navigation item "%s". It is dependent from item "%s".'
                    . ' Dependent items can only be unshared by unsharing their parent'
                ),
                $name,
                $parent
            );
        }

        $children = $this->getFlattenedChildren($name);
        $config->removeSection($name);
        $this->secondaryConfig = $config;

        if (! $itemConfig->owner || $itemConfig->owner === $this->getUser()->getUsername()) {
            $config = $this->getUserConfig();
        } else {
            $config = Config::navigation($itemConfig->type, $itemConfig->owner);
        }

        foreach ($children as $child) {
            $childConfig = $this->secondaryConfig->getSection($child);
            unset($childConfig->owner);
            $this->secondaryConfig->removeSection($child);
            $config->setSection($child, $childConfig);
        }

        unset($itemConfig->owner);
        unset($itemConfig->users);
        unset($itemConfig->groups);

        $config->setSection($name, $itemConfig);
        $this->setIniConfig($config);
        return $config;
    }

    /**
     * {@inheritdoc}
     */
    public function createElements(array $formData)
    {
        $shared = false;
        $itemTypes = $this->getItemTypes();
        $itemType = isset($formData['type']) ? $formData['type'] : key($itemTypes);
        if ($itemType === null) {
            throw new ProgrammingError(
                'This should actually not happen. Create a bug report at https://github.com/icinga/icingaweb2'
                . ' or remove this assertion if you know what you\'re doing'
            );
        }

        $itemForm = $this->getItemForm($itemType);

        $this->addElement(
            'text',
            'name',
            array(
                'required'      => true,
                'label'         => $this->translate('Name'),
                'description'   => $this->translate(
                    'The name of this navigation item that is used to differentiate it from others'
                )
            )
        );

        if ((! $itemForm->requiresParentSelection() || ! isset($formData['parent']) || ! $formData['parent'])
            && $this->getUser()->can('user/share/navigation')
        ) {
            $checked = isset($formData['shared']) ? null : (isset($formData['users']) || isset($formData['groups']));

            $this->addElement(
                'checkbox',
                'shared',
                array(
                    'autosubmit'    => true,
                    'ignore'        => true,
                    'value'         => $checked,
                    'label'         => $this->translate('Shared'),
                    'description'   => $this->translate('Tick this box to share this item with others')
                )
            );

            if ($checked || (isset($formData['shared']) && $formData['shared'])) {
                $shared = true;
                $this->addElement(
                    'textarea',
                    'users',
                    array(
                        'label'         => $this->translate('Users'),
                        'description'   => $this->translate(
                            'Comma separated list of usernames to share this item with'
                        )
                    )
                );
                $this->addElement(
                    'textarea',
                    'groups',
                    array(
                        'label'         => $this->translate('Groups'),
                        'description'   => $this->translate(
                            'Comma separated list of group names to share this item with'
                        )
                    )
                );
            }
        }

        if (empty($itemTypes) || count($itemTypes) === 1) {
            $this->addElement(
                'hidden',
                'type',
                array(
                    'value' => $itemType
                )
            );
        } else {
            $this->addElement(
                'select',
                'type',
                array(
                    'required'      => true,
                    'autosubmit'    => true,
                    'label'         => $this->translate('Type'),
                    'description'   => $this->translate('The type of this navigation item'),
                    'multiOptions'  => $itemTypes
                )
            );
        }

        if (! $shared && $itemForm->requiresParentSelection()) {
            if ($this->itemToLoad && $this->hasBeenShared($this->itemToLoad)) {
                $itemConfig = $this->getShareConfig()->getSection($this->itemToLoad);
                $availableParents = $this->listAvailableParents($itemType, $itemConfig->owner);
            } else {
                $availableParents = $this->listAvailableParents($itemType);
            }

            $this->addElement(
                'select',
                'parent',
                array(
                    'allowEmpty'    => true,
                    'autosubmit'    => true,
                    'label'         => $this->translate('Parent'),
                    'description'   => $this->translate(
                        'The parent item to assign this navigation item to. '
                        . 'Select "None" to make this a main navigation item'
                    ),
                    'multiOptions'  => ['' => $this->translate('None', 'No parent for a navigation item')]
                        + (empty($availableParents) ? [] : array_combine($availableParents, $availableParents))
                )
            );
        } else {
            $this->addElement('hidden', 'parent', ['disabled'  => true]);
        }

        $this->addSubForm($itemForm, 'item_form');
        $itemForm->create($formData); // May require a parent which gets set by addSubForm()
    }

    /**
     * DO NOT USE! This will be removed soon, very soon...
     */
    public function setDefaultUrl($url)
    {
        $this->defaultUrl = $url;
    }

    /**
     * Populate the configuration of the navigation item to load
     */
    public function onRequest()
    {
        if ($this->itemToLoad) {
            $data = $this->getConfigForItem($this->itemToLoad)->getSection($this->itemToLoad)->toArray();
            $data['name'] = $this->itemToLoad;
            $this->populate($data);
        } elseif ($this->defaultUrl !== null) {
            $this->populate(array('url' => $this->defaultUrl));
        }
    }

    /**
     * {@inheritdoc}
     */
    public function isValid($formData)
    {
        if (! parent::isValid($formData)) {
            return false;
        }

        $valid = true;
        if (isset($formData['users']) && $formData['users']) {
            $parsedUserRestrictions = array();
            foreach (Auth::getInstance()->getRestrictions('application/share/users') as $userRestriction) {
                $parsedUserRestrictions[] = array_map('trim', explode(',', $userRestriction));
            }

            if (! empty($parsedUserRestrictions)) {
                $desiredUsers = array_map('trim', explode(',', $formData['users']));
                array_unshift($parsedUserRestrictions, $desiredUsers);
                $forbiddenUsers = call_user_func_array('array_diff', $parsedUserRestrictions);
                if (! empty($forbiddenUsers)) {
                    $valid = false;
                    $this->getElement('users')->addError(
                        sprintf(
                            $this->translate(
                                'You are not permitted to share this navigation item with the following users: %s'
                            ),
                            implode(', ', $forbiddenUsers)
                        )
                    );
                }
            }
        }

        if (isset($formData['groups']) && $formData['groups']) {
            $parsedGroupRestrictions = array();
            foreach (Auth::getInstance()->getRestrictions('application/share/groups') as $groupRestriction) {
                $parsedGroupRestrictions[] = array_map('trim', explode(',', $groupRestriction));
            }

            if (! empty($parsedGroupRestrictions)) {
                $desiredGroups = array_map('trim', explode(',', $formData['groups']));
                array_unshift($parsedGroupRestrictions, $desiredGroups);
                $forbiddenGroups = call_user_func_array('array_diff', $parsedGroupRestrictions);
                if (! empty($forbiddenGroups)) {
                    $valid = false;
                    $this->getElement('groups')->addError(
                        sprintf(
                            $this->translate(
                                'You are not permitted to share this navigation item with the following groups: %s'
                            ),
                            implode(', ', $forbiddenGroups)
                        )
                    );
                }
            }
        }

        return $valid;
    }

    /**
     * {@inheritdoc}
     */
    protected function writeConfig(Config $config)
    {
        parent::writeConfig($config);

        if ($this->secondaryConfig !== null) {
            $this->config = $this->secondaryConfig; // Causes the config being displayed to the user in case of an error
            parent::writeConfig($this->secondaryConfig);
        }
    }

    /**
     * Return the navigation configuration the given item is a part of
     *
     * @param   string  $name
     *
     * @return  Config|null     In case the item is not part of any configuration
     */
    protected function getConfigForItem($name)
    {
        if ($this->getUserConfig()->hasSection($name)) {
            return $this->getUserConfig();
        } elseif ($this->getShareConfig()->hasSection($name)) {
            if ($this->getShareConfig()->get($name, 'owner') === $this->getUser()->getUsername()
                || $this->getUser()->can('user/share/navigation')
            ) {
                return $this->getShareConfig();
            }
        }
    }

    /**
     * Return whether the given navigation item has been shared
     *
     * @param   string  $name
     * @param   string  $type
     *
     * @return  bool
     */
    protected function hasBeenShared($name, $type = null)
    {
        return $this->getShareConfig($type) === $this->getConfigForItem($name);
    }

    /**
     * Return the form for the given type of navigation item
     *
     * @param   string  $type
     *
     * @return  Form
     */
    protected function getItemForm($type)
    {
        $className = StringHelper::cname($type, '-') . 'Form';

        $form = null;
        $classPath = null;
        foreach (Icinga::app()->getModuleManager()->getLoadedModules() as $module) {
            $classPath = 'Icinga\\Module\\'
                . ucfirst($module->getName())
                . '\\'
                . static::FORM_NS
                . '\\'
                . $className;
            if (class_exists($classPath)) {
                $form = new $classPath();
                break;
            }
        }

        if ($form === null) {
            $classPath = 'Icinga\\' . static::FORM_NS . '\\' . $className;
            if (class_exists($classPath)) {
                $form = new $classPath();
            }
        }

        if ($form === null) {
            Logger::debug(
                'Failed to find custom navigation item form %s for item %s. Using form NavigationItemForm now',
                $className,
                $type
            );

            $form = new NavigationItemForm();
        } elseif (! $form instanceof NavigationItemForm) {
            throw new ProgrammingError('Class %s must inherit from NavigationItemForm', $classPath);
        }

        return $form;
    }
}