<?php
namespace App\CMS\Observers;

use App\CMS\Contracts\Repositories\Content as ContentContract;
use App\Events\CreateNewContent;
use App\Events\DeleteContent;
use App\Events\EditContent;
use App\Events\MakeDraftFromContent;
use App\Events\PublishContent;
use App\Events\SetHomepage;
use App\Models\Content\Content as ContentModel;
use App\Models\Content\ContentHistory;
use Illuminate\Support\Facades\Event;

/**
 * Class Content
 *
 * Model observer for logging changes on content page.
 *
 * @package App\CMS\Observers
 */
class Content
{
    /**
     * @var string
     */
    protected $changeset;

    public function __construct()
    {
        $this->changeset = uniqid();
    }

    /**
     * Log changes on edit
     *
     * @param ContentModel $content
     */
    public function updated(ContentModel $content)
    {
        $fields = $this->getDirtyFields($content->getDirty(), $content->getOriginal());

        $normalFieldsEdited = 0;
        foreach ($fields as $field => $change) {
            if ($field == 'viewed')
                continue;

            $history = [
                'user_id'    => \Auth::user()->id,
                'content_id' => $content->id,
                'edit_batch' => $this->changeset,
                'column'     => $field,
                'old_value'  => $change['old'],
                'new_value'  => $change['new']
            ];

            // save history
            ContentHistory::create($history);

            // fire event
            $this->fireEvent($field, $change, $content, $normalFieldsEdited);
        }

        if ($normalFieldsEdited > 0) {
            Event::fire(new EditContent($content, $this->changeset));
        }
    }


    /**
     * Fire event when new instance of model is stored into database
     *
     * @param ContentModel $content
     */
    public function created(ContentModel $content)
    {
        Event::fire(new CreateNewContent($content));
    }

    /**
     * @param ContentModel $content
     */
    public function deleted(ContentModel $content)
    {
        Event::fire(new DeleteContent($content));
    }

    /**
     * Get all dirty changed from model.
     *
     * If user did not change moduleSettings column, return result from ContentModel::getDirty(). Otherwise append all
     * changed columns from module settings.
     *
     * @param $changed
     * @param $original
     *
     * @return array
     */
    protected function getDirtyFields($changed, $original)
    {
        unset($changed['updated_at']);

        $changes = $this->getNewAndOldValues(array_keys($changed), $changed, $original);

        if (!isset($changed['moduleSettings'])) {
            return $changes;
        }

        $moduleSettings = (array)json_decode($changed['moduleSettings']);
        $originalSettings = isset($original['moduleSettings']) ? (array)json_decode($original['moduleSettings']) : [];
        unset($changed['moduleSettings']);

        $settingChanged = array_keys(array_diff_assoc($moduleSettings, $originalSettings));
        $changesInSettings = $this->getNewAndOldValues($settingChanged, $moduleSettings, $originalSettings);

        return array_merge($changes, $changesInSettings);
    }

    /**
     * Get original and changed values in one array
     *
     * @param $fields
     * @param $new
     * @param $original
     *
     * @return array
     */
    protected function getNewAndOldValues($fields, $new, $original)
    {
        $changes = [];
        foreach ($fields as $field) {
            $changes[$field] = [
                'new' => isset($new[$field]) ? $new[$field] : null,
                'old' => isset($original[$field]) ? $original[$field] : null
            ];
        }

        return $changes;
    }

    /**
     * Fire events for publishing/making draft and setting homepage
     *
     * @param              $field
     * @param              $change
     * @param ContentModel $content
     * @param              $normalFieldsEdited
     */
    protected function fireEvent($field, $change, ContentModel $content, &$normalFieldsEdited)
    {
        switch ($field) {
            case 'status':
                if ($change['new'] !== ContentContract::STATUS_DRAFT) {
                    Event::fire(new PublishContent($content, $this->changeset));
                } else {
                    Event::fire(new MakeDraftFromContent($content, $this->changeset));
                }
                break;

            case 'isHomepage':
                Event::fire(new SetHomepage($content, $this->changeset));
                break;

            default:
                $normalFieldsEdited++;
        }
    }
}