<?php

namespace Botble\Revision;

use Botble\Base\Models\BaseModel;
use DateTime;
use Exception;
use Illuminate\Database\Eloquent\Relations\MorphMany;
use Illuminate\Database\Eloquent\SoftDeletes;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\DB;

/**
 * @mixin BaseModel|SoftDeletes
 */
trait RevisionableTrait
{
    protected array $originalData = [];

    protected array $updatedData = [];

    protected bool $updating = false;

    protected array $dontKeep = [];

    protected array $doKeep = [];

    protected array $dirtyData = [];

    protected array $revisionFormattedFields = [];

    protected array $revisionFormattedFieldNames = [];

    /**
     * Create the event listeners for the saving and saved events
     * This lets us save revisions whenever a save is made, no matter the
     * http method.
     */
    public static function bootRevisionableTrait(): void
    {
        static::saving(function ($model): void {
            $model->preSave();
        });

        static::saved(function ($model): void {
            $model->postSave();
        });

        static::created(function ($model): void {
            $model->postCreate();
        });

        static::deleted(function ($model): void {
            $model->preSave();
            $model->postDelete();
        });
    }

    /**
     * Generates a list of the last $limit revisions made to any objects of the class it is being called from.
     */
    public static function classRevisionHistory(int $limit = 100, string $order = 'desc')
    {
        return Revision::query()
            ->where('revisionable_type', get_called_class())
            ->orderBy('updated_at', $order)->limit($limit)->get();
    }

    /**
     * Invoked before a model is saved. Return false to abort the operation.
     */
    public function preSave(): bool
    {
        if (! isset($this->revisionEnabled) || $this->revisionEnabled) {
            // if there's no revisionEnabled. Or if there is, if it's true

            $this->originalData = $this->original;
            $this->updatedData = $this->attributes;

            // we can only safely compare basic items,
            // so for now we drop any object based items, like DateTime
            foreach ($this->updatedData as $key => $val) {
                if (gettype($val) == 'object' && ! method_exists($val, '__toString')) {
                    unset($this->originalData[$key]);
                    unset($this->updatedData[$key]);
                    $this->dontKeep[] = $key;
                }
            }

            // the below is ugly, for sure, but it's required so we can save the standard model
            // then use the keep / dontKeep values for later, in the isRevisionable method
            $this->dontKeep = isset($this->dontKeepRevisionOf) ?
                array_merge($this->dontKeepRevisionOf, $this->dontKeep)
                : $this->dontKeep;

            $this->doKeep = isset($this->keepRevisionOf) ?
                array_merge($this->keepRevisionOf, $this->doKeep)
                : $this->doKeep;

            unset($this->attributes['dontKeepRevisionOf']);
            unset($this->attributes['keepRevisionOf']);

            $this->dirtyData = $this->getDirty();
            $this->updating = $this->exists;
        }

        return true;
    }

    /**
     * Called after a model is successfully saved.
     */
    public function postSave(): void
    {
        if (isset($this->historyLimit) && $this->revisionHistory()->count() >= $this->historyLimit) {
            $limitReached = true;
        } else {
            $limitReached = false;
        }

        $revisionCleanup = $this->revisionCleanup ?? false;

        // check if the model already exists
        if (((! isset($this->revisionEnabled) || $this->revisionEnabled) && $this->updating) && (! $limitReached || $revisionCleanup)) {
            // if it does, it means we're updating

            $changesToRecord = $this->changedRevisionableFields();

            $revisions = [];

            foreach ($changesToRecord as $key => $change) {
                $data = [
                    'revisionable_type' => $this->getMorphClass(),
                    'revisionable_id' => $this->getKey(),
                    'key' => $key,
                    'old_value' => Arr::get($this->originalData, $key),
                    'new_value' => $this->updatedData[$key],
                    'user_id' => $this->getSystemUserId(),
                    'created_at' => new DateTime(),
                    'updated_at' => new DateTime(),
                ];

                if (BaseModel::isUsingStringId()) {
                    $data['id'] = (new BaseModel())->newUniqueId();
                }

                $revisions[] = $data;
            }

            if (count($revisions) > 0) {
                if ($limitReached && $revisionCleanup) {
                    $toDelete = $this->revisionHistory()->orderBy('id')->limit(count($revisions))->get();
                    foreach ($toDelete as $delete) {
                        $delete->delete();
                    }
                }
                $revision = new Revision();
                DB::table($revision->getTable())->insert($revisions);
                event('revisionable.saved', ['model' => $this, 'revisions' => $revisions]);
            }
        }
    }

    public function revisionHistory(): MorphMany
    {
        return $this->morphMany(Revision::class, 'revisionable');
    }

    /**
     * Get all the changes that have been made, that are also supposed
     * to have their changes recorded
     *
     * @return array fields with new data, that should be recorded
     */
    protected function changedRevisionableFields(): array
    {
        $changesToRecord = [];
        foreach ($this->dirtyData as $key => $value) {
            // check that the field is revisionable, and double check
            // that it's actually new data in case dirty is, well, clean
            if ($this->isRevisionable($key) && ! is_array($value)) {
                if (! isset($this->originalData[$key]) || $this->originalData[$key] != $this->updatedData[$key]) {
                    $changesToRecord[$key] = $value;
                }
            } else {
                // we don't need these anymore, and they could
                // contain a lot of data, so lets trash them.
                unset($this->updatedData[$key]);
                unset($this->originalData[$key]);
            }
        }

        return $changesToRecord;
    }

    /**
     * Check if this field should have a revision kept
     */
    protected function isRevisionable(string $key): bool
    {
        // If the field is explicitly revisionable, then return true.
        // If it's explicitly not revisionable, return false.
        // Otherwise, if neither condition is met, only return true if
        // we aren't specifying revisionable fields.
        if (isset($this->doKeep) && in_array($key, $this->doKeep)) {
            return true;
        }

        if (isset($this->dontKeep) && in_array($key, $this->dontKeep)) {
            return false;
        }

        return empty($this->doKeep);
    }

    /**
     * Attempt to find the user id of the currently logged in user
     **/
    public function getSystemUserId(): int|string|null
    {
        try {
            if (Auth::guard()->check()) {
                return Auth::guard()->id();
            }
        } catch (Exception) {
            return null;
        }

        return null;
    }

    /**
     * Called after record successfully created
     */
    public function postCreate(): bool
    {
        // Check if we should store creations in our revision history
        // Set this value to true in your model if you want to
        if (empty($this->revisionCreationsEnabled)) {
            // We should not store creations.
            return false;
        }

        if ((! isset($this->revisionEnabled) || $this->revisionEnabled)) {
            $revisions[] = [
                'revisionable_type' => $this->getMorphClass(),
                'revisionable_id' => $this->getKey(),
                'key' => self::CREATED_AT,
                'old_value' => null,
                'new_value' => $this->{self::CREATED_AT},
                'user_id' => $this->getSystemUserId(),
                'created_at' => new DateTime(),
                'updated_at' => new DateTime(),
            ];

            $revision = new Revision();
            DB::table($revision->getTable())->insert($revisions);
            event('revisionable.created', ['model' => $this, 'revisions' => $revisions]);
        }

        return false;
    }

    /**
     * If soft deletes are enabled, store the deleted time
     */
    public function postDelete(): void
    {
        if ((! isset($this->revisionEnabled) || $this->revisionEnabled)
            && $this->isSoftDelete()
            && method_exists($this, 'getDeletedAtColumn')
            && $this->isRevisionable($this->getDeletedAtColumn())
        ) {
            $revisions[] = [
                'revisionable_type' => $this->getMorphClass(),
                'revisionable_id' => $this->getKey(),
                'key' => $this->getDeletedAtColumn(),
                'old_value' => null,
                'new_value' => $this->{$this->getDeletedAtColumn()},
                'user_id' => $this->getSystemUserId(),
                'created_at' => new DateTime(),
                'updated_at' => new DateTime(),
            ];
            $revision = new Revision();
            DB::table($revision->getTable())->insert($revisions);
            event('revisionable.deleted', ['model' => $this, 'revisions' => $revisions]);
        }
    }

    /**
     * Check if soft deletes are currently enabled on this model
     */
    protected function isSoftDelete(): bool
    {
        // check flag variable used in laravel 4.2+
        if (isset($this->forceDeleting)) {
            return ! $this->forceDeleting;
        }

        // otherwise, look for flag used in older versions
        if (isset($this->softDelete)) {
            return $this->softDelete;
        }

        return false;
    }

    public function getRevisionFormattedFields(): ?array
    {
        return $this->revisionFormattedFields;
    }

    public function getRevisionFormattedFieldNames(): ?array
    {
        return $this->revisionFormattedFieldNames;
    }

    /**
     * Identifiable Name
     * When displaying revision history, when a foreign key is updated
     * instead of displaying the ID, you can choose to display a string
     * of your choice, just override this method in your model
     * By default, it will fall back to the models ID.
     *
     * @return string an identifying name for the model
     */
    public function identifiableName(): string
    {
        return $this->getKey();
    }

    /**
     * Revision Unknown String
     * When displaying revision history, when a foreign key is updated
     * instead of displaying the ID, you can choose to display a string
     * of your choice, just override this method in your model
     * By default, it will fall back to the models ID.
     *
     * @return string an identifying name for the model
     */
    public function getRevisionNullString(): string
    {
        return $this->revisionNullString ?? 'nothing';
    }

    /**
     * No revision string
     * When displaying revision history, if the revisions value
     * cant be figured out, this is used instead.
     * It can be overridden.
     *
     * @return string an identifying name for the model
     */
    public function getRevisionUnknownString(): string
    {
        return $this->revisionUnknownString ?? 'unknown';
    }

    /**
     * Disable a revisionable field temporarily
     * Need to do the adding to array longhanded, as there's a
     * PHP bug https://bugs.php.net/bug.php?id=42030
     *
     * @param mixed $field
     */
    public function disableRevisionField($field): void
    {
        if (! isset($this->dontKeepRevisionOf)) {
            $this->dontKeepRevisionOf = [];
        }
        if (is_array($field)) {
            foreach ($field as $oneField) {
                $this->disableRevisionField($oneField);
            }
        } else {
            $dont = $this->dontKeepRevisionOf;
            $dont[] = $field;
            $this->dontKeepRevisionOf = $dont;
            unset($dont);
        }
    }
}
