<?php

declare(strict_types = 1);

// {{{ License

// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.

// }}}

namespace App\Core;

use App\Entity\Actor;
use App\Util\Exception\BugFoundException;
use App\Util\Exception\NotFoundException;
use App\Util\Formatting;
use BadMethodCallException;
use Component\Notification\Entity\Attention;
use DateTime;
use DateTimeInterface;
use Exception;
use Functional as F;

/**
 * Base class to all entities, with some utilities
 *
 * @method int getId() // Not strictly true
 */
abstract class Entity
{
    /**
     * @return string Returns the name of this entity's DB table
     */
    public static function schemaName(): string
    {
        return static::schemaDef()['name'];
    }

    public function __call(string $name, array $arguments): mixed
    {
        if (Formatting::startsWith($name, 'has')) {
            $prop = Formatting::camelCaseToSnakeCase(Formatting::removePrefix($name, 'has'));
            // https://wiki.php.net/rfc/closure_apply#proposal
            $private_property_accessor = fn ($prop) => isset($this->{$prop});
            $private_property_accessor = $private_property_accessor->bindTo($this, static::class);
            return $private_property_accessor($prop);
        }
        throw new BadMethodCallException('Non existent non-static method ' . static::class . "->{$name} called with arguments: " . var_export($arguments, true));
    }

    abstract public static function schemaDef(): array;

    /**
     * Create an instance of the called class or fill in the
     * properties of $obj with the associative array $args. Doesn't
     * persist the result
     */
    public static function create(array $args, bool $_delegated_call = false): static
    {
        $date  = new DateTime();
        $class = static::class;
        $obj   = new $class();
        foreach (['created', 'modified'] as $prop) {
            if (property_exists($class, $prop) && !isset($args[$prop])) {
                $args[$prop] = $date;
            }
        }

        if (!$_delegated_call) {
            return static::createOrUpdate($obj, $args, _delegated_call: true);
        } else {
            return $obj;
        }
    }

    /**
     * @param ?static $obj
     */
    public static function createOrUpdate(?self $obj, array $args, bool $_delegated_call = false): static
    {
        $date  = new DateTime();
        $class = static::class;
        if (!$_delegated_call) {
            if (property_exists($class, 'modified') && !isset($args['modified'])) {
                $args['modified'] = $date;
            }
        }

        if (\is_null($obj)) {
            $obj = static::create($args, _delegated_call: true);
        }

        foreach ($args as $prop => $val) {
            if (property_exists($obj, $prop)) {
                $set = 'set' . ucfirst(Formatting::snakeCaseToCamelCase($prop));
                $obj->{$set}($val);
            } else {
                throw new BugFoundException("Property {$class}::{$prop} doesn't exist");
            }
        }

        return $obj;
    }

    /**
     * Create a new instance, but check for duplicates
     *
     * @throws \App\Util\Exception\ServerException
     *
     * @return array [$obj, $is_update]
     */
    public static function checkExistingAndCreateOrUpdate(array $args, array $find_by_keys = []): array
    {
        $find_by = $find_by_keys === [] ? $args : array_intersect_key($args, array_flip($find_by_keys));
        try {
            $obj = DB::findOneBy(static::class, $find_by, return_null: false);
        } catch (NotFoundException) {
            $obj = null;
            // @codeCoverageIgnoreStart
        } catch (Exception $e) {
            Log::unexpected_exception($e);
            // @codeCoverageIgnoreEnd
        }
        $is_update = !\is_null($obj);
        return [self::createOrUpdate($obj, $args), $is_update];
    }

    /**
     * Get an Entity from its primary key
     *
     * Support multiple formats:
     *  - mixed $values - convert to array and check next
     *  - array[int => mixed] $values - get keys for entity and set them in order and proceed to next case
     *  - array[string => mixed] $values - Perform a regular find
     *
     * Examples:
     *     Entity::getByPK(42);
     *     Entity::getByPK([42, 'foo']);
     *     Entity::getByPK(['key1' => 42, 'key2' => 'foo'])
     *
     * @throws \App\Util\Exception\DuplicateFoundException
     */
    public static function getByPK(mixed $values): ?self
    {
        $values  = \is_array($values) ? $values : [$values];
        $class   = static::class;
        $keys    = DB::getPKForClass($class);
        $find_by = [];
        foreach ($values as $k => $v) {
            if (\is_string($k)) {
                $find_by[$k] = $v;
            } else {
                $find_by[$keys[$k]] = $v;
            }
        }
        try {
            return DB::findOneBy($class, $find_by);
        } catch (NotFoundException $e) {
            return null;
        }
    }

    /**
     * Tests that this object is equal to another one based on a custom object comparison
     *
     * @param self $other the value to test
     *
     * @return bool true if equals, false otherwise
     */
    public function equals(self $other): bool
    {
        foreach (array_keys($this::schemaDef()['fields']) as $attribute) {
            $getter  = 'get' . Formatting::snakeCaseToPascalCase($attribute);
            $current = $this->{$getter}();
            $target  = $other->{$getter}();
            if ($current instanceof DateTimeInterface) {
                if ($current->getTimestamp() !== $target->getTimestamp()) {
                    return false;
                }
            } else {
                if ($current !== $target) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Ids of the Actors that should be informed about this object.
     * BEWARE: If you call this, your object must have a serial integer id!
     *
     * @return array int[] of Actor's id
     */
    public function getAttentionTargetIds(): array
    {
        $attention = DB::findBy(Attention::class, [
            'object_type' => static::schemaName(),
            'object_id'   => $this->getId(),
        ]);
        return F\map($attention, fn ($cc) => $cc->getTargetId());
    }

    /**
     * To whom should this be brought attention to?
     *
     * @return array Actor[]
     */
    public function getAttentionTargets(): array
    {
        $target_ids = $this->getAttentionTargetIds();
        return DB::findBy(Actor::class, ['id' => $target_ids]);
    }
}