<?php

namespace sammo;

use MeekroDBException;
use Ds\Map;

class KVStorage
{
    private $db;
    private $tableName;
    private $storNamespace;

    private ?Map $cacheData = null;

    /** @var null|Map<string, self> */
    static private ?Map $storageList = null;

    static public function getStorage(\MeekroDB $db, $storNamespace, string $tableName = 'storage'): self
    {
        if (self::$storageList === null) {
            self::$storageList = new Map();
        }
        $obj_id = spl_object_hash($db);
        $fullKey = $obj_id . ',' . $storNamespace . ',' . $tableName;
        if (self::$storageList->hasKey($fullKey)) {
            return self::$storageList[$fullKey];
        }
        $obj = new static($db, $storNamespace, $tableName);
        self::$storageList[$fullKey] = $obj;
        return $obj;
    }

    protected function __construct(\MeekroDB $db, $storNamespace, string $tableName = 'storage')
    {
        $this->db = $db;
        $this->storNamespace = $storNamespace;
        $this->tableName = $tableName;
        $this->turnOnCache();
    }

    public static function getValuesFromInterNamespace(\MeekroDB $db, string $tableName, string|int|\BackedEnum $key): array
    {
        $result = [];
        $key = Util::valueFromEnum($key);
        foreach ($db->queryAllLists(
            'SELECT `namespace`, `value` FROM %b WHERE `key`=%s',
            $tableName,
            $key
        ) as [$namespaceName, $value]) {
            $result[$namespaceName] = Json::decode($value);
        }
        return $result;
    }

    public function __get(string|int|\BackedEnum $key)
    {
        return $this->getValue($key);
    }

    public function __set(string|int|\BackedEnum $key, $value)
    {
        $this->setValue($key, $value);
    }

    public function __unset(string|int|\BackedEnum $key)
    {
        $this->deleteValue($key);
    }

    public function turnOnCache(): self
    {
        if ($this->cacheData === null) {
            $this->cacheData = new Map();
        }
        return $this;
    }

    public function turnOffCache(): self
    {
        if ($this->cacheData !== null) {
            $this->cacheData = null;
        }
        return $this;
    }

    public function resetCache(bool $disableCache = true): self
    {
        if ($disableCache) {
            $this->cacheData = null;
        } else {
            $this->cacheData = [];
        }
        return $this;
    }

    public function resetValues(): self
    {
        if ($this->cacheData !== null) {
            $this->cacheData = new Map();
        }
        return $this->resetDBNamespace();
    }

    public function invalidateCacheValue(string|int|\BackedEnum $key): self
    {
        if ($this->cacheData === null) {
            return $this;
        }
        $key = Util::valueFromEnum($key);
        $this->cacheData->remove($key, null);
        return $this;
    }

    public function invalidateCacheValues(array $keys): self
    {
        if ($this->cacheData === null) {
            return $this;
        }
        $keys = Util::valuesFromEnumArray($keys);

        foreach ($keys as $key) {
            $this->cacheData->remove($key, null);
        }

        return $this;
    }

    public function cacheAll(bool $invalidateAll = true): self
    {
        if (!$invalidateAll && $this->cacheData !== null && count($this->cacheData) > 0) {
            return $this;
        }
        $this->cacheData = $this->getDBAll();
        return $this;
    }

    public function cacheValues(array $keys, bool $invalidateAll = false): self
    {
        if ($this->cacheData === null) {
            $this->cacheData = new Map();
        }
        $keys = Util::valuesFromEnumArray($keys);

        if ($invalidateAll) {
            $notExists = $keys;
        } else {
            $notExists = [];
            foreach ($keys as $key) {
                if (!$this->cacheData->hasKey($key)) {
                    $notExists[] = $key;
                }
            }
            if (!$notExists) {
                return $this;
            }
        }

        $values = $this->getDBValues($notExists);
        foreach ($notExists as $key) {
            $this->cacheData[$key] = $values->get($key, null);
        }

        return $this;
    }

    public function getAll(bool $onlyCache = false): array
    {
        if ($onlyCache && $this->cacheData !== null && count($this->cacheData) > 0) {
            return $this->cacheData->toArray();
        }
        $result = $this->getDBAll();
        if ($this->cacheData !== null) {
            $this->cacheData = $result;
        }
        return $result->toArray();
    }

    public function getValuesAsArray(array $keys, bool $onlyCache = false): array
    {
        if (!$keys) {
            return [];
        }
        $keys = Util::valuesFromEnumArray($keys);

        $dictResult = $this->getValues($keys, $onlyCache);
        $result = [];
        foreach ($keys as $key) {
            $result[] = $dictResult[$key] ?? null;
        }
        return $result;
    }

    public function getValues(array $keys, bool $onlyCache = false): array
    {
        if (!$keys) {
            return [];
        }
        $keys = Util::valuesFromEnumArray($keys);

        if ($this->cacheData === null) {
            return $this->getDBValues($keys)->toArray();
        }

        $result = [];
        $notExists = [];

        //TODO: DB Select에서 as를 쓸 수 있으면 좋을 듯.
        foreach ($keys as $key) {

            if (!$this->cacheData->hasKey($key)) {
                $notExists[] = $key;
                continue;
            }

            $result[$key] = $this->cacheData[$key];
        }

        if ($onlyCache) {
            foreach ($notExists as $emptyKey) {
                $result[$emptyKey] = null;
            }

            return $result;
        }

        $dbResult = $this->getDBValues($notExists);
        foreach ($dbResult as $key => $value) {
            $result[$key] = $value;
            $this->cacheData[$key] = $value;
        }
        return $result;
    }

    public function getValue(string|int|\BackedEnum $key, bool $onlyCache = false)
    {
        $key = Util::valueFromEnum($key);
        if ($this->cacheData !== null && ($onlyCache || $this->cacheData->hasKey($key))) {
            return $this->cacheData->get($key, null);
        }

        $value = $this->getDBValue($key);
        if ($this->cacheData !== null) {
            $this->cacheData[$key] = $value;
        }
        return $value;
    }

    /**
     * @param mixed $value
     * @return KVStorage
     * @throws MeekroDBException
     */
    public function setValue(string|int|\BackedEnum $key, $value): self
    {
        $key = Util::valueFromEnum($key);

        if ($value === null) {
            return $this->deleteValue($key);
        }

        if ($this->cacheData) {
            $this->cacheData[$key] = $value;
        }
        return $this->setDBValue($key, $value);
    }

    /**
     *
     * @param string|int $key
     * @param mixed $value
     * @return KVStorage
     * @throws MeekroDBException
     */
    public function deleteValue(string|int|\BackedEnum $key): self
    {
        $key = Util::valueFromEnum($key);

        if($this->cacheData !== null){
            $this->cacheData->remove($key, null);
        }

        return $this->deleteDBValue($key);
    }

    private function getDBAll(): Map
    {
        $result = new Map();
        foreach ($this->db->queryAllLists(
            'SELECT `key`, `value` FROM %b WHERE `namespace`=%s',
            $this->tableName,
            $this->storNamespace
        ) as list($key, $value)) {
            $result[$key] = Json::decode($value);
        }
        return $result;
    }

    private function getDBValues(array $keys): Map
    {
        if (!$keys) {
            return new Map();
        }
        $result = new Map();
        foreach ($this->db->queryAllLists(
            'SELECT `key`, `value` FROM %b WHERE `namespace`=%s AND `key` IN %ls',
            $this->tableName,
            $this->storNamespace,
            $keys
        ) as list($key, $value)) {
            $result[$key] = Json::decode($value);
        }
        foreach ($keys as $key) {
            if (!$result->hasKey($key)) {
                $result[$key] = null;
            }
        }
        return $result;
    }

    private function getDBValue(string $key)
    {
        $value = $this->db->queryFirstField(
            'SELECT `value` FROM %b WHERE `namespace`=%s AND `key`=%s',
            $this->tableName,
            $this->storNamespace,
            $key
        );
        if ($value === null) {
            return null;
        }
        return Json::decode($value);
    }

    private function setDBValue(string $key, $value): self
    {
        if ($value === null) {
            return $this->deleteDBValue($key);
        }
        $this->db->insertUpdate($this->tableName, [
            'namespace' => $this->storNamespace,
            'key' => $key,
            'value' => Json::encode($value)
        ]);
        return $this;
    }

    private function deleteDBValue(string $key): self
    {
        $this->db->delete(
            $this->tableName,
            '`namespace`=%s AND `key`=%s',
            $this->storNamespace,
            $key
        );
        return $this;
    }

    private function resetDBNamespace(): self
    {
        $this->db->delete($this->tableName, 'namespace=%s', $this->storNamespace);
        return $this;
    }
}