<?php

namespace KTXC\Stores;

use KTXC\Db\DataStore;
use KTXC\Db\ObjectId;
use KTXC\Models\Tenant\TenantObject;

class TenantStore
{
    
    protected const COLLECTION_NAME = 'tenants';

    public function __construct(
        protected readonly DataStore $dataStore
    ) { }

    public function list(): array
    {
        $cursor = $this->dataStore->selectCollection(self::COLLECTION_NAME)->find();
        $list = [];
        foreach ($cursor as $entry) {
            $entry = (new TenantObject())->jsonDeserialize((array)$entry);
            $list[$entry->getId()] = $entry;
        }
        return $list;
    }

    public function fetch(string $identifier): ?TenantObject
    {
        $entry = $this->dataStore->selectCollection(self::COLLECTION_NAME)->findOne(['identifier' => $identifier]);
        if (!$entry) { return null; }
        return (new TenantObject())->jsonDeserialize((array)$entry);
    }

    public function fetchByDomain(string $domain): ?TenantObject
    {
        $entry = $this->dataStore->selectCollection(self::COLLECTION_NAME)->findOne(['domains' => $domain]);
        if (!$entry) { return null; }
        $entity = new TenantObject();
        $entity->jsonDeserialize((array)$entry);
        return $entity;
    }

    public function deposit(TenantObject $entry): ?TenantObject
    {
        if ($entry->getId()) {
            return $this->update($entry);
        } else {
            return $this->create($entry);
        }
    }

    private function create(TenantObject $entry): ?TenantObject
    {
        $document = $entry->jsonSerialize();
        unset($document['id']);
        $result = $this->dataStore->selectCollection(self::COLLECTION_NAME)->insertOne($document);
        $entry->setId((string)$result->getInsertedId());
        return $entry;
    }

    private function update(TenantObject $entry): ?TenantObject
    {
        $id = $entry->getId();
        if (!$id) { return null; }
        $document = $entry->jsonSerialize();
        unset($document['id']);
        $this->dataStore->selectCollection(self::COLLECTION_NAME)->updateOne(['_id' => new ObjectId($id)], ['$set' => $document]);
        return $entry;
    }

    public function destroy(TenantObject $entry): void
    {
        $id = $entry->getId();
        if (!$id) { return; }
        $this->dataStore->selectCollection(self::COLLECTION_NAME)->deleteOne(['_id' => new ObjectId($id)]);
    }

    // =========================================================================
    // Configuration Operations
    // =========================================================================

    public function fetchConfiguration(string $identifier, string $path): ?array
    {
        $entry = $this->dataStore->selectCollection(self::COLLECTION_NAME)->findOne(
            ['identifier' => $identifier],
            ['projection' => ['configuration.' . $path => 1]],
        );

        if (!$entry) {
            return null;
        }

        $value = $this->readPath($entry, "configuration.{$path}");
        return $value === null ? null : (array) $value;
    }

    public function storeConfiguration(string $identifier, string $path, array $value): bool
    {
        $result = $this->dataStore->selectCollection(self::COLLECTION_NAME)->updateOne(
            ['identifier' => $identifier],
            ['$set' => ['configuration.' . $path => $value]],
        );

        return $result->getMatchedCount() > 0;
    }

    public function removeConfiguration(string $identifier, string $path): ?bool
    {
        $result = $this->dataStore->selectCollection(self::COLLECTION_NAME)->updateOne(
            ['identifier' => $identifier],
            ['$unset' => ['configuration.' . $path => '']],
        );

        if ($result->getMatchedCount() === 0) {
            return null;
        }

        return $result->getModifiedCount() > 0;
    }

    // =========================================================================
    // Settings Operations
    // =========================================================================

    /**
     * Fetch settings for a tenant, optionally filtered to specific keys.
     *
     * @param string   $identifier Tenant identifier
     * @param string[] $keys       Optional list of keys to return; empty = all
     *
     * @return array<string, mixed>
     */
    public function fetchSettings(string $identifier, array $keys = []): array
    {
        $entry = $this->dataStore->selectCollection(self::COLLECTION_NAME)->findOne(
            ['identifier' => $identifier],
            ['projection' => ['settings' => 1]]
        );

        $settings = (array)($entry['settings'] ?? []);

        if (empty($keys)) {
            return $settings;
        }

        $result = [];
        foreach ($keys as $key) {
            $result[$key] = $settings[$key] ?? null;
        }
        return $result;
    }

    /**
     * Merge-update settings for a tenant using atomic $set on sub-fields.
     *
     * @param string               $identifier Tenant identifier
     * @param array<string, mixed> $settings   Key-value pairs to persist
     */
    public function storeSettings(string $identifier, array $settings): bool
    {
        $updates = [];
        foreach ($settings as $key => $value) {
            $updates["settings.{$key}"] = $value;
        }

        $result = $this->dataStore->selectCollection(self::COLLECTION_NAME)->updateOne(
            ['identifier' => $identifier],
            ['$set' => $updates]
        );

        return $result->getMatchedCount() > 0;
    }

    /**
     * Atomically creates or replaces one logical store reference.
     *
     * @param array{provider: string, service: string|int, namespace: string} $reference
     */
    public function storeConfigurationStore(string $identifier, string $name, array $reference): bool
    {
        return $this->storeConfiguration($identifier, "stores.{$name}", $reference);
    }

    /**
     * Atomically removes one logical store reference.
     */
    public function removeConfigurationStore(string $identifier, string $name): ?bool
    {
        return $this->removeConfiguration($identifier, "stores.{$name}");
    }

    public function fetchServiceConfiguration(string $identifier, string $name): ?array
    {
        $this->validateServiceName($name);
        return $this->fetchConfiguration($identifier, "services.{$name}");
    }

    /** Save one service atomically. */
    public function storeServiceConfiguration(string $identifier, string $name, array $configuration): bool
    {
        $this->validateServiceName($name);
        return $this->storeConfiguration($identifier, "services.{$name}", $configuration);
    }

    private function validateServiceName(string $name): void
    {
        if (preg_match('/^[a-z][a-z0-9_]*$/D', $name) !== 1) {
            throw new \InvalidArgumentException('Invalid service name.');
        }
    }

    private function readPath(array $data, string $path): mixed
    {
        $value = $data;
        foreach (explode('.', $path) as $segment) {
            if (!is_array($value) || !array_key_exists($segment, $value)) {
                return null;
            }
            $value = $value[$segment];
        }
        return $value;
    }

}