<?php

namespace KTXC\Stores;

use KTXC\Db\DataStore;
use KTXC\Db\Collection;

class UserStore
{

    public function __construct(protected DataStore $store)
    { }

    public function fetchByIdentity(string $tenant, string $identity): array | null
    {

        $pipeline = [
            [
                '$match' => [
                    'tid' => $tenant,
                    'identity' => $identity
                ]
            ],
            [
                '$lookup' => [
                    'from' => 'user_roles',
                    'localField' => 'roles',         // Array field in `users`
                    'foreignField' => 'rid',         // Scalar field in `user_roles`
                    'as' => 'role_details'
                ]
            ],
            // Add flattened, deduplicated permissions while preserving all original user fields
            [
                '$addFields' => [
                    'permissions' => [
                        '$reduce' => [
                            'input' => [
                                '$map' => [
                                    'input' => '$role_details',
                                    'as' => 'r',
                                    'in' => [ '$ifNull' => ['$$r.permissions', []] ]
                                ]
                            ],
                            'initialValue' => [],
                            'in' => [ '$setUnion' => ['$$value', '$$this'] ]
                        ]
                    ]
                ]
            ],
            // Optionally remove expanded role documents from output
            [ '$unset' => 'role_details' ]
        ];

        $entry = $this->store->selectCollection('users')->aggregate($pipeline)->toArray()[0] ?? null;
        if (!$entry) { return null; }
        return (array)$entry;
    }

    public function fetchByIdentifier(string $tenant, string $identifier): array | null
    {
        $entry = $this->store->selectCollection('users')->findOne(['tid' => $tenant, 'uid' => $identifier]);
        if (!$entry) { return null; }
        return (array)$entry;
    }

    /**
     * Fetch user settings from the embedded settings field in the user document
     * 
     * @param string $tenant Tenant identifier
     * @param string $identifier User identifier
     * @param array $settings Optional array of specific setting keys to retrieve
     * @return array|null Settings array or null if user not found
     */
    public function fetchSettings(string $tenant, string $identifier, array $keys = []): array | null
    {
        $entry = $this->store->selectCollection('users')->findOne(
            ['tid' => $tenant, 'uid' => $identifier],
            ['projection' => ['settings' => 1]]
        );
        
        if (!$entry) { 
            return null; 
        }
        
        $settings = (array)($entry['settings'] ?? []);
        
        if (empty($keys)) {
            return $settings;
        }
        
        // Filter to only requested keys
        return array_filter(
            $settings,
            fn($key) => in_array($key, $keys),
            ARRAY_FILTER_USE_KEY
        );
    }

    /**
     * Store/update user settings in the embedded settings field
     * 
     * @param string $tenant Tenant identifier
     * @param string $identifier User identifier
     * @param array $settings Key-value pairs to set/update
     * @return bool Whether the update was acknowledged
     */
    public function storeSettings(string $tenant, string $identifier, array $settings): bool
    {
        // Build dot-notation update for each setting key
        $setFields = [];
        foreach ($settings as $key => $value) {
            $setFields["settings.$key"] = $value;
        }
        
        $result = $this->store->selectCollection('users')->updateOne(
            ['tid' => $tenant, 'uid' => $identifier],
            ['$set' => $setFields]
        );
        
        return $result->isAcknowledged();
    }

    /**
     * Remove specific settings from a user
     * 
     * @param string $tenant Tenant identifier
     * @param string $identifier User identifier
     * @param array $keys Setting keys to remove
     * @return bool Whether the update was acknowledged
     */
    public function removeSettings(string $tenant, string $identifier, array $keys): bool
    {
        $unsetFields = [];
        foreach ($keys as $key) {
            $unsetFields["settings.$key"] = "";
        }
        
        $result = $this->store->selectCollection('users')->updateOne(
            ['tid' => $tenant, 'uid' => $identifier],
            ['$unset' => $unsetFields]
        );
        
        return $result->isAcknowledged();
    }

    /**
     * Create a new user
     * 
     * @param array $data User data including tid, uid, identity, label, provider, etc.
     * @return string|null The created user's UID or null on failure
     */
    public function create(array $data): ?string
    {
        // Ensure required fields
        if (empty($data['tid']) || empty($data['uid']) || empty($data['identity'])) {
            return null;
        }

        // Set defaults
        $data['enabled'] = $data['enabled'] ?? true;
        $data['roles'] = $data['roles'] ?? [];
        $data['profile'] = $data['profile'] ?? [];
        $data['settings'] = $data['settings'] ?? [];
        $data['initial_login'] = $data['initial_login'] ?? time();
        $data['recent_login'] = $data['recent_login'] ?? time();

        $result = $this->store->selectCollection('users')->insertOne($data);
        
        if ($result->isAcknowledged()) {
            return $data['uid'];
        }
        
        return null;
    }

    /**
     * Update user profile fields
     * 
     * @param string $tenant Tenant identifier
     * @param string $identifier User identifier
     * @param array $profile Profile data to update
     * @return bool Whether the update was acknowledged
     */
    public function updateProfile(string $tenant, string $identifier, array $profile): bool
    {
        $setFields = [];
        foreach ($profile as $key => $value) {
            $setFields["profile.$key"] = $value;
        }
        
        $result = $this->store->selectCollection('users')->updateOne(
            ['tid' => $tenant, 'uid' => $identifier],
            ['$set' => $setFields]
        );
        
        return $result->isAcknowledged();
    }

    /**
     * Update user's last login timestamp
     * 
     * @param string $tenant Tenant identifier
     * @param string $identifier User identifier
     * @return bool Whether the update was acknowledged
     */
    public function updateLastLogin(string $tenant, string $identifier): bool
    {
        $result = $this->store->selectCollection('users')->updateOne(
            ['tid' => $tenant, 'uid' => $identifier],
            ['$set' => ['recent_login' => time()]]
        );
        
        return $result->isAcknowledged();
    }

    /**
     * Update user's label
     * 
     * @param string $tenant Tenant identifier
     * @param string $identifier User identifier
     * @param string $label New label
     * @return bool Whether the update was acknowledged
     */
    public function updateLabel(string $tenant, string $identifier, string $label): bool
    {
        $result = $this->store->selectCollection('users')->updateOne(
            ['tid' => $tenant, 'uid' => $identifier],
            ['$set' => ['label' => $label]]
        );
        
        return $result->isAcknowledged();
    }

    /**
     * Find user by external subject (for external identity providers)
     * 
     * @param string $tenant Tenant identifier
     * @param string $provider Provider identifier
     * @param string $externalSubject External subject identifier
     * @return array|null User data or null if not found
     */
    public function fetchByExternalSubject(string $tenant, string $provider, string $externalSubject): ?array
    {
        $entry = $this->store->selectCollection('users')->findOne([
            'tid' => $tenant,
            'provider' => $provider,
            'external_subject' => $externalSubject
        ]);
        
        if (!$entry) { 
            return null; 
        }
        
        return (array)$entry;
    }

}