<?php
/**
 * Batch 10 — Memory layer (Pro-equivalent, net-new).
 *
 * A small option/transient-backed key-value store so MCP tools can persist context
 * across calls. Values are stored as strings (callers JSON-encode structured data).
 * GPL-2.0-or-later. See NOTICE.md.
 *
 * Registered via the asktam_mcp_register_tools hook (glob auto-loader).
 */

namespace AskTamMCP\Extensions;

defined('ABSPATH') || exit;

class Batch10 {

    private const PREFIX = 'ampmem_';

    public static function register($registry): void {
        $def = function (string $name, string $desc, array $props, array $required, string $scope, string $method) {
            $schema = ['type' => 'object', 'properties' => $props];
            if ($required) $schema['required'] = $required;
            return ['name' => $name, 'description' => $desc, 'scope' => $scope,
                    'handler' => 'AskTamMCP\\Extensions\\Batch10::' . $method, 'inputSchema' => $schema];
        };

        $registry->register($def('memory_set', 'Store a string value under a key. Optional ttl_minutes makes it expire (otherwise it persists). For structured data, pass JSON text as value.',
            ['key' => ['type' => 'string'], 'value' => ['type' => 'string'], 'ttl_minutes' => ['type' => 'integer', 'default' => 0]],
            ['key', 'value'], 'write', 'setVal'));

        $registry->register($def('memory_get', 'Retrieve a stored value by key.',
            ['key' => ['type' => 'string']], ['key'], 'read', 'getVal'));

        $registry->register($def('memory_list', 'List stored memory keys, optionally filtered by prefix.',
            ['prefix' => ['type' => 'string']], [], 'read', 'listKeys'));

        $registry->register($def('memory_delete', 'Delete a stored value by key.',
            ['key' => ['type' => 'string']], ['key'], 'write', 'deleteVal'));

        $registry->register($def('memory_append', 'Append an item to a newline-delimited list stored at key (created if absent).',
            ['key' => ['type' => 'string'], 'item' => ['type' => 'string']], ['key', 'item'], 'write', 'appendVal'));
    }

    private static function key(string $raw): string {
        $k = preg_replace('/[^a-z0-9_\-]/i', '', $raw);
        if ($k === '') throw new \RuntimeException('Invalid key.');
        return self::PREFIX . $k;
    }

    public static function setVal(array $args): array {
        $opt = self::key((string) ($args['key'] ?? ''));
        $val = (string) ($args['value'] ?? '');
        $ttl = (int) ($args['ttl_minutes'] ?? 0);
        if ($ttl > 0) { set_transient($opt, $val, $ttl * MINUTE_IN_SECONDS); delete_option($opt); }
        else { update_option($opt, $val, false); delete_transient($opt); }
        return ['key' => $args['key'], 'stored' => true, 'expires' => $ttl > 0 ? $ttl . 'm' : 'never'];
    }

    public static function getVal(array $args): array {
        $opt = self::key((string) ($args['key'] ?? ''));
        $v = get_option($opt, null);
        $source = 'option';
        if ($v === null) {
            $t = get_transient($opt);
            if ($t === false) { $v = null; $source = null; } else { $v = $t; $source = 'transient'; }
        }
        return ['key' => $args['key'], 'value' => $v, 'exists' => $v !== null, 'source' => $source];
    }

    public static function listKeys(array $args): array {
        global $wpdb;
        $prefix = isset($args['prefix']) ? (string) $args['prefix'] : '';
        $like1 = self::PREFIX . '%';
        $like2 = '_transient_' . self::PREFIX . '%';
        $names = $wpdb->get_col($wpdb->prepare(
            "SELECT option_name FROM {$wpdb->options} WHERE option_name LIKE %s OR option_name LIKE %s",
            $like1, $like2
        ));
        $keys = [];
        foreach ((array) $names as $n) {
            $k = str_replace(['_transient_timeout_', '_transient_', self::PREFIX], '', $n);
            if ($k === '' || strpos($n, '_transient_timeout_') === 0) continue;
            if ($prefix !== '' && strpos($k, $prefix) !== 0) continue;
            $keys[$k] = true;
        }
        $out = array_keys($keys);
        return ['count' => count($out), 'keys' => $out];
    }

    public static function deleteVal(array $args): array {
        $opt = self::key((string) ($args['key'] ?? ''));
        $a = delete_option($opt);
        $b = delete_transient($opt);
        return ['key' => $args['key'], 'deleted' => ($a || $b)];
    }

    public static function appendVal(array $args): array {
        $opt = self::key((string) ($args['key'] ?? ''));
        $item = (string) ($args['item'] ?? '');
        $cur = get_option($opt, '');
        if (!is_string($cur)) $cur = '';
        $list = $cur === '' ? [] : explode("\n", $cur);
        $list[] = $item;
        update_option($opt, implode("\n", $list), false);
        return ['key' => $args['key'], 'count' => count($list)];
    }
}