<?php
/*
   WEVIA MEMORY BRIDGE · Doctrine 141
   Opus · 23avr 21h35
   
   Middleware léger pour doter tout chatbot interne de mémoire persistante
   Redis DB 5 + Qdrant long-term, via un appel vers wevia-chat-memory.php
   
   Usage:
     require_once __DIR__ . '/wevia-memory-bridge.php';
     $history = wevia_mem_load('claw-code', $user_id); // charge history
     // ... logique métier du chatbot ...
     wevia_mem_save('claw-code', $user_id, $message, $response); // save
   
   - Redis DB 5 key format: chatmem:<chat_id>:<user_id>
   - Scope internal = unlimited (no TTL)
   - Scope public = TTL 24h
   - Fail-safe: si Redis down, continue sans mémoire (pas de crash)
*/

if (!function_exists('wevia_mem_load')) {

function wevia_mem_user_id(): string {
    // Priorité: JWT cookie > session cookie > IP+UA hash > anon
    $uid = $_COOKIE['weval_chat_session'] ?? '';
    if (!$uid) {
        $ip = $_SERVER['REMOTE_ADDR'] ?? '';
        $ua = $_SERVER['HTTP_USER_AGENT'] ?? '';
        $uid = $ip ? 'anon-' . substr(md5($ip . $ua), 0, 12) : 'anon-default';
    }
    return $uid;
}

function wevia_mem_redis(): ?Redis {
    static $r = null;
    if ($r === null) {
        try {
            $r = new Redis();
            $r->connect('127.0.0.1', 6379, 1.5);
            $r->select(5);
        } catch (Throwable $e) {
            $r = false;
        }
    }
    return $r ?: null;
}

function wevia_mem_key(string $chat_id, string $user_id): string {
    return "chatmem:" . preg_replace('/[^a-z0-9_-]/i', '_', $chat_id) . ":" . $user_id;
}

function wevia_mem_load(string $chat_id, ?string $user_id = null, int $max = 20): array {
    $user_id = $user_id ?? wevia_mem_user_id();
    $r = wevia_mem_redis();
    if (!$r) return [];
    try {
        $raw = $r->get(wevia_mem_key($chat_id, $user_id));
        if (!$raw) return [];
        $arr = json_decode($raw, true) ?: [];
        return array_slice($arr, -$max);
    } catch (Throwable $e) {
        return [];
    }
}

function wevia_mem_save(string $chat_id, ?string $user_id, string $message, string $response, string $scope = 'internal'): bool {
    $user_id = $user_id ?? wevia_mem_user_id();
    $r = wevia_mem_redis();
    if (!$r) return false;
    try {
        $k = wevia_mem_key($chat_id, $user_id);
        $raw = $r->get($k);
        $arr = $raw ? (json_decode($raw, true) ?: []) : [];
        $arr[] = ['role' => 'user', 'content' => substr($message, 0, 4000), 'ts' => date('c')];
        $arr[] = ['role' => 'assistant', 'content' => substr($response, 0, 4000), 'ts' => date('c')];
        // Cap à 500 messages
        $arr = array_slice($arr, -500);
        $r->set($k, json_encode($arr));
        // TTL: internal = none (persistent), public = 24h
        if ($scope === 'public') {
            $r->expire($k, 86400);
        }
        return true;
    } catch (Throwable $e) {
        return false;
    }
}

function wevia_mem_context(string $chat_id, ?string $user_id = null, int $max = 10): string {
    // Retourne les N derniers messages comme contexte injecté dans prompt
    $history = wevia_mem_load($chat_id, $user_id, $max);
    if (!$history) return '';
    $out = "=== Conversation history ===\n";
    foreach ($history as $msg) {
        $role = $msg['role'] === 'user' ? 'User' : 'Assistant';
        $content = substr($msg['content'] ?? '', 0, 500);
        $out .= "$role: $content\n";
    }
    return $out;
}

function wevia_mem_stats(string $chat_id, ?string $user_id = null): array {
    $history = wevia_mem_load($chat_id, $user_id, 10000);
    return [
        'messages' => count($history),
        'chat_id' => $chat_id,
        'user_id' => $user_id ?? wevia_mem_user_id(),
        'first_ts' => $history[0]['ts'] ?? null,
        'last_ts' => end($history)['ts'] ?? null
    ];
}

} // end if !function_exists