<?php
/**
 * ambre-session-chat.php v3 · onboarding + empathy + identity + LLM semaphore (6σ)
 * POST {message, session_id}
 * - Semaphore-protected LLM call (max 5 concurrent)
 * - Automatic identity extraction
 * - Memory persistence
 */
require_once __DIR__ . "/ambre-session-memory.php";
require_once __DIR__ . "/ambre-llm-semaphore.php";

header("Content-Type: application/json; charset=utf-8");

$raw = file_get_contents("php://input");
$in = json_decode($raw, true) ?: $_POST;
$msg = trim($in["message"] ?? "");
$sid = trim($in["session_id"] ?? "");

if (!$msg) { echo json_encode(["error"=>"message required"]); exit; }
if (!$sid) $sid = "anon-" . substr(md5(($_SERVER["REMOTE_ADDR"] ?? "x") . time()), 0, 10);

$history = AmbreSessionMemory::context_messages($sid, 12);
$turns_before = count($history);

$identity = null;
$history_full = AmbreSessionMemory::load($sid);
foreach ($history_full as $m) {
    if ($m["role"] === "meta" && strpos($m["content"], "identity:") === 0) {
        $identity = trim(substr($m["content"], 9));
        break;
    }
}

$extracted_name = null;
$extracted_org = null;
if (preg_match('/(?:je\s+m[\'\s]?appelle|mon\s+nom\s+est|je\s+suis|c[\'\s]?est\s+moi|i[\'\s]?m|my\s+name\s+is)\s+([A-ZÀ-Üa-zà-ü][A-ZÀ-Üa-zà-ü\-\s]{1,40}?)(?:\s+(?:de|from|at|chez|pour|travaille|,|\.|!|$))/iu', $msg, $m)) {
    $extracted_name = trim($m[1]);
}
if (preg_match('/(?:de|from|chez|at|travaille\s+(?:chez|pour|à))\s+([A-ZÀ-Üa-zà-ü][A-ZÀ-Üa-zà-ü0-9\-\s]{2,40}?)(?:\s*[\.,!]|\s+et|\s*$)/iu', $msg, $m)) {
    $extracted_org = trim($m[1]);
}

if (($extracted_name || $extracted_org) && !$identity) {
    $id_parts = [];
    if ($extracted_name) $id_parts[] = "nom=$extracted_name";
    if ($extracted_org) $id_parts[] = "org=$extracted_org";
    $identity = implode(" · ", $id_parts);
    AmbreSessionMemory::append($sid, "meta", "identity: $identity");
}

if ($turns_before === 0 && !$identity) {
    if ($extracted_name || $extracted_org) {
        $greeting_sys = "L'utilisateur vient de se présenter. Salue-le chaleureusement en utilisant son nom si connu et son entreprise si connue. Demande-lui comment tu peux l'aider. 2-3 phrases max. Reste en français.";
    } else {
        $greeting_sys = "Premier échange. Réponds brièvement à sa question, PUIS demande avec élégance son prénom et son entreprise. Style chaleureux, 3-4 phrases.";
    }
    $messages = [["role"=>"system","content"=>"Tu es WEVIA de WEVAL Consulting. $greeting_sys"]];
    $messages[] = ["role"=>"user","content"=>$msg];
} else {
    $sys_parts = [
        "Tu es WEVIA, l'IA de WEVAL Consulting.",
        "Tu mémorises les échanges et t'adaptes au ton et contexte.",
    ];
    if ($identity) {
        $sys_parts[] = "Identité: $identity. Utilise le nom naturellement.";
    }
    $sys_parts[] = "Réponds en français, concis, empathique si émotion détectée.";
    $sys_parts[] = "Si retour sur sujet antérieur, reconnais. Si changement, adapte-toi.";
    
    $messages = [["role"=>"system","content"=>implode(" ", $sys_parts)]];
    foreach ($history as $h) {
        if ($h["role"] !== "meta") $messages[] = $h;
    }
    $messages[] = ["role"=>"user","content"=>$msg];
}

// === LLM call WITH SEMAPHORE (6σ throttle) ===
$t0 = microtime(true);
$wait_ms_before = 0;
$sem_id = AmbreLLMSemaphore::acquire();
$wait_ms_before = round((microtime(true)-$t0)*1000);

if (!$sem_id) {
    // Queue full after 20s wait - fail gracefully
    echo json_encode([
        "response" => "Le service est saturé, réessayez dans quelques secondes.",
        "provider" => "ambre-session-v3",
        "intent" => "semaphore_timeout",
        "session_id" => $sid,
        "wait_ms" => $wait_ms_before,
    ], JSON_UNESCAPED_UNICODE);
    exit;
}

try {
    $llm_start = microtime(true);
    $raw_llm = @file_get_contents("http://127.0.0.1:4000/v1/chat/completions", false, stream_context_create([
        "http" => [
            "method"=>"POST",
            "header"=>"Content-Type: application/json\r\n",
            "content"=>json_encode(["model"=>"fast","messages"=>$messages,"max_tokens"=>1200,"temperature"=>0.5]),
            "timeout"=>30,
        ],
    ]));
    $llm_elapsed = round((microtime(true)-$llm_start)*1000);
} finally {
    AmbreLLMSemaphore::release($sem_id);
}

$d = @json_decode($raw_llm, true);
$reply = $d["choices"][0]["message"]["content"] ?? "";
if (!$reply) $reply = "Désolé, je n'ai pas pu traiter la demande. Peux-tu reformuler ?";

AmbreSessionMemory::append($sid, "user", $msg);
AmbreSessionMemory::append($sid, "assistant", $reply);

$summary = AmbreSessionMemory::summary($sid);

echo json_encode([
    "response" => $reply,
    "provider" => "ambre-session-v3",
    "intent" => $turns_before === 0 ? "onboarding" : "contextual_reply",
    "session_id" => $sid,
    "turns_in_memory" => $summary["turns"],
    "history_used" => count($history),
    "identity" => $identity,
    "wait_ms" => $wait_ms_before,
    "llm_ms" => $llm_elapsed ?? 0,
    "elapsed_ms" => round((microtime(true)-$t0)*1000),
], JSON_UNESCAPED_UNICODE);