<?php
header("Content-Type: application/json");
header("Access-Control-Allow-Origin: *");
if ($_SERVER["REQUEST_METHOD"]==="OPTIONS"){http_response_code(200);exit;}
require_once "/opt/wevads/vault/credentials.php";
$db = pg_connect("host=127.0.0.1 dbname=adx_system user=admin password=admin123");
$action = $_GET["action"] ?? $_POST["action"] ?? "";
$session = $_GET["session"] ?? $_POST["session"] ?? "";
$input = json_decode(file_get_contents("php://input"), true) ?: [];

switch($action) {
    case "save":
        $role = $input["role"] ?? "user";
        $content = $input["content"] ?? "";
        $provider = $input["provider"] ?? "";
        $tokens = (int)($input["tokens"] ?? 0);
        $sid = $input["session"] ?? $session;
        if (!$sid || !$content) { echo json_encode(["error"=>"session+content required"]); exit; }
        pg_query_params($db, "INSERT INTO wevia_conversations(session_id,role,content,provider,tokens) VALUES($1,$2,$3,$4,$5)",
            [$sid, $role, mb_substr($content,0,5000), $provider, $tokens]);
        echo json_encode(["ok"=>true,"session"=>$sid]);
        break;
    case "history":
        if (!$session) { echo json_encode(["error"=>"session required"]); exit; }
        $limit = min((int)($_GET["limit"] ?? 20), 50);
        $r = pg_query_params($db, "SELECT role,content,provider,tokens,created_at FROM wevia_conversations WHERE session_id=$1 ORDER BY created_at DESC LIMIT $2", [$session, $limit]);
        $msgs = [];
        while($row = pg_fetch_assoc($r)) $msgs[] = $row;
        echo json_encode(["session"=>$session,"messages"=>array_reverse($msgs),"count"=>count($msgs)]);
        break;
    case "sessions":
        $r = pg_query($db, "SELECT session_id, count(*) as msgs, max(created_at) as last_at FROM wevia_conversations GROUP BY session_id ORDER BY last_at DESC LIMIT 20");
        $sessions = [];
        while($row = pg_fetch_assoc($r)) $sessions[] = $row;
        echo json_encode(["sessions"=>$sessions]);
        break;
    case "compact":
        // Context compaction: summarize old messages
        if (!$session) { echo json_encode(["error"=>"session required"]); exit; }
        $r = pg_query_params($db, "SELECT count(*) as c FROM wevia_conversations WHERE session_id=$1", [$session]);
        $count = (int)pg_fetch_assoc($r)["c"];
        if ($count > 15) {
            // Keep last 5, summarize older ones
            $old = pg_query_params($db, "SELECT content FROM wevia_conversations WHERE session_id=$1 ORDER BY created_at ASC LIMIT $2",
                [$session, $count - 5]);
            $summary = "CONTEXT COMPACT: ";
            while($row = pg_fetch_assoc($old)) $summary .= mb_substr($row["content"],0,100) . " | ";
            pg_query_params($db, "DELETE FROM wevia_conversations WHERE session_id=$1 AND ctid NOT IN (SELECT ctid FROM wevia_conversations WHERE session_id=$1 ORDER BY created_at DESC LIMIT 5)", [$session, $session]);
            pg_query_params($db, "INSERT INTO wevia_conversations(session_id,role,content,provider) VALUES($1,'system',$2,'compaction')", [$session, mb_substr($summary,0,3000)]);
            echo json_encode(["ok"=>true,"compacted"=>$count-5,"remaining"=>6]);
        } else {
            echo json_encode(["ok"=>true,"no_compaction"=>true,"count"=>$count]);
        }
        break;
    case "stats":
        $r = pg_query($db, "SELECT count(*) as total, count(DISTINCT session_id) as sessions, max(created_at) as last FROM wevia_conversations");
        echo json_encode(pg_fetch_assoc($r));
        break;
    default:
        echo json_encode(["actions"=>["save","history","sessions","compact","stats"],"version"=>"1.0"]);
}
pg_close($db);