<?php
/**
 * intent-opus4-file_dump.php
 * AMBRE session · chunked file reader · offset + length
 * Invocation: /api/opus-arch-generic.php?tool=file_dump&path=X&offset=0&length=10000
 */
header("Content-Type: application/json");

$target = $_GET["path"] ?? "";
$offset = (int)($_GET["offset"] ?? 0);
$length = min((int)($_GET["length"] ?? 8000), 50000);

$real = realpath($target);
$allowed = ["/var/www/html/", "/opt/wevads/", "/opt/weval-l99/"];
$ok = false;
foreach ($allowed as $root) {
    if ($real && strpos($real, $root) === 0) { $ok = true; break; }
}
if (!$ok || !file_exists($real)) {
    echo json_encode(["ok"=>false, "error"=>"path denied or not found", "path"=>$target]);
    exit;
}

$fh = fopen($real, "r");
fseek($fh, $offset);
$chunk = fread($fh, $length);
fclose($fh);

echo json_encode([
    "ok"        => true,
    "path"      => $real,
    "offset"    => $offset,
    "length"    => strlen($chunk),
    "total"     => filesize($real),
    "eof"       => ($offset + strlen($chunk)) >= filesize($real),
    "content"   => $chunk,
    "source"    => "intent-opus4-file_dump.php · ambre · honest chunked read",
]);