/*
 * Copyright (C) 2026 oxmc / PawletOS
 * SPDX-License-Identifier: Apache-2.0
 */
#include "handlers.h"

#include <dlfcn.h>

#include <android-base/logging.h>

#include "util.h"

namespace pawlet::hwupdate {
namespace {

constexpr char kHandlerDir[] = "/system_ext/lib64/pawlet/hwh/";

// Handler ids come from the local allowlist; still, only accept a conservative
// character set so the id can never escape kHandlerDir.
bool ValidId(const std::string& id) {
    if (id.empty() || id.size() > 64) return false;
    for (char c : id) {
        bool ok = (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
                  (c >= '0' && c <= '9') || c == '_' || c == '-';
        if (!ok) return false;
    }
    return true;
}

}  // namespace

const pawlet_hwh_api* HandlerRegistry::Get(const std::string& id) {
    if (auto it = cache_.find(id); it != cache_.end()) return it->second;

    if (!ValidId(id)) {
        LOG(ERROR) << "hwupdate: rejecting invalid handler id '" << id << "'";
        return nullptr;
    }

    std::string path = std::string(kHandlerDir) + "libpawlethwh_" + id + ".so";
    void* dl = dlopen(path.c_str(), RTLD_NOW | RTLD_LOCAL);
    if (!dl) {
        LOG(ERROR) << "hwupdate: dlopen(" << path << ") failed: " << dlerror();
        return nullptr;
    }

    auto entry = reinterpret_cast<const pawlet_hwh_api* (*)()>(dlsym(dl, "pawlet_hwh_entry"));
    if (!entry) {
        LOG(ERROR) << "hwupdate: " << path << " missing pawlet_hwh_entry";
        dlclose(dl);
        return nullptr;
    }

    const pawlet_hwh_api* api = entry();
    if (!api || api->abi_version != PAWLET_HWH_ABI || !api->handler_id ||
        !util::IEquals(api->handler_id, id) || !api->detect || !api->get_version ||
        !api->flash) {
        LOG(ERROR) << "hwupdate: " << path << " failed ABI/id validation";
        dlclose(dl);
        return nullptr;
    }

    LOG(INFO) << "hwupdate: loaded handler '" << id << "' (abi " << api->abi_version << ")";
    // Intentionally keep dl open for the daemon's lifetime.
    cache_[id] = api;
    return api;
}

}  // namespace pawlet::hwupdate