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

#include <algorithm>
#include <filesystem>

#include <android-base/logging.h>

#include "catalog.h"
#include "detect.h"
#include "http.h"
#include "manifest.h"
#include "pawlet/hwh_abi.h"
#include "util.h"

namespace pawlet::hwupdate {
namespace {

namespace fs = std::filesystem;

bool Contains(const std::vector<std::string>& v, const std::string& s) {
    return std::find(v.begin(), v.end(), s) != v.end();
}

void ProgressCb(int percent, void* user) {
    const char* id = static_cast<const char*>(user);
    LOG(INFO) << "hwupdate: flashing " << (id ? id : "?") << " " << percent << "%";
}

}  // namespace

Engine::Engine(EngineConfig cfg) : cfg_(std::move(cfg)), state_(cfg_.stateDir + "/state.json") {}

Engine::~Engine() { Stop(); }

void Engine::Start() {
    std::error_code ec;
    fs::create_directories(cfg_.stateDir, ec);
    fs::create_directories(cfg_.stateDir + "/downloads", ec);
    worker_ = std::thread([this] { WorkerLoop(); });
    CheckNow();  // initial cycle at boot
}

void Engine::Stop() {
    {
        std::lock_guard<std::mutex> lk(reqMu_);
        if (stop_) return;
        stop_ = true;
        reqCv_.notify_all();
    }
    if (worker_.joinable()) worker_.join();
}

void Engine::CheckNow() {
    std::lock_guard<std::mutex> lk(reqMu_);
    requested_ = true;
    reqCv_.notify_all();
}

void Engine::WorkerLoop() {
    for (;;) {
        {
            std::unique_lock<std::mutex> lk(reqMu_);
            reqCv_.wait(lk, [this] { return requested_ || stop_; });
            if (stop_) return;
            requested_ = false;
        }
        busy_.store(true);
        int rc = RunCycle();
        lastResult_.store(rc);
        busy_.store(false);
    }
}

int Engine::RunCycle() {
    auto manifest = LoadManifest(cfg_.manifestPath);
    if (!manifest) return -1;

    state_.Load();
    std::vector<DetectedComponent> detected = Detect(*manifest);

    std::vector<ComponentStatus> comps;
    std::vector<PendingUpdate> pend;

    for (auto& dc : detected) {
        const ManifestProduct* prod = dc.product;
        const ManifestComponent* comp = dc.comp;

        ComponentStatus cs;
        cs.componentId = comp->id;
        cs.productId = prod->id;
        cs.componentClass = comp->cls;
        cs.role = comp->role;
        cs.transport = dc.transport;
        cs.present = dc.present;
        cs.hardwareRevision = dc.hardwareRev;
        cs.support = comp->support;

        if (!dc.present) {
            comps.push_back(std::move(cs));
            continue;
        }

        // Resolve a usable handler + read the installed version.
        const pawlet_hwh_api* handler = nullptr;
        for (const auto& hid : comp->installerHandlers) {
            handler = handlers_.Get(hid);
            if (handler) break;
        }

        pawlet_hw_ctx ctx{};
        ctx.component_id = comp->id.c_str();
        ctx.transport = dc.transport.c_str();
        ctx.usb_vendor_id = dc.usbVendorId.c_str();
        ctx.usb_product_id = dc.usbProductId.c_str();
        ctx.dev_path = dc.devPath.c_str();
        ctx.hardware_rev = dc.hardwareRev.c_str();

        std::string installed = state_.InstalledVersion(comp->id);
        if (handler) {
            char ver[128] = {0};
            if (handler->get_version(&ctx, ver, sizeof(ver)) == PAWLET_HWH_OK && ver[0]) {
                installed = ver;
            }
        }
        cs.installedVersion = installed;

        // Ask the server for the newest compatible update.
        CheckRequest req;
        req.device = manifest->device;
        req.pawletVersion = manifest->buildVersion;
        req.hardwareId = prod->id;
        req.componentId = comp->id;
        req.hardwareRevision = dc.hardwareRev;
        req.currentVersion = installed;

        auto update = CheckUpdate(cfg_.serverBaseUrl, req);

        PendingUpdate pu;
        pu.componentId = comp->id;
        if (update && update->version != installed) {
            pu.available = true;
            pu.version = update->version;
            pu.sizeBytes = update->sizeBytes;
            pu.changelogUrl = update->changelogUrl;

            // Trust boundary: the server-named handler MUST be allowlisted for
            // this component in the immutable manifest.
            if (!Contains(comp->installerHandlers, update->installerHandler)) {
                LOG(ERROR) << "hwupdate: refusing non-allowlisted handler '"
                           << update->installerHandler << "' for " << comp->id;
            } else if (cfg_.autoApply) {
                if (state_.RetryCount(comp->id) >= cfg_.maxRetries) {
                    LOG(WARNING) << "hwupdate: " << comp->id << " exceeded retries; skipping";
                } else {
                    const pawlet_hwh_api* flashHandler = handlers_.Get(update->installerHandler);
                    std::string dl = cfg_.stateDir + "/downloads/" + update->id + "-" +
                                     update->filename;
                    bool ok = flashHandler && http::Download(update->url, dl);
                    if (ok) {
                        std::string sum = util::Sha256File(dl);
                        if (!util::IEquals(sum, update->checksumSha256)) {
                            LOG(ERROR) << "hwupdate: checksum mismatch for " << comp->id;
                            ok = false;
                        }
                    }
                    if (ok) {
                        int r = flashHandler->flash(&ctx, dl.c_str(), ProgressCb,
                                                    const_cast<char*>(comp->id.c_str()));
                        if (r == PAWLET_HWH_OK) {
                            LOG(INFO) << "hwupdate: flashed " << comp->id << " -> "
                                      << update->version;
                            state_.SetInstalledVersion(comp->id, update->version);
                            state_.SetRetryCount(comp->id, 0);
                            cs.installedVersion = update->version;
                            pu.available = false;  // applied
                        } else {
                            LOG(ERROR) << "hwupdate: flash failed rc=" << r << " for " << comp->id;
                            state_.SetRetryCount(comp->id, state_.RetryCount(comp->id) + 1);
                            ok = false;
                        }
                    } else {
                        state_.SetRetryCount(comp->id, state_.RetryCount(comp->id) + 1);
                    }
                    std::error_code ec;
                    fs::remove(dl, ec);
                }
            }
        }

        if (pu.available) pend.push_back(std::move(pu));
        comps.push_back(std::move(cs));
    }

    state_.Save();

    {
        std::lock_guard<std::mutex> lk(snapMu_);
        components_ = std::move(comps);
        pending_ = std::move(pend);
    }
    return 0;
}

std::vector<ComponentStatus> Engine::Components() const {
    std::lock_guard<std::mutex> lk(snapMu_);
    return components_;
}

std::vector<PendingUpdate> Engine::Pending() const {
    std::lock_guard<std::mutex> lk(snapMu_);
    return pending_;
}

}  // namespace pawlet::hwupdate