#include "tactility/time.h"

#include <Tactility/DeprecatedPaths.h>
#include <Tactility/Tactility.h>
#include <Tactility/TactilityConfig.h>
#include <Tactility/Timer.h>

#include <app/event.h>
#include <app/manager.h>
#include <app/manifest.h>

#include <lvgl_window_manager/window_manager.h>

#include <algorithm>
#include <cstring>
#include <format>
#include <utility>

#include <lvgl/fonts.h>
#include <lvgl/lvgl.h>
#include <lvgl/widgets/toolbar.h>

#ifdef ESP_PLATFORM
#include <esp_vfs_fat.h>
#include <esp_heap_caps.h>
#include <Tactility/MountPoints.h>
#endif

namespace tt::app::systeminfo {

constexpr auto* TAG = "SystemInfo";

extern const ::AppManifest manifest;

namespace {

size_t getHeapFree() {
#ifdef ESP_PLATFORM
    return heap_caps_get_free_size(MALLOC_CAP_INTERNAL);
#else
    return 4096 * 1024;
#endif
}

size_t getHeapTotal() {
#ifdef ESP_PLATFORM
    return heap_caps_get_total_size(MALLOC_CAP_INTERNAL);
#else
    return 8192 * 1024;
#endif
}

size_t getSpiFree() {
#ifdef ESP_PLATFORM
    return heap_caps_get_free_size(MALLOC_CAP_SPIRAM);
#else
    return 4096 * 1024;
#endif
}

size_t getSpiTotal() {
#ifdef ESP_PLATFORM
    return heap_caps_get_total_size(MALLOC_CAP_SPIRAM);
#else
    return 8192 * 1024;
#endif
}

enum class StorageUnit {
    Bytes,
    Kilobytes,
    Megabytes,
    Gigabytes
};

StorageUnit getStorageUnit(uint64_t value) {
    using enum StorageUnit;
    if (value / (1024 * 1024 * 1024) > 0) {
        return Gigabytes;
    } else if (value / (1024 * 1024) > 0) {
        return Megabytes;
    } else if (value / 1024 > 0) {
        return Kilobytes;
    } else {
        return Bytes;
    }
}

std::string getStorageUnitString(StorageUnit unit) {
    using enum StorageUnit;
    switch (unit) {
        case Bytes:
            return "bytes";
        case Kilobytes:
            return "kB";
        case Megabytes:
            return "MB";
        case Gigabytes:
            return "GB";
        default:
            std::unreachable();
    }
}

std::string getStorageValue(StorageUnit unit, uint64_t bytes) {
    using enum StorageUnit;
    switch (unit) {
        case Bytes:
            return std::to_string(bytes);
        case Kilobytes:
            return std::to_string(bytes / 1024);
        case Megabytes:
            return std::format("{:.1f}", static_cast<float>(bytes) / 1024.f / 1024.f);
        case Gigabytes:
            return std::format("{:.1f}", static_cast<float>(bytes) / 1024.f / 1024.f / 1024.f);
        default:
            std::unreachable();
    }
}

struct MemoryBarWidgets {
    lv_obj_t* bar = nullptr;
    lv_obj_t* label = nullptr;
};

MemoryBarWidgets createMemoryBar(lv_obj_t* parent, const char* label) {
    auto* container = lv_obj_create(parent);
    lv_obj_set_size(container, LV_PCT(100), LV_SIZE_CONTENT);
    lv_obj_set_style_pad_all(container, 0, LV_STATE_DEFAULT);
    lv_obj_set_style_border_width(container, 0, LV_STATE_DEFAULT);
    lv_obj_set_flex_flow(container, LV_FLEX_FLOW_ROW);
    lv_obj_set_style_bg_opa(container, 0, LV_STATE_DEFAULT);

    auto* left_label = lv_label_create(container);
    lv_label_set_text(left_label, label);
    auto label_width = 6 * lvgl_get_text_font_height(FONT_SIZE_DEFAULT);
    lv_obj_set_width(left_label, label_width);

    auto* bar = lv_bar_create(container);
    lv_obj_set_flex_grow(bar, 1);

    auto* bottom_label = lv_label_create(parent);
    lv_obj_set_width(bottom_label, LV_PCT(100));
    lv_obj_set_style_text_align(bottom_label, LV_TEXT_ALIGN_RIGHT, 0);

    if (lvgl_get_ui_density() == LVGL_UI_DENSITY_COMPACT) {
        lv_obj_set_style_pad_bottom(bottom_label, 2, LV_STATE_DEFAULT);
    } else {
        lv_obj_set_style_pad_bottom(bottom_label, 12, LV_STATE_DEFAULT);
    }

    return {bar, bottom_label};
}

void updateMemoryBar(const MemoryBarWidgets& widgets, uint64_t free, uint64_t total) {
    uint64_t used = total - free;

    // Scale down the uint64_t until it fits int32_t for the lv_bar
    uint64_t free_scaled = free;
    uint64_t total_scaled = total;
    while (total_scaled > static_cast<uint64_t>(INT32_MAX)) {
        free_scaled /= 1024;
        total_scaled /= 1024;
    }

    if (total > 0) {
        lv_bar_set_range(widgets.bar, 0, total_scaled);
    } else {
        lv_bar_set_range(widgets.bar, 0, 1);
    }

    lv_bar_set_value(widgets.bar, (total_scaled - free_scaled), LV_ANIM_OFF);

    const auto unit = getStorageUnit(total);
    const auto unit_label = getStorageUnitString(unit);
    const auto free_converted = getStorageValue(unit, free);
    const auto total_converted = getStorageValue(unit, total);
    lv_label_set_text_fmt(widgets.label, "%s / %s %s free (%llu / %llu bytes)",
        free_converted.c_str(), total_converted.c_str(), unit_label.c_str(),
        (unsigned long long)free, (unsigned long long)total);
}

#if configUSE_TRACE_FACILITY

const char* getTaskState(const TaskStatus_t& task) {
    switch (task.eCurrentState) {
        case eRunning:
            return "running";
        case eReady:
            return "ready";
        case eBlocked:
            return "blocked";
        case eSuspended:
            return "suspended";
        case eDeleted:
            return "deleted";
        case eInvalid:
        default:
            return "invalid";
    }
}

void clearContainer(lv_obj_t* container) {
    lv_obj_clean(container);
}

void addRtosTask(lv_obj_t* parent, const TaskStatus_t& task) {
    auto* label = lv_label_create(parent);
    const char* name = (task.pcTaskName == nullptr || task.pcTaskName[0] == 0) ? "(unnamed)" : task.pcTaskName;
    lv_label_set_text_fmt(label, "%s (%s)", name, getTaskState(task));
}

void updateRtosTasks(lv_obj_t* parent) {
    clearContainer(parent);

    UBaseType_t count = uxTaskGetNumberOfTasks();
    auto* tasks = (TaskStatus_t*)malloc(sizeof(TaskStatus_t) * count);
    if (!tasks) {
        auto* error_label = lv_label_create(parent);
        lv_label_set_text(error_label, "Failed to allocate memory for task list");
        return;
    }
    uint32_t totalRuntime = 0;
    UBaseType_t actual = uxTaskGetSystemState(tasks, count, &totalRuntime);

    for (int i = 0; i < actual; ++i) {
        addRtosTask(parent, tasks[i]);
    }

    free(tasks);
}

#endif

lv_obj_t* createTab(lv_obj_t* tabview, const char* name) {
    auto* tab = lv_tabview_add_tab(tabview, name);
    lv_obj_set_flex_flow(tab, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_style_pad_row(tab, 0, LV_STATE_DEFAULT);
    lv_obj_set_style_border_width(tab, 0, LV_STATE_DEFAULT);
    return tab;
}

struct Context {
    uint32_t appInstanceId;

    std::unique_ptr<Timer> memoryTimer;
    std::unique_ptr<Timer> tasksTimer;

    MemoryBarWidgets internalMemBar;
    MemoryBarWidgets externalMemBar;
    MemoryBarWidgets dataStorageBar;
    MemoryBarWidgets sdcardStorageBar;
    MemoryBarWidgets systemStorageBar;

    lv_obj_t* tasksContainer = nullptr;
    lv_obj_t* psramContainer = nullptr;

    bool hasExternalMem = false;
    bool hasDataStorage = false;
    bool hasSystemStorage = false;
};


void updateMemory(Context* ctx) {
    updateMemoryBar(ctx->internalMemBar, getHeapFree(), getHeapTotal());

    if (ctx->hasExternalMem) {
        updateMemoryBar(ctx->externalMemBar, getSpiFree(), getSpiTotal());
    }
}

void updateStorage(Context* ctx) {
#ifdef ESP_PLATFORM
    uint64_t storage_total = 0;
    uint64_t storage_free = 0;

    if (ctx->hasDataStorage) {
        if (esp_vfs_fat_info(file::MOUNT_POINT_DATA, &storage_total, &storage_free) == ESP_OK) {
            updateMemoryBar(ctx->dataStorageBar, storage_free, storage_total);
        }
    }

    std::string sdcard_path;
    if (findFirstMountedSdCardPath(sdcard_path) && esp_vfs_fat_info(sdcard_path.c_str(), &storage_total, &storage_free) == ESP_OK) {
        updateMemoryBar(ctx->sdcardStorageBar, storage_free, storage_total);
    }

    if (ctx->hasSystemStorage) {
        if (esp_vfs_fat_info(file::MOUNT_POINT_SYSTEM, &storage_total, &storage_free) == ESP_OK) {
            updateMemoryBar(ctx->systemStorageBar, storage_free, storage_total);
        }
    }
#endif
}

void updateTasks(Context* ctx) {
#if configUSE_TRACE_FACILITY
    if (ctx->tasksContainer) {
        updateRtosTasks(ctx->tasksContainer);  // Tasks tab: show state
    }
#endif
}

void onBackPressed(lv_event_t* event) {
    auto* ctx = static_cast<Context*>(lv_event_get_user_data(event));
    // Async, non-blocking - must NOT call app_manager_stop() directly here: that bound-waits
    // (thread_join) for this app's own thread to finish, which needs the LVGL lock
    // (window_manager_remove()) - but this callback runs ON the LVGL task, which would
    // deadlock against itself.
    AppEvent closeEvent { .type = APP_EVENT_CLOSE, .timestamp = 0, .result = {} };
    app_event_emit(ctx->appInstanceId, &closeEvent);
}

void createWidgets(lv_obj_t* parent, void* userData) {
    auto* ctx = static_cast<Context*>(userData);

    lv_obj_set_flex_flow(parent, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_style_pad_row(parent, 0, LV_STATE_DEFAULT);

    auto* toolbar = lvgl_toolbar_create(parent, "System Info");
    // The global toolbar nav callback only knows how to stop old-model apps.
    lvgl_toolbar_set_nav_action(toolbar, LV_SYMBOL_CLOSE, onBackPressed, ctx);

    auto* wrapper = lv_obj_create(parent);
    lv_obj_set_style_border_width(wrapper, 0, LV_STATE_DEFAULT);
    lv_obj_set_flex_flow(wrapper, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_width(wrapper, LV_PCT(100));
    lv_obj_set_flex_grow(wrapper, 1);
    lv_obj_set_style_pad_all(wrapper, 0, LV_STATE_DEFAULT);

    auto* tabview = lv_tabview_create(wrapper);
    lv_tabview_set_tab_bar_position(tabview, LV_DIR_LEFT);
    auto tab_bar_width = 6 * lvgl_get_text_font_height(FONT_SIZE_DEFAULT);
    lv_tabview_set_tab_bar_size(tabview, tab_bar_width);

    // Create tabs
    auto* memory_tab = createTab(tabview, "Memory");
    auto* storage_tab = createTab(tabview, "Storage");
    auto* tasks_tab = createTab(tabview, "Tasks");
    auto* about_tab = createTab(tabview, "About");

    // Memory tab content
    ctx->internalMemBar = createMemoryBar(memory_tab, "Internal");

    ctx->hasExternalMem = getSpiTotal() > 0;
    if (ctx->hasExternalMem) {
        ctx->externalMemBar = createMemoryBar(memory_tab, "External");
    }

#ifdef ESP_PLATFORM
    // Storage tab content
    uint64_t storage_total = 0;
    uint64_t storage_free = 0;

    ctx->hasDataStorage = (esp_vfs_fat_info(file::MOUNT_POINT_DATA, &storage_total, &storage_free) == ESP_OK);
    if (ctx->hasDataStorage) {
        ctx->dataStorageBar = createMemoryBar(storage_tab, file::MOUNT_POINT_DATA);
    }

    std::string sdcard_path;
    if (findFirstMountedSdCardPath(sdcard_path) && esp_vfs_fat_info(sdcard_path.c_str(), &storage_total, &storage_free) == ESP_OK) {
        ctx->sdcardStorageBar = createMemoryBar(storage_tab, sdcard_path.c_str());
    }

    if (config::SHOW_SYSTEM_PARTITION) {
        ctx->hasSystemStorage = (esp_vfs_fat_info(file::MOUNT_POINT_SYSTEM, &storage_total, &storage_free) == ESP_OK);
        if (ctx->hasSystemStorage) {
            ctx->systemStorageBar = createMemoryBar(storage_tab, file::MOUNT_POINT_SYSTEM);
        }
    }
#endif

#if configUSE_TRACE_FACILITY
    // Tasks tab - container for dynamic updates
    ctx->tasksContainer = lv_obj_create(tasks_tab);
    lv_obj_set_size(ctx->tasksContainer, LV_PCT(100), LV_SIZE_CONTENT);
    lv_obj_set_style_pad_all(ctx->tasksContainer, 8, LV_STATE_DEFAULT);
    lv_obj_set_style_border_width(ctx->tasksContainer, 0, LV_STATE_DEFAULT);
    lv_obj_set_flex_flow(ctx->tasksContainer, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_style_bg_opa(ctx->tasksContainer, 0, LV_STATE_DEFAULT);
#endif

    // Build info
    auto* tactility_version = lv_label_create(about_tab);
    lv_label_set_text_fmt(tactility_version, "Tactility v%s", TT_VERSION);
#ifdef ESP_PLATFORM
    auto* esp_idf_version = lv_label_create(about_tab);
    lv_label_set_text_fmt(esp_idf_version, "ESP-IDF v%d.%d.%d", ESP_IDF_VERSION_MAJOR, ESP_IDF_VERSION_MINOR, ESP_IDF_VERSION_PATCH);
#endif

    auto* device_vendor = lv_label_create(about_tab);
    lv_label_set_text_fmt(device_vendor, "Hardware vendor: %s", CONFIG_TT_DEVICE_VENDOR);
    auto* device_device_name = lv_label_create(about_tab);
    lv_label_set_text_fmt(device_device_name, "Hardware model: %s", CONFIG_TT_DEVICE_NAME_SIMPLE);

    // Initial updates
    updateMemory(ctx);
    updateStorage(ctx);  // Storage: one-time update on show (doesn't change frequently)
    updateTasks(ctx);
}

int32_t appMain(uint32_t appInstanceId, int argc, char* argv[]) {
    Context ctx {};
    ctx.appInstanceId = appInstanceId;

    // Run for this app instance's whole lifetime (mirrors GpsSettings) - both timers keep the
    // displayed values fresh regardless of whether the app is currently topmost.
    ctx.memoryTimer = std::make_unique<Timer>(Timer::Type::Periodic, millis_to_ticks(10000), [&ctx] {
        lvgl_lock();
        updateMemory(&ctx);
        lvgl_unlock();
    });

    ctx.tasksTimer = std::make_unique<Timer>(Timer::Type::Periodic, millis_to_ticks(15000), [&ctx] {
        lvgl_lock();
        updateTasks(&ctx);
        lvgl_unlock();
    });

    AppEventSubscription sub {};
    sub.app_instance_id = appInstanceId;
    app_event_subscribe(&sub);

    WindowId window = window_manager_create(appInstanceId, createWidgets, &ctx);
    ctx.memoryTimer->start();   // Memory: every 10s
    ctx.tasksTimer->start();    // Tasks/CPU: every 15s

    bool shouldClose = false;
    while (!shouldClose) {
        AppEvent event {};
        if (app_event_await(&sub, &event, portMAX_DELAY) != ERROR_NONE) {
            break;
        }
        switch (event.type) {
            case APP_EVENT_CLOSE:
                app_manager_finish(appInstanceId);
                shouldClose = true;
                break;
            default:
                break;
        }
    }

    ctx.memoryTimer->stop();
    ctx.tasksTimer->stop();
    window_manager_remove(window);
    app_event_unsubscribe(&sub);

    return 0;
}

} // namespace

extern const ::AppManifest manifest = {
    .id = "tactility.systeminfo",
    .name = "System Info",
    .category = APP_CATEGORY_SYSTEM,
    .location = { APP_LOCATION_MEMORY, reinterpret_cast<void*>(appMain) }
};

} // namespace