#include "ActionRegistry.hpp"

#include "GUI_App.hpp"

#include <libslic3r/AppConfig.hpp>

#include <wx/thread.h>

#include <algorithm>
#include <cmath>
#include <ctime>

namespace Slic3r { namespace GUI {

namespace {

constexpr const char* kConfigSection = "speed_dial";

nlohmann::json parse_config_json(const std::string& value, nlohmann::json fallback)
{
    nlohmann::json parsed = nlohmann::json::parse(value, nullptr, false);
    return parsed.is_discarded() ? std::move(fallback) : parsed;
}

nlohmann::json read_section(const char* key, nlohmann::json fallback)
{
    return parse_config_json(wxGetApp().app_config->get(kConfigSection, key), std::move(fallback));
}

void write_section(const char* key, const nlohmann::json& j)
{
    wxGetApp().app_config->set(kConfigSection, key, j.dump());
}

std::vector<std::string> read_string_array(const char* key)
{
    auto j = read_section(key, nlohmann::json::array());
    std::vector<std::string> v;
    for (auto& e : j)
        if (e.is_string())
            v.push_back(e.get<std::string>());
    return v;
}

// frecency = frequency + recency; score halves every 30 idle days.
double frecency_score(int count, long long last, long long now)
{
    if (count <= 0)
        return 0.0;
    constexpr double HALF_LIFE_DAYS = 30.0;
    double age = std::max(0.0, double(now - last) / 86400.0);
    return count * std::pow(2.0, -age / HALF_LIFE_DAYS);
}

} // namespace

void ActionRegistry::init()
{
    assert(wxThread::IsMain());
    for (auto& source : m_sources)
        source->start(*this);
}

void ActionRegistry::add_source(std::unique_ptr<IActionSource> source)
{
    assert(wxThread::IsMain());
    if (source)
        m_sources.push_back(std::move(source));
}

void ActionRegistry::upsert(std::unique_ptr<AppAction> action)
{
    assert(wxThread::IsMain());
    if (!action)
        return;

    seed_state(*action);
    std::string id = action->id();
    std::shared_ptr<AppAction> stored = std::move(action);
    m_actions.insert_or_assign(std::move(id), std::move(stored));
}

void ActionRegistry::remove(const std::string& id)
{
    assert(wxThread::IsMain());
    m_actions.erase(id);
}

void ActionRegistry::seed_state(AppAction& a) const
{
    auto favs = read_string_array("favourite_actions");
    a.favourite = std::find(favs.begin(), favs.end(), a.id()) != favs.end();

    nlohmann::json stats = read_section("stats", nlohmann::json::object());
    auto it = stats.find(a.id());
    if (it != stats.end() && it->is_object()) {
        a.count = it->value("count", 0);
        a.last  = it->value("last", 0LL);
    } else {
        a.count = 0;
        a.last  = 0;
    }
}

// ---- read surface -----------------------------------------------------------

const AppAction* ActionRegistry::by_id(const std::string& id) const
{
    assert(wxThread::IsMain());
    auto it = m_actions.find(id);
    return it == m_actions.end() ? nullptr : it->second.get();
}

AppAction* ActionRegistry::find(const std::string& id)
{
    return const_cast<AppAction*>(by_id(id));
}

// ---- dispatch + write-through ----------------------------------------------

AppActionRunResult ActionRegistry::run(const std::string& id)
{
    assert(wxThread::IsMain());
    auto it = m_actions.find(id);
    if (it == m_actions.end())
        return {}; // default Info, empty message
    // why: hold a shared_ptr keep-alive, never a bare map entry. A runner may pump a
    // nested event loop; a queued source refresh can erase the entry while the
    // keep-alive preserves the action until run returns.
    std::shared_ptr<AppAction> keep = it->second;
    AppActionRunResult o = keep->run();
    if (o.level == AppActionRunResult::Level::Busy)
        return o;

    // Bump stats (write-through). Re-read to avoid clobbering a concurrent field.
    nlohmann::json stats = read_section("stats", nlohmann::json::object());
    if (!stats.is_object())  // corrupt (valid-JSON, non-object) value degrades to empty
        stats = nlohmann::json::object();
    nlohmann::json& e = stats[id];
    if (!e.is_object())
        e = nlohmann::json::object();
    e["count"] = e.value("count", 0) + 1;
    e["last"]  = (long long) std::time(nullptr);
    write_section("stats", stats);
    if (AppAction* live = find(id)) { live->count = e["count"]; live->last = e["last"]; }
    return o;
}

void ActionRegistry::set_favourite(const std::string& id, bool on)
{
    assert(wxThread::IsMain());
    auto favs = read_string_array("favourite_actions");
    auto it   = std::find(favs.begin(), favs.end(), id);
    if (on && it == favs.end())
        favs.push_back(id);
    if (!on && it != favs.end())
        favs.erase(it);
    write_section("favourite_actions", nlohmann::json(favs));
    if (AppAction* live = find(id))
        live->favourite = on;
}

void ActionRegistry::reorder_favourites(const std::vector<std::string>& ids)
{
    assert(wxThread::IsMain());
    auto cur = read_string_array("favourite_actions");
    std::vector<std::string> next;
    // keep the requested order, but only ids that are actually favourites (guard a bad payload)
    for (const auto& id : ids)
        if (std::find(cur.begin(), cur.end(), id) != cur.end() &&
            std::find(next.begin(), next.end(), id) == next.end())
            next.push_back(id);
    // why: don't drop favourites the page omitted (e.g. pins with no live action hidden from the bar)
    for (const auto& id : cur)
        if (std::find(next.begin(), next.end(), id) == next.end())
            next.push_back(id);
    write_section("favourite_actions", nlohmann::json(next));
}

bool ActionRegistry::should_ask(const std::string& id) const
{
    assert(wxThread::IsMain());
    auto arr = read_string_array("ask_suppressed");
    return std::find(arr.begin(), arr.end(), id) == arr.end();
}

void ActionRegistry::suppress_ask(const std::string& id)
{
    assert(wxThread::IsMain());
    auto arr = read_string_array("ask_suppressed");
    if (std::find(arr.begin(), arr.end(), id) == arr.end())
        arr.push_back(id);
    write_section("ask_suppressed", nlohmann::json(arr));
}

// ---- snapshot ---------------------------------------------------------------

nlohmann::json ActionRegistry::snapshot() const
{
    assert(wxThread::IsMain());
    std::vector<const AppAction*> sorted;
    sorted.reserve(m_actions.size());
    for (const auto& entry : m_actions)
        sorted.push_back(entry.second.get());

    const long long now = (long long) std::time(nullptr);
    std::sort(sorted.begin(), sorted.end(), [&](const AppAction* a, const AppAction* b) {
        double sa = frecency_score(a->count, a->last, now);
        double sb = frecency_score(b->count, b->last, now);
        if (sa != sb)
            return sa > sb;
        if (a->title() != b->title())
            return a->title() < b->title();
        if (a->source() != b->source())
            return a->source() < b->source();
        return a->id() < b->id();
    });

    nlohmann::json actions = nlohmann::json::array();
    for (const AppAction* a : sorted)
        actions.push_back({{"id", a->id()},
                           {"title", a->title()},
                           {"source", a->source()},
                           {"shortcut", ""}});
    // why: favourites is the ORDERED pin list - it must come from favourite_actions
    // as stored, not be re-derived from the frecency-sorted actions (that would
    // reorder the favourites bar). The page (js) filters out ids with no live action itself.
    nlohmann::json favourites(read_string_array("favourite_actions"));
    return {{"actions", std::move(actions)}, {"favourites", std::move(favourites)}};
}

}} // namespace Slic3r::GUI