#include <filesystem>

#include "engine/Engine.hpp"
#include "files/files.hpp"
#include "frontend/hud.hpp"
#include "frontend/screens/Screen.hpp"
#include "graphics/ui/GUI.hpp"
#include "graphics/ui/elements/Container.hpp"
#include "util/stringutil.hpp"
#include "window/Events.hpp"
#include "window/input.hpp"
#include "libgui.hpp"

namespace scripting {
    extern Hud* hud;
}
using namespace scripting;

static int l_keycode(lua::State* L) {
    auto name = lua::require_string(L, 1);
    return lua::pushinteger(
        L, static_cast<int>(input_util::keycode_from(name))
    );
}

static int l_mousecode(lua::State* L) {
    auto name = lua::require_string(L, 1);
    return lua::pushinteger(
        L, static_cast<int>(input_util::mousecode_from(name))
    );
}

static int l_add_callback(lua::State* L) {
    std::string bindname = lua::require_string(L, 1);
    size_t pos = bindname.find(':');

    lua::pushvalue(L, 2);
    auto actual_callback = lua::create_simple_handler(L);
    observer_handler handler;
    
    if (pos != std::string::npos) {
        std::string prefix = bindname.substr(0, pos);
        if (prefix == "key") {
            auto key = input_util::keycode_from(bindname.substr(pos + 1));
            handler = Events::keyCallbacks[key].add(actual_callback);
        }
    }
    auto callback = [=]() -> bool {
        if (!scripting::engine->getGUI()->isFocusCaught()) {
            return actual_callback();
        }
        return false;
    };
    if (handler == nullptr) {
        const auto& bind = Events::bindings.find(bindname);
        if (bind == Events::bindings.end()) {
            throw std::runtime_error("unknown binding " + util::quote(bindname));
        }
        handler = bind->second.onactived.add(callback);
    }

    if (hud) {
        hud->keepAlive(handler);
        return 0;
    } else if (lua::gettop(L) >= 3) {
        auto node = get_document_node(L, 3);
        if (auto container = std::dynamic_pointer_cast<gui::Container>(node.node)) {
            container->keepAlive(handler);
            return 0;
        }
        throw std::runtime_error("owner expected to be a container");
    }
    throw std::runtime_error("on_hud_open is not called yet");
}

static int l_get_mouse_pos(lua::State* L) {
    return lua::pushvec2(L, Events::cursor);
}

static int l_get_bindings(lua::State* L) {
    auto& bindings = Events::bindings;
    lua::createtable(L, bindings.size(), 0);

    int i = 0;
    for (auto& entry : bindings) {
        lua::pushstring(L, entry.first);
        lua::rawseti(L, i + 1);
        i++;
    }
    return 1;
}

static int l_get_binding_text(lua::State* L) {
    auto bindname = lua::require_string(L, 1);
    auto index = Events::bindings.find(bindname);
    
    if (index == Events::bindings.end()) {
        throw std::runtime_error("unknown binding " + util::quote(bindname));
        lua::pushstring(L, "");
    } else {
        lua::pushstring(L, index->second.text());
    }

    return 1;
}

static int l_is_active(lua::State* L) {
    auto bindname = lua::require_string(L, 1);
    const auto& bind = Events::bindings.find(bindname);
    if (bind == Events::bindings.end()) {
        throw std::runtime_error("unknown binding " + util::quote(bindname));
    }
    return lua::pushboolean(L, bind->second.active());
}

static int l_is_pressed(lua::State* L) {
    std::string code = lua::require_string(L, 1);
    size_t sep = code.find(':');
    if (sep == std::string::npos) {
        throw std::runtime_error("expected 'input_type:key' format");
    }
    auto prefix = code.substr(0, sep);
    auto name = code.substr(sep + 1);
    if (prefix == "key") {
        return lua::pushboolean(
            L, Events::pressed(static_cast<int>(input_util::keycode_from(name)))
        );
    } else if (prefix == "mouse") {
        return lua::pushboolean(
            L,
            Events::clicked(static_cast<int>(input_util::mousecode_from(name)))
        );
    } else {
        throw std::runtime_error("unknown input type " + util::quote(code));
    }
}

static void resetPackBindings(fs::path& packFolder) {
    auto configFolder = packFolder/fs::path("config");
    auto bindsFile = configFolder/fs::path("bindings.toml");
    if (fs::is_regular_file(bindsFile)) {
        Events::loadBindings(
            bindsFile.u8string(),
            files::read_string(bindsFile),
            BindType::REBIND
        );
    }
}

static int l_reset_bindings(lua::State*) {
    auto resFolder = engine->getPaths().getResourcesFolder();
    resetPackBindings(resFolder);
    for (auto& pack : engine->getContentPacks()) {
        resetPackBindings(pack.folder);
    }
    return 0;
}

static int l_set_enabled(lua::State* L) {
    std::string bindname = lua::require_string(L, 1);
    bool enable = lua::toboolean(L, 2);
    const auto& bind = Events::bindings.find(bindname);
    if (bind == Events::bindings.end()) {
        throw std::runtime_error("unknown binding " + util::quote(bindname));
    }
    Events::bindings[bindname].enable = enable;
    return 0;
}

const luaL_Reg inputlib[] = {
    {"keycode", lua::wrap<l_keycode>},
    {"mousecode", lua::wrap<l_mousecode>},
    {"add_callback", lua::wrap<l_add_callback>},
    {"get_mouse_pos", lua::wrap<l_get_mouse_pos>},
    {"get_bindings", lua::wrap<l_get_bindings>},
    {"get_binding_text", lua::wrap<l_get_binding_text>},
    {"is_active", lua::wrap<l_is_active>},
    {"is_pressed", lua::wrap<l_is_pressed>},
    {"reset_bindings", lua::wrap<l_reset_bindings>},
    {"set_enabled", lua::wrap<l_set_enabled>},
    {NULL, NULL}};
