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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2022                                                               *
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#include <modules/base/scale/luascale.h>

#include <openspace/documentation/documentation.h>
#include <openspace/documentation/verifier.h>
#include <openspace/util/updatestructures.h>
#include <ghoul/filesystem/file.h>
#include <ghoul/filesystem/filesystem.h>
#include <ghoul/logging/logmanager.h>
#include <ghoul/lua/ghoul_lua.h>
#include <ghoul/lua/lua_helper.h>
#include <chrono>

namespace {
    constexpr openspace::properties::Property::PropertyInfo ScriptInfo = {
        "Script",
        "Script",
        "This value is the path to the Lua script that will be executed to compute the "
        "scaling factor for this transformation. The script needs to define a function "
        "'scale' that takes the current simulation time in seconds past the J2000 epoch "
        "as the first argument, the current wall time as milliseconds past the J2000 "
        "epoch the second argument and computes the three scaling factors."
    };

    struct [[codegen::Dictionary(LuaScale)]] Parameters {
        // [[codegen::verbatim(ScriptInfo.description)]]
        std::string script;
    };
#include "luascale_codegen.cpp"
} // namespace

namespace openspace {

documentation::Documentation LuaScale::Documentation() {
    return codegen::doc<Parameters>("base_scale_lua");
}

LuaScale::LuaScale()
    : _luaScriptFile(ScriptInfo)
    , _state(ghoul::lua::LuaState::IncludeStandardLibrary::No)
{
    addProperty(_luaScriptFile);

    _luaScriptFile.onChange([&]() {
        requireUpdate();
        _fileHandle = std::make_unique<ghoul::filesystem::File>(_luaScriptFile.value());
        _fileHandle->setCallback([this]() { requireUpdate(); });
    });
}

LuaScale::LuaScale(const ghoul::Dictionary& dictionary) : LuaScale() {
    const Parameters p = codegen::bake<Parameters>(dictionary);
    _luaScriptFile = absPath(p.script).string();
}

glm::dvec3 LuaScale::scaleValue(const UpdateData& data) const {
    ghoul::lua::runScriptFile(_state, _luaScriptFile.value());

    // Get the scaling function
    lua_getglobal(_state, "scale");
    const bool isFunction = lua_isfunction(_state, -1);
    if (!isFunction) {
        LERRORC(
            "LuaScale",
            fmt::format(
                "Script '{}' does not have a function 'scale'", _luaScriptFile.value()
            )
        );
        return glm::dvec3(1.0);
    }

    // First argument is the number of seconds past the J2000 epoch in ingame time
    ghoul::lua::push(_state, data.time.j2000Seconds());

    // Second argument is the number of seconds past the J2000 epoch of last frame
    ghoul::lua::push(_state, data.previousFrameTime.j2000Seconds());

    // Second argument is the number of milliseconds past the J2000 epoch in wallclock
    using namespace std::chrono;
    const auto now = std::chrono::high_resolution_clock::now();
    ghoul::lua::push(_state, duration_cast<milliseconds>(now.time_since_epoch()).count());

    // Execute the scaling function
    const int success = lua_pcall(_state, 2, 1, 0);
    if (success != 0) {
        LERRORC(
            "LuaScale",
            fmt::format("Error executing 'scale': {}", lua_tostring(_state, -1))
        );
    }

    const double x = luaL_checknumber(_state, -1);
    const double y = luaL_checknumber(_state, -2);
    const double z = luaL_checknumber(_state, -3);
    lua_settop(_state, 0);
    return glm::dvec3(x, y, z);
}

} // namespace openspace