// MassBuilderSaveTool
// Copyright (C) 2021-2024 Guillaume Jacquemin
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

#include <cstring>

#include <Corrade/Containers/Array.h>
#include <Corrade/Containers/Optional.h>
#include <Corrade/Containers/String.h>
#include <Corrade/Utility/Path.h>

#include "../BinaryIo/Reader.h"
#include "../Configuration/Configuration.h"
#include "../Logger/Logger.h"
#include "../Utilities/Crc32.h"

#include "Keys.h"

#include "Import.h"

namespace mbst::ImportExport {

static Containers::String last_import_error;

Containers::StringView
lastImportError() {
    return last_import_error;
}

Containers::Optional<GameObjects::CustomStyle>
importStyle(Containers::StringView filename) {
    auto path = Utility::Path::join(conf().directories().styles, filename);
    if(!Utility::Path::exists(path)) {
        LOG_ERROR(last_import_error = path + " doesn't exist.");
        return Containers::NullOpt;
    }

    BinaryIo::Reader reader{path};
    if(!reader.open()) {
        last_import_error = path + " couldn't be opened.";
        return Containers::NullOpt;
    }

    Containers::Array<char> magic_bytes;
    if(!reader.readArray(magic_bytes, 9)) {
        LOG_ERROR(last_import_error = "Couldn't read the magic bytes.");
        return Containers::NullOpt;
    }

    Containers::StringView magic_bytes_view = magic_bytes;
    static const auto expected_magic_bytes = "MBSTSTYLE"_s;
    if(magic_bytes_view != expected_magic_bytes) {
        LOG_ERROR(last_import_error = "Magic bytes are mismatched.");
        return Containers::NullOpt;
    }

    std::size_t data_size;
    if(!reader.readUint64(data_size)) {
        LOG_ERROR(last_import_error = "Couldn't read data size.");
        return Containers::NullOpt;
    }

    std::uint32_t crc;
    if(!reader.readUint32(crc)) {
        LOG_ERROR(last_import_error = "Couldn't read CRC-32 checksum.");
        return Containers::NullOpt;
    }

    auto position = reader.position();

    {
        Containers::Array<char> data;
        if(!reader.readArray(data, data_size)) {
            LOG_ERROR(last_import_error = "Couldn't read data.");
            return Containers::NullOpt;
        }

        auto computed_crc = Utilities::crc32(0, data);
        if(computed_crc != crc) {
            LOG_ERROR(last_import_error = Utility::format("CRC-32 checksum doesn't match. "
                                                          "Expected {}, got {} instead.",
                                                          crc, computed_crc));
            return Containers::NullOpt;
        }
    }

    if(!reader.seek(position)) {
        LOG_ERROR(last_import_error = Utility::format("Couldn't seek to position {}.", position));
        return Containers::NullOpt;
    }

    GameObjects::CustomStyle style{};

    while(!reader.eof()) {
        Keys::CustomStyle key;
        if(!reader.readValue(key)) {
            if(reader.eof()) {
                break;
            }
            LOG_ERROR(last_import_error = "Couldn't read key.");
            return Containers::NullOpt;
        }

        switch(key) {
            case Keys::Name:
                if(!reader.readUEString(style.name)) {
                    LOG_ERROR(last_import_error = "Couldn't read style name.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::Colour:
                if(!reader.readValue<Color4>(style.colour)) {
                    LOG_ERROR(last_import_error = "Couldn't read style colour.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::Metallic:
                if(!reader.readFloat(style.metallic)) {
                    LOG_ERROR(last_import_error = "Couldn't read style metallic.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::Gloss:
                if(!reader.readFloat(style.gloss)) {
                    LOG_ERROR(last_import_error = "Couldn't read style gloss.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::Glow:
                if(!reader.readValue(style.glow)) {
                    LOG_ERROR(last_import_error = "Couldn't read style glow.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::PatternId:
                if(!reader.readInt32(style.patternId)) {
                    LOG_ERROR(last_import_error = "Couldn't read style pattern ID.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::PatternOpacity:
                if(!reader.readFloat(style.opacity)) {
                    LOG_ERROR(last_import_error = "Couldn't read style pattern opacity.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::PatternOffset:
                if(!reader.readValue(style.offset)) {
                    LOG_ERROR(last_import_error = "Couldn't read style pattern offset.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::PatternRotation:
                if(!reader.readFloat(style.rotation)) {
                    LOG_ERROR(last_import_error = "Couldn't read style pattern rotation.");
                    return Containers::NullOpt;
                }
                break;
            case Keys::PatternScale:
                if(!reader.readFloat(style.scale)) {
                    LOG_ERROR(last_import_error = "Couldn't read style pattern scale.");
                    return Containers::NullOpt;
                }
                break;
            default:
                LOG_ERROR(last_import_error = Utility::format("Unknown key {}.", key));
                return Containers::NullOpt;
        }
    }

    return Utility::move(style);
}

}