#include "hyprcursor/hyprcursor.hpp"
#include "internalSharedTypes.hpp"
#include "internalDefines.hpp"
#include <array>
#include <filesystem>
#include <hyprlang.hpp>
#include <zip.h>
#include <cstring>
#include <algorithm>
#include <librsvg/rsvg.h>

#include "Log.hpp"

using namespace Hyprcursor;

// directories for lookup
constexpr const std::array<const char*, 1> systemThemeDirs = {"/usr/share/icons"};
constexpr const std::array<const char*, 2> userThemeDirs   = {"/.local/share/icons", "/.icons"};

//
static std::string themeNameFromEnv() {
    const auto ENV = getenv("HYPRCURSOR_THEME");
    if (!ENV)
        return "";

    return std::string{ENV};
}

static bool themeAccessible(const std::string& path) {
    try {
        if (!std::filesystem::exists(path + "/manifest.hl"))
            return false;

    } catch (std::exception& e) { return false; }

    return true;
}

static std::string getFirstTheme() {
    // try user directories first

    const auto HOMEENV = getenv("HOME");
    if (!HOMEENV)
        return "";

    const std::string HOME{HOMEENV};

    for (auto& dir : userThemeDirs) {
        const auto FULLPATH = HOME + dir;
        if (!std::filesystem::exists(FULLPATH))
            continue;

        // loop over dirs and see if any has a manifest.hl
        for (auto& themeDir : std::filesystem::directory_iterator(FULLPATH)) {
            if (!themeDir.is_directory())
                continue;

            const auto MANIFESTPATH = themeDir.path().string() + "/manifest.hl";

            if (std::filesystem::exists(MANIFESTPATH))
                return themeDir.path().stem().string();
        }
    }

    for (auto& dir : systemThemeDirs) {
        const auto FULLPATH = dir;
        if (!std::filesystem::exists(FULLPATH))
            continue;

        // loop over dirs and see if any has a manifest.hl
        for (auto& themeDir : std::filesystem::directory_iterator(FULLPATH)) {
            if (!themeDir.is_directory())
                continue;

            const auto MANIFESTPATH = themeDir.path().string() + "/manifest.hl";

            if (std::filesystem::exists(MANIFESTPATH))
                return themeDir.path().stem().string();
        }
    }

    return "";
}

static std::string getFullPathForThemeName(const std::string& name) {
    const auto HOMEENV = getenv("HOME");
    if (!HOMEENV)
        return "";

    const std::string HOME{HOMEENV};

    for (auto& dir : userThemeDirs) {
        const auto FULLPATH = HOME + dir;
        if (!std::filesystem::exists(FULLPATH))
            continue;

        // loop over dirs and see if any has a manifest.hl
        for (auto& themeDir : std::filesystem::directory_iterator(FULLPATH)) {
            if (!themeDir.is_directory())
                continue;

            if (!name.empty() && themeDir.path().stem().string() != name)
                continue;

            const auto MANIFESTPATH = themeDir.path().string() + "/manifest.hl";

            if (std::filesystem::exists(MANIFESTPATH))
                return std::filesystem::canonical(themeDir.path()).string();
        }
    }

    for (auto& dir : systemThemeDirs) {
        const auto FULLPATH = dir;
        if (!std::filesystem::exists(FULLPATH))
            continue;

        // loop over dirs and see if any has a manifest.hl
        for (auto& themeDir : std::filesystem::directory_iterator(FULLPATH)) {
            if (!themeDir.is_directory())
                continue;

            if (!name.empty() && themeDir.path().stem().string() != name)
                continue;

            if (!themeAccessible(themeDir.path().string()))
                continue;

            const auto MANIFESTPATH = themeDir.path().string() + "/manifest.hl";

            if (std::filesystem::exists(MANIFESTPATH))
                return std::filesystem::canonical(themeDir.path()).string();
        }
    }

    if (!name.empty()) // try without name
        return getFullPathForThemeName("");

    return "";
}

CHyprcursorManager::CHyprcursorManager(const char* themeName_) {
    std::string themeName = themeName_ ? themeName_ : "";

    if (themeName.empty()) {
        // try reading from env
        themeName = themeNameFromEnv();
    }

    if (themeName.empty()) {
        // try finding first, in the hierarchy
        themeName = getFirstTheme();
    }

    if (themeName.empty()) {
        // holy shit we're done
        return;
    }

    // initialize theme
    impl               = new CHyprcursorImplementation;
    impl->themeName    = themeName;
    impl->themeFullDir = getFullPathForThemeName(themeName);

    if (impl->themeFullDir.empty())
        return;

    Debug::log(LOG, "Found theme {} at {}\n", impl->themeName, impl->themeFullDir);

    const auto LOADSTATUS = impl->loadTheme();

    if (LOADSTATUS.has_value()) {
        Debug::log(ERR, "Theme failed to load with {}\n", LOADSTATUS.value());
        return;
    }

    finalizedAndValid = true;
}

CHyprcursorManager::~CHyprcursorManager() {
    if (impl)
        delete impl;
}

bool CHyprcursorManager::valid() {
    return finalizedAndValid;
}

SCursorImageData** CHyprcursorManager::getShapesC(int& outSize, const char* shape_, const SCursorStyleInfo& info) {
    std::string                      REQUESTEDSHAPE = shape_;

    std::vector<SLoadedCursorImage*> resultingImages;
    float                            hotX = 0, hotY = 0;

    for (auto& shape : impl->theme.shapes) {
        if (REQUESTEDSHAPE != shape->directory && std::find(shape->overrides.begin(), shape->overrides.end(), REQUESTEDSHAPE) == shape->overrides.end())
            continue;

        hotX = shape->hotspotX;
        hotY = shape->hotspotY;

        // matched :)
        bool foundAny = false;
        for (auto& image : impl->loadedShapes[shape.get()].images) {
            if (image->side != info.size)
                continue;

            // found size
            resultingImages.push_back(image.get());
            foundAny = true;
        }

        if (foundAny || shape->shapeType == SHAPE_SVG /* something broke, this shouldn't happen with svg */)
            break;

        // if we get here, means loadThemeStyle wasn't called most likely. If resize algo is specified, this is an error.
        if (shape->resizeAlgo != RESIZE_NONE) {
            Debug::log(ERR, "getSurfaceFor didn't match a size?");
            return nullptr;
        }

        // find nearest
        int leader = 13371337;
        for (auto& image : impl->loadedShapes[shape.get()].images) {
            if (std::abs((int)(image->side - info.size)) > leader)
                continue;

            leader = image->side;
        }

        if (leader == 13371337) { // ???
            Debug::log(ERR, "getSurfaceFor didn't match any nearest size?");
            return nullptr;
        }

        // we found nearest size
        for (auto& image : impl->loadedShapes[shape.get()].images) {
            if (image->side != leader)
                continue;

            // found size
            resultingImages.push_back(image.get());
            foundAny = true;
        }

        if (foundAny)
            break;

        Debug::log(ERR, "getSurfaceFor didn't match any nearest size (2)?");
        return nullptr;
    }

    // alloc and return what we need
    SCursorImageData** data = (SCursorImageData**)malloc(sizeof(SCursorImageData*) * resultingImages.size());
    for (size_t i = 0; i < resultingImages.size(); ++i) {
        data[i]           = (SCursorImageData*)malloc(sizeof(SCursorImageData));
        data[i]->delay    = resultingImages[i]->delay;
        data[i]->size     = resultingImages[i]->side;
        data[i]->surface  = resultingImages[i]->cairoSurface;
        data[i]->hotspotX = hotX * data[i]->size;
        data[i]->hotspotY = hotY * data[i]->size;
    }

    outSize = resultingImages.size();

    return data;
}

bool CHyprcursorManager::loadThemeStyle(const SCursorStyleInfo& info) {
    for (auto& shape : impl->theme.shapes) {
        if (shape->resizeAlgo == RESIZE_NONE && shape->shapeType != SHAPE_SVG)
            continue; // don't resample NONE style cursors

        bool sizeFound = false;

        if (shape->shapeType == SHAPE_PNG) {
            for (auto& image : impl->loadedShapes[shape.get()].images) {
                if (image->side != info.size)
                    continue;

                sizeFound = true;
                break;
            }

            // size wasn't found, let's resample.
            if (sizeFound)
                continue;

            SLoadedCursorImage* leader    = nullptr;
            int                 leaderVal = 1000000;
            for (auto& image : impl->loadedShapes[shape.get()].images) {
                if (image->side < info.size)
                    continue;

                if (image->side > leaderVal)
                    continue;

                leaderVal = image->side;
                leader    = image.get();
            }

            if (!leader) {
                for (auto& image : impl->loadedShapes[shape.get()].images) {
                    if (std::abs((int)(image->side - info.size)) > leaderVal)
                        continue;

                    leaderVal = image->side;
                    leader    = image.get();
                }
            }

            if (!leader) {
                Debug::log(ERR, "Resampling failed to find a candidate???");
                return false;
            }

            const auto FRAMES = impl->getFramesFor(shape.get(), leader->side);

            for (auto& f : FRAMES) {
                auto& newImage           = impl->loadedShapes[shape.get()].images.emplace_back(std::make_unique<SLoadedCursorImage>());
                newImage->artificial     = true;
                newImage->side           = info.size;
                newImage->artificialData = new char[info.size * info.size * 4];
                newImage->cairoSurface   = cairo_image_surface_create_for_data((unsigned char*)newImage->artificialData, CAIRO_FORMAT_ARGB32, info.size, info.size, info.size * 4);
                newImage->delay          = f->delay;

                const auto PCAIRO = cairo_create(newImage->cairoSurface);

                cairo_set_antialias(PCAIRO, shape->resizeAlgo == RESIZE_BILINEAR ? CAIRO_ANTIALIAS_GOOD : CAIRO_ANTIALIAS_NONE);

                cairo_save(PCAIRO);
                cairo_set_operator(PCAIRO, CAIRO_OPERATOR_CLEAR);
                cairo_paint(PCAIRO);
                cairo_restore(PCAIRO);

                const auto PTN = cairo_pattern_create_for_surface(f->cairoSurface);
                cairo_pattern_set_extend(PTN, CAIRO_EXTEND_NONE);
                const float scale = info.size / (float)f->side;
                cairo_scale(PCAIRO, scale, scale);
                cairo_pattern_set_filter(PTN, shape->resizeAlgo == RESIZE_BILINEAR ? CAIRO_FILTER_GOOD : CAIRO_FILTER_NEAREST);
                cairo_set_source(PCAIRO, PTN);

                cairo_rectangle(PCAIRO, 0, 0, info.size, info.size);

                cairo_fill(PCAIRO);
                cairo_surface_flush(newImage->cairoSurface);

                cairo_pattern_destroy(PTN);
                cairo_destroy(PCAIRO);
            }
        } else if (shape->shapeType == SHAPE_SVG) {
            const auto FRAMES = impl->getFramesFor(shape.get(), 0);

            for (auto& f : FRAMES) {
                auto& newImage           = impl->loadedShapes[shape.get()].images.emplace_back(std::make_unique<SLoadedCursorImage>());
                newImage->artificial     = true;
                newImage->side           = info.size;
                newImage->artificialData = new char[info.size * info.size * 4];
                newImage->cairoSurface   = cairo_image_surface_create_for_data((unsigned char*)newImage->artificialData, CAIRO_FORMAT_ARGB32, info.size, info.size, info.size * 4);
                newImage->delay          = f->delay;

                const auto PCAIRO = cairo_create(newImage->cairoSurface);

                cairo_save(PCAIRO);
                cairo_set_operator(PCAIRO, CAIRO_OPERATOR_CLEAR);
                cairo_paint(PCAIRO);
                cairo_restore(PCAIRO);

                GError*     error  = nullptr;
                RsvgHandle* handle = rsvg_handle_new_from_data((unsigned char*)f->data, f->dataLen, &error);

                if (!handle) {
                    Debug::log(ERR, "Failed reading svg: {}", error->message);
                    return false;
                }

                RsvgRectangle rect = {0, 0, (double)info.size, (double)info.size};

                if (!rsvg_handle_render_document(handle, PCAIRO, &rect, &error)) {
                    Debug::log(ERR, "Failed rendering svg: {}", error->message);
                    return false;
                }

                // done
                cairo_surface_flush(newImage->cairoSurface);
                cairo_destroy(PCAIRO);
            }
        } else {
            Debug::log(ERR, "Invalid shapetype in loadThemeStyle");
            return false;
        }
    }

    return true;
}

void CHyprcursorManager::cursorSurfaceStyleDone(const SCursorStyleInfo& info) {
    for (auto& shape : impl->theme.shapes) {
        if (shape->resizeAlgo == RESIZE_NONE && shape->shapeType != SHAPE_SVG)
            continue;

        std::erase_if(impl->loadedShapes[shape.get()].images, [info, shape](const auto& e) {
            const bool isSVG        = shape->shapeType == SHAPE_SVG;
            const bool isArtificial = e->artificial;

            // clean artificial rasters made for this
            if (isArtificial && e->side == info.size)
                return true;

            // clean invalid non-svg rasters
            if (!isSVG && e->side == 0)
                return true;

            return false;
        });
    }
}

/*

Implementation

*/

static std::string removeBeginEndSpacesTabs(std::string str) {
    if (str.empty())
        return str;

    int countBefore = 0;
    while (str[countBefore] == ' ' || str[countBefore] == '\t') {
        countBefore++;
    }

    int countAfter = 0;
    while ((int)str.length() - countAfter - 1 >= 0 && (str[str.length() - countAfter - 1] == ' ' || str[str.length() - 1 - countAfter] == '\t')) {
        countAfter++;
    }

    str = str.substr(countBefore, str.length() - countBefore - countAfter);

    return str;
}

SCursorTheme*                 currentTheme;

static Hyprlang::CParseResult parseDefineSize(const char* C, const char* V) {
    Hyprlang::CParseResult result;
    const std::string      VALUE = V;

    if (!VALUE.contains(",")) {
        result.setError("Invalid define_size");
        return result;
    }

    auto         LHS   = removeBeginEndSpacesTabs(VALUE.substr(0, VALUE.find_first_of(",")));
    auto         RHS   = removeBeginEndSpacesTabs(VALUE.substr(VALUE.find_first_of(",") + 1));
    auto         DELAY = 0;

    SCursorImage image;

    if (RHS.contains(",")) {
        const auto LL = removeBeginEndSpacesTabs(RHS.substr(0, RHS.find(",")));
        const auto RR = removeBeginEndSpacesTabs(RHS.substr(RHS.find(",") + 1));

        try {
            image.delay = std::stoull(RR);
        } catch (std::exception& e) {
            result.setError(e.what());
            return result;
        }

        RHS = LL;
    }

    image.filename = RHS;

    try {
        image.size = std::stoull(LHS);
    } catch (std::exception& e) {
        result.setError(e.what());
        return result;
    }

    currentTheme->shapes.back()->images.push_back(image);

    return result;
}

static Hyprlang::CParseResult parseOverride(const char* C, const char* V) {
    Hyprlang::CParseResult result;
    const std::string      VALUE = V;

    currentTheme->shapes.back()->overrides.push_back(V);

    return result;
}

/*

PNG reading

*/

static cairo_status_t readPNG(void* data, unsigned char* output, unsigned int len) {
    const auto DATA = (SLoadedCursorImage*)data;

    if (!DATA->data)
        return CAIRO_STATUS_READ_ERROR;

    size_t toRead = len > DATA->dataLen - DATA->readNeedle ? DATA->dataLen - DATA->readNeedle : len;

    std::memcpy(output, DATA->data + DATA->readNeedle, toRead);
    DATA->readNeedle += toRead;

    if (DATA->readNeedle >= DATA->dataLen) {
        delete[] (char*)DATA->data;
        DATA->data = nullptr;
        Debug::log(TRACE, "cairo: png read, freeing mem");
    }

    return CAIRO_STATUS_SUCCESS;
}

/*

General

*/

std::optional<std::string> CHyprcursorImplementation::loadTheme() {

    if (!themeAccessible(themeFullDir))
        return "Theme inaccessible";

    currentTheme = &theme;

    // load manifest
    std::unique_ptr<Hyprlang::CConfig> manifest;
    try {
        // TODO: unify this between util and lib
        manifest = std::make_unique<Hyprlang::CConfig>((themeFullDir + "/manifest.hl").c_str(), Hyprlang::SConfigOptions{});
        manifest->addConfigValue("cursors_directory", Hyprlang::STRING{""});
        manifest->commence();
        manifest->parse();
    } catch (const char* err) {
        Debug::log(ERR, "Failed parsing manifest due to {}", err);
        return std::string{"failed: "} + err;
    }

    const std::string CURSORSSUBDIR = std::any_cast<Hyprlang::STRING>(manifest->getConfigValue("cursors_directory"));
    const std::string CURSORDIR     = themeFullDir + "/" + CURSORSSUBDIR;

    if (CURSORSSUBDIR.empty() || !std::filesystem::exists(CURSORDIR))
        return "loadTheme: cursors_directory missing or empty";

    for (auto& cursor : std::filesystem::directory_iterator(CURSORDIR)) {
        if (!cursor.is_regular_file())
            continue;

        auto& SHAPE       = theme.shapes.emplace_back(std::make_unique<SCursorShape>());
        auto& LOADEDSHAPE = loadedShapes[SHAPE.get()];

        // extract zip to raw data.
        int         errp = 0;
        zip_t*      zip  = zip_open(cursor.path().string().c_str(), ZIP_RDONLY, &errp);

        zip_file_t* meta_file = zip_fopen(zip, "meta.hl", ZIP_FL_UNCHANGED);
        if (!meta_file)
            return "cursor" + cursor.path().string() + "failed to load meta";

        char* buffer = new char[1024 * 1024]; /* 1MB should be more than enough */

        int   readBytes = zip_fread(meta_file, buffer, 1024 * 1024 - 1);

        zip_fclose(meta_file);

        if (readBytes < 0) {
            delete[] buffer;
            return "cursor" + cursor.path().string() + "failed to read meta";
        }

        buffer[readBytes] = '\0';

        std::unique_ptr<Hyprlang::CConfig> meta;

        try {
            meta = std::make_unique<Hyprlang::CConfig>(buffer, Hyprlang::SConfigOptions{.pathIsStream = true});
            meta->addConfigValue("hotspot_x", Hyprlang::FLOAT{0.F});
            meta->addConfigValue("hotspot_y", Hyprlang::FLOAT{0.F});
            meta->addConfigValue("resize_algorithm", Hyprlang::STRING{"nearest"});
            meta->registerHandler(::parseDefineSize, "define_size", {.allowFlags = false});
            meta->registerHandler(::parseOverride, "define_override", {.allowFlags = false});
            meta->commence();
            meta->parse();
        } catch (const char* err) { return "failed parsing meta: " + std::string{err}; }

        delete[] buffer;

        for (auto& i : SHAPE->images) {
            if (SHAPE->shapeType == SHAPE_INVALID) {
                if (i.filename.ends_with(".svg"))
                    SHAPE->shapeType = SHAPE_SVG;
                else if (i.filename.ends_with(".png"))
                    SHAPE->shapeType = SHAPE_PNG;
                else {
                    std::cout << "WARNING: image " << i.filename << " has no known extension, assuming png.\n";
                    SHAPE->shapeType = SHAPE_PNG;
                }
            } else {
                if (SHAPE->shapeType == SHAPE_SVG && !i.filename.ends_with(".svg"))
                    return "meta invalid: cannot add .png files to an svg shape";
                else if (SHAPE->shapeType == SHAPE_PNG && i.filename.ends_with(".svg"))
                    return "meta invalid: cannot add .svg files to a png shape";
            }

            // load image
            Debug::log(TRACE, "Loading {} for shape {}", i.filename, cursor.path().stem().string());
            auto* IMAGE  = LOADEDSHAPE.images.emplace_back(std::make_unique<SLoadedCursorImage>()).get();
            IMAGE->side  = i.size;
            IMAGE->delay = i.delay;

            // read from zip
            zip_file_t* image_file = zip_fopen(zip, i.filename.c_str(), ZIP_FL_UNCHANGED);
            if (!image_file)
                return "cursor" + cursor.path().string() + "failed to load image_file";

            IMAGE->data = new char[1024 * 1024]; /* 1MB should be more than enough, again. This probably should be in the spec. */

            IMAGE->dataLen = zip_fread(image_file, IMAGE->data, 1024 * 1024 - 1);

            zip_fclose(image_file);

            Debug::log(TRACE, "Cairo: set up surface read");

            if (SHAPE->shapeType == SHAPE_PNG) {

                IMAGE->cairoSurface = cairo_image_surface_create_from_png_stream(::readPNG, IMAGE);

                if (const auto STATUS = cairo_surface_status(IMAGE->cairoSurface); STATUS != CAIRO_STATUS_SUCCESS) {
                    delete[] (char*)IMAGE->data;
                    IMAGE->data = nullptr;
                    return "Failed reading cairoSurface, status " + std::to_string((int)STATUS);
                }
            } else {
                Debug::log(LOG, "Skipping cairo load for a svg surface");
            }
        }

        if (SHAPE->images.empty())
            return "meta invalid: no images for shape " + cursor.path().stem().string();

        SHAPE->directory  = cursor.path().stem().string();
        SHAPE->hotspotX   = std::any_cast<float>(meta->getConfigValue("hotspot_x"));
        SHAPE->hotspotY   = std::any_cast<float>(meta->getConfigValue("hotspot_y"));
        SHAPE->resizeAlgo = stringToAlgo(std::any_cast<Hyprlang::STRING>(meta->getConfigValue("resize_algorithm")));

        zip_discard(zip);
    }

    return {};
}

std::vector<SLoadedCursorImage*> CHyprcursorImplementation::getFramesFor(SCursorShape* shape, int size) {
    std::vector<SLoadedCursorImage*> frames;

    for (auto& image : loadedShapes[shape].images) {
        if (!image->isSVG && image->side != size)
            continue;

        if (image->artificial)
            continue;

        frames.push_back(image.get());
    }

    return frames;
}