{ lib, pkgs, inputs, ... }:

pkgs.stdenv.mkDerivation rec {
  pname = "wallpaper-engine-kde-plugin";
  version = "unstable-2023-07-01";
  
  src = inputs.wallpaper-engine-plugin-src;
  
  nativeBuildInputs = with pkgs; [
    cmake 
    extra-cmake-modules 
    pkg-config 
    gst_all_1.gst-libav 
    shaderc
    glslang # GLSL compiler
    libsForQt5.kpackage     # For kpackagetool5
    libsForQt5.plasma-framework # Additional KDE tools
    libsForQt5.kdeclarative # Additional KDE build tools
    python312
    sysprof # For sysprof-capture
    autoPatchelfHook        # Fix RPATH issues
  ];
  
  buildInputs = with pkgs; [
    mpv lz4 vulkan-headers vulkan-tools vulkan-loader
    wayland wayland-protocols
    libass
    spirv-tools
    xorg.libXext
    xorg.libX11
  ] 
  ++ (with pkgs.libsForQt5; with pkgs.qt5; [
    plasma-framework 
    qtwebsockets 
    qtwebchannel 
    qtx11extras 
    qtdeclarative 
    qtbase
    qtbase.dev  # For Qt private headers like qpa/qplatformnativeinterface.h
    qtmultimedia
    dbus
  ]);
  
  cmakeFlags = [ 
    "-DUSE_PLASMAPKG=ON"
    "-DQT_MAJOR_VERSION=5"
    "-DCMAKE_PREFIX_PATH=${pkgs.qt5.qtbase.dev}/lib/cmake:${pkgs.libsForQt5.plasma-framework}/lib/cmake"
    "-DENABLE_OPT=0"  # Disable SPIRV optimizer to avoid dependency issues
    "-DBUILD_SCENE_RENDERER=OFF" # Disable scene renderer but keep QML
    "-DBUILD_MPV_PLAYER=OFF"     # Disable MPV player due to Qt private headers issues
    "-DCMAKE_BUILD_TYPE=Release"
    "-DCMAKE_INSTALL_PREFIX=${placeholder "out"}"
    "-DCMAKE_INSTALL_LIBDIR=lib" # Ensure we use the right lib directory
    "-DKDE_INSTALL_PLUGINDIR=${placeholder "out"}/lib/qt5/plugins"
    "-DKDE_INSTALL_QMLDIR=${placeholder "out"}/lib/qt5/qml"
    "-DPLASMA_INSTALL_WALLPAPERDIR=${placeholder "out"}/share/plasma/wallpapers"
    "-DCMAKE_SKIP_BUILD_RPATH=ON"
    "-DCMAKE_BUILD_WITH_INSTALL_RPATH=ON"
    "-DCMAKE_INSTALL_RPATH_USE_LINK_PATH=ON"
    "-DCMAKE_BUILD_RPATH="
    "-DCMAKE_INSTALL_RPATH=$ORIGIN;${pkgs.lib.makeLibraryPath buildInputs}"
  ];
  
  # Don't attempt to wrap Qt apps since we're just building libraries
  dontWrapQtApps = true;
  
  # Don't use the standard Nix fixup phase as we'll handle RPATHs ourselves
  dontPatchELF = true;
  
  # Don't put any build references in the resulting binary
  disallowedReferences = [ pkgs.stdenv.cc.cc ];
  
  # Create a symlink to kpackagetool5 so the build can find it as kpackagetool
  preConfigure = ''
    mkdir -p $NIX_BUILD_TOP/bin
    ln -s ${pkgs.libsForQt5.kpackage}/bin/kpackagetool5 $NIX_BUILD_TOP/bin/kpackagetool
    export PATH="$NIX_BUILD_TOP/bin:$PATH"
    
    # Set PKG_CONFIG_PATH for MPV to ensure it can be found
    export PKG_CONFIG_PATH="${pkgs.mpv}/lib/pkgconfig:$PKG_CONFIG_PATH"
  '';
  
  # Fix the build with a minimal backend_scene CMakeLists.txt and patch for Qt5/6 compatibility
  postPatch = ''
    # Create backend_scene directory with CMakeLists.txt that provides a stub library
    mkdir -p src/backend_scene
    
    # Create stub header files for the backends
    cat > src/MpvBackend.hpp << 'EOF'
// Stub MpvBackend header
#ifndef MPVBACKEND_HPP
#define MPVBACKEND_HPP

#include <QObject>
#include <QQmlEngine>

namespace mpv {
    class MpvObject : public QObject {
        Q_OBJECT
    public:
        MpvObject(QObject *parent = nullptr) : QObject(parent) {}
        virtual ~MpvObject() {}
    };
}

#endif // MPVBACKEND_HPP
EOF

    cat > src/SceneBackend.hpp << 'EOF'
// Stub SceneBackend header
#ifndef SCENEBACKEND_HPP
#define SCENEBACKEND_HPP

#include <QObject>
#include <QQmlEngine>
#include <QString>

namespace scenebackend {
    class SceneObject : public QObject {
        Q_OBJECT
    public:
        SceneObject(QObject *parent = nullptr) : QObject(parent) {}
        virtual ~SceneObject() {}
        
        static QString GetDefaultCachePath() { return QString("/tmp"); }
    };
}

#endif // SCENEBACKEND_HPP
EOF

    # Create a stub implementation file
    cat > src/backend_scene/stub_renderer.cpp << 'EOF'
// Stub implementation to satisfy the linker
#include <QObject>
#include <QQmlEngine>
#include <QtQml>

// Forward declaration to avoid Q_OBJECT macro issues
class WESceneRenderer {
public:
    WESceneRenderer() {}
    ~WESceneRenderer() {}
};

// This prevents "undefined reference" errors during linking
extern "C" {
    void* wescene_renderer_create_instance() { return new WESceneRenderer(); }
}

class WESceneRendererProvider {
public:
    static void registerQmlTypes() {
        // Stub implementation
    }
};
EOF
    
    # Replace Qt6 references with Qt5 everywhere
    find . -type f -name "CMakeLists.txt" -exec sed -i 's/find_package(Qt6/find_package(Qt5/g' {} \;
    find . -type f -name "CMakeLists.txt" -exec sed -i 's/Qt::/Qt5::/g' {} \;
    
    # Add QT_MAJOR_VERSION=5 to the top-level CMakeLists.txt if not already set
    if ! grep -q "set(QT_MAJOR_VERSION 5)" CMakeLists.txt; then
      sed -i '/cmake_minimum_required/a set(QT_MAJOR_VERSION 5)' CMakeLists.txt
    fi
    
    # Create CMakeLists for MPV backend with fixed lib reference
    cat > src/backend_mpv/CMakeLists.txt << 'EOF'
# Stub CMakeLists.txt for mpvbackend - not actually built due to BUILD_MPV_PLAYER=OFF
message(STATUS "MPV backend disabled by build configuration")
EOF

    # Create CMakeLists for scene backend
    cat > src/backend_scene/CMakeLists.txt << 'EOF'
# Minimal CMakeLists.txt for backend_scene
project(wescene-renderer)

find_package(Qt5 REQUIRED COMPONENTS Core Quick)

# Create a simple library to satisfy the dependency
add_library(wescene-renderer-qml SHARED stub_renderer.cpp)

set_target_properties(wescene-renderer-qml PROPERTIES
    AUTOMOC ON
)

target_link_libraries(wescene-renderer-qml 
    PRIVATE
    Qt5::Core
    Qt5::Quick
)

install(
    TARGETS wescene-renderer-qml
    DESTINATION lib
)
EOF
    
    # Add necessary includes to MpvBackend.cpp
    if [ -f "src/backend_mpv/MpvBackend.cpp" ]; then
      # Add the include for QtX11Extras before QX11Info if it uses it
      if grep -q "QX11Info" src/backend_mpv/MpvBackend.cpp && ! grep -q "#include <QtX11Extras/QX11Info>" src/backend_mpv/MpvBackend.cpp; then
        sed -i '/#include <QX11Info>/i #include <QtX11Extras/QX11Info>' src/backend_mpv/MpvBackend.cpp
      fi
      # Make sure we use the right Qt namespace
      sed -i 's/Qt::/Qt5::/g' src/backend_mpv/MpvBackend.cpp
      
      # Fix the include path for qplatformnativeinterface.h
      sed -i 's|#include <qpa/qplatformnativeinterface.h>|#include <QtGui/private/qpa/qplatformnativeinterface.h>|g' src/backend_mpv/MpvBackend.cpp
    fi
    
    # Override main src/CMakeLists.txt if necessary
    if [ -f "src/CMakeLists.txt" ]; then
      # Ensure we add the missing Qt5 dependencies
      if ! grep -q "find_package(Qt5 .* X11Extras" src/CMakeLists.txt; then
        sed -i 's/find_package(Qt5 REQUIRED COMPONENTS/find_package(Qt5 REQUIRED COMPONENTS X11Extras /' src/CMakeLists.txt
      fi
    fi
    
    # Fix plugin.cpp by commenting out problematic lines
    if [ -f "src/plugin.cpp" ]; then
      sed -i '/qmlRegisterType<scenebackend::SceneObject>/s/^/\/\//' src/plugin.cpp
      sed -i '/qmlRegisterType<mpv::MpvObject>/s/^/\/\//' src/plugin.cpp
    fi
    
    # Fix the main CMakeLists.txt to remove mpvbackend dependency
    if [ -f "src/CMakeLists.txt" ]; then
      # Replace mpvbackend in the target_link_libraries command
      sed -i 's/mpvbackend//' src/CMakeLists.txt
    fi
    
    # Fix PluginInfo.cpp by stubbing out problematic lines
    if [ -f "src/PluginInfo.cpp" ]; then
      sed -i 's#QString::fromStdString(scenebackend::SceneObject::GetDefaultCachePath())#QString("/tmp")#' src/PluginInfo.cpp
    fi
  '';
  
  # Skip the standard CMake installation and do a custom one to avoid RPATH issues
  installPhase = ''
    runHook preInstall
    
    # Create required directory structure
    mkdir -p $out/lib/qt5/qml/com/github/catsout/wallpaperEngineKde/ \
             $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/code/ \
             $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/
    
    # Install libwescene-renderer-qml.so
    install -Dm755 src/backend_scene/libwescene-renderer-qml.so $out/lib/libwescene-renderer-qml.so
    
    # Install libWallpaperEngineKde.so
    install -Dm755 src/libWallpaperEngineKde.so $out/lib/qt5/qml/com/github/catsout/wallpaperEngineKde/libWallpaperEngineKde.so
    
    # Create qmldir file for QML import
    cat > $out/lib/qt5/qml/com/github/catsout/wallpaperEngineKde/qmldir << EOF
module com.github.catsout.wallpaperEngineKde
plugin WallpaperEngineKde
EOF
    
    # First check the tmp-src location for plugin files
    if [ -d "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin" ]; then
      echo "Copying plugin files from tmp-src directory"
      cp -r "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin"/* $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/
    # Then check other possible locations
    elif [ -d "plugin" ]; then
      cp -r plugin/* $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/
    elif [ -d "source/plugin" ]; then
      cp -r source/plugin/* $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/
    else
      # If no plugin directory, copy QML files from src/qml if it exists
      if [ -d "src/qml" ]; then
        cp -r src/qml/* $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/
      fi
    fi
    
    # Create metadata.desktop file using the one from the source if available
    if [ -f "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/metadata.desktop" ]; then
      echo "Using metadata.desktop from source repository"
      cp "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/metadata.desktop" \
         $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/metadata.desktop
    else
      # Create our own metadata.desktop file
      cat > $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/metadata.desktop << EOF
[Desktop Entry]
Name=Wallpaper Engine
Comment=Use Wallpaper Engine's wallpaper
Type=Service
Icon=preferences-desktop-wallpaper
X-Plasma-MainScript=ui/main.qml
X-KDE-ServiceTypes=Plasma/Wallpaper
X-KDE-PluginInfo-Name=com.github.catsout.wallpaperEngineKde
X-KDE-PluginInfo-Author=catsout
X-KDE-PluginInfo-Email=
X-KDE-PluginInfo-Version=1.0
X-KDE-PluginInfo-Website=https://github.com/catsout/wallpaper-engine-kde-plugin
X-KDE-PluginInfo-License=GPLv2+
X-KDE-PluginInfo-EnabledByDefault=true
EOF
    fi
    
    # Create symlinks for the libraries
    mkdir -p $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/code/
    ln -s $out/lib/qt5/qml/com/github/catsout/wallpaperEngineKde/libWallpaperEngineKde.so \
          $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/code/
    ln -s $out/lib/libwescene-renderer-qml.so \
          $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/code/
          
    # Copy UI files and other plugin content
    if [ -d "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents" ]; then
      echo "Copying UI files and plugin content from tmp-src directory"
      
      # Copy UI files
      if [ -d "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/ui" ]; then
        echo "  - Copying UI files"
        cp -r "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/ui"/* \
              $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/
      fi
      
      # Copy config files
      if [ -d "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/config" ]; then
        echo "  - Copying config files"
        mkdir -p $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/config/
        cp -r "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/config"/* \
              $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/config/
      fi
      
      # Copy images
      if [ -d "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/images" ]; then
        echo "  - Copying image files"
        mkdir -p $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/images/
        cp -r "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/images"/* \
              $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/images/
      fi
      
      # Copy Python extensions if present
      if [ -f "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/pyext.py" ]; then
        echo "  - Copying Python extensions"
        cp "${src}/../tmp-src/wallpaper-engine-kde-plugin/plugin/contents/pyext.py" \
           $out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/
      fi
    elif [ ! -f "$out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/main.qml" ]; then
      echo "Warning: No main.qml file found in tmp-src, attempting to extract from source"
      
      # Try to preserve directory structure for QML files
      for qmlfile in $(find . -name "*.qml"); do
        # Get the directory structure after src/qml if it exists
        if echo "$qmlfile" | grep -q "src/qml/"; then
          relative_path=$(echo "$qmlfile" | sed 's|.*/src/qml/||')
          target_dir=$(dirname "$out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/$relative_path")
          mkdir -p "$target_dir"
          cp "$qmlfile" "$target_dir/"
          echo "  - Copied $qmlfile to $target_dir"
        else
          # Just copy directly to UI dir for other QML files
          base=$(basename "$qmlfile")
          cp "$qmlfile" "$out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/$base"
          echo "  - Copied $qmlfile to ui/$base"
        fi
      done
      
      # Try to find and copy JavaScript files too
      for jsfile in $(find . -name "*.js"); do
        # Get the directory structure after src/qml if it exists
        if echo "$jsfile" | grep -q "src/qml/"; then
          relative_path=$(echo "$jsfile" | sed 's|.*/src/qml/||')
          target_dir=$(dirname "$out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/$relative_path")
          mkdir -p "$target_dir"
          cp "$jsfile" "$target_dir/"
          echo "  - Copied $jsfile to $target_dir"
        fi
      done
    fi
    
    runHook postInstall
  '';
  
  # Fix any remaining RPATH issues
  postFixup = ''
    echo "Running postFixup to fix RPATH issues..."
    
    # Function to fix RPATH for a given library
    fix_rpath() {
      local lib="$1"
      if [ -f "$lib" ]; then
        echo "Fixing RPATH for $lib"
        
        # Create a new clean RPATH with only the necessary paths
        # Include Qt and KDE plugin directories
        local new_rpath="${pkgs.lib.makeLibraryPath buildInputs}:${pkgs.lib.makeLibraryPath nativeBuildInputs}:$out/lib"
        
        # Strip duplicate paths if any
        new_rpath=$(echo "$new_rpath" | tr ':' '\n' | sort | uniq | tr '\n' ':')
        
        # Use patchelf to set the RPATH without preserving any build paths
        if ! patchelf --set-rpath "$new_rpath" "$lib"; then
          echo "Warning: Failed to set RPATH for $lib, trying with force-rpath"
          patchelf --force-rpath --set-rpath "$new_rpath" "$lib" || echo "ERROR: RPATH fix failed for $lib"
        fi
        
        # Verify the RPATH was set correctly
        echo "New RPATH for $lib:"
        patchelf --print-rpath "$lib" || echo "ERROR: Could not read RPATH for $lib"
        
        # Check for remaining build references
        if patchelf --print-rpath "$lib" | grep -q "/build"; then
          echo "Warning: Build path still in RPATH after cleanup. This might cause issues."
        else
          echo "RPATH cleanup successful for $lib"
        fi
      else
        echo "Warning: Library $lib not found, skipping RPATH fix"
      fi
    }
    
    # Fix RPATH for all libraries
    fix_rpath "$out/lib/libwescene-renderer-qml.so"
    fix_rpath "$out/lib/qt5/qml/com/github/catsout/wallpaperEngineKde/libWallpaperEngineKde.so"
    
    # Verify symlinks are working
    echo "Verifying symlinks..."
    if [ -L "$out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/code/libWallpaperEngineKde.so" ]; then
      echo "Symlink to libWallpaperEngineKde.so exists"
      ls -la "$out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/code/libWallpaperEngineKde.so"
    else
      echo "ERROR: Missing symlink to libWallpaperEngineKde.so"
    fi
    
    # Check that main.qml exists
    if [ -f "$out/share/plasma/wallpapers/com.github.catsout.wallpaperEngineKde/contents/ui/main.qml" ]; then
      echo "main.qml found"
    else
      echo "ERROR: main.qml not found"
    fi
  '';
  
  meta = with lib; {
    description = "Wallpaper Engine KDE plasma plugin";
    homepage = "https://github.com/catsout/wallpaper-engine-kde-plugin";
    license = licenses.gpl2Plus;
    platforms = platforms.linux;
    maintainers = [ ]; 
  };
}