# This function downloads a binary library package from our external repo.
# Params:
#   remote_path: path to the file to download, relative to the remote repository root
#   prefix_var: name of a variable which will be set with the path to the extracted contents
function(download_bundled_external remote_path lib_name prefix_var)
    get_external_prefix(${lib_name} prefix)
    if (NOT EXISTS "${prefix}")
        message(STATUS "Downloading binaries for ${lib_name}...")

        if (WIN32)
            set(repo_base "ext-windows-bin/raw/master")
        elseif (APPLE)
            set(repo_base "ext-macos-bin/raw/main")
        else()
            message(FATAL_ERROR "Bundled libraries are unsupported for this OS.")
        endif()

        file(DOWNLOAD
            https://github.com/citra-emu/${repo_base}/${remote_path}${lib_name}.7z
            "${CMAKE_BINARY_DIR}/externals/${lib_name}.7z" SHOW_PROGRESS)
        execute_process(COMMAND ${CMAKE_COMMAND} -E tar xf "${CMAKE_BINARY_DIR}/externals/${lib_name}.7z"
            WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/externals")
    endif()

    # For packages that include the /usr/local prefix, include it in the prefix path.
    if (EXISTS "${prefix}/usr/local")
        set(prefix "${prefix}/usr/local")
    endif()

    message(STATUS "Using bundled binaries at ${prefix}")
    set(${prefix_var} "${prefix}" PARENT_SCOPE)
endfunction()

# This function downloads Qt using aqt.
# Params:
#   target: Qt dependency to install. Specify a version number to download Qt, or "tools_(name)" for a specific build tool.
#   prefix_var: Name of a variable which will be set with the path to the extracted contents.
function(download_qt_external target prefix_var)
    # Determine installation parameters for OS, architecture, and compiler
    if (WIN32)
        set(host "windows")
        if (MINGW)
            set(arch_path "mingw81")
        elseif ((MSVC_VERSION GREATER_EQUAL 1920 AND MSVC_VERSION LESS 1940) AND "x86_64" IN_LIST ARCHITECTURE)
            if ("arm64" IN_LIST ARCHITECTURE)
                set(arch_path "msvc2019_arm64")
            elseif ("x86_64" IN_LIST ARCHITECTURE)
                set(arch_path "msvc2019_64")
            else()
                message(FATAL_ERROR "Unsupported bundled Qt architecture. Disable CITRA_USE_BUNDLED_QT and provide your own.")
            endif()
        else()
            message(FATAL_ERROR "Unsupported bundled Qt toolchain. Disable CITRA_USE_BUNDLED_QT and provide your own.")
        endif()
        set(arch "win64_${arch_path}")
    elseif (APPLE)
        set(host "mac")
        set(arch "clang_64")
        set(arch_path "macos")
    else()
        set(host "linux")
        set(arch "gcc_64")
        set(arch_path "linux")
    endif()

    get_external_prefix(qt base_path)
    if (target MATCHES "tools_.*")
        set(prefix "${base_path}")
        set(install_args install-tool --outputdir ${base_path} ${host} desktop ${target})
    else()
        set(prefix "${base_path}/${target}/${arch_path}")
        set(install_args install-qt --outputdir ${base_path} ${host} desktop ${target} ${arch} -m qtmultimedia)
    endif()

    if (NOT EXISTS "${prefix}")
        message(STATUS "Downloading binaries for Qt...")
        if (WIN32)
            set(aqt_path "${CMAKE_BINARY_DIR}/externals/aqt.exe")
            file(DOWNLOAD
                https://github.com/miurahr/aqtinstall/releases/download/v3.1.4/aqt.exe
                ${aqt_path} SHOW_PROGRESS)
            execute_process(COMMAND ${aqt_path} ${install_args})
        else()
            # aqt does not offer binary releases for other platforms, so download and run from pip.
            set(aqt_install_path "${CMAKE_BINARY_DIR}/externals/aqt")
            execute_process(COMMAND python3 -m pip install --target=${aqt_install_path} aqtinstall)
            execute_process(COMMAND ${CMAKE_COMMAND} -E env PYTHONPATH=${aqt_install_path} python3 -m aqt ${install_args})
        endif()
    endif()

    message(STATUS "Using downloaded Qt binaries at ${prefix}")
    set(${prefix_var} "${prefix}" PARENT_SCOPE)
endfunction()

function(get_external_prefix lib_name prefix_var)
    set(${prefix_var} "${CMAKE_BINARY_DIR}/externals/${lib_name}" PARENT_SCOPE)
endfunction()