include(CheckCSourceCompiles)
include(CheckSymbolExists)
include(CheckIncludeFile)
include(CheckFunctionExists)
include(CheckTypeSize)
include(GNUInstallDirs) # For install paths

# We install so many files... skip up-to-date messages
set(CMAKE_INSTALL_MESSAGE LAZY)

# Language support
set(CMAKE_C_STANDARD 99)
set(CMAKE_C_STANDARD_REQUIRED TRUE)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)

# Should be available in C++11 but not all systems have it
check_function_exists(at_quick_exit HAVE_AT_QUICK_EXIT)

# Required to generate the network protocol implementation
find_package(Python3 REQUIRED)

# Required as the main networking and utility library
find_package(Qt6 6.6 COMPONENTS Core Gui Network REQUIRED)

# Required for utility
if(FREECIV_ENABLE_SERVER)
  find_package(Readline REQUIRED)
  check_symbol_exists(rl_completion_suppress_append "readline/readline.h" HAVE_SUPPRESS_APPEND)
endif()

# Internationalization
add_custom_target(freeciv_translations)
if(FREECIV_ENABLE_NLS)
  find_package(Intl REQUIRED)
  if (${CMAKE_VERSION} VERSION_EQUAL 3.20.0 AND NOT Intl_LIBRARIES)
    message(FATAL_ERROR
      "Due to a bug in CMake, translations can not be used with "
      "CMake 3.20.0 on your system. "
      "You can turn off translations by passing -DFREECIV_ENABLE_NLS=NO to "
      "CMake at configure time. "
      "Please see https://github.com/longturn/freeciv21/issues/383")
  endif()

  set(ENABLE_NLS TRUE)
  include(GettextTranslate)
  set(GettextTranslate_GMO_BINARY TRUE)
  set(GettextTranslate_POT_BINARY TRUE)
  add_subdirectory(translations/core)
  add_subdirectory(translations/nations)
  add_dependencies(freeciv_translations freeciv21-core.pot-update)
  add_dependencies(freeciv_translations freeciv21-nations.pot-update)
  if (FREECIV_BUILD_TOOLS EQUAL ON)
    add_subdirectory(translations/ruledit)
    add_dependencies(ruledit_translations freeciv21-ruledit.pot-update)
  endif()
  add_dependencies(freeciv_translations update-po)
  add_dependencies(freeciv_translations update-gmo)
endif()

# SDL2 for audio
find_package(SDL2)
find_package(SDL2_mixer)
if (EMSCRIPTEN OR (SDL2_mixer_FOUND AND SDL2_FOUND))
  message(STATUS "Building with audio support enabled")
  set(AUDIO_SDL TRUE)
else()
  if (NOT SDL2_FOUND)
    message(STATUS "SDL2 not found - audio support disabled")
  endif()
  if (NOT SDL2_mixer_FOUND)
    message(STATUS "SDL2_mixer not found - audio support disabled")
  endif()
endif()

# Lua
#
# Lua is not binary compatible even between minor releases. We stick to Lua 5.3.
#
# The tolua program is compatible with Lua 5.3, but the library may not be (eg
# on Debian it's linked to Lua 5.2). We always build the library. When not
# cross-compiling, we can also build the program. When cross-compiling, an
# externally provided tolua program is required (or an emulator for the target
# platform, eg qemu).
find_package(Lua 5.3 REQUIRED)

# Create an imported target since it's not created by CMake :(
# Get a library name for IMPORTED_LOCATION

if(NOT TARGET lua)
    if (NOT EMSCRIPTEN AND NOT APPLE)
      add_library(lua UNKNOWN IMPORTED GLOBAL)
      list(GET LUA_LIBRARIES 0 loc)
      set_target_properties(lua PROPERTIES
        IMPORTED_LOCATION "${loc}"
        INTERFACE_INCLUDE_DIRECTORIES "${LUA_INCLUDE_DIR}")
      # Link to all libs, not just the first
      target_link_libraries(lua INTERFACE "${LUA_LIBRARIES}")
    endif()
endif()

if (CMAKE_CROSSCOMPILING AND NOT CMAKE_CROSSCOMPILING_EMULATOR)
  find_package(ToLuaProgram REQUIRED)
else()
  find_package(ToLuaProgram)
endif()
add_subdirectory(dependencies/tolua-5.2) # Will build the program if not found.
add_subdirectory(dependencies/sol2)

# backward-cpp
include(FreecivBackward)

# Compression
find_package(KF6Archive REQUIRED)
set(FREECIV_HAVE_BZ2 ${KArchive_HAVE_BZIP2})
set(FREECIV_HAVE_LZMA ${KArchive_HAVE_LZMA})
set(FREECIV_HAVE_ZSTD ${KArchive_HAVE_ZSTD})

find_package(ZLIB REQUIRED) # Network protocol code

# Some systems don't have a well-defined root user
if (EMSCRIPTEN)
  set(ALWAYS_ROOT TRUE)
endif()

# Networking library
if (WIN32 OR MSYS)
  set(FREECIV_MSWINDOWS TRUE)
endif()

# Define the GUI type for Win32 Qt programs
# Removes the console window that pops up with the GUI app
if (WIN32 OR MSYS)
  set(GUI_TYPE WIN32)
else()
  set(GUI_TYPE "")
endif()

if (EMSCRIPTEN)
  # This is a bit hacky and maybe it should be removed.
  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -s ERROR_ON_UNDEFINED_SYMBOLS=0")
endif()

if (FREECIV_ENABLE_CLIENT
    OR FREECIV_ENABLE_FCMP_CLI
    OR FREECIV_ENABLE_FCMP_QT)
  # Version comparison library (this should really be part of utility/)
  add_subdirectory(dependencies/cvercmp)
endif()

# GUI dependencies
if (FREECIV_ENABLE_CLIENT
    OR FREECIV_ENABLE_FCMP_QT
    OR FREECIV_ENABLE_RULEDIT)
  # May want to relax the version later
  find_package(Qt6 6.6 COMPONENTS Widgets REQUIRED)
endif()
if (FREECIV_ENABLE_CLIENT)
  find_package(Qt6 6.6 COMPONENTS Multimedia Svg REQUIRED)
  if(NOT APPLE)
    # Check that we can decode ogg/vorbis
    include(CheckSourceRuns)
    set(CMAKE_REQUIRED_LIBRARIES Qt6::Multimedia)
    check_source_runs(CXX [[
      #include <QMediaFormat>
      int main() {
        auto fmt = QMediaFormat(QMediaFormat::Ogg);
        fmt.setAudioCodec(QMediaFormat::AudioCodec::Vorbis);
        return fmt.isSupported(QMediaFormat::Decode) ? 0 : 1;
      }
      ]]
      HAVE_OGG_VORBIS)
    unset(CMAKE_REQUIRED_LIBRARIES)
    if (NOT HAVE_OGG_VORBIS)
      message(WARNING "Qt Multimedia does not support OGG Vorbis on your system. "
                      "Additional runtime libraries or environment variables "
                      "(QT_MEDIA_BACKEND) may be needed to play in-game music.")
    endif()
  endif()
endif()

# FCMP-specific dependencies
if (FREECIV_ENABLE_FCMP_CLI OR FREECIV_ENABLE_FCMP_QT)
  find_package(SQLite3 REQUIRED)
endif()

# Testing
if (NOT EMSCRIPTEN)
  include(CTest)
  if (BUILD_TESTING)
    find_package(Qt6Test REQUIRED)
  endif()
endif()