cmake_minimum_required(VERSION 3.10)

set(EPHEMERAL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ephemeral")

# Configuration provided via flutter tool.
include(${EPHEMERAL_DIR}/generated_config.cmake)

# TODO: Move the rest of this into files in ephemeral. See
# https://github.com/flutter/flutter/issues/57146.
set(WRAPPER_ROOT "${EPHEMERAL_DIR}/cpp_client_wrapper_glfw")

# Serves the same purpose as list(TRANSFORM ... PREPEND ...),
# which isn't available in 3.10.
function(list_prepend LIST_NAME PREFIX)
    set(NEW_LIST "")
    foreach(element ${${LIST_NAME}})
        list(APPEND NEW_LIST "${PREFIX}${element}")
    endforeach(element)
    set(${LIST_NAME} "${NEW_LIST}" PARENT_SCOPE)
endfunction()

# === Flutter Library ===
set(FLUTTER_LIBRARY "${EPHEMERAL_DIR}/libflutter_linux_glfw.so")

# Published to parent scope for install step.
set(FLUTTER_LIBRARY_DIR "${EPHEMERAL_DIR}" PARENT_SCOPE)
set(FLUTTER_ICU_DATA_FILE "${EPHEMERAL_DIR}/icudtl.dat" PARENT_SCOPE)
set(PROJECT_BUILD_DIR "${PROJECT_DIR}/build/" PARENT_SCOPE)

list(APPEND FLUTTER_LIBRARY_HEADERS
  "flutter_export.h"
  "flutter_glfw.h"
  "flutter_messenger.h"
  "flutter_plugin_registrar.h"
)
list_prepend(FLUTER_LIBRARY_HEADERS "${EPHEMERAL_DIR}/")
add_library(flutter INTERFACE)
target_include_directories(flutter INTERFACE
  "${EPHEMERAL_DIR}"
)
target_link_libraries(flutter INTERFACE "${FLUTTER_LIBRARY}")
add_dependencies(flutter flutter_assemble)

# === Wrapper ===
list(APPEND CPP_WRAPPER_SOURCES_CORE
  "engine_method_result.cc"
	"standard_codec.cc"
)
list_prepend(CPP_WRAPPER_SOURCES_CORE "${WRAPPER_ROOT}/")
list(APPEND CPP_WRAPPER_SOURCES_PLUGIN
  "plugin_registrar.cc"
)
list_prepend(CPP_WRAPPER_SOURCES_PLUGIN "${WRAPPER_ROOT}/")
list(APPEND CPP_WRAPPER_SOURCES_APP
  "flutter_engine.cc"
  "flutter_window_controller.cc"
)
list_prepend(CPP_WRAPPER_SOURCES_APP "${WRAPPER_ROOT}/")

# Wrapper sources needed for a plugin.
add_library(flutter_wrapper_plugin STATIC
  ${CPP_WRAPPER_SOURCES_CORE}
  ${CPP_WRAPPER_SOURCES_PLUGIN}
)
apply_standard_settings(flutter_wrapper_plugin)
set_target_properties(flutter_wrapper_plugin PROPERTIES
  POSITION_INDEPENDENT_CODE ON)
set_target_properties(flutter_wrapper_plugin PROPERTIES
  CXX_VISIBILITY_PRESET hidden)
target_link_libraries(flutter_wrapper_plugin PUBLIC flutter)
target_include_directories(flutter_wrapper_plugin PUBLIC
  "${WRAPPER_ROOT}/include"
)
add_dependencies(flutter_wrapper_plugin flutter_assemble)

# Wrapper sources needed for the runner.
add_library(flutter_wrapper_app STATIC
  ${CPP_WRAPPER_SOURCES_CORE}
  ${CPP_WRAPPER_SOURCES_APP}
)
apply_standard_settings(flutter_wrapper_app)
target_link_libraries(flutter_wrapper_app PUBLIC flutter)
target_include_directories(flutter_wrapper_app PUBLIC
  "${WRAPPER_ROOT}/include"
)
add_dependencies(flutter_wrapper_app flutter_assemble)

# === Flutter tool backend ===
# _phony_ is a non-existent file to force this command to run every time,
# since currently there's no way to get a full input/output list from the
# flutter tool.
add_custom_command(
  OUTPUT ${FLUTTER_LIBRARY} ${FLUTTER_LIBRARY_HEADERS}
    ${CPP_WRAPPER_SOURCES_CORE} ${CPP_WRAPPER_SOURCES_PLUGIN}
    ${CPP_WRAPPER_SOURCES_APP}
    ${CMAKE_CURRENT_BINARY_DIR}/_phony_
  COMMAND ${CMAKE_COMMAND} -E env
    ${FLUTTER_TOOL_ENVIRONMENT}
    "${FLUTTER_ROOT}/packages/flutter_tools/bin/tool_backend.sh"
      linux-x64 ${CMAKE_BUILD_TYPE}
)
add_custom_target(flutter_assemble DEPENDS
  "${FLUTTER_LIBRARY}"
  ${FLUTTER_LIBRARY_HEADERS}
  ${CPP_WRAPPER_SOURCES_CORE}
  ${CPP_WRAPPER_SOURCES_PLUGIN}
  ${CPP_WRAPPER_SOURCES_APP}
)