cmake_minimum_required(VERSION 3.1.0 FATAL_ERROR)

# metadata
set(META_PROJECT_NAME syncthing)
set(META_PROJECT_TYPE library)
set(META_APP_NAME "Syncthing library")
set(META_APP_DESCRIPTION "Syncthing itself, built as a shared or static library")
set(META_PROJECT_VARNAME_UPPER LIB_SYNCTHING)

# add project files
set(HEADER_FILES
    interface.h
)
set(SRC_FILES
    "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.h"
    interface.cpp
)

set(TEST_HEADER_FILES
)
set(TEST_SRC_FILES
    tests/interfacetests.cpp
)

# find the go binary
find_program(GO_BIN go)
if(NOT GO_BIN)
    message(FATAL_ERROR "The go binary could not be located.")
endif()

# determine GOARCH for target
set(GO_TARGET_ARCH_OVERRIDE "" CACHE STRING "overrides the 'GOARCH' variable")
if(GO_TARGET_ARCH_OVERRIDE)
    set(GO_TARGET_ARCH "${GO_TARGET_ARCH_OVERRIDE}")
elseif(NOT CMAKE_CROSSCOMPILING)
    set(GO_TARGET_ARCH "")
elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
    set(GO_TARGET_ARCH "amd64")
elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "i[3-6]86")
    set(GO_TARGET_ARCH "386")
elseif(CMAKE_SYSTEM_NAME MATCHES "(ppc64|ppc64le|arm|arm64|s390x)")
    set(GO_TARGET_ARCH "${CMAKE_SYSTEM_NAME}")
else()
    message(FATAL_ERROR "Unable to auto-determine GOARCH. Please set GO_TARGET_ARCH_OVERRIDE manually.")
endif()
# determine GOOS for target
set(GO_TARGET_OS_OVERRIDE "" CACHE STRING "overrides the 'GOOS' variable")
if(GO_TARGET_OS_OVERRIDE)
    set(GO_TARGET_OS "${GO_TARGET_OS_OVERRIDE}")
elseif(NOT CMAKE_CROSSCOMPILING)
    set(GO_TARGET_OS "")
elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
    set(GO_TARGET_OS "linux")
elseif(CMAKE_SYSTEM_NAME STREQUAL "Android")
    set(GO_TARGET_OS "android")
elseif(CMAKE_SYSTEM_NAME STREQUAL "Windows")
    set(GO_TARGET_OS "windows")
elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
    set(GO_TARGET_OS "freebsd")
elseif(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
    set(GO_TARGET_OS "darwin")
else()
    message(FATAL_ERROR "Unable to auto-determine GOOS. Please set GO_TARGET_OS_OVERRIDE manually.")
endif()
message(STATUS "Using GOOS=${GO_TARGET_OS} and GOARCH=${GO_TARGET_ARCH}")

# locate the Syncthing checkout
set(GO_DEVELOPMENT_PATH "${CMAKE_CURRENT_SOURCE_DIR}/go" CACHE PATH "the 'GOPATH'")
set(SYNCTHING_PATH "${CMAKE_CURRENT_SOURCE_DIR}/go/src/github.com/syncthing/syncthing" CACHE PATH "path of Syncthing checkout")

# find Syncthing's assets
# caveat: newly added assets will not cause CMake to automatically regenerate
file(GLOB_RECURSE SRC_FILES_SYNCTHING_ASSETS
    LIST_DIRECTORIES false
    RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}"
    "${SYNCTHING_PATH}/gui/*"
)
if(NOT SRC_FILES_SYNCTHING_ASSETS)
    message(FATAL_ERROR "No asset files found in Syncthing checkout \"${CMAKE_CURRENT_SOURCE_DIR}/go/src/github.com/syncthing/syncthing\".")
endif()

# find Syncthing's source code
# caveat: newly added files will not cause CMake to automatically regenerate
file(GLOB_RECURSE SRC_FILES_SYNCTHING
    LIST_DIRECTORIES false
    RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}"
    "${SYNCTHING_PATH}/cmd/*.go"
    "${SYNCTHING_PATH}/cmd/*.h"
    "${SYNCTHING_PATH}/cmd/*.c"
)
if(NOT SRC_FILES_SYNCTHING)
    message(FATAL_ERROR "No *.go files found in Syncthing checkout \"${CMAKE_CURRENT_SOURCE_DIR}/go/src/github.com/syncthing/syncthing\".")
endif()
list(APPEND SRC_FILES_SYNCTHING "${SYNCTHING_PATH}/lib/auto/gui.files.go")
message(STATUS "Syncthing's go files: ${SRC_FILES_SYNCTHING}")

# generate Syncthing's assets: don't set GOARCH/GOOS here, this is supposed to run on the host
add_custom_command(
    OUTPUT
        "${SYNCTHING_PATH}/lib/auto/gui.files.go"
    COMMAND
        "GOPATH=${GO_DEVELOPMENT_PATH}"
        "${GO_BIN}" run ./script/genassets.go gui > lib/auto/gui.files.go
    DEPENDS ${SRC_FILES_SYNCTHING_ASSETS}
    WORKING_DIRECTORY "${SYNCTHING_PATH}"
    COMMENT "Building Syncthing's assets"
)

# compile Syncthing as static library
add_custom_command(
    OUTPUT
        "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.a"
        "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.h"
    COMMAND
        "CC=${CMAKE_C_COMPILER}"
        "CXX=${CMAKE_CXX_COMPILER}"
        "AR=${CMAKE_C_COMPILER_AR}"
        "GOOS=${GO_TARGET_OS}"
        "GOARCH=${GO_TARGET_ARCH}"
        "CGO_ENABLED=1"
        "GOPATH=${GO_DEVELOPMENT_PATH}"
        "${GO_BIN}" build -v -buildmode c-archive
        -o "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.a"
        ./cmd/syncthing
        && "${CMAKE_RANLIB}" "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.a"
    DEPENDS ${SRC_FILES_SYNCTHING}
    WORKING_DIRECTORY "${SYNCTHING_PATH}"
    COMMENT "Building Syncthing itself"
)

# do not use this library directly but depend on it
list(APPEND PRIVATE_LIBRARIES "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.a")
# add additional libraries (not sure if go build could provide this list somehow to make this more generic)
if(WIN32)
    list(APPEND PRIVATE_LIBRARIES -lws2_32 -lwinmm)
elseif(UNIX)
    list(APPEND PRIVATE_LIBRARIES -lpthread)
endif()

# ensure we can find libsyncthing.h from Syncthing's source tree when building the interface
list(APPEND PRIVATE_SHARED_INCLUDE_DIRS "${SYNCTHING_PATH}/cmd/syncthing")
list(APPEND PRIVATE_STATIC_INCLUDE_DIRS "${SYNCTHING_PATH}/cmd/syncthing")

# find c++utilities
find_package(c++utilities 4.17.0 REQUIRED)
list(APPEND CMAKE_MODULE_PATH ${CPP_UTILITIES_MODULE_DIRS})
list(APPEND PRIVATE_SHARED_INCLUDE_DIRS ${CPP_UTILITIES_INCLUDE_DIRS})
list(APPEND PRIVATE_STATIC_INCLUDE_DIRS ${CPP_UTILITIES_INCLUDE_DIRS})

# include modules to apply configuration
include(BasicConfig)
include(WindowsResources)
include(LibraryTarget)
include(TestTarget)
include(Doxygen)
include(ConfigHeader)

# create install target for static libsyncthinginternal.a if we're also creating a static libsyncthing.a
if(BUILD_STATIC_LIBS AND NOT META_NO_INSTALL_TARGETS AND ENABLE_INSTALL_TARGETS)
    install(
        FILES "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.a"
        DESTINATION "lib${SELECTED_LIB_SUFFIX}"
        COMPONENT binary
    )
endif()