# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: BSD-3-Clause
#.rst:
# FindFFmpeg
# ----------
#
# Try to find the required ffmpeg components (default: AVFORMAT, AVUTIL, AVCODEC)
#
# Next variables can be used to hint FFmpeg libs search:
#
# ::
#
#   PC_<component>_LIBRARY_DIRS
#   PC_FFMPEG_LIBRARY_DIRS
#   PC_<component>_INCLUDE_DIRS
#   PC_FFMPEG_INCLUDE_DIRS
#
# Once done this will define
#
# ::
#
#   FFMPEG_FOUND         - System has the all required components.
#   FFMPEG_SHARED_LIBRARIES - Found FFmpeg shared libraries.
#
# For each of the components it will additionally set.
#
# ::
#
#   AVCODEC
#   AVDEVICE
#   AVFORMAT
#   AVFILTER
#   AVUTIL
#   POSTPROC
#   SWSCALE
#
# the following variables will be defined
#
# ::
#
#   <component>_FOUND        - System has <component>
#   FFMPEG_<component>_FOUND - System has <component> (as checked by FHSPA)
#   <component>_INCLUDE_DIRS - Include directory necessary for using the <component> headers
#   <component>_LIBRARIES    - Link these to use <component>
#   <component>_LIBRARY_DIRS - Link directories
#   <component>_DEFINITIONS  - Compiler switches required for using <component>
#   <component>_VERSION      - The components version
#
# the following import targets is created
#
# ::
#
#   FFmpeg::FFmpeg - for all components
#   FFmpeg::<component> - where <component> in lower case (FFmpeg::avcodec) for each components
#
# Copyright (c) 2006, Matthias Kretz, <kretz@kde.org>
# Copyright (c) 2008, Alexander Neundorf, <neundorf@kde.org>
# Copyright (c) 2011, Michael Jansen, <kde@michael-jansen.biz>
# Copyright (c) 2017, Alexander Drozdov, <adrozdoff@gmail.com>
#

include(FindPackageHandleStandardArgs)

# The default components were taken from a survey over other FindFFMPEG.cmake files
if (NOT FFmpeg_FIND_COMPONENTS)
    set(FFmpeg_FIND_COMPONENTS AVCODEC AVFORMAT AVUTIL)
endif ()

if (QT_DEPLOY_FFMPEG AND BUILD_SHARED_LIBS)
    set(shared_libs_desired TRUE)
endif()

if(IOS)
    set(QT_FFMPEG_SHARED_LIBRARY_SUFFIX ".xcframework")
else()
    set(QT_FFMPEG_SHARED_LIBRARY_SUFFIX "${CMAKE_SHARED_LIBRARY_SUFFIX}")
endif()

# finds FFmpeg libs, including symlinks, for the specified component.
macro(find_shared_libs_for_component _component)
    # the searching pattern is pretty rough but it seems to be sufficient to gather dynamic libs
    get_filename_component(name_we ${${_component}_LIBRARY} NAME_WE)

    if (WIN32)
        get_filename_component(dir_name ${${_component}_LIBRARY_DIR} NAME)
        if (${dir_name} STREQUAL "lib" AND EXISTS "${${_component}_LIBRARY_DIR}/../bin")
            # llvm-mingv builds aux ffmpeg static libs like lib/libavutil.dll.a and cmake finds
            # only them even though the folder bin/ contains proper *.dll and *.lib.

            string(REGEX REPLACE "^lib" "" name_we "${name_we}")
            set(shared_lib_pattern "../bin/${name_we}*${QT_FFMPEG_SHARED_LIBRARY_SUFFIX}")
        else()
            set(shared_lib_pattern "${name_we}*${QT_FFMPEG_SHARED_LIBRARY_SUFFIX}")
        endif()

    else()
        set(shared_lib_pattern "${name_we}*${QT_FFMPEG_SHARED_LIBRARY_SUFFIX}*")
    endif()

    file(GLOB ${_component}_SHARED_LIBRARIES "${${_component}_LIBRARY_DIR}/${shared_lib_pattern}")
endmacro()

#
### Macro: set_component_found
#
# Marks the given component as found if both *_LIBRARY_NAME AND *_INCLUDE_DIRS is present.
#
macro(set_component_found _component)
    if (${_component}_LIBRARY_NAME AND ${_component}_INCLUDE_DIR)
        # message(STATUS "  - ${_component} found.")
        set(${_component}_FOUND TRUE)
        set(${CMAKE_FIND_PACKAGE_NAME}_${_component}_FOUND TRUE)
    else ()
        # message(STATUS "  - ${_component} not found.")
    endif ()
endmacro()

find_package(PkgConfig QUIET)
if (NOT PKG_CONFIG_FOUND AND NOT FFMPEG_DIR)
    set(FFMPEG_DIR "/usr/local")
endif()
#
### Macro: find_component
#
# Checks for the given component by invoking pkgconfig and then looking up the libraries and
# include directories.
#
macro(find_component _component _pkgconfig _library _header)
    # use pkg-config to get the directories and then use these values
    # in the FIND_PATH() and FIND_LIBRARY() calls
    if (PKG_CONFIG_FOUND AND NOT FFMPEG_DIR)
        pkg_check_modules(PC_${_component} ${_pkgconfig})
    endif ()

    if (FFMPEG_DIR OR FFMPEG_ROOT)
        set(__find_ffmpeg_backup_root_dir "${CMAKE_FIND_ROOT_PATH}")
    endif()

    if(FFMPEG_DIR)
        list(APPEND CMAKE_FIND_ROOT_PATH "${FFMPEG_DIR}")
    endif()

    if(FFMPEG_ROOT)
        list(APPEND CMAKE_FIND_ROOT_PATH "${FFMPEG_ROOT}")
    endif()

    if (${_component}_INCLUDE_DIR AND NOT EXISTS ${${_component}_INCLUDE_DIR})
        message(STATUS "Cached include dir ${${_component}_INCLUDE_DIR} doesn't exist")
        unset(${_component}_INCLUDE_DIR CACHE)
    endif()

    find_path(${_component}_INCLUDE_DIR ${_header}
        HINTS
            ${PC_${_component}_INCLUDEDIR}
            ${PC_${_component}_INCLUDE_DIRS}
            ${PC_FFMPEG_INCLUDE_DIRS}
        PATHS
            ${FFMPEG_DIR}
        PATH_SUFFIXES
            ffmpeg include
    )

    if (shared_libs_desired AND NOT WIN32)
        set(CMAKE_FIND_LIBRARY_SUFFIXES "${QT_FFMPEG_SHARED_LIBRARY_SUFFIX};${CMAKE_STATIC_LIBRARY_SUFFIX}")
    endif()

    if (${_component}_LIBRARY AND NOT EXISTS ${${_component}_LIBRARY})
        message(STATUS "Cached library ${${_component}_LIBRARY} doesn't exist")
        unset(${_component}_LIBRARY CACHE)
    endif()

    # Search for the relevant libraries. On iOS we deploy .xcframeworks, which aren't found by
    # find_library, so we rely on find_path.
    if (APPLE AND IOS)
        find_path(${_component}_LIBRARY
            NAMES lib${_library}${QT_FFMPEG_SHARED_LIBRARY_SUFFIX}
            PATHS
                ${FFMPEG_DIR}
            PATH_SUFFIXES
                lib bin framework
        )
        # If found, append the path with the file we were looking for.
        if (${_component}_LIBRARY)
            set(${_component}_LIBRARY "${${_component}_LIBRARY}/lib${_library}${QT_FFMPEG_SHARED_LIBRARY_SUFFIX}")
        endif()
    else()
        find_library(${_component}_LIBRARY
            NAMES ${PC_${_component}_LIBRARIES} ${_library}
            HINTS
                ${PC_${_component}_LIBDIR}
                ${PC_${_component}_LIBRARY_DIRS}
                ${PC_FFMPEG_LIBRARY_DIRS}
            PATHS
                ${FFMPEG_DIR}
            PATH_SUFFIXES
                lib bin
        )
    endif()

    if(FFMPEG_DIR OR FFMPEG_ROOT)
        set(CMAKE_FIND_ROOT_PATH "${__find_ffmpeg_backup_root_dir}")
    endif()

    if (${_component}_LIBRARY)
        get_filename_component(${_component}_LIBRARY_DIR ${${_component}_LIBRARY} DIRECTORY)
        get_filename_component(${_component}_LIBRARY_NAME ${${_component}_LIBRARY} NAME)

        # On Windows, shared linking goes through 'integration' static libs, so we should look for shared ones anyway
        # On Unix, we gather symlinks as well so that we could install them.
        if (WIN32 OR ${${_component}_LIBRARY_NAME} MATCHES "\\${QT_FFMPEG_SHARED_LIBRARY_SUFFIX}$")
            find_shared_libs_for_component(${_component})
        endif()

    endif()

    set(${_component}_DEFINITIONS  ${PC_${_component}_CFLAGS_OTHER})
    set_component_found(${_component})

    mark_as_advanced(${_component}_LIBRARY)
endmacro()

# Clear the previously cached variables, because they are recomputed every time
# the Find script is included.
unset(FFMPEG_SHARED_LIBRARIES CACHE)
unset(FFMPEG_STUBS CACHE)

# Check for components.
foreach (_component ${FFmpeg_FIND_COMPONENTS})
    string(TOLOWER ${_component} library)
    find_component(${_component} "lib${library}" ${library} "lib${library}/${library}.h")

    if (${_component}_FOUND)
        list(APPEND FFMPEG_LIBRARIES    ${${_component}_LIBRARY_NAME})
        list(APPEND FFMPEG_DEFINITIONS  ${${_component}_DEFINITIONS})
        list(APPEND FFMPEG_INCLUDE_DIRS ${${_component}_INCLUDE_DIR})
        list(APPEND FFMPEG_LIBRARY_DIRS ${${_component}_LIBRARY_DIR})

        if (${_component}_SHARED_LIBRARIES)
            list(APPEND FFMPEG_SHARED_LIBRARIES ${${_component}_SHARED_LIBRARIES})
            list(APPEND FFMPEG_SHARED_COMPONENTS ${_component})
        else()
            list(APPEND FFMPEG_STATIC_COMPONENTS ${_component})
        endif()

        mark_as_advanced(${_component}_LIBRARY_NAME ${_component}_DEFINITIONS ${_component}_INCLUDE_DIR
            ${_component}_LIBRARY_DIR ${_component}_SHARED_LIBRARIES)
    endif()
endforeach()


function(qt_internal_multimedia_try_add_dynamic_resolve_dependency _component dep)
    set(dynamic_resolve_added FALSE PARENT_SCOPE)

    if (NOT ANDROID AND NOT LINUX)
        return()
    endif()

    set(supported_stubs "ssl|crypto|va|va-drm|va-x11")
    if(${_component}_SHARED_LIBRARIES)
        set(stub_prefix "Qt${PROJECT_VERSION_MAJOR}FFmpegStub-")
        if (${dep} MATCHES "^${stub_prefix}(${supported_stubs})$")
            string(REPLACE "${stub_prefix}" "" dep "${dep}")
            set(FFMPEG_STUBS ${FFMPEG_STUBS} ${dep} CACHE INTERNAL "")

            set(dynamic_resolve_added TRUE PARENT_SCOPE)
        endif()
    elseif (${dep} MATCHES "^(${supported_stubs})$")
        set(FFMPEG_STUBS ${FFMPEG_STUBS} ${dep} CACHE INTERNAL "")
        set(dynamic_resolve_added TRUE PARENT_SCOPE)
    endif()
endfunction()

# Function parses package config file to find the static library dependencies
# and adds them to the target library.
function(__ffmpeg_internal_set_dependencies _component)
    string(TOLOWER ${_component} lib)

    if (WIN32)
        set(PC_FILE ${${_component}_LIBRARY_DIR}/../lib/pkgconfig/lib${lib}.pc)
    else()
        set(PC_FILE ${${_component}_LIBRARY_DIR}/pkgconfig/lib${lib}.pc)
    endif()

    if(EXISTS ${PC_FILE})
        file(READ ${PC_FILE} pcfile)

        set(prefix_l "(^| )\\-l")
        set(suffix_lib "\\.lib($| )")

        string(REGEX REPLACE ".*Libs:([^\n\r]+).*" "\\1" out "${pcfile}")
        string(REGEX MATCHALL "${prefix_l}[^ ]+" libs_dependency ${out})
        string(REGEX MATCHALL "[^ ]+${suffix_lib}" libs_dependency_lib ${out})

        string(REGEX REPLACE ".*Libs.private:([^\n\r]+).*" "\\1" out "${pcfile}")
        string(REGEX MATCHALL "${prefix_l}[^ ]+" libs_private_dependency ${out})
        string(REGEX MATCHALL "[^ ]+${suffix_lib}" libs_private_dependency_lib ${out})

        list(APPEND deps_no_suffix ${libs_dependency} ${libs_private_dependency})
        foreach(dependency ${deps_no_suffix})
            string(REGEX REPLACE ${prefix_l} "" dependency ${dependency})
            if(NOT ${lib} STREQUAL ${dependency})
                qt_internal_multimedia_try_add_dynamic_resolve_dependency(${_component} ${dependency})
                if(NOT dynamic_resolve_added AND NOT ${_component}_SHARED_LIBRARIES)
                    target_link_libraries(FFmpeg::${lib} INTERFACE ${dependency})
                endif()
            endif()
        endforeach()

        if(NOT ${_component}_SHARED_LIBRARIES)
            list(APPEND deps_lib_suffix ${libs_dependency_lib} ${libs_private_dependency_lib})
            foreach(dependency ${deps_lib_suffix})
                string(REGEX REPLACE ${suffix_lib} "" dependency ${dependency})
                target_link_libraries(FFmpeg::${lib} INTERFACE ${dependency})
            endforeach()
        endif()
    else()
        message(WARNING "FFmpeg pc file ${PC_FILE} is not found")
    endif()
endfunction()

# Check for cached results. If there are skip the costly part.
#if (NOT FFMPEG_LIBRARIES)

  # Check if the required components were found and add their stuff to the FFMPEG_* vars.


foreach (_component ${FFmpeg_FIND_COMPONENTS})
    if (${_component}_FOUND)
        string(TOLOWER ${_component} _lowerComponent)
        if (NOT TARGET FFmpeg::${_lowerComponent})
            add_library(FFmpeg::${_lowerComponent} INTERFACE IMPORTED)
            set_target_properties(FFmpeg::${_lowerComponent} PROPERTIES
                INTERFACE_COMPILE_OPTIONS "${${_component}_DEFINITIONS}"
                INTERFACE_INCLUDE_DIRECTORIES ${${_component}_INCLUDE_DIR}
                INTERFACE_LINK_LIBRARIES "${${_component}_LIBRARY_NAME}"
                INTERFACE_LINK_DIRECTORIES "${${_component}_LIBRARY_DIR}"
            )

            __ffmpeg_internal_set_dependencies(${_component})
            target_link_libraries(FFmpeg::${_lowerComponent} INTERFACE "${${_component}_LIBRARY_NAME}")
            if (UNIX AND NOT APPLE)
                target_link_options(FFmpeg::${_lowerComponent} INTERFACE  "-Wl,--exclude-libs=lib${_lowerComponent}")
            endif ()
        endif()
    endif()
endforeach ()

# Build the include path with duplicates removed.
list(REMOVE_DUPLICATES FFMPEG_INCLUDE_DIRS)
list(REMOVE_DUPLICATES FFMPEG_LIBRARY_DIRS)
list(REMOVE_DUPLICATES FFMPEG_SHARED_LIBRARIES)
list(REMOVE_DUPLICATES FFMPEG_STUBS)

message(STATUS "FFmpeg shared libs: ${FFMPEG_SHARED_LIBRARIES}")
message(STATUS "FFmpeg stubs: ${FFMPEG_STUBS}")

# cache the vars.
set(FFMPEG_SHARED_LIBRARIES ${FFMPEG_SHARED_LIBRARIES} CACHE STRING "The FFmpeg dynamic libraries." FORCE)
set(FFMPEG_STUBS ${FFMPEG_STUBS} CACHE STRING "The FFmpeg stubs." FORCE)

mark_as_advanced(FFMPEG_SHARED_LIBRARIES)
mark_as_advanced(FFMPEG_STUBS)

# endif ()

list(LENGTH FFMPEG_LIBRARY_DIRS DIRS_COUNT)
if (${DIRS_COUNT} GREATER 1)
    message(WARNING "One ffmpeg library dir is expected, found dirs: ${FFMPEG_LIBRARY_DIRS}")
endif()

if(FFMPEG_SHARED_COMPONENTS AND FFMPEG_STATIC_COMPONENTS)
    message(WARNING
        "Only static or shared components are expected\n"
        "  static components: ${FFMPEG_STATIC_COMPONENTS}\n"
        "  shared components: ${FFMPEG_SHARED_COMPONENTS}")
endif()

if (shared_libs_desired AND NOT FFMPEG_SHARED_COMPONENTS)
    message(WARNING
        "Shared FFmpeg libs are desired as QT_DEPLOY_FFMPEG=TRUE, but haven't been found!\n"
        "Remove QT_DEPLOY_FFMPEG or set the proper path to shared FFmpeg via FFMPEG_DIR.")
endif()

if (NOT TARGET FFmpeg::FFmpeg)
    add_library(FFmpeg INTERFACE)
    set_target_properties(FFmpeg PROPERTIES
        INTERFACE_COMPILE_OPTIONS "${FFMPEG_DEFINITIONS}"
        INTERFACE_INCLUDE_DIRECTORIES "${FFMPEG_INCLUDE_DIRS}"
        INTERFACE_LINK_LIBRARIES "${FFMPEG_LIBRARIES}"
        INTERFACE_LINK_DIRECTORIES "${FFMPEG_LIBRARY_DIRS}"
    )
    add_library(FFmpeg::FFmpeg ALIAS FFmpeg)
endif()

# Compile the list of required vars
set(_FFmpeg_REQUIRED_VARS FFMPEG_LIBRARIES FFMPEG_INCLUDE_DIRS)
foreach (_component ${FFmpeg_FIND_COMPONENTS})
    list(APPEND _FFmpeg_REQUIRED_VARS ${_component}_LIBRARY ${_component}_INCLUDE_DIR)
endforeach ()

set(FIND_FFMPEG_HELP_STRING
[=[FFMPEG_DIR CMake variable is not correct.
    Make sure that the FFMPEG_DIR CMake variable is set to a path that
    contains FFmpeg 'lib' and 'include' directories and that the FFmpeg
    installation is built with the avformat, avcodec, swresample,
    swscale, and avutil libraries. To resolve the issue, please delete
    CMakeCache.txt and run configure again with the correct FFMPEG_DIR
    CMake variable set.
]=])

# Give a nice error message if some of the required vars are missing.
find_package_handle_standard_args(FFmpeg
    REQUIRED_VARS ${_FFmpeg_REQUIRED_VARS}
    HANDLE_COMPONENTS
    REASON_FAILURE_MESSAGE
    ${FIND_FFMPEG_HELP_STRING}
)
