# FindFFmpeg.cmake
# CMake module to find FFmpeg installation
#
# This module defines:
#   FFMPEG_FOUND          - True if FFmpeg was found
#   FFMPEG_VERSION        - FFmpeg version
#   FFMPEG_INCLUDE_DIR   - FFmpeg include directory
#   FFMPEG_LIBRARIES     - List of FFmpeg libraries to link
#   FFMPEG_DLL_DIR       - Directory containing FFmpeg DLLs

# Use environment variable or default path
if(NOT DEFINED FFMPEG_ROOT)
    if(DEFINED ENV{FFMPEG_ROOT})
        set(FFMPEG_ROOT $ENV{FFMPEG_ROOT})
    else()
        # Default: look in third_party/ffmpeg relative to project root
        set(FFMPEG_ROOT "${CMAKE_SOURCE_DIR}/third_party/ffmpeg")
    endif()
endif()

# Find FFmpeg include directory
find_path(FFMPEG_INCLUDE_DIR
    NAMES libavcodec/avcodec.h
    PATHS ${FFMPEG_ROOT}/include
    NO_DEFAULT_PATH
    DOC "FFmpeg include directory"
)

# Find FFmpeg libraries
find_library(AVCODEC_LIBRARY
    NAMES avcodec
    PATHS ${FFMPEG_ROOT}/lib
    NO_DEFAULT_PATH
    DOC "FFmpeg avcodec library"
)

find_library(AVFORMAT_LIBRARY
    NAMES avformat
    PATHS ${FFMPEG_ROOT}/lib
    NO_DEFAULT_PATH
    DOC "FFmpeg avformat library"
)

find_library(AVUTIL_LIBRARY
    NAMES avutil
    PATHS ${FFMPEG_ROOT}/lib
    NO_DEFAULT_PATH
    DOC "FFmpeg avutil library"
)

find_library(SWSCALE_LIBRARY
    NAMES swscale
    PATHS ${FFMPEG_ROOT}/lib
    NO_DEFAULT_PATH
    DOC "FFmpeg swscale library"
)

find_library(SWRESAMPLE_LIBRARY
    NAMES swresample
    PATHS ${FFMPEG_ROOT}/lib
    NO_DEFAULT_PATH
    DOC "FFmpeg swresample library"
)

# Collect libraries
set(FFMPEG_LIBRARIES)
foreach(LIB AVCODEC AVFORMAT AVUTIL SWSCALE SWRESAMPLE)
    if(${LIB}_LIBRARY)
        list(APPEND FFMPEG_LIBRARIES "${${LIB}_LIBRARY}")
    endif()
endforeach()

# Set DLL directory
set(FFMPEG_DLL_DIR "${FFMPEG_ROOT}/bin" CACHE PATH "FFmpeg DLL directory")

# Handle QUIET and REQUIRED arguments
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(FFmpeg
    REQUIRED_VARS 
        FFMPEG_INCLUDE_DIR
        AVCODEC_LIBRARY
        AVFORMAT_LIBRARY
        AVUTIL_LIBRARY
        SWSCALE_LIBRARY
)

# Mark as advanced
mark_as_advanced(
    FFMPEG_INCLUDE_DIR
    AVCODEC_LIBRARY
    AVFORMAT_LIBRARY
    AVUTIL_LIBRARY
    SWSCALE_LIBRARY
    SWRESAMPLE_LIBRARY
    FFMPEG_DLL_DIR
)

# Print status message
if(NOT FFmpeg_FIND_QUIETLY)
    if(FFMPEG_FOUND)
        message(STATUS "Found FFmpeg: ${FFMPEG_ROOT}")
    else()
        message(STATUS "FFmpeg not found. Set FFMPEG_ROOT environment variable.")
    endif()
endif()