# ==============================================================================
# Find imgui
# ==============================================================================
# Builds Dear ImGui from the bundled sources in deps/imgui/.
#
# Targets provided:
#   imgui::imgui - The Dear ImGui library target
#
# Variables set:
#   imgui_FOUND       - TRUE if imgui is available
#   imgui_LIBRARIES   - The imgui library target (imgui::imgui)
#   imgui_INCLUDE_DIR - Include directories for imgui
#
# Configuration (set before find_package):
#   IMGUI_BACKEND_PLATFORM  - Platform backend (default: glfw)
#   IMGUI_BACKEND_RENDERER  - Renderer backend (default: opengl3)
#   IMGUI_BUILD_DEMO        - Include demo sources (default: ON)
# ==============================================================================

if (DEFINED _FINDIMGUI_INCLUDED)
    return()
endif()
set(_FINDIMGUI_INCLUDED TRUE)

set(IMGUI_BACKEND_PLATFORM "glfw"    CACHE STRING "Dear ImGui platform backend")
set(IMGUI_BACKEND_RENDERER "opengl3" CACHE STRING "Dear ImGui renderer backend")
option(IMGUI_BUILD_DEMO "Include Dear ImGui demo window sources" ON)

set(_imgui_source_dir "${CMAKE_CURRENT_LIST_DIR}/imgui")

if (NOT EXISTS "${_imgui_source_dir}/imgui.cpp")
    message(FATAL_ERROR "imgui sources not found at '${_imgui_source_dir}'")
endif()

# On Emscripten, GLFW is provided by compiler flags (-sUSE_GLFW=3), not a CMake target.
# Create a stub interface target so imgui's CMakeLists skips find_package(glfw3).
if (IS_EMSCRIPTEN AND NOT TARGET glfw)
    add_library(glfw INTERFACE)
endif()

add_subdirectory("${_imgui_source_dir}" "${CMAKE_BINARY_DIR}/_deps/imgui-build" EXCLUDE_FROM_ALL)

if (NOT TARGET imgui::imgui)
    message(FATAL_ERROR "imgui: target imgui::imgui was not created")
endif()

set(imgui_FOUND      TRUE)
set(imgui_LIBRARIES  imgui::imgui)
get_target_property(_imgui_inc imgui INTERFACE_INCLUDE_DIRECTORIES)
set(imgui_INCLUDE_DIR "${_imgui_inc}")

# Mark imgui includes as SYSTEM to suppress warnings from its headers
if (_imgui_inc AND TARGET imgui)
    set_target_properties(imgui PROPERTIES
        INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${_imgui_inc}"
    )
endif()

set(IMGUI_LICENSE_FILE "${_imgui_source_dir}/LICENSE.txt" CACHE FILEPATH "Path to Dear ImGui license file")