# Generates CMakeUserPresets.json, pinning "cmakeExecutable" to the CMake that is
# running this script - i.e. the one build.cmd itself uses.
#
# Why: both drivers share one binaryDir per configuration, so build.cmd and Visual
# Studio write the same Ninja tree. Visual Studio otherwise uses its own bundled
# CMake, and two CMake versions generating one tree emit different compile command
# lines, which makes Ninja rebuild everything on every switch. See CLAUDE.md.
#
# Why generated rather than committed: Visual Studio resolves "cmakeExecutable"
# against the current directory only - a bare "cmake" is not looked up on PATH - so
# the value must be an absolute path, which is machine-specific and cannot live in
# the committed CMakePresets.json.
#
# Run as:  cmake -P cmake/write_user_presets.cmake

cmake_minimum_required(VERSION 3.21)

# Marks the file as ours, so a hand-written one is never clobbered.
set(GENERATED_MARKER "local-cmake")

set(TEMPLATE [==[
{
    "version": 2,
    "configurePresets": [
        {
            "name": "local-cmake",
            "hidden": true,
            "cmakeExecutable": "@CMAKE_COMMAND@"
        },
        {
            "name": "build-release-msvc-local",
            "inherits": [
                "local-cmake",
                "build-release-msvc"
            ],
            "displayName": "Release (MSVC) [local CMake]",
            "description": "Select this in Visual Studio: same build tree as build.cmd, pinned to the same CMake. Generated by build.cmd - do not edit."
        },
        {
            "name": "build-debug-msvc-local",
            "inherits": [
                "local-cmake",
                "build-debug-msvc"
            ],
            "displayName": "Debug (MSVC) [local CMake]",
            "description": "Select this in Visual Studio: same build tree as build.cmd, pinned to the same CMake. Generated by build.cmd - do not edit."
        },
        {
            "name": "build-release-clang-cl-local",
            "inherits": [
                "local-cmake",
                "build-release-clang-cl"
            ],
            "displayName": "Release (Clang) [local CMake]",
            "description": "Select this in Visual Studio: same build tree as build.cmd, pinned to the same CMake. Generated by build.cmd - do not edit."
        },
        {
            "name": "build-debug-clang-cl-local",
            "inherits": [
                "local-cmake",
                "build-debug-clang-cl"
            ],
            "displayName": "Debug (Clang) [local CMake]",
            "description": "Select this in Visual Studio: same build tree as build.cmd, pinned to the same CMake. Generated by build.cmd - do not edit."
        }
    ],
    "buildPresets": [
        {
            "name": "release-msvc-local",
            "configurePreset": "build-release-msvc-local",
            "displayName": "Release (MSVC) [local CMake]"
        },
        {
            "name": "debug-msvc-local",
            "configurePreset": "build-debug-msvc-local",
            "displayName": "Debug (MSVC) [local CMake]"
        },
        {
            "name": "release-clang-cl-local",
            "configurePreset": "build-release-clang-cl-local",
            "displayName": "Release (Clang) [local CMake]"
        },
        {
            "name": "debug-clang-cl-local",
            "configurePreset": "build-debug-clang-cl-local",
            "displayName": "Debug (Clang) [local CMake]"
        }
    ]
}
]==])

string(CONFIGURE "${TEMPLATE}" CONTENT @ONLY)

get_filename_component(OUTPUT_FILE "${CMAKE_CURRENT_LIST_DIR}/../CMakeUserPresets.json" ABSOLUTE)

if(EXISTS "${OUTPUT_FILE}")
    file(READ "${OUTPUT_FILE}" EXISTING)

    # Unchanged: leave the timestamp alone, or Visual Studio reloads the presets
    # after every command-line build.
    if(EXISTING STREQUAL CONTENT)
        return()
    endif()

    string(FIND "${EXISTING}" "\"${GENERATED_MARKER}\"" MARKER_POS)
    if(MARKER_POS EQUAL -1)
        message(WARNING
            "CMakeUserPresets.json was not generated by build.cmd - leaving it untouched.\n"
            "Delete it to let build.cmd manage it, or add \"cmakeExecutable\": \"${CMAKE_COMMAND}\" to it yourself."
        )
        return()
    endif()
endif()

file(WRITE "${OUTPUT_FILE}" "${CONTENT}")
message(STATUS "Wrote CMakeUserPresets.json (cmakeExecutable: ${CMAKE_COMMAND})")