# - Find the Catch test framework or download it (single header)

#

# This is a quick module for internal use. It assumes that Catch is

# REQUIRED and that a minimum version is provided (not EXACT). If

# a suitable version isn't found locally, the single header file

# will be downloaded and placed in the build dir: PROJECT_BINARY_DIR.

#

# This code sets the following variables:

#  CATCH_INCLUDE_DIR      - path to catch.hpp

#  CATCH_VERSION          - version number

if(NOT Catch_FIND_VERSION)

  message(FATAL_ERROR "A version number must be specified.")

elseif(Catch_FIND_REQUIRED)

  message(FATAL_ERROR "This module assumes Catch is not required.")

elseif(Catch_FIND_VERSION_EXACT)

  message(FATAL_ERROR "Exact version numbers are not supported, only minimum.")

endif()

# Extract the version number from catch.hpp

function(_get_catch_version)

  file(STRINGS "${CATCH_INCLUDE_DIR}/catch.hpp" version_line REGEX "Catch v.*" LIMIT_COUNT 1)

  if(version_line MATCHES "Catch v([0-9]+)\\.([0-9]+)\\.([0-9]+)")

    set(CATCH_VERSION "${CMAKE_MATCH_1}.${CMAKE_MATCH_2}.${CMAKE_MATCH_3}" PARENT_SCOPE)

  endif()

endfunction()

# Download the single-header version of Catch

function(_download_catch version destination_dir)

  message(STATUS "Downloading catch v${version}...")

  set(url https://github.com/philsquared/Catch/releases/download/v${version}/catch.hpp)

  file(DOWNLOAD ${url} "${destination_dir}/catch.hpp" STATUS status)

  list(GET status 0 error)

  if(error)

    message(FATAL_ERROR "Could not download ${url}")

  endif()

  set(CATCH_INCLUDE_DIR "${destination_dir}" CACHE INTERNAL "")

endfunction()

# Look for catch locally

find_path(CATCH_INCLUDE_DIR NAMES catch.hpp PATH_SUFFIXES catch)

if(CATCH_INCLUDE_DIR)

  _get_catch_version()

endif()

# Download the header if it wasn't found or if it's outdated

if(NOT CATCH_VERSION OR CATCH_VERSION VERSION_LESS ${Catch_FIND_VERSION})

  if(DOWNLOAD_CATCH)

    _download_catch(${Catch_FIND_VERSION} "${PROJECT_BINARY_DIR}/catch/")

    _get_catch_version()

  else()

    set(CATCH_FOUND FALSE)

    return()

  endif()

endif()

set(CATCH_FOUND TRUE)