# Paho.cmake - provide Eclipse Paho MQTT C and C++ via FetchContent.
#
# Rationale (security): we build Paho from its OFFICIAL upstream Git repos
# rather than from the AUR. This removes the anonymous AUR packager from the
# trust chain - you trust only the Eclipse project source.
#
# HARDENING (recommended): the tags below are mutable refs. For maximum
# integrity, pin PAHO_C_TAG / PAHO_CPP_TAG to a full commit SHA (immutable),
# or switch to URL + URL_HASH (SHA256) of the signed release tarballs and
# verify the hash out-of-band. Bump the versions deliberately, not silently.
#
# NOTE: these exact tag strings and the cross-build wiring below must be
# verified on a machine with network access + cmake; they could not be built
# offline in the environment where this file was authored.

include(FetchContent)

set(PAHO_C_TAG   "v1.3.14" CACHE STRING "Eclipse paho.mqtt.c git tag/commit")
set(PAHO_CPP_TAG "v1.4.1"  CACHE STRING "Eclipse paho.mqtt.cpp git tag/commit")

# ---- Paho MQTT C (dependency of the C++ wrapper) ----
set(PAHO_BUILD_SHARED   OFF CACHE BOOL "" FORCE)
set(PAHO_BUILD_STATIC   ON  CACHE BOOL "" FORCE)
set(PAHO_WITH_SSL       OFF CACHE BOOL "" FORCE)  # current code uses plain tcp://
set(PAHO_ENABLE_TESTING OFF CACHE BOOL "" FORCE)
set(PAHO_BUILD_SAMPLES  OFF CACHE BOOL "" FORCE)
set(PAHO_BUILD_DOCUMENTATION OFF CACHE BOOL "" FORCE)

FetchContent_Declare(paho_mqtt_c
  GIT_REPOSITORY https://github.com/eclipse-paho/paho.mqtt.c.git
  GIT_TAG        ${PAHO_C_TAG}
  GIT_SHALLOW    TRUE
)

# ---- Paho MQTT C++ ----
set(PAHO_BUILD_CPP_SHARED OFF CACHE BOOL "" FORCE)
set(PAHO_BUILD_CPP_STATIC ON  CACHE BOOL "" FORCE)

FetchContent_Declare(paho_mqtt_cpp
  GIT_REPOSITORY https://github.com/eclipse-paho/paho.mqtt.cpp.git
  GIT_TAG        ${PAHO_CPP_TAG}
  GIT_SHALLOW    TRUE
)

FetchContent_MakeAvailable(paho_mqtt_c paho_mqtt_cpp)

# Provide a stable alias the top-level CMakeLists links against, regardless of
# the exact target name the upstream version exports.
if(NOT TARGET PahoMqttCpp::paho-mqttpp3-static)
  if(TARGET paho-mqttpp3-static)
    add_library(PahoMqttCpp::paho-mqttpp3-static ALIAS paho-mqttpp3-static)
  elseif(TARGET paho-mqttpp3)
    add_library(PahoMqttCpp::paho-mqttpp3-static ALIAS paho-mqttpp3)
  else()
    message(FATAL_ERROR "Paho C++ static target not found after FetchContent; "
                        "check PAHO_CPP_TAG and upstream target names.")
  endif()
endif()