logos-plugin-qt/lib/default.nix

# Logos Qt Plugin Backend
#
# Builds Logos modules as Qt 6 plugins. Encapsulates Qt-specific build logic:
# CMake configuration, Qt dependencies, plugin compilation, and macOS fixups.
#
# This backend does NOT know about logos-cpp-sdk. It only knows about:
# - Qt (cmake, ninja, qtbase, qtremoteobjects)
# - logosModule (interface.h — the plugin interface contract)
#
# The logos-cpp-sdk (generator, SDK lib, headers) is added by the caller
# (logos-module-builder) via extraNativeBuildInputs / extraBuildInputs / env.
#
{ nixpkgs, lib }:

let
  common = import ./common.nix { inherit lib; };
  mkBuildPlugin = import ./buildPlugin.nix { inherit lib common; };
  mkBuildHeaders = import ./buildHeaders.nix { inherit lib common; };

in {
  # Build a Qt plugin from sources.
  # logosModule provides interface.h. Everything else (SDK, generator) comes
  # via extraNativeBuildInputs/extraBuildInputs passed by the caller.
  # Returns: derivation with lib/{name}_plugin.so
  buildPlugin = {
    pkgs,
    src,
    config,
    logosModule,
    moduleDeps ? {},
    interfaceDeps ? [],
    staticDeps ? [],
    externalLibs ? {},
    extraNativeBuildInputs ? [],
    extraBuildInputs ? [],
    extraCmakeFlags ? [],
    extraEnv ? {},
    preConfigure ? "",
    postInstall ? "",
  }:
  let
    commonArgs = {
      pname = "logos-${config.name}-module";
      version = config.version;
      nativeBuildInputs = common.commonNativeBuildInputs pkgs ++ extraNativeBuildInputs;
      buildInputs = common.commonBuildInputs pkgs ++ extraBuildInputs;
      cmakeFlags = common.commonCmakeFlags { inherit logosModule; } ++ extraCmakeFlags;
      # LOGOS_MODULE_BUILDER_ROOT is NOT defaulted here. This backend used to
      # point it at its own root, which shipped a second copy of
      # LogosModule.cmake; the caller only overrode it when the module itself
      # carried one, so ui_qml plugins silently configured with the backend's
      # copy. The CMake module belongs to logos-module-builder, which now always
      # passes this in extraEnv. With no default, a caller that forgets gets a
      # loud FATAL_ERROR from the module's CMakeLists instead of a build against
      # whatever this repo happens to contain.
      env = {
        LOGOS_MODULE_ROOT = "${logosModule}";
        # The LogosView*.in templates logos_module(REP_FILE ...) instantiates.
        # They are owned by THIS repo (see ../cmake/README.md) because
        # logos-module-builder depends on it and not the reverse — that
        # direction is what lets the one copy serve both that repo's
        # LogosModule.cmake and this repo's tests/rep-file-plugin fixture.
        # Passed as an env var as well as a cmake flag so a module that drives
        # cmake itself still resolves it; LogosModule.cmake hard-errors when
        # neither is set rather than falling back to a sibling directory.
        LOGOS_VIEW_TEMPLATE_DIR = "${common.viewTemplateDir}";
      } // extraEnv;
      meta = with lib; {
        description = config.description;
        platforms = platforms.unix ++ platforms.windows;
      };
    };
  in mkBuildPlugin.build {
    inherit pkgs src config commonArgs moduleDeps interfaceDeps staticDeps externalLibs preConfigure postInstall;
    logosSdk = null;  # not used by buildPlugin.nix directly, kept for compat
  };

  # Generate-only: run the same code generators as buildPlugin but emit a
  # ready-to-build source tree (module source + generated_code/) instead of a
  # compiled plugin. Same args as buildPlugin so the caller (logos-module-builder)
  # can pass the identical inputs and get a tree that matches a real build.
  # Returns: derivation whose $out is the snapshotted source tree.
  generate = {
    pkgs,
    src,
    config,
    logosModule,
    moduleDeps ? {},
    interfaceDeps ? [],
    staticDeps ? [],
    externalLibs ? {},
    extraNativeBuildInputs ? [],
    extraBuildInputs ? [],
    extraCmakeFlags ? [],
    extraEnv ? {},
    preConfigure ? "",
    postInstall ? "",
  }:
  let
    commonArgs = {
      pname = "logos-${config.name}-module";
      version = config.version;
      nativeBuildInputs = common.commonNativeBuildInputs pkgs ++ extraNativeBuildInputs;
      buildInputs = common.commonBuildInputs pkgs ++ extraBuildInputs;
      cmakeFlags = common.commonCmakeFlags { inherit logosModule; } ++ extraCmakeFlags;
      # LOGOS_MODULE_BUILDER_ROOT is NOT defaulted here. This backend used to
      # point it at its own root, which shipped a second copy of
      # LogosModule.cmake; the caller only overrode it when the module itself
      # carried one, so ui_qml plugins silently configured with the backend's
      # copy. The CMake module belongs to logos-module-builder, which now always
      # passes this in extraEnv. With no default, a caller that forgets gets a
      # loud FATAL_ERROR from the module's CMakeLists instead of a build against
      # whatever this repo happens to contain.
      env = {
        LOGOS_MODULE_ROOT = "${logosModule}";
        # The LogosView*.in templates logos_module(REP_FILE ...) instantiates.
        # They are owned by THIS repo (see ../cmake/README.md) because
        # logos-module-builder depends on it and not the reverse — that
        # direction is what lets the one copy serve both that repo's
        # LogosModule.cmake and this repo's tests/rep-file-plugin fixture.
        # Passed as an env var as well as a cmake flag so a module that drives
        # cmake itself still resolves it; LogosModule.cmake hard-errors when
        # neither is set rather than falling back to a sibling directory.
        LOGOS_VIEW_TEMPLATE_DIR = "${common.viewTemplateDir}";
      } // extraEnv;
      meta = with lib; {
        description = config.description;
        platforms = platforms.unix ++ platforms.windows;
      };
    };
  in mkBuildPlugin.generate {
    inherit pkgs src config commonArgs moduleDeps interfaceDeps staticDeps externalLibs preConfigure postInstall;
    logosSdk = null;  # not used by buildPlugin.nix directly, kept for compat
  };

  # Generate SDK headers from a compiled plugin.
  # `apiStyle` picks which type surface the generated `<Module>` client
  # wrapper exposes ("qt" or "lp"); each module is built once per
  # style so downstream consumers can pick the variant matching their
  # own --api-style without re-running the codegen. Default is "qt"
  # — historically the only option, kept for backward compat.
  # Returns: derivation with include/*.h
  buildHeaders = {
    pkgs,
    src,
    config,
    pluginLib,
    logosSdk,
    apiStyle ? "qt",
    # Path to this module's LIDL contract (or null). This is the PRIMARY input
    # for the qt surface — a module that publishes a contract has its wrapper
    # generated from it and is never introspected. Only a module with no
    # contract falls back to reading its compiled plugin.
    contractLidl ? null,
    # logos-qt-generator (build-platform). Required to take the contract-driven
    # qt path; null demotes it to the legacy emitter, loudly.
    qtGenerator ? null,
  }:
  let
    commonArgs = {
      pname = "logos-${config.name}-module";
      version = config.version;
      meta = with lib; {
        description = config.description;
        platforms = platforms.unix ++ platforms.windows;
      };
    };
  in mkBuildHeaders.build {
    inherit pkgs src config commonArgs logosSdk apiStyle contractLidl qtGenerator;
    lib = pluginLib;
  };

  # Dev shell dependencies — Qt only.
  # SDK env vars, including LOGOS_MODULE_BUILDER_ROOT, are exported by the
  # caller (logos-module-builder) — it owns cmake/LogosModule.cmake now.
  devShellInputs = pkgs: {
    logosModule ? null,
  }: {
    nativeBuildInputs = common.commonNativeBuildInputs pkgs;
    buildInputs = common.commonBuildInputs pkgs;
    shellHook = ''
      ${if logosModule != null then ''export LOGOS_MODULE_ROOT="${logosModule}"'' else ""}
      # Same directory the nix build passes in, so a hand-run `cmake` inside a
      # module's dev shell resolves the templates the way logos_module() does.
      # Without it a ui_qml module would hit LogosModule.cmake's hard error.
      export LOGOS_VIEW_TEMPLATE_DIR="${common.viewTemplateDir}"
    '';
  };

  # Backend metadata
  name = "qt";
  version = "0.1.0";
  inherit common;
}