import os
import sys
from building import *
from SCons.Subst import quote_spaces

cwd = GetCurrentDir()

sys.path.append(os.path.join(cwd, '../tools'))
from build_support import (
    detect_rust_target,
    make_rustflags,
    make_cargo_build_std_args,
    collect_features,
    verify_rust_toolchain,
    ensure_rust_target_installed,
    cargo_build_staticlib,
    get_staticlib_link_name,
    clean_rust_build,
)
def _has(sym: str) -> bool:
    try:
        return bool(GetDepend([sym]))
    except Exception:
        return bool(GetDepend(sym))


group = []
if not _has('RT_RUST_CORE') and not GetOption('clean'):
    Return('group')


def get_staticlib_link_name_from_artifact(lib_path):
    """Derive the link name from the actual staticlib artifact file name."""
    artifact_name = os.path.basename(os.fspath(lib_path))
    if artifact_name.startswith("lib") and artifact_name.endswith(".a"):
        return artifact_name[3:-2]
    return None


# Source files – MSH command glue.
# rust_cmd.c references rust_init(), which is only provided by the Rust core
# static library. It must only enter the build when that library is actually
# produced; otherwise the C link stage fails with 'undefined reference to
# rust_init' instead of failing/skipping cleanly at the Rust build step.
LIBS = []
LIBPATH = []
LINKFLAGS = ""
include_rust_cmd = False

if GetOption('clean'):
    # Register Rust artifacts for cleaning
    rust_build_dir = clean_rust_build(Dir('#').abspath)
    if os.path.exists(rust_build_dir):
        print(f'Registering {rust_build_dir} for cleanup')
        Clean('.', rust_build_dir)
    else:
        print('No rust build artifacts to clean')
    # Keep rust_cmd.c in the group during clean so its object is cleaned too.
    include_rust_cmd = True
else:
    if verify_rust_toolchain():
        import rtconfig
        rust_build_dir = clean_rust_build(Dir('#').abspath)

        target = detect_rust_target(_has, rtconfig)
        if not target:
            print('Error: Unable to detect Rust target; please check configuration')
            sys.exit(1)
        else:
            print(f'Detected Rust target: {target}')

            # Optional hint if target missing
            if not ensure_rust_target_installed(target):
                print('Error: Rust target is not installed; Rust library build failed')
                sys.exit(1)
            else:
                # Build mode and features
                debug = bool(_has('RUST_DEBUG_BUILD'))
                features = collect_features(_has)

                rustflags = make_rustflags(rtconfig, target)
                cargo_extra_args = make_cargo_build_std_args(rtconfig, target)
                rust_lib = cargo_build_staticlib(
                    rust_dir=cwd, target=target, features=features, debug=debug, rustflags=rustflags, build_root=rust_build_dir, cargo_extra_args=cargo_extra_args
                )

                if rust_lib:
                    # Derive the link name from the actual artifact so it always
                    # matches the file that was built. Only fall back to
                    # re-parsing Cargo.toml when the artifact name does not
                    # follow the lib<name>.a convention.
                    link_lib_name = get_staticlib_link_name_from_artifact(rust_lib)
                    if not link_lib_name:
                        link_lib_name = get_staticlib_link_name(cwd)
                    LIBS = [link_lib_name]
                    LIBPATH = [os.path.dirname(rust_lib)]
                    if rtconfig.PLATFORM == 'armclang':
                        if not (os.path.isfile(rust_lib) and os.path.getsize(rust_lib) > 0):
                            print(f'Error: ArmClang Rust core link requires a non-empty archive, but got: {rust_lib}')
                            sys.exit(1)
                        LINKFLAGS = " " + quote_spaces(os.fspath(rust_lib))
                        LIBS = []
                        LIBPATH = []
                    include_rust_cmd = True
                    print('Rust library linked successfully')
                else:
                    print('Error: Failed to build Rust library')
                    sys.exit(1)
    else:
        print('Error: Rust toolchain not found')
        print('Please install Rust from https://rustup.rs')
        sys.exit(1)

# Only define the component group (with rust_cmd.c) when the Rust core static
# library was actually produced, so its rust_init() reference always resolves.
if include_rust_cmd:
    group = DefineGroup('rust', ['rust_cmd.c'], depend=['RT_USING_RUST', 'RT_RUST_CORE'], LIBS=LIBS, LIBPATH=LIBPATH, LINKFLAGS=LINKFLAGS)

Return('group')