"""Load the step-1600 Wan-Fun generator adapter through the evaluated loader."""

from perflow_lora import apply_adapter_strength, attach_wan_lora


def load_wan_fun_lora(transformer, checkpoint_path, strength=1.0):
    """Attach once to a freshly loaded native VideoX-Fun 5B Control transformer.

    ``checkpoint_path`` is the downloaded ``generator_lora.pt``. The returned
    receipt proves exact target coverage. Call before CPU/group offloading.
    Safetensors is a separate PEFT-format export, not this function's input.
    """
    name = "wan_fun_dmd_step1600"
    if any(name in getattr(m, "lora_A", {}) for m in transformer.modules()):
        raise ValueError("Adapter already installed; load a fresh transformer")
    conv = transformer.patch_embedding
    if conv.in_channels != 148:
        raise ValueError("Expected the complete 148-channel Wan2.2-Fun-5B-Control transformer")
    report = attach_wan_lora(
        transformer, checkpoint_path, style="native", expected_rank=64,
        lora_alpha=64, adapter_name=name, checkpoint_kind="wan_fun_control_dmd",
        report_prefix="WAN_FUN_LORA", expected_step=1600, enabled=True,
    )
    report.update(apply_adapter_strength(transformer, adapter_name=name, strength=strength))
    return report