import os
import time
from fastvideo import VideoGenerator

OUTPUT_PATH = "video_samples_dmd2"


def main():
    os.environ["FASTVIDEO_ATTENTION_BACKEND"] = "VIDEO_SPARSE_ATTN"

    load_start_time = time.perf_counter()
    model_name = "FastVideo/FastWan2.1-T2V-1.3B-Diffusers"
    generator = VideoGenerator.from_config({
        "model_path": model_name,
        "engine": {
            # FastVideo will automatically handle distributed setup
            "num_gpus": 1,
            "use_fsdp_inference": False,  # set to True if GPU is out of memory
            # Adjust these offload parameters if you have < 32GB of VRAM
            "offload": {
                "text_encoder": True,
                "pin_cpu_memory": True,  # set to false if low CPU RAM or hit obscure "CUDA error: Invalid argument"
                "dit": False,
                "vae": False,
            },
            "attention": {"vsa_sparsity": 0.8},
        },
    })
    load_end_time = time.perf_counter()
    load_time = load_end_time - load_start_time

    prompt = (
        "A neon-lit alley in futuristic Tokyo during a heavy rainstorm at night. The puddles reflect glowing signs in kanji, advertising ramen, karaoke, and VR arcades. A woman in a translucent raincoat walks briskly with an LED umbrella. Steam rises from a street food cart, and a cat darts across the screen. Raindrops are visible on the camera lens, creating a cinematic bokeh effect."
    )
    start_time = time.perf_counter()
    video = generator.generate({
        "prompt": prompt,
        "sampling": {"num_frames": 81},
        "output": {"output_path": OUTPUT_PATH, "save_video": True},
    })
    end_time = time.perf_counter()
    gen_time = end_time - start_time

    # Generate another video with a different prompt, without reloading the
    # model!
    prompt2 = ("A majestic lion strides across the golden savanna, its powerful frame "
               "glistening under the warm afternoon sun. The tall grass ripples gently in "
               "the breeze, enhancing the lion's commanding presence. The tone is vibrant, "
               "embodying the raw energy of the wild. Low angle, steady tracking shot, "
               "cinematic.")
    start_time = time.perf_counter()
    video2 = generator.generate({
        "prompt": prompt2,
        "sampling": {"num_frames": 81},
        "output": {"output_path": OUTPUT_PATH, "save_video": True},
    })
    end_time = time.perf_counter()
    gen_time2 = end_time - start_time

    print(f"Time taken to load model: {load_time} seconds")
    print(f"Time taken to generate video: {gen_time} seconds")
    print(f"Time taken to generate video2: {gen_time2} seconds")


if __name__ == "__main__":
    main()