import io
import numpy as np
import torch
from decord import cpu, VideoReader, bridge
from transformers import AutoModelForCausalLM, AutoTokenizer, BitsAndBytesConfig
import argparse

MODEL_PATH = "THUDM/cogvlm2-video-llama3-chat"
DEVICE = 'cuda' if torch.cuda.is_available() else 'cpu'
TORCH_TYPE = torch.bfloat16 if torch.cuda.is_available() and torch.cuda.get_device_capability()[
    0] >= 8 else torch.float16

parser = argparse.ArgumentParser(description="CogVLM2-Video CLI Demo")
parser.add_argument('--quant', type=int, choices=[4, 8], help='Enable 4-bit or 8-bit precision loading', default=0)
args = parser.parse_args()

if 'int4' in MODEL_PATH:
    args.quant = 4


def load_video(video_path, strategy='chat'):
    bridge.set_bridge('torch')
    with open(video_path, 'rb') as f:
        mp4_stream = f.read()
    num_frames = 24

    if mp4_stream is not None:
        decord_vr = VideoReader(io.BytesIO(mp4_stream), ctx=cpu(0))
    else:
        decord_vr = VideoReader(video_path, ctx=cpu(0))
    frame_id_list = None
    total_frames = len(decord_vr)
    if strategy == 'base':
        clip_end_sec = 60
        clip_start_sec = 0
        start_frame = int(clip_start_sec * decord_vr.get_avg_fps())
        end_frame = min(total_frames,
                        int(clip_end_sec * decord_vr.get_avg_fps())) if clip_end_sec is not None else total_frames
        frame_id_list = np.linspace(start_frame, end_frame - 1, num_frames, dtype=int)
    elif strategy == 'chat':
        timestamps = decord_vr.get_frame_timestamp(np.arange(total_frames))
        timestamps = [i[0] for i in timestamps]
        max_second = round(max(timestamps)) + 1
        frame_id_list = []
        for second in range(max_second):
            closest_num = min(timestamps, key=lambda x: abs(x - second))
            index = timestamps.index(closest_num)
            frame_id_list.append(index)
            if len(frame_id_list) >= num_frames:
                break
    video_data = decord_vr.get_batch(frame_id_list)
    video_data = video_data.permute(3, 0, 1, 2)
    return video_data


tokenizer = AutoTokenizer.from_pretrained(
    MODEL_PATH,
    trust_remote_code=True,
    # padding_side="left"
)

if torch.cuda.is_available() and torch.cuda.get_device_properties(0).total_memory < 48 * 1024 ** 3 and not args.quant:
    print("GPU memory is less than 48GB. Please use cli_demo_multi_gpus.py or pass `--quant 4` or `--quant 8`.")
    exit()

# Load the model
if args.quant == 4:
    model = AutoModelForCausalLM.from_pretrained(
        MODEL_PATH,
        torch_dtype=TORCH_TYPE,
        trust_remote_code=True,
        quantization_config=BitsAndBytesConfig(
            load_in_4bit=True,
            bnb_4bit_compute_dtype=TORCH_TYPE,
        ),
        low_cpu_mem_usage=True
    ).eval()
elif args.quant == 8:
    model = AutoModelForCausalLM.from_pretrained(
        MODEL_PATH,
        torch_dtype=TORCH_TYPE,
        trust_remote_code=True,
        quantization_config=BitsAndBytesConfig(
            load_in_8bit=True,
            bnb_4bit_compute_dtype=TORCH_TYPE,
        ),
        low_cpu_mem_usage=True
    ).eval()
else:
    model = AutoModelForCausalLM.from_pretrained(
        MODEL_PATH,
        torch_dtype=TORCH_TYPE,
        trust_remote_code=True
    ).eval().to(DEVICE)

while True:
    strategy = 'base' if 'cogvlm2-video-llama3-base' in MODEL_PATH else 'chat'
    print(f"using with {strategy} model")
    video_path = input("video path >>>>> ")
    if video_path == '':
        print('You did not enter video path, the following will be a plain text conversation.')
        video = None
    else:
        video = load_video(video_path, strategy=strategy)

    history = []
    while True:
        query = input("Human:")
        if query == "clear":
            break

        inputs = model.build_conversation_input_ids(
            tokenizer=tokenizer,
            query=query,
            images=[video],
            history=history,
            template_version=strategy
        )

        inputs = {
            'input_ids': inputs['input_ids'].unsqueeze(0).to(DEVICE),
            'token_type_ids': inputs['token_type_ids'].unsqueeze(0).to(DEVICE),
            'attention_mask': inputs['attention_mask'].unsqueeze(0).to(DEVICE),
            'images': [[inputs['images'][0].to('cuda').to(TORCH_TYPE)]],
        }
        gen_kwargs = {
            "max_new_tokens": 2048,
            "pad_token_id": 128002,
            "top_k": 1,
            "do_sample": True,
            "top_p": 0.1,
            "temperature": 0.1,
        }
        with torch.no_grad():
            outputs = model.generate(**inputs, **gen_kwargs)
            outputs = outputs[:, inputs['input_ids'].shape[1]:]
            response = tokenizer.decode(outputs[0], skip_special_tokens=True)
            print("\nCogVLM2-Video:", response)
        history.append((query, response))
