import os
import random
import uuid
import json
import time
import asyncio
from threading import Thread

import gradio as gr
import spaces
import torch
import numpy as np
from PIL import Image
import cv2

from transformers import (
    AutoModelForCausalLM,
    AutoTokenizer,
    TextIteratorStreamer,
    Qwen2VLForConditionalGeneration,
    AutoProcessor,
)
from transformers.image_utils import load_image

# Constants for text generation
MAX_MAX_NEW_TOKENS = 2048
DEFAULT_MAX_NEW_TOKENS = 1024
MAX_INPUT_TOKEN_LENGTH = int(os.getenv("MAX_INPUT_TOKEN_LENGTH", "4096"))

device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")

# Load text-only model and tokenizer
model_id = "prithivMLmods/Pocket-Llama-3.2-3B-Instruct"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    device_map="auto",
    torch_dtype=torch.bfloat16,
)
model.eval()

MODEL_ID = "prithivMLmods/Callisto-OCR3-2B-Instruct" 
processor = AutoProcessor.from_pretrained(MODEL_ID, trust_remote_code=True)
model_m = Qwen2VLForConditionalGeneration.from_pretrained(
    MODEL_ID,
    trust_remote_code=True,
    torch_dtype=torch.float16
).to("cuda").eval()


def clean_chat_history(chat_history):
    """
    Filter out any chat entries whose "content" is not a string.
    This helps prevent errors when concatenating previous messages.
    """
    cleaned = []
    for msg in chat_history:
        if isinstance(msg, dict) and isinstance(msg.get("content"), str):
            cleaned.append(msg)
    return cleaned


def downsample_video(video_path):
    """
    Downsamples the video to 10 evenly spaced frames.
    Each frame is returned as a PIL image along with its timestamp.
    """
    vidcap = cv2.VideoCapture(video_path)
    total_frames = int(vidcap.get(cv2.CAP_PROP_FRAME_COUNT))
    fps = vidcap.get(cv2.CAP_PROP_FPS)
    frames = []
    # Sample 10 evenly spaced frames.
    frame_indices = np.linspace(0, total_frames - 1, 10, dtype=int)
    for i in frame_indices:
        vidcap.set(cv2.CAP_PROP_POS_FRAMES, i)
        success, image = vidcap.read()
        if success:
            image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)  # Convert BGR to RGB
            pil_image = Image.fromarray(image)
            timestamp = round(i / fps, 2)
            frames.append((pil_image, timestamp))
    vidcap.release()
    return frames


def progress_bar_html(label: str) -> str:
    """
    Returns an HTML snippet for a thin progress bar with a label.
    The progress bar is styled as a dark red animated bar.
    """
    return f'''
<div style="display: flex; align-items: center;">
    <span style="margin-right: 10px; font-size: 14px;">{label}</span>
    <div style="width: 110px; height: 5px; background-color: #FFF0F5; border-radius: 2px; overflow: hidden;">
        <div style="width: 100%; height: 100%; background-color: #FF69B4; animation: loading 1.5s linear infinite;"></div>
    </div>
</div>
<style>
@keyframes loading {{
    0% {{ transform: translateX(-100%); }}
    100% {{ transform: translateX(100%); }}
}}
</style>
    '''


@spaces.GPU(duration=60, enable_queue=True)
def generate(input_dict: dict, chat_history: list[dict],
             max_new_tokens: int = 1024,
             temperature: float = 0.6,
             top_p: float = 0.9,
             top_k: int = 50,
             repetition_penalty: float = 1.2):
    """
    Generates chatbot responses with support for multimodal input and video processing.
    Special command:
      - "@video-infer": triggers video processing using Qwen2VL.
    """
    text = input_dict["text"]
    files = input_dict.get("files", [])
    lower_text = text.strip().lower()

    # Branch for video processing with Qwen2VL.
    if lower_text.startswith("@video-infer"):
        prompt = text[len("@video-infer"):].strip()
        if files:
            # Assume the first file is a video.
            video_path = files[0]
            frames = downsample_video(video_path)
            messages = [
                {"role": "system", "content": [{"type": "text", "text": "You are a helpful assistant."}]},
                {"role": "user", "content": [{"type": "text", "text": prompt}]}
            ]
            # Append each frame with its timestamp.
            for frame in frames:
                image, timestamp = frame
                image_path = f"video_frame_{uuid.uuid4().hex}.png"
                image.save(image_path)
                messages[1]["content"].append({"type": "text", "text": f"Frame {timestamp}:"})
                messages[1]["content"].append({"type": "image", "url": image_path})
        else:
            messages = [
                {"role": "system", "content": [{"type": "text", "text": "You are a helpful assistant."}]},
                {"role": "user", "content": [{"type": "text", "text": prompt}]}
            ]
        inputs = processor.apply_chat_template(
            messages, tokenize=True, add_generation_prompt=True, return_dict=True, return_tensors="pt"
        ).to("cuda")
        streamer = TextIteratorStreamer(processor, skip_prompt=True, skip_special_tokens=True)
        generation_kwargs = {
            **inputs,
            "streamer": streamer,
            "max_new_tokens": max_new_tokens,
            "do_sample": True,
            "temperature": temperature,
            "top_p": top_p,
            "top_k": top_k,
            "repetition_penalty": repetition_penalty,
        }
        thread = Thread(target=model_m.generate, kwargs=generation_kwargs)
        thread.start()
        buffer = ""
        yield progress_bar_html("Processing video with Qwen2VL")
        for new_text in streamer:
            buffer += new_text
            buffer = buffer.replace("<|im_end|>", "")
            time.sleep(0.01)
            yield buffer
        return

    # Normal text or multimodal conversation processing.
    if files:
        if len(files) > 1:
            images = [load_image(image) for image in files]
        elif len(files) == 1:
            images = [load_image(files[0])]
        else:
            images = []
        messages = [{
            "role": "user",
            "content": [
                *[{"type": "image", "image": image} for image in images],
                {"type": "text", "text": text},
            ]
        }]
        prompt_full = processor.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
        inputs = processor(text=[prompt_full], images=images, return_tensors="pt", padding=True).to("cuda")
        streamer = TextIteratorStreamer(processor, skip_prompt=True, skip_special_tokens=True)
        generation_kwargs = {**inputs, "streamer": streamer, "max_new_tokens": max_new_tokens}
        thread = Thread(target=model_m.generate, kwargs=generation_kwargs)
        thread.start()
        buffer = ""
        yield progress_bar_html("Thinking...")
        for new_text in streamer:
            buffer += new_text
            buffer = buffer.replace("<|im_end|>", "")
            time.sleep(0.01)
            yield buffer
    else:
        conversation = clean_chat_history(chat_history)
        conversation.append({"role": "user", "content": text})
        input_ids = tokenizer.apply_chat_template(conversation, add_generation_prompt=True, return_tensors="pt")
        if input_ids.shape[1] > MAX_INPUT_TOKEN_LENGTH:
            input_ids = input_ids[:, -MAX_INPUT_TOKEN_LENGTH:]
            gr.Warning(f"Trimmed input from conversation as it was longer than {MAX_INPUT_TOKEN_LENGTH} tokens.")
        input_ids = input_ids.to(model.device)
        streamer = TextIteratorStreamer(tokenizer, timeout=20.0, skip_prompt=True, skip_special_tokens=True)
        generation_kwargs = {
            "input_ids": input_ids,
            "streamer": streamer,
            "max_new_tokens": max_new_tokens,
            "do_sample": True,
            "top_p": top_p,
            "top_k": top_k,
            "temperature": temperature,
            "num_beams": 1,
            "repetition_penalty": repetition_penalty,
        }
        t = Thread(target=model.generate, kwargs=generation_kwargs)
        t.start()
        outputs = []
        yield progress_bar_html("Processing...")
        for new_text in streamer:
            outputs.append(new_text)
            yield "".join(outputs)
        final_response = "".join(outputs)
        yield final_response

# Create the Gradio ChatInterface with the custom CSS applied
demo = gr.ChatInterface(
    fn=generate,
    additional_inputs=[
        gr.Slider(label="Max new tokens", minimum=1, maximum=MAX_MAX_NEW_TOKENS, step=1, value=DEFAULT_MAX_NEW_TOKENS),
        gr.Slider(label="Temperature", minimum=0.1, maximum=4.0, step=0.1, value=0.6),
        gr.Slider(label="Top-p (nucleus sampling)", minimum=0.05, maximum=1.0, step=0.05, value=0.9),
        gr.Slider(label="Top-k", minimum=1, maximum=1000, step=1, value=50),
        gr.Slider(label="Repetition penalty", minimum=1.0, maximum=2.0, step=0.05, value=1.2),
    ],
    examples=[
        ["Write the code that converts temperatures between celsius and fahrenheit"],
        [{"text": "Create a short story based on the image.", "files": ["examples/1.jpg"]}],
    ],
    cache_examples=False,
    type="messages",
    fill_height=True,
    textbox=gr.MultimodalTextbox(label="Query Input", file_types=["image", "video"], file_count="multiple"),
    stop_btn="Stop Generation",
    multimodal=True,
    theme="YTheme/GMaterial",
)

if __name__ == "__main__":
    demo.queue(max_size=20).launch(share=True)