import torch
from transformers import AutoModel, AutoProcessor
from PIL import Image, UnidentifiedImageError
import requests
from io import BytesIO
import time

# Configuration
MODEL_ID = "TomoroAI/tomoro-colqwen3-embed-4b"
DTYPE = torch.bfloat16
# DEVICE = "cuda" if torch.cuda.is_available() else "cpu"
# DEVICE = "cuda"
DEVICE = "cpu"

# Load Model & Processor
processor = AutoProcessor.from_pretrained(
    MODEL_ID,
    trust_remote_code=True,
    max_num_visual_tokens=1280,
)
model = AutoModel.from_pretrained(
    MODEL_ID,
    dtype=DTYPE,
    attn_implementation="flash_attention_2",
    trust_remote_code=True,
    device_map=DEVICE,
).eval()

# Sample Data
queries = [
    "Retrieve the city of Singapore",
    "Retrieve the city of Beijing",
    "Retrieve the city of London",
]
docs = [
    "https://upload.wikimedia.org/wikipedia/commons/2/27/Singapore_skyline_2022.jpg",
    "https://upload.wikimedia.org/wikipedia/commons/6/61/Beijing_skyline_at_night.JPG",
    "https://upload.wikimedia.org/wikipedia/commons/4/49/London_skyline.jpg",
]

def load_image(url: str) -> Image.Image:
    # Some CDNs (e.g., Wikimedia) expect a browser-like UA to avoid 403s.
    for headers in ({}, {"User-Agent": "Mozilla/5.0 (compatible; ColQwen3-demo/1.0)"}):
        resp = requests.get(url, headers=headers, timeout=10)
        if resp.status_code == 403:
            continue
        resp.raise_for_status()
        try:
            return Image.open(BytesIO(resp.content)).convert("RGB")
        except UnidentifiedImageError as e:
            raise RuntimeError(f"Failed to decode image from {url}") from e
    raise RuntimeError(f"Could not fetch image (HTTP 403) from {url}; try downloading locally and loading from file path.")

# Helper Functions
def encode_queries(texts, batch_size=8):
    outputs = []
    for start in range(0, len(texts), batch_size):
        batch = processor.process_texts(texts=texts[start : start + batch_size])
        batch = {k: v.to(DEVICE) for k, v in batch.items()}
        with torch.inference_mode():
            out = model(**batch)
            vecs = out.embeddings.to(torch.bfloat16).cpu()
        outputs.extend(vecs)
    return outputs

def encode_docs(urls):
    outputs = []
    for idx, url in enumerate(urls):
        img = load_image(url)
        features = processor.process_images(images=[img])
        features = {k: v.to(DEVICE) if isinstance(v, torch.Tensor) else v for k, v in features.items()}
        # Warm up on the first image, measure only 2nd and 3rd embeddings generation
        if idx in (1, 2):
            start_ns = time.perf_counter_ns()
            with torch.inference_mode():
                out = model(**features)
                vecs = out.embeddings.to(torch.bfloat16).cpu()
            end_ns = time.perf_counter_ns()
            duration_ns = end_ns - start_ns
            print(f"Duration encode_docs image {idx + 1}: {duration_ns:,} ns")
        else:
            with torch.inference_mode():
                out = model(**features)
                vecs = out.embeddings.to(torch.bfloat16).cpu()
        outputs.extend(vecs)
    return outputs

# Execution
query_embeddings = encode_queries(queries)

doc_embeddings = encode_docs(docs)

# MaxSim Scoring
scores = processor.score_multi_vector(query_embeddings, doc_embeddings)
print(scores)