#!/usr/bin/env python3

import argparse
import datasets
import json
import os
import requests
import sys
import torch
from glob import glob
from PIL import Image
from transformers import AutoProcessor, AutoModelForImageTextToText


def clean_str(s):
    return s.removeprefix("```json").removesuffix("```").replace("\n", "").strip()


def captioning_prompt(image):
    return [
        {
            "role": "system",
            "content": [{"type": "text", "text": "You are a professional English-German translator and also a renowned photography critic."}]
        },
        {
            "role": "user",
            "content": [
                {"type": "image", "image": image},
                {"type": "text", "text": "Write a detailed caption for this image in a single sentence. Translate the caption into German. The output needs to be JSON, the keys being 'English' and 'German' for the respective captions. Only output the JSON, nothing else."}
            ]
        }
    ]


def captioning_prompt_with_source(image, source):
    prompt = captioning_prompt(image)
    prefix = json.dumps({"English": source}).removesuffix("}") + ', "German": "'
    prompt.append({"role": "assistant", "content": [{"type": "text", "text": prefix}]})

    return prompt


def translation_prompt(source):
    return [
        {
            "role": "system",
            "content": [{"type": "text", "text": "You are a professional English-German translator."}]
        },
        {
            "role": "user",
            "content": [
                {"type": "text", "text": f"Translate the following caption into German. The output needs to be JSON, the only being 'Translation' for the translation. Only output the JSON, nothing else. Caption: {source}"}
            ]
        }
    ]


def make_inputs(processor,
                messages,
                device):
    return processor.apply_chat_template(
        messages,
        add_generation_prompt=True,
        tokenize=True,
        return_dict=True,
        return_tensors="pt"
    ).to(device, dtype=torch.bfloat16)


def generate_and_parse(model,
                       processor,
                       messages,
                       args,
                       example_id=None):
    sys.stderr.write(f"Processing {example_id=}\n")
    inputs = make_inputs(processor, messages, model.device)
    input_len = inputs["input_ids"].shape[-1]

    stop_token_ids = [processor.tokenizer.eos_token_id, processor.tokenizer.convert_tokens_to_ids("<end_of_turn>")]

    with torch.inference_mode():
        generation = model.generate(
            **inputs,
            max_new_tokens=args.max_new_tokens,
            do_sample=not args.do_not_sample,
            temperature=args.temperature,
            top_p=args.top_p,
            top_k=args.top_k,
            eos_token_id=stop_token_ids,
            disable_compile=True,
        )

    output_tokens = generation[0][input_len:]
    output_text = clean_str(processor.decode(output_tokens, skip_special_tokens=True))

    try:
        return json.loads(output_text)
    except Exception:
        if example_id is not None:
            sys.stderr.write(
                f"Error loading JSON from string '{output_text}' for id={example_id}\n"
            )
        else:
            sys.stderr.write(
                f"Error loading JSON from string '{output_text}'\n"
            )
        return output_text


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("--model", default="google/gemma-3-4b-it", type=str)
    parser.add_argument("--attention-implementation", default="eager", type=str)
    parser.add_argument("--lora-adapter", default=None, type=str)
    parser.add_argument("--mode", choices=["from_scratch", "with_prefix", "translate"], type=str, required=True)
    parser.add_argument("--dataset", default="asdf2k/caption_translation", type=str)
    parser.add_argument("--data-subset", choices=["train", "dev", "test"], default="test", type=str)
    parser.add_argument("--max-new-tokens", default=300, type=int)
    parser.add_argument("--top-p", default=1.0, type=int)
    parser.add_argument("--top-k", default=50, type=int)
    parser.add_argument("--temperature", default=0.8, type=int)
    parser.add_argument("--do-not-sample", action="store_true")
    args = parser.parse_args()

    model = AutoModelForImageTextToText.from_pretrained(
        args.model,
        device_map="cuda",
        dtype=torch.bfloat16,
        attn_implementation=args.attention_implementation,
    ).eval()
    processor = AutoProcessor.from_pretrained(args.model, use_fast=True)

    if args.lora_adapter:
        from peft import PeftModel
        model = PeftModel.from_pretrained(model, args.lora_adapter)

    dataset = datasets.load_dataset(args.dataset)[args.data_subset]

    if args.mode == "from_scratch":  # Generate caption & translation from scratch
        for x in dataset:
            output = generate_and_parse(
                model,
                processor,
                captioning_prompt(x["image"]),
                args,
                example_id=x["id"],
            )
            print(f"{x['id']}\t{json.dumps(output)}")

    elif args.mode == "translate":  # Generate German translation given English source
        for x in dataset:
            input_data = json.loads(x["assistant"])
            output = generate_and_parse(
                model,
                processor,
                translation_prompt(input_data["English"]),
                args,
                example_id=x["id"],
            )
            output = {"English": input_data["English"], "German": output["Translation"]}
            print(f"{x['id']}\t{json.dumps(output)}")

    elif args.mode == "with_prefix":  # Generate German translation given English caption and image
        for x in dataset:
            assistant_output_as_input = json.loads(x["assistant"])
            output = generate_and_parse(
                model,
                processor,
                captioning_prompt_with_source(x["image"], assistant_output_as_input["English"]),
                args,
                example_id=x["id"],
            )
            print(f"{x['id']}\t{json.dumps(output)}")
    else:
        sys.stderr.write(f"Unkown mode '{args.mode}'")


if __name__ == "__main__":
    main()