"""
EE Sanity Check
Usage:
  python debug_ee.py --original Qwen/Qwen3-0.6B --ee your/model-dp-ee --seed 424242
"""
import torch
import numpy as np
from transformers import AutoModelForCausalLM, AutoTokenizer
import argparse

def get_sigma(hidden_size, seed):
    rng = np.random.default_rng(seed)
    return rng.permutation(hidden_size)

def run_check(original_name, ee_name, seed, prompt="Hello, how are you?"):
    print(f"\n{'='*60}")
    print(f"Original : {original_name}")
    print(f"EE model : {ee_name}")
    print(f"Seed     : {seed}")
    print(f"Prompt   : {prompt}")
    print('='*60)

    tokenizer = AutoTokenizer.from_pretrained(original_name, trust_remote_code=True)
    inputs = tokenizer(prompt, return_tensors="pt")
    input_ids = inputs.input_ids

    print("\n[1] Loading models...")
    orig = AutoModelForCausalLM.from_pretrained(original_name, torch_dtype=torch.float32, device_map="cpu", trust_remote_code=True)
    ee   = AutoModelForCausalLM.from_pretrained(ee_name,       torch_dtype=torch.float32, device_map="cpu", trust_remote_code=True)
    orig.eval(); ee.eval()

    hidden_size = orig.config.hidden_size
    sigma = get_sigma(hidden_size, seed)
    sigma_t = torch.tensor(sigma, dtype=torch.long)

    # --- CHECK 1: Embed layers must be identical ---
    embed_match = torch.allclose(
        orig.model.embed_tokens.weight.data,
        ee.model.embed_tokens.weight.data, atol=1e-3
    )
    print(f"\n[CHECK 1] Embed layers identical: {embed_match}")
    if not embed_match:
        print("  ⚠️  Embed was permuted — client-side encryption will be double-permuted")

    # --- CHECK 2 & 3: Forward pass with encrypted embeds ---
    print("\n[CHECK 2] Running plain forward on original...")
    with torch.no_grad():
        plain_embeds = orig.model.embed_tokens(input_ids)  # use ORIGINAL embed
        orig_logits = orig(inputs_embeds=plain_embeds).logits

    print("[CHECK 3] Running encrypted forward on EE model...")
    with torch.no_grad():
        # Client encrypts: take plain embeds, apply sigma
        encrypted_embeds = plain_embeds[..., sigma_t]
        ee_logits = ee(inputs_embeds=encrypted_embeds).logits

    # --- CHECK 4: Logits ---
    max_diff = (orig_logits - ee_logits).abs().max().item()
    match = max_diff < 0.5
    print(f"\n[CHECK 4] Logits match (atol=0.1): {match}")
    print(f"  Max logit diff: {max_diff:.4f}")
    if not match:
        print("  ⚠️  Equivariance BROKEN")

    # --- CHECK 5: Greedy decode ---
    # Both models must use inputs_embeds (not input_ids).
    # Original uses plain embeds, EE uses sigma-encrypted embeds.
    # Their outputs should be identical token sequences.
    print("\n[CHECK 5] Greedy decode comparison (10 tokens)...")
    with torch.no_grad():
        orig_ids = orig.generate(
            inputs_embeds=plain_embeds,
            attention_mask=inputs.attention_mask,
            max_new_tokens=10,
            do_sample=False,
            pad_token_id=tokenizer.eos_token_id
        )
        ee_ids = ee.generate(
            inputs_embeds=encrypted_embeds,
            attention_mask=inputs.attention_mask,
            max_new_tokens=10,
            do_sample=False,
            pad_token_id=tokenizer.eos_token_id
        )

    orig_text = tokenizer.decode(orig_ids[0], skip_special_tokens=True)
    ee_text   = tokenizer.decode(ee_ids[0],   skip_special_tokens=True)
    print(f"  Original output : {repr(orig_text)}")
    print(f"  EE model output : {repr(ee_text)}")
    print(f"  Match: {orig_text == ee_text}")

    if orig_text == ee_text:
        print("\n✅ All checks passed — EE transform is correct")
    else:
        print("\n⚠️  Text differs despite logits matching.")
        print("  This usually means floating point drift in autoregressive generation.")
        print("  Check if token IDs match even if decoded text differs slightly:")
        print(f"  orig_ids: {orig_ids[0].tolist()}")
        print(f"  ee_ids:   {ee_ids[0].tolist()}")
        ids_match = orig_ids[0].tolist() == ee_ids[0].tolist()
        print(f"  Token IDs match: {ids_match}")

    print(f"\n{'='*60}\n")

'''if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--original", required=True)
    parser.add_argument("--ee",       required=True)
    parser.add_argument("--seed",     type=int, required=True)
    parser.add_argument("--prompt",   default="Hello, how are you?")
    args = parser.parse_args()
    run_check(args.original, args.ee, args.seed, args.prompt)'''

if __name__ == "__main__":

    original_name='Qwen/Qwen3-0.6B'
    ee_name = 'broadfield-dev/Qwen3-0.6B-dp-ee'
    seed = 424242
    run_check(original_name, ee_name, seed, prompt="Hello, how are you?")
    '''parser = argparse.ArgumentParser()
    parser.add_argument("--original", required=True)
    parser.add_argument("--ee",       required=True)
    parser.add_argument("--seed",     type=int, required=True)
    parser.add_argument("--prompt",   default="Hello, how are you?")
    args = parser.parse_args()
    run_check(args.original, args.ee, args.seed, args.prompt)'''