"""Run UPH+Base with per-user scores, then compute significance tests vs PEFT baselines.

Loads PEFT per-user data from run_peft_baselines.py output, runs UPH and Base
to get per-user R-L, then computes paired significance tests.

Usage:
    python scripts/run_significance.py --task review --setting user --device cuda:0
"""

import sys
import os
import json
import time
import numpy as np
import torch
from scipy import stats

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from data.longlamp import load_longlamp, select_k_profile_items
from data.templates import build_query_prompt
from models.qwen_wrapper import QwenWrapper
from models.cvh import UnconditionalHead
from adapt.cache_hidden import cache_support_hidden_states
from adapt.fit_theta import fit_theta
from eval.metrics import compute_rouge, compute_meteor


def per_user_scores(predictions, references):
    """Compute per-example ROUGE-L and METEOR."""
    rl_scores = []
    meteor_scores = []
    for pred, ref in zip(predictions, references):
        r = compute_rouge([pred], [ref])
        m = compute_meteor([pred], [ref])
        rl_scores.append(r['rougeL'])
        meteor_scores.append(m)
    return rl_scores, meteor_scores


def generate_base(wrapper, prompt, max_new_tokens=512, min_new_tokens=128):
    chat_messages = [
        {"role": "system", "content": "You are a helpful writing assistant."},
        {"role": "user", "content": prompt},
    ]
    prompt_text = wrapper.tokenizer.apply_chat_template(
        chat_messages, tokenize=False, add_generation_prompt=True
    )
    input_ids = wrapper.tokenizer.encode(prompt_text, return_tensors="pt").to(wrapper.device)
    with torch.no_grad():
        outputs = wrapper.model.generate(
            input_ids,
            max_new_tokens=max_new_tokens,
            min_new_tokens=min_new_tokens,
            temperature=None, top_p=None, do_sample=False,
            pad_token_id=wrapper.tokenizer.pad_token_id,
        )
    return wrapper.tokenizer.decode(outputs[0, input_ids.shape[1]:], skip_special_tokens=True)


def run_base(wrapper, examples, N):
    preds = []
    for i, ex in enumerate(examples):
        prompt = build_query_prompt(ex['query_input'], ex['task'])
        pred = generate_base(wrapper, prompt)
        preds.append(pred)
        if (i + 1) % 40 == 0:
            print(f"    Base: {i+1}/{N}")
    return preds


def run_uph(wrapper, examples, support_sets, N, device):
    H = wrapper.hidden_size
    uncond = UnconditionalHead(H, d=64, alpha=0.1, basis_seed=42).to(device)
    lm_head_bias = None
    if hasattr(wrapper.model.lm_head, 'bias') and wrapper.model.lm_head.bias is not None:
        lm_head_bias = wrapper.model.lm_head.bias.data

    preds = []
    for i, (ex, support) in enumerate(zip(examples, support_sets)):
        cached_h = cache_support_hidden_states(wrapper, support, ex['task'])
        if not cached_h:
            prompt = build_query_prompt(ex['query_input'], ex['task'])
            pred = generate_base(wrapper, prompt)
            preds.append(pred)
            continue

        theta = fit_theta(
            cached_h=cached_h,
            lm_head_weight=wrapper.lm_head_weight,
            lm_head_bias=lm_head_bias,
            head_module=uncond,
            d=64, lr=0.05, steps=30, beta=0.05, lam=1e-4,
            max_grad_norm=5.0, device=device,
        )

        prompt = build_query_prompt(ex['query_input'], ex['task'])
        pred = wrapper.generate_with_head_blended(
            prompt, theta, uncond.forward_fn,
            blend_gamma=0.5, max_new_tokens=512,
            min_new_tokens=128, temperature=0.0,
        )
        preds.append(pred)
        del cached_h, theta
        torch.cuda.empty_cache()

        if (i + 1) % 40 == 0:
            print(f"    UPH: {i+1}/{N}")
    return preds


def paired_tests(scores_a, scores_b, name_a, name_b):
    a = np.array(scores_a)
    b = np.array(scores_b)
    diff = a - b

    mean_a, mean_b = np.mean(a), np.mean(b)
    mean_diff = np.mean(diff)

    t_stat, t_pval = stats.ttest_rel(a, b)
    try:
        w_stat, w_pval = stats.wilcoxon(a, b)
    except ValueError:
        w_stat, w_pval = float('nan'), float('nan')

    se = stats.sem(diff)
    ci_low = mean_diff - 1.96 * se
    ci_high = mean_diff + 1.96 * se

    print(f"\n  {name_a} vs {name_b}:")
    print(f"    Mean {name_a}: {mean_a:.4f}, Mean {name_b}: {mean_b:.4f}, Diff: {mean_diff:+.4f}")
    print(f"    95% CI: [{ci_low:+.4f}, {ci_high:+.4f}]")
    print(f"    Paired t-test: t={t_stat:.3f}, p={t_pval:.2e}")
    print(f"    Wilcoxon: W={w_stat:.0f}, p={w_pval:.2e}")

    return {
        'mean_a': float(mean_a), 'mean_b': float(mean_b),
        'mean_diff': float(mean_diff),
        'ci_low': float(ci_low), 'ci_high': float(ci_high),
        't_stat': float(t_stat), 't_pval': float(t_pval),
        'w_stat': float(w_stat), 'w_pval': float(w_pval),
    }


def main():
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument('--num_eval', type=int, default=200)
    parser.add_argument('--task', type=str, default='review', choices=['review', 'topic'])
    parser.add_argument('--setting', type=str, default='user', choices=['user', 'temporal'])
    parser.add_argument('--device', type=str, default='cuda:0')
    parser.add_argument('--peft_dir', type=str, default='outputs/peft_baselines')
    parser.add_argument('--output_dir', type=str, default='outputs/significance')
    args = parser.parse_args()

    N = args.num_eval
    device = args.device
    task = args.task
    setting = args.setting

    config_map = {
        ('review', 'user'): 'product_review_user',
        ('review', 'temporal'): 'product_review_temporal',
        ('topic', 'user'): 'topic_writing_user',
        ('topic', 'temporal'): 'topic_writing_temporal',
    }
    config_name = config_map[(task, setting)]

    # Load PEFT per-user data
    peft_path = os.path.join(args.peft_dir, f"{task}_{setting}_K4_N{N}_peft_per_user.json")
    if not os.path.exists(peft_path):
        print(f"PEFT per-user data not found: {peft_path}")
        print("Run run_peft_baselines.py first.")
        return

    with open(peft_path) as f:
        peft_data = json.load(f)

    # Extract PEFT per-user R-L scores
    peft_rl = {}
    peft_meteor = {}
    for method, users in peft_data['per_user'].items():
        peft_rl[method] = [u['metrics']['rougeL'] for u in users]
        peft_meteor[method] = [u['metrics']['meteor'] for u in users]

    print(f"=== Significance Tests: {task}_{setting}, N={N} ===")
    print(f"Loaded PEFT per-user data: {list(peft_rl.keys())}")

    # Load data and run UPH + Base
    print("\nLoading data...")
    examples = load_longlamp(config_name, split='val')[:N]
    K = 4
    support_sets = [select_k_profile_items(ex['profile_items'], K, seed=0) for ex in examples]
    references = [ex['target_output'] for ex in examples]

    print(f"Loading model on {device}...")
    wrapper = QwenWrapper('Qwen/Qwen2.5-1.5B-Instruct', device=device)

    # Run Base
    print("\n--- Base ---")
    base_preds = run_base(wrapper, examples, N)
    base_rl, base_meteor = per_user_scores(base_preds, references)
    print(f"  Mean R-L: {np.mean(base_rl):.4f}, METEOR: {np.mean(base_meteor):.4f}")

    # Run UPH
    print("\n--- UPH ---")
    uph_preds = run_uph(wrapper, examples, support_sets, N, device)
    uph_rl, uph_meteor = per_user_scores(uph_preds, references)
    print(f"  Mean R-L: {np.mean(uph_rl):.4f}, METEOR: {np.mean(uph_meteor):.4f}")

    # Significance tests
    all_rl = {'Base': base_rl, 'UPH': uph_rl}
    all_rl.update(peft_rl)

    all_meteor = {'Base': base_meteor, 'UPH': uph_meteor}
    all_meteor.update(peft_meteor)

    print("\n" + "=" * 80)
    print("SIGNIFICANCE TESTS — ROUGE-L (paired)")
    print("=" * 80)

    rl_tests = {}
    comparisons = [
        ('UPH', 'Base'),
        ('UPH', 'lora'),
        ('UPH', 'tiny_lora'),
        ('UPH', 'vera'),
    ]
    for name_a, name_b in comparisons:
        if name_b in all_rl:
            r = paired_tests(all_rl[name_a], all_rl[name_b], name_a, name_b)
            rl_tests[f'{name_a}_vs_{name_b}'] = r

    print("\n" + "=" * 80)
    print("SIGNIFICANCE TESTS — METEOR (paired)")
    print("=" * 80)

    meteor_tests = {}
    for name_a, name_b in comparisons:
        if name_b in all_meteor:
            r = paired_tests(all_meteor[name_a], all_meteor[name_b], name_a, name_b)
            meteor_tests[f'{name_a}_vs_{name_b}'] = r

    # Save
    os.makedirs(args.output_dir, exist_ok=True)
    output_path = os.path.join(args.output_dir, f'{task}_{setting}_significance.json')

    save_data = {
        'per_user_rougeL': {k: [float(x) for x in v] for k, v in all_rl.items()},
        'per_user_meteor': {k: [float(x) for x in v] for k, v in all_meteor.items()},
        'significance_rougeL': rl_tests,
        'significance_meteor': meteor_tests,
        'num_examples': N,
        'task': task,
        'setting': setting,
        'base_predictions': base_preds,
        'uph_predictions': uph_preds,
    }
    with open(output_path, 'w') as f:
        json.dump(save_data, f, indent=2, default=str)
    print(f"\nResults saved to {output_path}")


if __name__ == '__main__':
    main()