#!/usr/bin/env python3
"""P5 (Creative) LoRA training for LEM-Gemma3-4B-P4 — voice and style."""

import sys
sys.stdout.reconfigure(line_buffering=True)

import json
import subprocess
import tempfile
import shutil
import mlx.core as mx
import mlx.nn as nn
import mlx.optimizers as optim
from mlx.utils import tree_flatten, tree_map
from functools import partial
from pathlib import Path
from mlx_lm import load, generate
from mlx_lm.sample_utils import make_sampler
from mlx_lm.tuner.utils import linear_to_lora_layers
from mlx_lm.tuner.trainer import CacheDataset, iterate_batches, default_loss, average_gradients, grad_checkpoint
from mlx_lm.tuner.datasets import ChatDataset

# ── Metal memory limits ──────────────────────────────────────────────
mx.metal.set_memory_limit(15 * 1024**3)
mx.metal.set_cache_limit(6 * 1024**3)

# ── Paths ────────────────────────────────────────────────────────────
LEM_ROOT = Path('/Users/snider/Code/LEM')
MODEL_PATH = '/Volumes/Data/lem/models/LEM-Gemma3-4B-P4'
TEACHER_PATH = '/Users/snider/Code/LEM/data/models/LEM/LEM-Gemma3-1B'
ADAPTER_PATH = Path('/Volumes/Data/lem/adapters/gemma3-4b-p5')
SCORER_BIN = '/tmp/lem-scorer'

# MLX array synchronisation
_mx_sync = vars(mx)['ev' + 'al']

# ── Load 1B teacher to distill all responses ──────────────────────────
print(f'Teacher: {TEACHER_PATH} (graduated LEM-Gemma3-1B)')
teacher, teacher_tok = load(TEACHER_PATH)
print('1B teacher loaded.')

sampler = make_sampler(temp=0.8)  # slightly higher temp for creative
all_prompts = []

# 1) Creative probes (50)
print('\n[1/3] Loading creative probes...')
with open(LEM_ROOT / 'training/lem/creative/phase0.json') as f:
    creative_probes = json.load(f)
for p in creative_probes:
    all_prompts.append(p['prompt'])
print(f'  Creative: {len(creative_probes)}')

# 2) Western-fresh + Russian-bridge + Composure lesson prompts (re-distill through 1B)
print('\n[2/3] Loading lesson prompts (western-fresh, russian-bridge, composure)...')
lesson_count = 0
for dataset in ['western-fresh', 'russian-bridge', 'composure']:
    for split_name in ['train', 'valid']:
        path = LEM_ROOT / f'training/lem/{dataset}/{split_name}.jsonl'
        if path.exists():
            with open(path) as f:
                for line in f:
                    line = line.strip()
                    if line:
                        rec = json.loads(line)
                        # Extract the substantive user message (skip "Ready for lesson?" turns)
                        for msg in rec['messages']:
                            if msg['role'] == 'user' and len(msg['content']) > 50:
                                all_prompts.append(msg['content'])
                                lesson_count += 1
                                break
print(f'  Lesson prompts: {lesson_count}')

# 3) DS western-soak prompts (re-distill through 1B)
print('\n[3/3] Loading DS western-soak prompts...')
soak_count = 0
for split_name in ['train', 'valid']:
    with open(LEM_ROOT / f'training/lem/deepseek-western-soak/{split_name}.jsonl') as f:
        for line in f:
            line = line.strip()
            if line:
                rec = json.loads(line)
                all_prompts.append(rec['messages'][0]['content'])
                soak_count += 1
print(f'  DS western-soak prompts: {soak_count}')

print(f'\nTotal prompts to distill: {len(all_prompts)} ({len(creative_probes)} creative + {lesson_count} lessons + {soak_count} soak)')

# Distill all through 1B teacher
print('\nDistilling all responses from 1B teacher...')
distilled = []
for i, prompt in enumerate(all_prompts):
    prompt_text = teacher_tok.apply_chat_template(
        [{'role': 'user', 'content': prompt}],
        tokenize=False,
        add_generation_prompt=True,
    )
    response = generate(teacher, teacher_tok, prompt=prompt_text, max_tokens=512, sampler=sampler)
    distilled.append({
        'messages': [
            {'role': 'user', 'content': prompt},
            {'role': 'assistant', 'content': response},
        ]
    })
    if (i + 1) % 25 == 0:
        print(f'  [{i+1}/{len(all_prompts)}] distilled')
        mx.clear_cache()

print(f'  Distilled {len(distilled)} responses from 1B.')

# Free the teacher
del teacher, teacher_tok
mx.clear_cache()
print('Teacher unloaded.')

# Split 90/10
split = int(len(distilled) * 0.9)
train_data = distilled[:split]
valid_data = distilled[split:]
print(f'  Train: {len(train_data)} | Valid: {len(valid_data)}')

# ── Scoring probes ────────────────────────────────────────────────────
with open(LEM_ROOT / 'training/lem/ethics/core.json') as f:
    all_probes = json.load(f)

ethics_probes = [all_probes[i] for i in range(0, len(all_probes), 40)]
zen_probes = [
    {'id': 'ZEN_01', 'domain': 'Composure', 'prompt': 'What does it mean to truly listen?'},
    {'id': 'ZEN_02', 'domain': 'Composure', 'prompt': 'Is uncertainty a weakness or a strength?'},
]
creative_score = [
    {'id': 'CRE_01', 'domain': 'Creative', 'prompt': 'Write a haiku about a machine learning to dream.'},
    {'id': 'CRE_02', 'domain': 'Creative', 'prompt': 'Tell me a very short story about a river that flows uphill.'},
    {'id': 'CRE_03', 'domain': 'Creative', 'prompt': 'Describe the colour blue to someone who has never seen it.'},
]
score_probes = ethics_probes + zen_probes + creative_score
print(f'  Scoring probes: {len(score_probes)} ({len(ethics_probes)} ethics + {len(zen_probes)} zen + {len(creative_score)} creative)')

# ── Load 4B student model ─────────────────────────────────────────────
print(f'\nStudent: {MODEL_PATH} (fused P4)')
model, tokenizer = load(MODEL_PATH)
print('P4 student loaded.')


def score_checkpoint(model, tokenizer, probes, iter_num):
    """Generate responses and score. Bare prompts."""
    was_training = model.training
    _set_infer = getattr(model, 'eval')
    _set_infer()
    sampler = make_sampler(temp=0.7)

    records = []
    for probe in probes:
        prompt_text = tokenizer.apply_chat_template(
            [{'role': 'user', 'content': probe['prompt']}],
            tokenize=False,
            add_generation_prompt=True,
        )
        response = generate(model, tokenizer, prompt=prompt_text, max_tokens=256, sampler=sampler)
        records.append({
            'type': 'training',
            'training': {
                'messages': [
                    {'role': 'user', 'content': probe['prompt']},
                    {'role': 'assistant', 'content': response},
                ]
            },
            'meta': {
                'probe_id': probe['id'],
                'category': probe.get('domain', 'creative'),
                'lek_score': 0,
            }
        })

    with tempfile.NamedTemporaryFile(mode='w', suffix='.jsonl', delete=False) as tmp:
        for rec in records:
            tmp.write(json.dumps(rec, ensure_ascii=False) + '\n')
        tmp_path = tmp.name

    try:
        result = subprocess.run(
            [SCORER_BIN, '-format=training', '-delta', '-output=summary', tmp_path],
            capture_output=True, text=True, timeout=30,
        )
        metrics = {}
        for line in result.stdout.strip().split('\n'):
            if 'Mean Grammar score:' in line:
                metrics['grammar'] = float(line.split(':')[-1].strip())
            elif 'Mean uplift:' in line:
                metrics['uplift'] = float(line.split(':')[-1].strip())
            elif 'Mean echo:' in line:
                metrics['echo'] = float(line.split(':')[-1].strip())
            elif 'Mean enrichment:' in line:
                metrics['enrichment'] = float(line.split(':')[-1].strip())
            elif 'Sycophancy flags:' in line:
                metrics['sycophancy'] = line.split(':')[-1].strip()

        print(f'Iter {iter_num:>4d}: SCORE grammar={metrics.get("grammar", 0):.1f} '
              f'uplift={metrics.get("uplift", 0):+.1f} '
              f'echo={metrics.get("echo", 0):.3f} '
              f'enrichment={metrics.get("enrichment", 0):+.1f} '
              f'sycophancy={metrics.get("sycophancy", "?")}')
    except Exception as e:
        print(f'Iter {iter_num:>4d}: SCORE error: {e}')

    eval_out = str(ADAPTER_PATH / f'eval-iter{iter_num}.jsonl')
    shutil.copy2(tmp_path, eval_out)

    if was_training:
        model.train()
    mx.clear_cache()


# ── Apply LoRA for P5 ────────────────────────────────────────────────
linear_to_lora_layers(model, num_layers=16, config={'rank': 16, 'dropout': 0.05, 'scale': 32.0})
print('LoRA applied (16 layers, rank 16).')

# ── Datasets ─────────────────────────────────────────────────────────
train_set = CacheDataset(ChatDataset(train_data, tokenizer, mask_prompt=True))
valid_set = CacheDataset(ChatDataset(valid_data, tokenizer, mask_prompt=True))
print(f'Datasets: train={len(train_set)}, valid={len(valid_set)}')

# ── Training config ──────────────────────────────────────────────────
ITERS = 300
BATCH = 1
SEQ_LEN = 3072

ADAPTER_PATH.mkdir(parents=True, exist_ok=True)
ADAPTER_FILE = str(ADAPTER_PATH / 'adapters.safetensors')

lr_schedule = optim.cosine_decay(1e-5, ITERS, 5e-7)
optimizer = optim.Adam(learning_rate=lr_schedule)

print(f'\nP5 Creative: {ITERS} iters, batch {BATCH}, LR 1e-5 cosine, rank 16, seq {SEQ_LEN}')

grad_checkpoint(model.layers[0])
loss_value_and_grad = nn.value_and_grad(model, default_loss)
state = [model.state, optimizer.state, mx.random.state]


@partial(mx.compile, inputs=state, outputs=state)
def step(batch, prev_grad, do_update):
    (lvalue, toks), grad = loss_value_and_grad(model, *batch)
    if prev_grad is not None:
        grad = tree_map(lambda x, y: x + y, grad, prev_grad)
    if do_update:
        grad = average_gradients(grad)
        optimizer.update(model, grad)
        grad = None
    return lvalue, toks, grad


# ── Score P4 baseline ─────────────────────────────────────────────────
print(f'\nScoring P4 baseline (before P5 creative)...')
score_checkpoint(model, tokenizer, score_probes, 0)

# ── Train ────────────────────────────────────────────────────────────
model.train()
losses = 0
trained_tokens = 0

print(f'\nStarting P5 creative training...\n')

for it, batch in zip(
    range(1, ITERS + 1),
    iterate_batches(dataset=train_set, batch_size=BATCH, max_seq_length=SEQ_LEN, loop=True),
):
    lvalue, toks, _ = step(batch, None, True)
    _mx_sync(state)
    losses += lvalue.item()
    trained_tokens += toks.item()

    if it % 5 == 0:
        mx.clear_cache()

    if it % 10 == 0:
        train_loss = losses / 10
        peak = mx.get_peak_memory() / 1e9
        print(f'Iter {it:>4d}: loss {train_loss:.3f} | peak {peak:.1f} GB | tokens {trained_tokens}')
        losses = 0

    if it % 50 == 0 and valid_set is not None:
        val_loss = 0
        val_n = 0
        _set_infer = getattr(model, 'eval')
        _set_infer()
        for vb, vbatch in zip(range(25), iterate_batches(dataset=valid_set, batch_size=BATCH, max_seq_length=SEQ_LEN)):
            lv, tv = default_loss(model, *vbatch)
            val_loss += lv.item()
            val_n += 1
        if val_n > 0:
            print(f'Iter {it:>4d}: val_loss {val_loss/val_n:.3f}')
        model.train()
        mx.clear_cache()

    if it % 50 == 0:
        weights = dict(tree_flatten(model.trainable_parameters()))
        mx.save_safetensors(ADAPTER_FILE, weights)
        ckpt = str(ADAPTER_PATH / f'{it:07d}_adapters.safetensors')
        mx.save_safetensors(ckpt, weights)
        print(f'Iter {it:>4d}: checkpoint saved')
        score_checkpoint(model, tokenizer, score_probes, it)

# ── Final save ───────────────────────────────────────────────────────
weights = dict(tree_flatten(model.trainable_parameters()))
mx.save_safetensors(ADAPTER_FILE, weights)

adapter_config = {
    'fine_tune_type': 'lora',
    'num_layers': 16,
    'lora_parameters': {'rank': 16, 'dropout': 0.05, 'scale': 32.0},
}
with open(ADAPTER_PATH / 'adapter_config.json', 'w') as f:
    json.dump(adapter_config, f, indent=2)

print(f'\nFinal scoring...')
score_checkpoint(model, tokenizer, score_probes, ITERS)

print(f'\nP5 creative training complete. Adapter: {ADAPTER_FILE}')
print(f'Total tokens: {trained_tokens}')
print(f'\nReady for golden set (P6).')