import json
import os
import sys
import time
import traceback

import torch
from huggingface_hub import HfApi

from netfm.data.datasets import load_and_prepare, PRETRAIN_DATASETS, HOLDOUT_DATASETS
from netfm.models.encoder import GraphSAGEEncoder
from netfm.pretrain.trainer import NetFMPretrainer
from netfm.evaluate.pipeline import run_full_evaluation


HF_REPO = os.environ.get("HF_REPO", "GitHunter/netfm-checkpoints")
DATA_ROOT = "./data"
CKPT_DIR = "./checkpoints"
RESULTS_DIR = "./results"

PRETRAIN_CONFIG = {
    "hidden_channels": 256,
    "out_channels": 128,
    "num_layers": 3,
    "dropout": 0.1,
    "lr": 1e-3,
    "weight_decay": 1e-4,
    "lambda_mask": 1.0,
    "lambda_link": 1.0,
    "lambda_subgraph": 0.5,
    "mask_ratio": 0.15,
    "edge_drop_ratio": 0.1,
    "epochs": 100,
}


def upload_to_hub(local_path: str, repo_path: str) -> None:
    """Upload a file to the HuggingFace Hub."""
    api = HfApi()
    try:
        api.upload_file(
            path_or_fileobj=local_path,
            path_in_repo=repo_path,
            repo_id=HF_REPO,
            repo_type="model",
        )
        print(f"Uploaded {local_path} -> {repo_path}")
    except Exception as e:
        print(f"Upload failed for {repo_path}: {e}")


def log(msg: str) -> None:
    """Print and flush a log message."""
    print(msg, flush=True)


def main() -> None:
    """Run full pre-training and evaluation pipeline."""
    os.makedirs(CKPT_DIR, exist_ok=True)
    os.makedirs(RESULTS_DIR, exist_ok=True)

    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    log(f"Device: {device}")
    if device.type == "cuda":
        log(f"GPU: {torch.cuda.get_device_name(0)}")
        log(f"VRAM: {torch.cuda.get_device_properties(0).total_mem / 1e9:.1f} GB")

    log("=" * 60)
    log("PHASE 1: Loading and preparing datasets")
    log("=" * 60)

    all_graphs = []
    dataset_stats = {}
    for name in PRETRAIN_DATASETS:
        log(f"Loading {name}...")
        t0 = time.time()
        try:
            graphs = load_and_prepare(name, root=DATA_ROOT)
            for g in graphs:
                all_graphs.append(g.data)
            elapsed = time.time() - t0
            dataset_stats[name] = {
                "num_graphs": len(graphs),
                "num_nodes": graphs[0].num_nodes,
                "num_edges": graphs[0].num_edges,
                "load_time_s": round(elapsed, 1),
            }
            log(f"  -> {len(graphs)} graph(s), {graphs[0].num_nodes} nodes, {elapsed:.1f}s")
        except Exception as e:
            log(f"  -> FAILED: {e}")
            traceback.print_exc()
            dataset_stats[name] = {"error": str(e)}

    stats_path = os.path.join(RESULTS_DIR, "dataset_stats.json")
    with open(stats_path, "w") as f:
        json.dump(dataset_stats, f, indent=2)
    upload_to_hub(stats_path, "dataset_stats.json")

    log(f"\nTotal pre-training graphs: {len(all_graphs)}")
    if len(all_graphs) == 0:
        log("ERROR: No graphs loaded. Exiting.")
        sys.exit(1)

    log("=" * 60)
    log("PHASE 2: Pre-training")
    log("=" * 60)

    encoder = GraphSAGEEncoder(
        in_channels=6,
        hidden_channels=PRETRAIN_CONFIG["hidden_channels"],
        out_channels=PRETRAIN_CONFIG["out_channels"],
        num_layers=PRETRAIN_CONFIG["num_layers"],
        dropout=PRETRAIN_CONFIG["dropout"],
    )
    log(f"Model parameters: {sum(p.numel() for p in encoder.parameters()):,}")

    trainer = NetFMPretrainer(
        encoder=encoder,
        device=device,
        lr=PRETRAIN_CONFIG["lr"],
        weight_decay=PRETRAIN_CONFIG["weight_decay"],
        lambda_mask=PRETRAIN_CONFIG["lambda_mask"],
        lambda_link=PRETRAIN_CONFIG["lambda_link"],
        lambda_subgraph=PRETRAIN_CONFIG["lambda_subgraph"],
        mask_ratio=PRETRAIN_CONFIG["mask_ratio"],
        edge_drop_ratio=PRETRAIN_CONFIG["edge_drop_ratio"],
        num_epochs=PRETRAIN_CONFIG["epochs"],
    )

    history = trainer.train(all_graphs)

    ckpt_path = os.path.join(CKPT_DIR, "netfm_pretrained.pt")
    trainer.save(ckpt_path)

    config_path = os.path.join(CKPT_DIR, "config.json")
    with open(config_path, "w") as f:
        json.dump(PRETRAIN_CONFIG, f, indent=2)

    history_path = os.path.join(RESULTS_DIR, "pretrain_history.json")
    with open(history_path, "w") as f:
        json.dump(history, f, indent=2)

    upload_to_hub(ckpt_path, "netfm_pretrained.pt")
    upload_to_hub(config_path, "config.json")
    upload_to_hub(history_path, "pretrain_history.json")

    log("=" * 60)
    log("PHASE 3: Evaluation on held-out datasets")
    log("=" * 60)

    all_results = {}
    for name in HOLDOUT_DATASETS:
        log(f"Evaluating on {name}...")
        try:
            graphs = load_and_prepare(name, root=DATA_ROOT)
            data = graphs[0].data
            results = run_full_evaluation(encoder, data, device, name)
            all_results.update(results)
            log(f"  Done: {list(results[name].keys())}")
        except Exception as e:
            log(f"  FAILED: {e}")
            traceback.print_exc()
            all_results[name] = {"error": str(e)}

    results_path = os.path.join(RESULTS_DIR, "evaluation_results.json")
    with open(results_path, "w") as f:
        json.dump(all_results, f, indent=2, default=str)

    upload_to_hub(results_path, "evaluation_results.json")

    log("=" * 60)
    log("DONE! All results uploaded to HuggingFace Hub.")
    log("=" * 60)
    log(f"Checkpoint: {HF_REPO}")
    log(json.dumps(all_results, indent=2, default=str))


if __name__ == "__main__":
    main()