import torch
import os
import sys
from pathlib import Path
root_path = Path(__file__).parent.parent
sys.path.append(str(root_path))
import glob
import numpy as np
import h5py
from tqdm import tqdm
from model.fengwu import Fengwu
from onescience.utils.YParams import YParams
from onescience.datapipes.climate import ERA5Datapipe


def get_stats(data_dir, channels):
    """从新版 h5 中读取变量列表与归一化参数（均值/标准差）"""
    h5_files = sorted(glob.glob(os.path.join(data_dir, "data", "*.h5")))
    with h5py.File(h5_files[0], "r") as f:
        ds = f["fields"]
        all_variables = [v.decode() if isinstance(v, bytes) else v for v in ds.attrs["variables"]]
        mu = f["global_means"][:]   # [1, C, 1, 1]
        std = f["global_stds"][:]

    channel_indices = [all_variables.index(v) for v in channels]
    means = mu[:, channel_indices, :, :]
    stds = std[:, channel_indices, :, :]
    return means, stds


if __name__ == "__main__":
    current_path = os.getcwd()
    sys.path.append(current_path)

    ## Model config init
    config_file_path = os.path.join(current_path, "conf/config.yaml")
    cfg = YParams(config_file_path, "model")

    ## DataLoader init
    cfg_data = YParams(config_file_path, "datapipe")
    means, stds = get_stats(cfg_data.dataset.data_dir, cfg_data.dataset.channels)

    datapipe = ERA5Datapipe(
        dataset_dir=cfg_data.dataset.data_dir,
        used_variables=cfg_data.dataset.channels,
        used_years=cfg_data.dataset.test_time,
        distributed=False,
        batch_size=1,
        num_workers=4,
    )
    test_dataloader, _ = datapipe.get_dataloader("test")

    ckpt = torch.load(f"{cfg.checkpoint_dir}/model_bak.pth", map_location="cuda:0")
    model = Fengwu(img_size=cfg_data.dataset.img_size,
                   pressure_level=cfg.pressure_level,
                   embed_dim=cfg.embed_dim,
                   patch_size=cfg.patch_size,
                   num_heads=cfg.num_heads,
                   window_size=cfg.window_size,
                   ).to('cuda:0')
    model.load_state_dict(ckpt["model_state_dict"])

    model.eval()
    os.makedirs('result/output/', exist_ok=True)
    print(f"📂 samples will be generated to './result/output/'")
    with torch.no_grad():
        for data in tqdm(test_dataloader, desc="Inferring testset", unit="batch"):
            invar = data[0].to("cuda:0", dtype=torch.float32)
            outvar = data[1].to("cuda:0", dtype=torch.float32)
            filename = data[4][-1][0]
            surface = invar[:, :4, :, :]
            z = invar[:, 4:41, :, :]
            r = invar[:, 41:78, :, :]
            u = invar[:, 78:115, :, :]
            v = invar[:, 115:152, :, :]
            t = invar[:, 152:189, :, :]

            surface_p, z_p, r_p, u_p, v_p, t_p = model(surface, z, r, u, v, t)
            pred_var = torch.concat([surface_p, z_p, r_p, u_p, v_p, t_p], dim=1).cpu().numpy()
            pred_var = pred_var * stds + means
            np.save(f"result/output/{filename}.npy", pred_var)