"""Generate 5-to-15 synthetic radar sequences at the paper's 100x100 size."""

from pathlib import Path

import numpy as np
import yaml


ROOT = Path(__file__).resolve().parents[1]


def make_split(path, count, config, seed):
    rng = np.random.default_rng(seed)
    data = config["data"]
    total = int(data["input_frames"]) + int(data["output_frames"])
    height, width = int(data["height"]), int(data["width"])
    y, x = np.mgrid[-1:1:complex(height), -1:1:complex(width)].astype(np.float32)
    sequences = np.empty((count, total, 1, height, width), np.float32)
    for sample in range(count):
        centers = rng.uniform(-0.55, 0.55, (3, 2))
        velocities = rng.uniform(-0.035, 0.035, (3, 2))
        amplitudes = rng.uniform(0.25, 0.95, 3)
        scales = rng.uniform(0.10, 0.28, 3)
        for step in range(total):
            field = np.zeros((height, width), np.float32)
            for storm in range(3):
                cy, cx = centers[storm] + velocities[storm] * step
                distance = ((x - cx) ** 2 + (y - cy) ** 2) / (2 * scales[storm] ** 2)
                field += amplitudes[storm] * np.exp(-distance)
            sequences[sample, step, 0] = np.clip(field + rng.normal(0, 0.01, field.shape), 0, 1)
    split = int(data["input_frames"])
    np.savez_compressed(path, format_version=np.asarray(data["format_version"]),
                        data_source=np.asarray("synthetic_hko_radar_like"),
                        inputs=sequences[:, :split], targets=sequences[:, split:])


def main():
    config = yaml.safe_load((ROOT / "conf/config.yaml").read_text())
    output = ROOT / config["data"]["root"]
    output.mkdir(parents=True, exist_ok=True)
    for offset, (filename, count) in enumerate((("train.npz", config["data"]["train_samples"]),
                                                 ("test.npz", config["data"]["test_samples"]))):
        target = output / filename
        if not target.exists():
            make_split(target, int(count), config, int(config["seed"]) + offset)
        print(f"generated={target.relative_to(ROOT)} input=5x1x100x100 target=15x1x100x100")


if __name__ == "__main__":
    main()