from __future__ import annotations

import argparse
import pickle
from pathlib import Path

import matplotlib.pyplot as plt
import numpy as np

try:
    from .config import CORE_FEATURE_NAMES, evaluation_dir, make_experiment_config
    from .dataset import build_record_from_file
except ImportError:
    from config import CORE_FEATURE_NAMES, evaluation_dir, make_experiment_config
    from dataset import build_record_from_file


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Predict task1 RMS from a single harmonic waveform CSV.")
    parser.add_argument("--file", type=str, required=True)
    parser.add_argument("--checkpoint", type=str, default=None)
    return parser.parse_args()


def resolve_checkpoint_path(project_root: Path, checkpoint_arg: str | None) -> Path:
    if checkpoint_arg:
        return Path(checkpoint_arg).resolve()
    return project_root / "checkpoints_final" / "task1_final" / "task1_final_model.pkl"


def save_prediction_figure(file_path: Path, record, pred_rms: float, output_dir: Path) -> Path:
    time_middle = record.time_middle.reshape(-1)
    x_middle = record.x_middle.reshape(-1)
    y_middle = record.y_middle.reshape(-1)
    sampling_rate = record.sampling_rate
    fft_values = np.fft.rfft(x_middle - np.mean(x_middle))
    freqs = np.fft.rfftfreq(x_middle.size, d=1.0 / sampling_rate)
    amplitudes = np.abs(fft_values)

    fig, axes = plt.subplots(4, 1, figsize=(12, 12))
    fig.suptitle(f"Task1 Final Single-File Prediction | {file_path.name}")

    axes[0].plot(time_middle, x_middle, color="tab:blue")
    axes[0].set_title("Input Base Excitation (Middle Segment)")
    axes[0].set_xlabel("Time")
    axes[0].set_ylabel("Acceleration")
    axes[0].grid(True, alpha=0.3)

    axes[1].plot(time_middle, y_middle, color="tab:green")
    axes[1].set_title("True Top Response (Middle Segment)")
    axes[1].set_xlabel("Time")
    axes[1].set_ylabel("Acceleration")
    axes[1].grid(True, alpha=0.3)

    axes[2].plot(freqs, amplitudes, color="tab:purple")
    axes[2].axvline(record.frequency_hz, color="tab:red", linestyle="--", label=f"Frequency = {record.frequency_hz:.4f} Hz")
    axes[2].set_xlim(0.0, 5.0)
    axes[2].set_title("Input Spectrum")
    axes[2].set_xlabel("Frequency (Hz)")
    axes[2].set_ylabel("Amplitude")
    axes[2].grid(True, alpha=0.3)
    axes[2].legend()

    axes[3].bar(["True RMS", "Pred RMS"], [record.y_rms, pred_rms], color=["tab:green", "tab:orange"])
    error_percent = abs(pred_rms - record.y_rms) / max(abs(record.y_rms), 1e-12) * 100.0
    axes[3].set_title(
        f"True RMS = {record.y_rms:.6f} | Pred RMS = {pred_rms:.6f} | Error = {error_percent:.2f}%"
    )
    axes[3].set_ylabel("RMS")
    axes[3].grid(True, axis="y", alpha=0.3)

    plt.tight_layout()
    output_dir.mkdir(parents=True, exist_ok=True)
    figure_path = output_dir / f"{file_path.stem}_prediction.png"
    plt.savefig(figure_path, dpi=180, bbox_inches="tight")
    plt.close(fig)
    return figure_path


def main() -> None:
    args = parse_args()
    config = make_experiment_config()
    ckpt_path = resolve_checkpoint_path(config.data.project_root, args.checkpoint)
    with ckpt_path.open("rb") as handle:
        payload = pickle.load(handle)
    model = payload["model"]

    file_path = Path(args.file).resolve()
    record = build_record_from_file(file_path, config.data)
    pred_tr = max(float(model.predict([record.features.tolist()])[0]), config.data.normalization_eps)
    pred_rms = pred_tr * record.x_rms

    out_dir = evaluation_dir(config)
    fig_path = save_prediction_figure(file_path, record, pred_rms, out_dir)

    print(f"Checkpoint: {ckpt_path}")
    print(f"Model: {payload['model_name']}")
    print(f"Input file: {file_path}")
    for feature_name, feature_value in zip(CORE_FEATURE_NAMES, record.features.tolist()):
        print(f"{feature_name}: {feature_value:.6f}")
    print(f"Predicted TR: {pred_tr:.6f}")
    print(f"Predicted RMS: {pred_rms:.6f}")
    print(f"True RMS: {record.y_rms:.6f}")
    print(f"Relative RMS Error (%): {abs(pred_rms - record.y_rms) / max(abs(record.y_rms), 1e-12) * 100.0:.4f}")
    print(f"Figure saved to: {fig_path}")


if __name__ == "__main__":
    main()