#!/usr/bin/env python3
from pathlib import Path

import matplotlib.pyplot as plt
import numpy as np
import pykmertools as kt


def read_first_fasta_sequence(path: Path) -> str:
    seq_parts: list[str] = []
    for line in path.read_text(encoding="utf-8").splitlines():
        if not line:
            continue
        if line.startswith(">"):
            if seq_parts:
                break
            continue
        seq_parts.append(line.strip())
    if not seq_parts:
        raise ValueError(f"No FASTA sequence found in {path}")
    return "".join(seq_parts)


def plot_api_scatter(points: list[tuple[float, float]], output_path: Path) -> None:
    x = [p[0] for p in points]
    y = [p[1] for p in points]

    plt.figure(figsize=(8, 8))
    plt.scatter(x, y, s=3, alpha=0.35, color="#1f77b4")
    plt.title("CGR Scatter from Python API (NC_001802.1)")
    plt.xlabel("X coordinate")
    plt.ylabel("Y coordinate")
    plt.tight_layout()
    plt.savefig(output_path, dpi=150)
    plt.close()


def plot_api_density(points: list[tuple[float, float]], output_path: Path) -> None:
    arr = np.array(points, dtype=float)

    plt.figure(figsize=(8, 8))
    hist = plt.hist2d(arr[:, 0], arr[:, 1], bins=64, cmap="viridis")
    plt.title("CGR Density from Python API (NC_001802.1)")
    plt.xlabel("X coordinate")
    plt.ylabel("Y coordinate")
    cbar = plt.colorbar(hist[3])
    cbar.set_label("Point count")
    plt.tight_layout()
    plt.savefig(output_path, dpi=150)
    plt.close()


def main() -> None:
    base_dir = Path(__file__).resolve().parent
    fasta_path = base_dir / "data" / "cgr" / "NC_001802.1.fasta"

    seq = read_first_fasta_sequence(fasta_path)
    cgr = kt.CgrComputer(1)
    points = cgr.vectorise_one(seq)

    scatter_out = base_dir / "cgr_scatter_from_api.png"
    density_out = base_dir / "cgr_density_from_api.png"

    plot_api_scatter(points, scatter_out)
    plot_api_density(points, density_out)

    print(f"Sequence length: {len(seq)}")
    print(f"CGR points: {len(points)}")
    print(f"Saved: {scatter_out}")
    print(f"Saved: {density_out}")


if __name__ == "__main__":
    main()