import os
from pathlib import Path
import sys

os.environ.setdefault("MPLCONFIGDIR", "/tmp/matplotlib")

import matplotlib.pyplot as plt

FONT_NAME = "STIXGeneral"
BG_COLOR = "white"
LINE_COLOR = "#111111"
DEFAULT_OUTPUT = (
    Path(__file__).resolve().parent.parent / "image" / "exp0" / "ro_measure_diagram.svg"
)


def draw_diagram(save_path=DEFAULT_OUTPUT):
    save_path = Path(save_path)
    save_path.parent.mkdir(parents=True, exist_ok=True)

    plt.rcParams["font.family"] = FONT_NAME
    plt.rcParams["axes.unicode_minus"] = False

    fig, ax = plt.subplots(figsize=(5.2, 5.5), dpi=160)
    fig.patch.set_facecolor(BG_COLOR)
    ax.set_facecolor(BG_COLOR)

    # 坐标范围
    ax.set_xlim(-0.6, 9.8)
    ax.set_ylim(-0.45, 9.85)
    ax.axis("off")

    # 关键点
    origin = (0.0, 0.0)
    u_oc = (0.0, 8.8)
    i_sc = (8.3, 0.0)
    a_pt = (2.6, 6.05)
    b_pt = (5.5, 2.95)

    # 坐标轴
    ax.annotate(
        "",
        xy=(9.35, 0.0),
        xytext=origin,
        arrowprops=dict(arrowstyle="-|>", lw=1.9, color=LINE_COLOR),
    )
    ax.annotate(
        "",
        xy=(0.0, 9.65),
        xytext=origin,
        arrowprops=dict(arrowstyle="-|>", lw=1.9, color=LINE_COLOR),
    )

    # 主特性直线
    ax.plot([u_oc[0], i_sc[0]], [u_oc[1], i_sc[1]], color=LINE_COLOR, lw=2.2)

    # A/B 点
    ax.text(a_pt[0] + 0.18, a_pt[1] + 0.22, "A", fontsize=14)
    ax.text(b_pt[0] + 0.18, b_pt[1] - 0.1, "B", fontsize=14)

    # ΔU / ΔI 虚线框
    x_left = a_pt[0]
    x_right = b_pt[0]
    y_top = a_pt[1]
    y_bottom = b_pt[1]
    dash = (0, (6, 4))

    ax.plot([x_left, x_left], [0, y_top], color=LINE_COLOR, lw=1.3, ls=dash)
    ax.plot([x_right, x_right], [0, y_bottom], color=LINE_COLOR, lw=1.3, ls=dash)
    ax.plot([0, x_left], [y_top, y_top], color=LINE_COLOR, lw=1.3, ls=dash)
    ax.plot([0, x_right], [y_bottom, y_bottom], color=LINE_COLOR, lw=1.3, ls=dash)

    # ΔU 竖向双箭头
    x_du = 1.45
    ax.annotate(
        "",
        xy=(x_du, y_top),
        xytext=(x_du, y_bottom),
        arrowprops=dict(arrowstyle="<|-|>", lw=1.4, color=LINE_COLOR),
    )
    ax.text(x_du - 0.55, (y_top + y_bottom) / 2 - 0.15, r"$\Delta U$", fontsize=14)

    # ΔI 横向双箭头
    y_di = 1.05
    ax.annotate(
        "",
        xy=(x_right, y_di),
        xytext=(x_left, y_di),
        arrowprops=dict(arrowstyle="<|-|>", lw=1.4, color=LINE_COLOR),
    )
    ax.text((x_left + x_right) / 2 - 0.35, y_di - 0.72, r"$\Delta I$", fontsize=14)

    # 角度 phi
    ax.text(4.32, 2.3, r"$\varphi$", fontsize=16)

    # 轴与截距标注
    ax.text(9.05, -0.48, r"$I$", fontsize=18)
    ax.text(0.25, 9.35, r"$U$", fontsize=18)
    ax.text(-0.18, -0.35, "0", fontsize=13)
    ax.text(0.22, 8.9, r"$U_{oc}$", fontsize=14)
    ax.text(8.06, -0.62, r"$I_{sc}$", fontsize=14)

    fig.tight_layout(pad=0.2)
    fig.savefig(save_path, bbox_inches="tight")
    plt.close(fig)
    print(f"saved to: {save_path}")


if __name__ == "__main__":
    output_path = sys.argv[1] if len(sys.argv) > 1 else DEFAULT_OUTPUT
    draw_diagram(output_path)