import os

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

import schemdraw
import schemdraw.elements as elm
from schemdraw.segments import SegmentText, SegmentCircle

FONT_NAME = "LXGW WenKai"
BG_COLOR = "white"

# 这里改成你自己的输出目录
OUTDIR = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "image"))
os.makedirs(OUTDIR, exist_ok=True)


def make_drawing():
    d = schemdraw.Drawing(show=False)
    d.config(
        unit=1.0,
        fontsize=16,
        font=FONT_NAME,
        lw=2.2,
        margin=0.18,
        bgcolor=BG_COLOR,
    )
    return d


def add_text(
    drawing,
    position,
    content,
    *,
    rotation=0,
    align=("center", "center"),
    fontsize=16,
):
    element = elm.Element().at(position).anchor("center").hold()
    element.anchors["center"] = (0, 0)
    element.segments.append(
        SegmentText(
            (0, 0),
            content,
            rotation=rotation,
            align=align,
            fontsize=fontsize,
            font=FONT_NAME,
        )
    )
    drawing.add(element)


def add_dot(drawing, position, *, open_dot=False, radius=0.085):
    drawing.add(elm.Dot(open=open_dot, radius=radius).at(position).hold())


def wire(drawing, start, end):
    drawing.add(elm.Line().at(start).to(end).hold())


def save_drawing(drawing, filename):
    drawing.save(os.path.join(OUTDIR, filename), transparent=False)


# -------------------------
# 图 (a)
# -------------------------
def make_circuit_a():
    d = make_drawing()

    x_left = 0.9
    x_meter = 3.0
    x_node = 5.7
    x_res_top = 7.2
    x_right = 10.1

    y_top = 4.2
    y_bottom = 1.0
    y_mid = 2.55

    # 左侧电池
    batt = d.add(elm.BatteryCell().at((x_left, y_bottom)).up(2.1).hold())
    wire(d, batt.end, (x_left, y_top))
    wire(d, batt.start, (x_left, y_bottom))

    # 上边：A表 + 节点 + 1k
    wire(d, (x_left, y_top), (x_meter, y_top))
    am = d.add(elm.MeterA().at((x_meter, y_top)).right().hold())
    wire(d, am.end, (x_node, y_top))
    add_dot(d, (x_node, y_top))

    wire(d, (x_node, y_top), (x_res_top, y_top))
    r1 = d.add(elm.ResistorIEC().at((x_res_top, y_top)).right(1.5).hold())
    wire(d, r1.end, (x_right, y_top))

    # 右侧竖直 2k 电阻
    r2 = d.add(elm.ResistorIEC().at((x_right, y_top)).down(1.9).hold())
    wire(d, r2.end, (x_right, y_bottom))

    # 中间 V 表支路
    wire(d, (x_node, y_top), (x_node, 3.45))
    vm = d.add(elm.MeterV().at((x_node, 3.45)).down().hold())
    wire(d, vm.end, (x_node, y_bottom))
    add_dot(d, (x_node, y_bottom))

    # 底边闭合
    wire(d, (x_left, y_bottom), (x_node, y_bottom))
    wire(d, (x_node, y_bottom), (x_right, y_bottom))

    # 文字
    add_text(d, (8.0, 4.75), "1kΩ", fontsize=16)
    add_text(d, (10.75, 2.45), "2kΩ", fontsize=16)
    add_text(d, (5.4, 0.25), "(a)", fontsize=18)

    save_drawing(d, "circuit_a.svg")


# -------------------------
# 图 (b)
# -------------------------
def make_circuit_b():
    d = make_drawing()

    x_left = 0.9
    x_node = 3.4
    x_meter = 5.0
    x_res_top = 7.2
    x_right = 10.1

    y_top = 4.2
    y_bottom = 1.0

    # 左侧电池
    batt = d.add(elm.BatteryCell().at((x_left, y_bottom)).up(2.1).hold())
    wire(d, batt.end, (x_left, y_top))
    wire(d, batt.start, (x_left, y_bottom))

    # 上边左节点
    wire(d, (x_left, y_top), (x_node, y_top))
    add_dot(d, (x_node, y_top))

    # 中间 V 表
    wire(d, (x_node, y_top), (x_node, 3.45))
    vm = d.add(elm.MeterV().at((x_node, 3.45)).down().hold())
    wire(d, vm.end, (x_node, y_bottom))
    add_dot(d, (x_node, y_bottom))

    # 上边右支路：A + 1k
    wire(d, (x_node, y_top), (x_meter, y_top))
    am = d.add(elm.MeterA().at((x_meter, y_top)).right().hold())
    wire(d, am.end, (x_res_top, y_top))
    r1 = d.add(elm.ResistorIEC().at((x_res_top, y_top)).right(1.5).hold())
    wire(d, r1.end, (x_right, y_top))

    # 右侧竖直 2k
    r2 = d.add(elm.ResistorIEC().at((x_right, y_top)).down(1.9).hold())
    wire(d, r2.end, (x_right, y_bottom))

    # 下边闭合
    wire(d, (x_left, y_bottom), (x_node, y_bottom))
    wire(d, (x_node, y_bottom), (x_right, y_bottom))

    # 文字
    add_text(d, (8.0, 4.75), "1kΩ", fontsize=16)
    add_text(d, (9.1, 3.0), "2kΩ", fontsize=16)
    add_text(d, (5.6, 0.25), "(b)", fontsize=18)

    save_drawing(d, "circuit_b.svg")


# -------------------------
# 图 (c)
# -------------------------
def make_circuit_c():
    d = make_drawing()

    x_left = 1.2
    x_v = 3.2
    x_node = 6.0
    x_right = 8.8

    y_top = 4.2
    y_bottom = 1.0

    # 左侧电压源
   # 左侧理想电压源：圆圈 + 竖线
    source_center_y = 2.45
    source_radius = 0.55

# 上下导线
    wire(d, (x_left, y_top), (x_left, source_center_y + source_radius))
    wire(d, (x_left, source_center_y - source_radius), (x_left, y_bottom))

# 圆圈
    src = elm.Element().at((x_left, source_center_y)).anchor("center").hold()
    src.anchors["center"] = (0, 0)
    src.segments.append(SegmentCircle((0, 0), radius=source_radius))
    d.add(src)

# 圆圈中间竖线
    wire(d, (x_left, source_center_y - 0.5), (x_left, source_center_y + 0.5))

    # 顶部 V 表
    wire(d, (x_left, y_top), (x_v, y_top))
    vm = d.add(elm.MeterV().at((x_v, y_top)).right().hold())
    wire(d, vm.end, (x_node, y_top))
    add_dot(d, (x_node, y_top))

    # 右侧电阻支路
    wire(d, (x_node, y_top), (x_right, y_top))
    r = d.add(elm.ResistorIEC().at((x_right, y_top)).down(1.9).hold())
    wire(d, r.end, (x_right, y_bottom))

    # 中间开关支路
    wire(d, (x_node, y_top), (x_node, 3.2))
    add_dot(d, (x_node, 3.2), open_dot=True, radius=0.11)
    add_dot(d, (x_node, 2.1), open_dot=True, radius=0.11)
    d.add(elm.Line().at((x_node - 0.05, 2.18)).to((x_node + 0.35, 2.95)).hold())
    wire(d, (x_node, 2.1), (x_node, y_bottom))
    add_dot(d, (x_node, y_bottom))

    # 下边闭合
    wire(d, (x_left, y_bottom), (x_node, y_bottom))
    wire(d, (x_node, y_bottom), (x_right, y_bottom))

    # 文字
    add_text(d, (0.25, 2.25), "Uₛ", fontsize=18)
    add_text(d, (6.65, 2.6), "K", fontsize=18)
    add_text(d, (9.5, 2.55), "R", fontsize=18)

    save_drawing(d, "circuit_c.svg")


# -------------------------
# 图 (d)
# -------------------------
def make_circuit_d():
    d = make_drawing()

    x_left = 1.0
    x_mid = 4.2
    x_right = 7.2

    y_top = 6.5
    y_bottom = 0.7

    # 外框
    wire(d, (x_left, y_top), (x_mid, y_top))
    add_dot(d, (x_mid, y_top))
    wire(d, (x_mid, y_top), (x_right, y_top))

    wire(d, (x_left, y_bottom), (x_mid, y_bottom))
    add_dot(d, (x_mid, y_bottom))
    wire(d, (x_mid, y_bottom), (x_right, y_bottom))

    # 左支路：电流源
    # 左支路：理想电流源（圆圈 + 竖线）
    source_center_y = 4.2
    source_radius = 0.55

    wire(d, (x_left, y_top), (x_left, source_center_y + source_radius))
    wire(d, (x_left, source_center_y - source_radius), (x_left, y_bottom))

# 圆圈
    src = elm.Element().at((x_left, source_center_y)).anchor("center").hold()
    src.anchors["center"] = (0, 0)
    src.segments.append(SegmentCircle((0, 0), radius=source_radius))
    d.add(src)

# 圆圈中间竖线
    wire(d, (x_left, source_center_y - 0.5), (x_left, source_center_y + 0.5))

# 标注
    add_text(d, (x_left + 0.7, source_center_y - 0.6), "Iₛ", fontsize=18)

    # 右支路：A 表
    wire(d, (x_right, y_top), (x_right, 5.0))
    am = d.add(elm.MeterA().at((x_right, 5.0)).down().hold())
    wire(d, am.end, (x_right, y_bottom))

    # 中间支路：开关 + 可变电阻
    wire(d, (x_mid, y_top), (x_mid, 5.2))
    add_dot(d, (x_mid, 5.2), open_dot=True, radius=0.11)
    add_dot(d, (x_mid, 4.25), open_dot=True, radius=0.11)
    d.add(elm.Line().at((x_mid - 0.05, 4.35)).to((x_mid + 0.4, 5.0)).hold())
    wire(d, (x_mid, 4.25), (x_mid, 3.6))

    r = d.add(elm.ResistorIEC().at((x_mid, 3.6)).down(1.5).hold())
    wire(d, r.end, (x_mid, y_bottom))

    # 文字
    add_text(d, (4.85, 4.85), "K", fontsize=18)
    add_text(d, (4.8, 2.05), "R", fontsize=18)

    save_drawing(d, "circuit_d.svg")


def main():
    make_circuit_a()
    make_circuit_b()
    make_circuit_c()
    make_circuit_d()
    print("Created: circuit_a.svg, circuit_b.svg, circuit_c.svg, circuit_d.svg")


if __name__ == "__main__":
    main()