import base64
import math
import pathlib
from collections import namedtuple
from flask import Flask, render_template, request, Response
from html import escape
from fontTools.ttLib import TTFont
from fontTools.pens.svgPathPen import SVGPathPen

app = Flask(__name__)

VERSION = "1.0"

_LOGO_PATH = pathlib.Path(__file__).parent / "static" / "logo.png"
_LOGO_B64 = base64.b64encode(_LOGO_PATH.read_bytes()).decode()

_FontData = namedtuple(
    "_FontData", ["key", "label", "b64", "glyph_set", "cmap", "hmtx", "upm", "glyf"]
)

_FONT_LABELS = {
    "GOST_2.30481_type_A": "GOST Type A",
    "GOST_2.30481_type_A_Bold": "GOST Type A Bold",
    "Gost2.30481TypeB": "GOST Type B",
    "ISOCPEUR": "ISOCPEUR",
    "SIEMENS_GOST_Type_A": "Siemens GOST Type A",
    "TGL_31034-1": "TGL 31 034",
    "alte-din-1451-mittelschrift.regular": "Alte DIN 1451 Mittelschrift",
    "alte-din-1451-mittelschrift.gepraegt": "Alte DIN 1451 Mittelschrift (Gepraegt)",
}


def _load_fonts():
    font_dir = pathlib.Path(__file__).parent / "fonts"
    if not font_dir.exists():
        font_dir = pathlib.Path(__file__).parent.parent / "fonts"
    fonts = {}
    for path in sorted(font_dir.glob("*.ttf")):
        key = path.stem
        obj = TTFont(str(path))
        fonts[key] = _FontData(
            key=key,
            label=_FONT_LABELS.get(key, key.replace("_", " ")),
            b64=base64.b64encode(path.read_bytes()).decode(),
            glyph_set=obj.getGlyphSet(),
            cmap=obj.getBestCmap(),
            hmtx=obj["hmtx"].metrics,
            upm=obj["head"].unitsPerEm,
            glyf=obj["glyf"],
        )
    return fonts


_FONTS = _load_fonts()
_DEFAULT_FONT = "alte-din-1451-mittelschrift.regular"

# SVG absolute coordinate constants (1 user unit = 1 mm), pre-layer-translate
# local frame — the <g> wrapper applies translate(-60.717741,-107.14126).
PIVOT_X, PIVOT_Y = 107.42845, 162.62819
R0 = 43.842751  # rim / inner-tick radius
ANGLE_MIN, ANGLE_MAX = (
    -45.667193,
    45.667193,
)  # degrees from vertical, clockwise-positive

MAJOR_LEN, MAJOR_W = 4.7839203, 0.79658329
MEDIUM_LEN, MEDIUM_W = 3.1215858, 0.37985462
SMALL_LEN, SMALL_W = 1.8121802, 0.27478597

LABEL_RADIUS = 49.862

UNIT_X, UNIT_Y = 107.03512, 136.64594

LEFT_X, LEFT_Y0 = 73.432251, 145.16051
RIGHT_X, RIGHT_Y0 = 142.4485, 145.32773
CORNER_LINE_SPACING = 4.4586
CORNER_FONT_SIZE = 3.56685

PIVOT_CIRCLE_R = 1.7287594

BODY_D = (
    "m 62.162097,107.14126 c -0.800087,0 -1.444356,0.64428 -1.444356,1.44436 v 45.44839 "
    "c 0,0.80008 0.644269,1.44436 1.444356,1.44436 h 7.345288 c 0.902634,0 1.233517,1.12706 "
    "1.233517,1.12706 l 0.09043,3.03909 21.903573,-0.0904 2.226221,-5.98775 c 8.352594,-2.8884 "
    "16.624974,-2.8884 24.817094,0 l 2.22674,5.98775 21.90357,0.0904 0.0904,-3.03909 c 0,0 "
    "0.33088,-1.12706 1.23352,-1.12706 h 7.86567 c 0.80009,0 1.44384,-0.64428 1.44384,-1.44436 "
    "v -45.44839 c 0,-0.80008 -0.64375,-1.44436 -1.44384,-1.44436 z m 29.619898,45.85354 "
    "a 1.3990685,1.3990685 0 0 1 1.398881,1.39939 1.3990685,1.3990685 0 0 1 -1.398881,1.39888 "
    "1.3990685,1.3990685 0 0 1 -1.399398,-1.39888 1.3990685,1.3990685 0 0 1 1.399398,-1.39939 "
    "z m 31.220835,0 a 1.3990685,1.3990685 0 0 1 1.39888,1.39939 1.3990685,1.3990685 0 0 1 "
    "-1.39888,1.39888 1.3990685,1.3990685 0 0 1 -1.3994,-1.39888 1.3990685,1.3990685 0 0 1 "
    "1.3994,-1.39939 z"
)

# --- Inline markup for the unit label -------------------------------------
_SUP_SCALE = 0.62
_SUP_RISE = 0.36
_SUB_DROP = 0.14
_FRAC_SCALE = 0.62
_FRAC_AXIS = 0.32
_FRAC_GAP = 0.14
_FRAC_SIDE = 0.12

_SYM_WIDTH = 0.75
_SYM_HEIGHT = 0.50
_SYM_LW = 0.08
_SYM_RISE = 0.25


def _symbol_svg(name: str, x: float, y: float, fs: float, fill: str) -> str:
    w = fs * _SYM_WIDTH
    h = fs * _SYM_HEIGHT
    lw = fs * _SYM_LW
    yc = y - _SYM_RISE * fs
    stroke = f"fill:none;stroke:{fill};stroke-width:{lw:.5f};stroke-linecap:round"

    if name == "ac":
        d = (
            f"M {x:.5f},{yc:.5f}"
            f" C {x + w / 3:.5f},{yc - h / 2:.5f}"
            f"  {x + 2 * w / 3:.5f},{yc + h / 2:.5f}"
            f"  {x + w:.5f},{yc:.5f}"
        )
        return f'<path style="{stroke}" d="{d}"/>'

    elif name == "dc":
        dash = w / 5
        gap = w / 5
        y1 = yc - h / 4
        y2 = yc + h / 4
        p1 = f'<line x1="{x:.5f}" y1="{y1:.5f}" x2="{x + w:.5f}" y2="{y1:.5f}" style="{stroke}" />'
        p2 = f'<line x1="{x:.5f}" y1="{y2:.5f}" x2="{x + dash:.5f}" y2="{y2:.5f}" style="{stroke}" />'
        p3 = f'<line x1="{x + dash + gap:.5f}" y1="{y2:.5f}" x2="{x + 2 * dash + gap:.5f}" y2="{y2:.5f}" style="{stroke}" />'
        p4 = f'<line x1="{x + 2 * dash + 2 * gap:.5f}" y1="{y2:.5f}" x2="{x + w:.5f}" y2="{y2:.5f}" style="{stroke}" />'
        return p1 + "\n    " + p2 + "\n    " + p3 + "\n    " + p4

    else:  # acdc
        y_wave = yc - h / 4
        y_dash = yc + h / 4
        dash = w / 5
        gap = w / 5
        d = (
            f"M {x:.5f},{y_wave:.5f}"
            f" C {x + w / 3:.5f},{y_wave - h / 2:.5f}"
            f"  {x + 2 * w / 3:.5f},{y_wave + h / 2:.5f}"
            f"  {x + w:.5f},{y_wave:.5f}"
        )
        p1 = f'<path style="{stroke}" d="{d}"/>'
        p2 = f'<line x1="{x:.5f}" y1="{y_dash:.5f}" x2="{x + dash:.5f}" y2="{y_dash:.5f}" style="{stroke}" />'
        p3 = f'<line x1="{x + dash + gap:.5f}" y1="{y_dash:.5f}" x2="{x + 2 * dash + gap:.5f}" y2="{y_dash:.5f}" style="{stroke}" />'
        p4 = f'<line x1="{x + 2 * dash + 2 * gap:.5f}" y1="{y_dash:.5f}" x2="{x + w:.5f}" y2="{y_dash:.5f}" style="{stroke}" />'
        return p1 + "\n    " + p2 + "\n    " + p3 + "\n    " + p4


_UNIT_BOX_X0, _UNIT_BOX_X1 = UNIT_X - 15.0, UNIT_X + 15.0
_UNIT_BOX_Y0, _UNIT_BOX_Y1 = UNIT_Y - 6.0, UNIT_Y + 6.0
_UNIT_MAX_FS = 9.46938021


def _point_at(radius: float, angle_deg: float):
    th = math.radians(angle_deg)
    return PIVOT_X + radius * math.sin(th), PIVOT_Y - radius * math.cos(th)


def _glyph_svg(ch: str, x: float, y: float, fs: float, fill: str, fd: _FontData):
    gn = fd.cmap.get(ord(ch))
    if gn is None:
        return None, 0.0
    s = fs / fd.upm
    adv = fd.hmtx.get(gn, (0, 0))[0] * s
    pen = SVGPathPen(fd.glyph_set)
    fd.glyph_set[gn].draw(pen)
    d = pen.getCommands()
    if not d:
        return None, adv
    t = f"translate({x:.5f},{y:.5f}) scale({s:.8f},{-s:.8f})"
    return f'<path style="fill:{fill}" transform="{t}" d="{d}"/>', adv


def _glyph_ybounds(ch: str, fd: _FontData):
    gn = fd.cmap.get(ord(ch))
    if gn is None:
        return 0.0, 0.0
    g = fd.glyf[gn]
    if g.numberOfContours == 0:
        return 0.0, 0.0
    g.recalcBounds(fd.glyf)
    return g.yMin / fd.upm, g.yMax / fd.upm


def _extract_braced(s: str, i: int):
    depth, j = 1, i + 1
    while j < len(s) and depth:
        if s[j] == "{":
            depth += 1
        elif s[j] == "}":
            depth -= 1
            if depth == 0:
                break
        j += 1
    return s[i + 1 : j], j + 1


def _parse_braced(inner: str):
    depth = 0
    for k, ch in enumerate(inner):
        if ch == "{":
            depth += 1
        elif ch == "}":
            depth -= 1
        elif ch == "/" and depth == 0:
            return ("frac", _parse_markup(inner[:k]), _parse_markup(inner[k + 1 :]))
    return ("group", _parse_markup(inner))


def _parse_atom(s: str, i: int):
    if i >= len(s):
        return [], i
    if s[i] == "{":
        inner, j = _extract_braced(s, i)
        return [_parse_braced(inner)], j
    return [("lit", s[i])], i + 1


def _parse_markup(s: str):
    nodes, i = [], 0
    while i < len(s):
        c = s[i]
        if c in "^_":
            atom, i = _parse_atom(s, i + 1)
            nodes.append(("sup" if c == "^" else "sub", atom))
        elif c == "{":
            inner, j = _extract_braced(s, i)
            nodes.append(_parse_braced(inner))
            i = j
        elif c == "[":
            end = s.find("]", i + 1)
            if end > i:
                name = s[i + 1 : end].lower()
                if name in ("ac", "dc", "acdc"):
                    nodes.append(("sym", name))
                    i = end + 1
                    continue
            nodes.append(("lit", c))
            i += 1
        else:
            nodes.append(("lit", c))
            i += 1
    return nodes


def _measure(nodes, fs: float, fd: _FontData) -> float:
    w = 0.0
    for n in nodes:
        if n[0] == "lit":
            gn = fd.cmap.get(ord(n[1]))
            if gn:
                w += fd.hmtx.get(gn, (0, 0))[0] / fd.upm * fs
        elif n[0] == "group":
            w += _measure(n[1], fs, fd)
        elif n[0] in ("sup", "sub"):
            w += _measure(n[1], fs * _SUP_SCALE, fd)
        elif n[0] == "frac":
            fs2 = fs * _FRAC_SCALE
            w += (
                max(_measure(n[1], fs2, fd), _measure(n[2], fs2, fd))
                + 2 * _FRAC_SIDE * fs2
            )
        elif n[0] == "sym":
            w += fs * _SYM_WIDTH
    return w


def _frac_layout(n, fs: float, fd: _FontData):
    fs2 = fs * _FRAC_SCALE
    axis = -_FRAC_AXIS * fs
    _, num_bot = _vbounds(n[1], fs2, fd)
    num_base = axis - _FRAC_GAP * fs2 - num_bot
    den_top, _ = _vbounds(n[2], fs2, fd)
    den_base = axis + _FRAC_GAP * fs2 - den_top
    return fs2, axis, num_base, den_base


def _vbounds(nodes, fs: float, fd: _FontData):
    lo, hi = math.inf, -math.inf
    for n in nodes:
        if n[0] == "lit":
            ymin, ymax = _glyph_ybounds(n[1], fd)
            a, b = -ymax * fs, -ymin * fs
        elif n[0] == "group":
            a, b = _vbounds(n[1], fs, fd)
        elif n[0] == "sup":
            a, b = _vbounds(n[1], fs * _SUP_SCALE, fd)
            a, b = a - _SUP_RISE * fs, b - _SUP_RISE * fs
        elif n[0] == "sub":
            a, b = _vbounds(n[1], fs * _SUP_SCALE, fd)
            a, b = a + _SUB_DROP * fs, b + _SUB_DROP * fs
        elif n[0] == "frac":
            fs2, axis, num_base, den_base = _frac_layout(n, fs, fd)
            nt, nb = _vbounds(n[1], fs2, fd)
            dt, db = _vbounds(n[2], fs2, fd)
            a = min(nt + num_base, axis)
            b = max(db + den_base, axis)
        elif n[0] == "sym":
            a, b = -_SYM_HEIGHT / 2 * fs, _SYM_HEIGHT / 2 * fs
        else:
            continue
        lo, hi = min(lo, a), max(hi, b)
    return (0.0, 0.0) if lo > hi else (lo, hi)


def _draw_nodes(nodes, x: float, y: float, fs: float, fill: str, fd: _FontData):
    parts, cx = [], x
    for n in nodes:
        if n[0] == "lit":
            p, adv = _glyph_svg(n[1], cx, y, fs, fill, fd)
            if p:
                parts.append(p)
            cx += adv
        elif n[0] == "group":
            p, adv = _draw_nodes(n[1], cx, y, fs, fill, fd)
            parts += p
            cx += adv
        elif n[0] in ("sup", "sub"):
            fs2 = fs * _SUP_SCALE
            y2 = y - _SUP_RISE * fs if n[0] == "sup" else y + _SUB_DROP * fs
            p, adv = _draw_nodes(n[1], cx, y2, fs2, fill, fd)
            parts += p
            cx += adv
        elif n[0] == "frac":
            fs2, axis, num_base, den_base = _frac_layout(n, fs, fd)
            wn, wd = _measure(n[1], fs2, fd), _measure(n[2], fs2, fd)
            bar_w = max(wn, wd) + 2 * _FRAC_SIDE * fs2
            pn, _ = _draw_nodes(
                n[1], cx + (bar_w - wn) / 2, y + num_base, fs2, fill, fd
            )
            pd, _ = _draw_nodes(
                n[2], cx + (bar_w - wd) / 2, y + den_base, fs2, fill, fd
            )
            parts += pn + pd
            ay = y + axis
            parts.append(
                f'<line x1="{cx:.5f}" y1="{ay:.5f}" x2="{cx + bar_w:.5f}" y2="{ay:.5f}"'
                f' style="stroke:{fill};stroke-width:{fs * 0.055:.5f};stroke-linecap:butt" />'
            )
            cx += bar_w
        elif n[0] == "sym":
            parts.append(_symbol_svg(n[1], cx, y, fs, fill))
            cx += fs * _SYM_WIDTH
    return parts, cx - x


def _markup_unit_svg(unit: str, fd: _FontData, fill="#1a1a1a") -> str:
    nodes = _parse_markup(unit)
    x0, x1 = _UNIT_BOX_X0, _UNIT_BOX_X1
    y0, y1 = _UNIT_BOX_Y0, _UNIT_BOX_Y1
    xc = (x0 + x1) / 2

    w1 = _measure(nodes, 1.0, fd)
    top1, bot1 = _vbounds(nodes, 1.0, fd)
    fs = _UNIT_MAX_FS
    if w1 > 0:
        fs = min(fs, (x1 - x0) / w1)
    if bot1 - top1 > 0:
        fs = min(fs, (y1 - y0) / (bot1 - top1))

    w = _measure(nodes, fs, fd)
    parts, _ = _draw_nodes(nodes, xc - w / 2, UNIT_Y, fs, fill, fd)
    return "\n".join(parts)


def _markup_corner_svg(
    text: str, x: float, y: float, fd: _FontData, fill="#1a1a1a", anchor="start"
) -> str:
    nodes = _parse_markup(text)
    fs = CORNER_FONT_SIZE
    w = _measure(nodes, fs, fd)
    if anchor == "end":
        x -= w
    parts, _ = _draw_nodes(nodes, x, y, fs, fill, fd)
    return "\n".join(parts)


def _text_to_paths(
    text,
    x,
    y,
    font_size,
    fd: _FontData,
    anchor="start",
    fill="#1a1a1a",
    wrap_transform=None,
):
    s = font_size / fd.upm

    if anchor in ("middle", "end"):
        total_w = sum(
            fd.hmtx.get(fd.cmap.get(ord(ch)), (0, 0))[0] * s
            for ch in text
            if fd.cmap.get(ord(ch))
        )
        x -= total_w / 2 if anchor == "middle" else total_w

    parts = []
    cx = x
    for ch in text:
        gn = fd.cmap.get(ord(ch))
        if gn is None:
            continue
        pen = SVGPathPen(fd.glyph_set)
        fd.glyph_set[gn].draw(pen)
        d = pen.getCommands()
        if d:
            t = f"translate({cx:.5f},{y:.5f}) scale({s:.8f},{-s:.8f})"
            parts.append(f'<path style="fill:{fill}" transform="{t}" d="{d}"/>')
        cx += fd.hmtx.get(gn, (0, 0))[0] * s

    inner = "\n".join(parts)
    if wrap_transform:
        return f'<g transform="{wrap_transform}">{inner}</g>'
    return inner


def _fmt(v: float) -> str:
    if math.isinf(v):
        return "∞"
    r = round(v)
    if abs(v - r) < 1e-9 * max(1.0, abs(v)):
        return str(int(r))
    exp = math.floor(math.log10(abs(v)))
    decimals = max(0, 4 - 1 - exp)
    s = f"{v:.{decimals}f}"
    return s.rstrip("0").rstrip(".") if "." in s else s


def generate_svg(
    unit,
    min_val,
    max_val,
    left_label,
    right_label,
    big_ticks,
    small_ticks,
    label_count,
    use_paths=True,
    scale_type="linear",
    custom_labels=None,
    label_size=5.1126,
    font_key=None,
    major_len=MAJOR_LEN,
    major_w=MAJOR_W,
    medium_len=MEDIUM_LEN,
    medium_w=MEDIUM_W,
    small_len=SMALL_LEN,
    small_w=SMALL_W,
):
    fd = (
        _FONTS.get(font_key) or _FONTS.get(_DEFAULT_FONT) or next(iter(_FONTS.values()))
    )

    if scale_type == "log":
        if min_val <= 0 or max_val <= 0:
            raise ValueError(
                "Logarithmic scale requires min and max values greater than 0."
            )
        lmin, lmax = math.log(min_val), math.log(max_val)
        lspan = lmax - lmin
        if lspan == 0:
            raise ValueError("Logarithmic scale requires min and max values to differ.")

        def value_to_angle(v):
            return ANGLE_MIN + (ANGLE_MAX - ANGLE_MIN) * (math.log(v) - lmin) / lspan

        def major_value(i):
            return min_val * (max_val / min_val) ** (i / big_ticks)

    elif scale_type == "sqrt":
        if min_val < 0:
            raise ValueError("Square-root scale requires min value ≥ 0.")
        span = max_val - min_val
        if span <= 0:
            raise ValueError("Square-root scale requires max value greater than min.")

        def value_to_angle(v):
            return ANGLE_MIN + (ANGLE_MAX - ANGLE_MIN) * math.sqrt((v - min_val) / span)

        def major_value(i):
            return min_val + span * (i / big_ticks) ** 2

    elif scale_type == "reciprocal":
        if min_val <= 0:
            raise ValueError(
                "Reciprocal scale requires min and max values greater than 0."
            )
        if not math.isinf(max_val) and max_val <= min_val:
            raise ValueError("Reciprocal scale requires max value greater than min.")
        if math.isinf(max_val):

            def value_to_angle(v):
                if math.isinf(v):
                    return ANGLE_MIN
                return ANGLE_MIN + (ANGLE_MAX - ANGLE_MIN) * min_val / v

            def major_value(i):
                if i == 0:
                    return math.inf
                return min_val * big_ticks / i
        else:
            k = 1.0 / min_val - 1.0 / max_val

            def value_to_angle(v):
                return (
                    ANGLE_MIN + (ANGLE_MAX - ANGLE_MIN) * (1.0 / v - 1.0 / max_val) / k
                )

            def major_value(i):
                return 1.0 / (1.0 / max_val + i / big_ticks * k)

    else:
        span = max_val - min_val
        if span == 0:
            raise ValueError("Linear scale requires min and max values to differ.")

        def value_to_angle(v):
            return ANGLE_MIN + (ANGLE_MAX - ANGLE_MIN) * (v - min_val) / span

        def major_value(i):
            return min_val + span * i / big_ticks

    big_interval_angle = (ANGLE_MAX - ANGLE_MIN) / big_ticks
    big_angles = [ANGLE_MIN + i * big_interval_angle for i in range(big_ticks + 1)]
    big_vals = [major_value(i) for i in range(big_ticks + 1)]

    if custom_labels:
        label_count = max(1, min(len(custom_labels), big_ticks + 1))
        custom_labels = custom_labels[:label_count]
    else:
        label_count = max(2, min(label_count, big_ticks + 1))

    if label_count == 1:
        label_indices = [0]
    else:
        label_indices = [
            round(k * big_ticks / (label_count - 1)) for k in range(label_count)
        ]

    def _tick_line(angle_deg, length, width):
        x = PIVOT_X
        y1 = PIVOT_Y - R0
        y2 = PIVOT_Y - R0 - length
        return (
            f'    <line x1="{x:.5f}" y1="{y1:.5f}" x2="{x:.5f}" y2="{y2:.5f}"'
            f' style="stroke:#1a1a1a;stroke-width:{width:.5f};stroke-linecap:butt"'
            f' transform="rotate({angle_deg:.5f},{PIVOT_X:.5f},{PIVOT_Y:.5f})" />'
        )

    font_face = (
        "  <defs><style>"
        f'@font-face {{font-family:"{fd.label}";'
        f'src:url("data:font/truetype;base64,{fd.b64}") format("truetype");}}'
        "</style></defs>"
    )

    parts = [
        '<?xml version="1.0" encoding="UTF-8" standalone="no"?>',
        '<svg width="93.824249mm" height="57.215687mm"'
        ' viewBox="0 0 93.824249 57.215687" version="1.1"'
        ' xmlns="http://www.w3.org/2000/svg">',
    ]

    if use_paths:
        parts.append('  <g transform="translate(-60.717741,-107.14126)">')
    else:
        parts += [font_face, '  <g transform="translate(-60.717741,-107.14126)">']

    parts.append(
        f'    <path style="fill:#f9f9f9;stroke:#1a1a1a;stroke-width:0.184;'
        f'stroke-linecap:round;stroke-miterlimit:10" d="{BODY_D}" />'
    )

    p0 = _point_at(R0, ANGLE_MIN)
    pmid = _point_at(R0, 0.0)
    p1 = _point_at(R0, ANGLE_MAX)
    parts.append(
        f'    <path style="fill:none;stroke:#000000;stroke-width:0.484;'
        f'stroke-linecap:round;stroke-miterlimit:10"'
        f' d="M {p0[0]:.5f},{p0[1]:.5f} A {R0:.5f},{R0:.5f} 0 0 1 {pmid[0]:.5f},{pmid[1]:.5f}'
        f' A {R0:.5f},{R0:.5f} 0 0 1 {p1[0]:.5f},{p1[1]:.5f}" />'
    )

    parts.append(
        f'    <circle style="fill:none;stroke:#b3b3b3;stroke-width:0.184;'
        f'stroke-linecap:round;stroke-miterlimit:10"'
        f' cx="{PIVOT_X:.5f}" cy="{PIVOT_Y:.5f}" r="{PIVOT_CIRCLE_R:.5f}" />'
    )

    for angle in big_angles:
        parts.append(_tick_line(angle, major_len, major_w))

    if small_ticks > 0:
        sub = small_ticks + 1
        medium_j = sub // 2 if small_ticks % 2 == 1 else None
        for i in range(big_ticks):
            for j in range(1, small_ticks + 1):
                if scale_type == "reciprocal":
                    angle = big_angles[i] + (j / sub) * (
                        big_angles[i + 1] - big_angles[i]
                    )
                else:
                    v = big_vals[i] + j * (big_vals[i + 1] - big_vals[i]) / sub
                    angle = value_to_angle(v)
                length, width = (
                    (medium_len, medium_w) if j == medium_j else (small_len, small_w)
                )
                parts.append(_tick_line(angle, length, width))

    lx, ly = PIVOT_X, PIVOT_Y - LABEL_RADIUS
    for k, idx in enumerate(label_indices):
        angle = big_angles[idx]
        label = custom_labels[k] if custom_labels else _fmt(big_vals[idx])
        wrap = f"rotate({angle:.5f},{PIVOT_X:.5f},{PIVOT_Y:.5f})"
        if use_paths:
            parts.append(
                "    "
                + _text_to_paths(
                    label, lx, ly, label_size, fd, anchor="middle", wrap_transform=wrap
                )
            )
        else:
            parts.append(
                f"    <text style=\"font-size:{label_size:.5f}px;font-family:'{fd.label}',monospace;fill:#1a1a1a\""
                f' text-anchor="middle" x="{lx:.5f}" y="{ly:.5f}" transform="{wrap}">{escape(label)}</text>'
            )

    parts.append("    " + _markup_unit_svg(unit, fd))

    left_lines = left_label.splitlines()[:2]
    right_lines = right_label.splitlines()[:2]

    for i, line in enumerate(left_lines):
        if not line:
            continue
        y = LEFT_Y0 + i * CORNER_LINE_SPACING
        parts.append("    " + _markup_corner_svg(line, LEFT_X, y, fd, anchor="start"))

    for i, line in enumerate(right_lines):
        if not line:
            continue
        y = RIGHT_Y0 + i * CORNER_LINE_SPACING
        parts.append("    " + _markup_corner_svg(line, RIGHT_X, y, fd, anchor="end"))

    parts += ["  </g>", "</svg>"]
    return "\n".join(parts)


@app.route("/")
def index():
    fonts = list(_FONTS.values())
    return render_template(
        "index.html",
        logo_b64=_LOGO_B64,
        version=VERSION,
        fonts=fonts,
        default_font=_DEFAULT_FONT,
    )


@app.route("/generate", methods=["POST"])
def generate():
    unit = request.form.get("unit", "%")
    left_label = request.form.get("left_label", "")
    right_label = request.form.get("right_label", "")
    use_paths = request.form.get("output_mode", "paths") == "paths"
    scale_type = request.form.get("scale_type", "linear")
    font_key = request.form.get("font", _DEFAULT_FONT)
    custom_labels = [
        s.strip() for s in request.form.get("labels", "").split(",") if s.strip()
    ] or None

    try:
        min_val = float(request.form.get("min", 0))
        max_val = float(request.form.get("max", 100))
        big_ticks = max(1, min(50, int(request.form.get("big_ticks", 10))))
        small_ticks = max(0, min(20, int(request.form.get("small_ticks", 4))))
        label_count = max(2, int(request.form.get("label_count", 6)))
        label_size = max(0.5, min(25.0, float(request.form.get("label_size", 5.1126))))
        major_len = max(0.1, min(25.0, float(request.form.get("major_len", MAJOR_LEN))))
        major_w = max(0.01, min(10.0, float(request.form.get("major_w", MAJOR_W))))
        medium_len = max(
            0.1, min(25.0, float(request.form.get("medium_len", MEDIUM_LEN)))
        )
        medium_w = max(0.01, min(10.0, float(request.form.get("medium_w", MEDIUM_W))))
        small_len = max(0.1, min(25.0, float(request.form.get("small_len", SMALL_LEN))))
        small_w = max(0.01, min(10.0, float(request.form.get("small_w", SMALL_W))))
        if request.form.get("max_is_inf") == "1":
            max_val = math.inf

        svg = generate_svg(
            unit,
            min_val,
            max_val,
            left_label,
            right_label,
            big_ticks,
            small_ticks,
            label_count,
            use_paths,
            scale_type,
            custom_labels,
            label_size,
            font_key,
            major_len,
            major_w,
            medium_len,
            medium_w,
            small_len,
            small_w,
        )
    except ValueError as err:
        return Response(str(err), status=400, mimetype="text/plain")
    return Response(svg, mimetype="image/svg+xml")


if __name__ == "__main__":
    app.run(debug=True)