"""Function Plot 的解析与静态 SVG 渲染测试。

覆盖 parser 的白名单表达式（幂/隐式乘法/函数/常量）、拒绝项（属性访问、任意调用等）、
parse_source 指令与回退，以及 render 的 SVG 输出与 HTML 导出链路集成。
"""

from __future__ import annotations

import asyncio
import math

import pytest

from app.contracts import ExportOptions
from app.export.exporters.html import HtmlExporter
from app.export.markdown import parse_document
from app.plot.parser import PlotParseError, evaluate, parse_expression, parse_source
from app.plot.render import render_svg


# --------------------------------------------------------------------------- #
# 表达式解析
# --------------------------------------------------------------------------- #
def test_parse_expression_power_and_implicit_multiplication() -> None:
    assert evaluate(parse_expression("x^2"), 3) == 9.0
    assert evaluate(parse_expression("2^3"), 0) == 8.0
    assert evaluate(parse_expression("2x+1"), 3) == 7.0
    assert evaluate(parse_expression("2(x+1)"), 3) == 8.0
    assert evaluate(parse_expression("(x+1)(x-1)"), 3) == 8.0


def test_parse_expression_functions_and_constants() -> None:
    assert evaluate(parse_expression("sin(0)"), 0) == 0.0
    assert math.isclose(evaluate(parse_expression("sin(pi/2)"), 0), 1.0)
    assert math.isclose(evaluate(parse_expression("ln(e)"), 0), 1.0)
    assert evaluate(parse_expression("abs(-3)"), 0) == 3.0


def test_parse_expression_rejects_unsafe() -> None:
    unsafe = [
        "os.system('x')",
        "__import__('os')",
        "foo(x)",
        "eval('x')",
        "x[0]",
        "x.attr",
        "lambda: 1",
    ]
    for expr in unsafe:
        with pytest.raises(PlotParseError) as exc:
            parse_expression(expr)
        assert exc.value.diagnostic.code == "FUNCTION_PLOT_EXPRESSION_UNSAFE", expr


def test_parse_expression_syntax_error() -> None:
    with pytest.raises(PlotParseError) as exc:
        parse_expression("x +")
    assert exc.value.diagnostic.code == "FUNCTION_PLOT_PARSE_FAILED"


# --------------------------------------------------------------------------- #
# fenced 源码解析
# --------------------------------------------------------------------------- #
def test_parse_source_directives() -> None:
    result = parse_source("domain: 0, 10\nrange: -1, 1\nxlabel: x\ngrid: false\ny = x^2")
    assert result.plot is not None
    assert result.plot.domain == (0.0, 10.0)
    assert result.plot.range == (-1.0, 1.0)
    assert result.plot.axes.xlabel == "x"
    assert result.plot.axes.grid is False
    assert len(result.plot.expressions) == 1
    assert result.plot.expressions[0].expression == "x^2"


def test_parse_source_bare_and_multi_expression() -> None:
    result = parse_source("x^2\nsin(x)")
    assert result.plot is not None
    assert [e.expression for e in result.plot.expressions] == ["x^2", "sin(x)"]


def test_parse_source_unknown_directive_warns() -> None:
    result = parse_source("foo: bar\ny = x")
    assert result.plot is not None  # 未知指令仅 warning，不阻断
    assert any(d.severity == "warning" for d in result.diagnostics)


def test_parse_source_error_returns_no_plot() -> None:
    result = parse_source("y = os.system('x')")
    assert result.plot is None
    assert any(d.severity == "error" for d in result.diagnostics)


# --------------------------------------------------------------------------- #
# SVG 渲染
# --------------------------------------------------------------------------- #
def test_render_svg_contains_polyline_and_axes() -> None:
    plot = parse_source("y = x^2").plot
    rendered = render_svg(plot)
    svg = rendered.content
    assert "<svg" in svg
    assert "<polyline" in svg
    assert "<line" in svg  # 坐标轴/网格
    assert "<script" not in svg
    assert rendered.width == 640
    assert rendered.height == 480


def test_render_svg_multiple_functions() -> None:
    plot = parse_source("y = x^2\ny = sin(x)").plot
    rendered = render_svg(plot)
    assert rendered.content.count("<polyline") >= 2


def test_render_svg_labels() -> None:
    plot = parse_source("xlabel: 时间\nylabel: 数值\ny = x").plot
    rendered = render_svg(plot)
    assert "时间" in rendered.content
    assert "数值" in rendered.content


# --------------------------------------------------------------------------- #
# HTML 导出链路集成
# --------------------------------------------------------------------------- #
def test_html_exporter_embeds_function_plot_svg() -> None:
    md = "```function-plot\ny = x^2\n```"
    result = asyncio.run(HtmlExporter().export(parse_document(md), ExportOptions()))
    html = result.content.decode("utf-8")
    assert '<figure class="function-plot">' in html
    assert "<svg" in html
    assert "<polyline" in html


def test_html_exporter_function_plot_fallback_on_error() -> None:
    md = "```function-plot\ny = os.system('x')\n```"
    result = asyncio.run(HtmlExporter().export(parse_document(md), ExportOptions()))
    html = result.content.decode("utf-8")
    assert '<pre class="function-plot">' in html
    assert "<svg" not in html
    assert any("函数图像" in w for w in result.warnings)


# --------------------------------------------------------------------------- #
# 审阅回归：浮点刻度 / 求值异常 / 无效范围
# --------------------------------------------------------------------------- #
def test_render_svg_huge_domain_ticks_bounded() -> None:
    # P1：巨大 domain 下步长受浮点精度限制无法推进，刻度应有限而非死循环
    plot = parse_source("domain: 10000000000000000, 10000000000000002\nrange: -1, 1\ny = 0").plot
    rendered = render_svg(plot)
    assert "<svg" in rendered.content


def test_parse_expression_rejects_wrong_arg_count() -> None:
    # P2：sin() / sin(1, 2) 应在解析期拒绝，而非求值期 TypeError
    with pytest.raises(PlotParseError):
        parse_expression("sin()")
    with pytest.raises(PlotParseError):
        parse_expression("sin(1, 2)")


def test_render_svg_nonreal_samples_are_break_points() -> None:
    # P2：x^0.5 在负数域产生复数，应作为断点处理，正半轴仍可绘制
    plot = parse_source("domain: -4, 4\ny = x^0.5").plot
    rendered = render_svg(plot)
    assert "<polyline" in rendered.content


def test_render_svg_invalid_range_falls_back() -> None:
    # P2：退化 range（1, 1）应丢弃并自动采样，而非 ZeroDivisionError
    plot = parse_source("range: 1, 1\ny = x").plot
    rendered = render_svg(plot)
    assert "<polyline" in rendered.content
    assert any("range" in w for w in rendered.warnings)


def test_render_svg_nonfinite_range_falls_back() -> None:
    # P2：非有限 range 端点应丢弃并自动采样
    plot = parse_source("range: nan, 1\ny = x").plot
    rendered = render_svg(plot)
    assert "<polyline" in rendered.content


def test_html_exporter_function_plot_render_error_falls_back(monkeypatch) -> None:
    # P2：渲染异常不阻断整篇导出，回退占位并记 warning
    import app.export.exporters.html as html_mod

    def boom(plot):
        raise RuntimeError("boom")

    monkeypatch.setattr(html_mod, "render_svg", boom)
    md = "```function-plot\ny = x\n```"
    result = asyncio.run(HtmlExporter().export(parse_document(md), ExportOptions()))
    html = result.content.decode("utf-8")
    assert '<pre class="function-plot">' in html
    assert any("渲染失败" in w for w in result.warnings)


# --------------------------------------------------------------------------- #
# 审阅回归：复杂表达式 / 极端数值范围
# --------------------------------------------------------------------------- #
def test_parse_expression_rejects_excessive_depth() -> None:
    # P2：超长加法链的 AST 深度超限，应拒绝为 PlotParseError 而非触发 RecursionError
    expr = "+".join(["1"] * 300)
    with pytest.raises(PlotParseError) as exc:
        parse_expression(expr)
    assert exc.value.diagnostic.code == "FUNCTION_PLOT_EXPRESSION_UNSAFE"


def test_parse_expression_rejects_excessive_nodes() -> None:
    # P2：浅层但节点超限的表达式（满二叉树）应被节点数上限拦截
    def balanced(depth: int) -> str:
        if depth == 0:
            return "x"
        return f"({balanced(depth - 1)}+{balanced(depth - 1)})"

    expr = balanced(10)  # ~2047 个节点，深度仅 ~10
    with pytest.raises(PlotParseError) as exc:
        parse_expression(expr)
    assert exc.value.diagnostic.code == "FUNCTION_PLOT_EXPRESSION_UNSAFE"


def test_html_exporter_function_plot_deep_expression_falls_back() -> None:
    # P2：复杂表达式解析失败应回退占位，不阻断整篇导出
    expr = "+".join(["1"] * 300)
    md = f"```function-plot\ny = {expr}\n```"
    result = asyncio.run(HtmlExporter().export(parse_document(md), ExportOptions()))
    html = result.content.decode("utf-8")
    assert '<pre class="function-plot">' in html
    assert "<svg" not in html
    assert any("函数图像" in w for w in result.warnings)


def test_render_svg_extreme_domain_no_nan() -> None:
    # P2：有限但跨度溢出的 domain 应回退安全范围，SVG 不得含 nan/inf
    plot = parse_source("domain: -1e308, 1e308\nrange: -1, 1\ny = 0").plot
    rendered = render_svg(plot)
    assert "<svg" in rendered.content
    assert "nan" not in rendered.content
    assert "inf" not in rendered.content
    assert any("domain" in w for w in rendered.warnings)


def test_render_svg_extreme_range_no_nan() -> None:
    # P2：有限但跨度溢出的 range 应回退自动范围，SVG 不得含 nan/inf
    plot = parse_source("domain: -1, 1\nrange: -1e308, 1e308\ny = x").plot
    rendered = render_svg(plot)
    assert "<svg" in rendered.content
    assert "nan" not in rendered.content
    assert "inf" not in rendered.content
    assert any("range" in w for w in rendered.warnings)