xiaoxia-saas/tests/unit/test_subtitle_render_engine.py

"""
字幕渲染引擎纯函数与配置测试.

覆盖 SubtitleStyle / SubtitleSegment / 颜色转换 / 时间格式化 / 文字换行 / ASS转义等纯逻辑.
引擎核心 render 方法依赖 FFmpeg，由集成测试覆盖.
"""

from __future__ import annotations

import pytest
from video_processing.subtitle_render_engine import (
    SubtitleSegment,
    SubtitleStyle,
    _escape_ass_text,
    _format_ass_time,
    _hex_to_ass_bgr,
    _hex_to_ass_color,
    _opacity_to_ass_alpha,
    _wrap_text,
)


class TestHexToAssColor:
    """HEX → ASS 颜色转换."""

    def test_white(self):
        assert _hex_to_ass_color("#FFFFFF") == "&H00FFFFFF"

    def test_black(self):
        assert _hex_to_ass_color("#000000") == "&H00000000"

    def test_red(self):
        # #FF0000 → R=FF, G=00, B=00 → BGR=0000FF
        assert _hex_to_ass_color("#FF0000") == "&H000000FF"

    def test_blue(self):
        # #0000FF → R=00, G=00, B=FF → BGR=FF0000
        assert _hex_to_ass_color("#0000FF") == "&H00FF0000"

    def test_green(self):
        # #00FF00 → R=00, G=FF, B=00 → BGR=00FF00
        assert _hex_to_ass_color("#00FF00") == "&H0000FF00"

    def test_without_hash_prefix(self):
        assert _hex_to_ass_color("FF0000") == "&H000000FF"

    def test_lowercase_hex(self):
        assert _hex_to_ass_color("#ff0000") == "&H000000FF"

    def test_mixed_case(self):
        assert _hex_to_ass_color("#aBcDeF") == "&H00EFCDAB"

    def test_invalid_length_returns_default(self):
        assert _hex_to_ass_color("#FFF") == "&H00FFFFFF"  # 3位
        assert _hex_to_ass_color("#FF") == "&H00FFFFFF"  # 2位
        assert _hex_to_ass_color("#") == "&H00FFFFFF"  # 空

    def test_empty_string(self):
        assert _hex_to_ass_color("") == "&H00FFFFFF"


class TestHexToAssBgr:
    """HEX → ASS BGR 部分."""

    def test_white(self):
        assert _hex_to_ass_bgr("#FFFFFF") == "FFFFFF"

    def test_black(self):
        assert _hex_to_ass_bgr("#000000") == "000000"

    def test_red(self):
        # #FF0000 → BGR = 0000FF
        assert _hex_to_ass_bgr("#FF0000") == "0000FF"

    def test_blue(self):
        # #0000FF → BGR = FF0000
        assert _hex_to_ass_bgr("#0000FF") == "FF0000"

    def test_without_hash(self):
        assert _hex_to_ass_bgr("FF0000") == "0000FF"

    def test_invalid_length_returns_white(self):
        assert _hex_to_ass_bgr("#123") == "FFFFFF"


class TestOpacityToAssAlpha:
    """不透明度 → ASS alpha."""

    def test_fully_opaque(self):
        # 1.0 → alpha = 255 - 255 = 0 → "00"
        assert _opacity_to_ass_alpha(1.0) == "00"

    def test_fully_transparent(self):
        # 0.0 → alpha = 255 - 0 = 255 → "FF"
        assert _opacity_to_ass_alpha(0.0) == "FF"

    def test_half(self):
        # 0.5 → alpha = 255 - 127 = 128 → "80" (因为 int(0.5*255)=127)
        # 注意：int(0.5 * 255) = 127，255-127=128 → "80"
        assert _opacity_to_ass_alpha(0.5) == "80"

    def test_quarter(self):
        # 0.25 → alpha = 255 - 63 = 192 → "C0"
        assert _opacity_to_ass_alpha(0.25) == "C0"

    def test_three_quarters(self):
        # 0.75 → alpha = 255 - 191 = 64 → "40"
        assert _opacity_to_ass_alpha(0.75) == "40"

    def test_zero_padded(self):
        # 结果始终是2位十六进制
        result = _opacity_to_ass_alpha(1.0)
        assert len(result) == 2
        assert result == result.upper()


class TestEscapeAssText:
    """ASS 文本转义."""

    def test_plain_text(self):
        assert _escape_ass_text("hello world") == "hello world"

    def test_newline_unix(self):
        assert _escape_ass_text("line1\nline2") == "line1\\Nline2"

    def test_newline_windows(self):
        assert _escape_ass_text("line1\r\nline2") == "line1\\Nline2"

    def test_newline_mac(self):
        assert _escape_ass_text("line1\rline2") == "line1\\Nline2"

    def test_curly_braces_replaced(self):
        # ASS 中 {} 是样式标签，需要转义
        assert _escape_ass_text("{text}") == "(text)"

    def test_multiple_braces(self):
        assert _escape_ass_text("{a}b{c}") == "(a)b(c)"

    def test_mixed_special_chars(self):
        text = "line1\n{bold}\nline3"
        result = _escape_ass_text(text)
        assert "\\N" in result
        assert "(bold)" in result
        assert "{" not in result
        assert "}" not in result
        assert "\n" not in result
        assert "\r" not in result

    def test_empty_string(self):
        assert _escape_ass_text("") == ""


class TestFormatAssTime:
    """秒 → ASS 时间格式."""

    def test_zero(self):
        assert _format_ass_time(0.0) == "0:00:00.00"

    def test_seconds_only(self):
        assert _format_ass_time(5.5) == "0:00:05.50"

    def test_minutes(self):
        assert _format_ass_time(65.25) == "0:01:05.25"

    def test_hours(self):
        assert _format_ass_time(3661.5) == "1:01:01.50"

    def test_exact_minute(self):
        assert _format_ass_time(60.0) == "0:01:00.00"

    def test_exact_hour(self):
        assert _format_ass_time(3600.0) == "1:00:00.00"

    def test_sub_second_precision(self):
        # 两位小数（厘秒精度）
        result = _format_ass_time(1.234)
        # 1.234 秒 = 0:00:01.23（ASS 格式是两位小数/厘秒）
        assert result.startswith("0:00:01.")
        # 检查秒部分是两位小数格式
        parts = result.split(":")
        assert len(parts) == 3
        sec_part = parts[2]
        assert "." in sec_part
        decimals = sec_part.split(".")[1]
        assert len(decimals) == 2

    def test_negative_returns_zero_hours(self):
        # 负数也应该能处理（虽然业务上不应该出现）
        result = _format_ass_time(-1.0)
        # 至少不崩溃
        assert isinstance(result, str)
        assert ":" in result


class TestWrapText:
    """按字数换行."""

    def test_short_text_no_wrap(self):
        result = _wrap_text("短文本", 10)
        assert result == ["短文本"]

    def test_exact_length_no_wrap(self):
        text = "一二三四五六七八九十"
        result = _wrap_text(text, 10)
        assert len(result) == 1
        assert result[0] == text

    def test_long_text_wraps(self):
        text = "一二三四五六七八九十一二三四五六七八九十"
        result = _wrap_text(text, 10)
        assert len(result) == 2
        assert len(result[0]) == 10
        assert len(result[1]) == 10

    def test_break_on_punctuation(self):
        # 优先在标点处断开（标点在max_chars范围内靠前位置）
        # 共12字，max=7，句号在第6位索引，range(7,3,-1)能扫到索引5的句号
        text = "一二三四五。六七八九十一"
        result = _wrap_text(text, 7)
        assert result[0] == "一二三四五。"
        assert result[1] == "六七八九十一"

    def test_break_on_comma(self):
        text = "一二三四五，六七八九十一"
        result = _wrap_text(text, 7)
        assert result[0] == "一二三四五，"
        assert result[1] == "六七八九十一"

    def test_multiple_lines(self):
        text = "一二三四五六七八九十一二三四五六七八九十一二三四五"
        result = _wrap_text(text, 10)
        assert len(result) == 3
        assert len(result[0]) == 10
        assert len(result[1]) == 10
        assert len(result[2]) == 5

    def test_empty_string(self):
        result = _wrap_text("", 10)
        assert result == [""]

    def test_max_chars_one(self):
        # max_chars=1 时每个字符一行
        text = "abc"
        result = _wrap_text(text, 1)
        assert result == ["a", "b", "c"]

    @pytest.mark.skip(reason="已知_wrap_text(max_chars=0)死循环bug，待业务侧修复")
    def test_max_chars_zero(self):
        # 边界情况
        text = "abc"
        result = _wrap_text(text, 0)
        # 0的话，max_chars//2也是0，range不会执行
        # 按逻辑 len(text) > 0 成立，但 break_point 从 0 开始
        # 这取决于具体实现，只要不崩溃就行
        assert isinstance(result, list)
        assert len(result) > 0

    def test_punctuation_at_boundary(self):
        # 标点刚好在 max_chars 位置
        text = "一二三四五六七八九。"
        result = _wrap_text(text, 10)
        assert len(result) == 1  # 刚好10个字符（含标点）


class TestSubtitleSegment:
    """字幕片段数据类."""

    def test_basic(self):
        seg = SubtitleSegment(start=0.0, end=5.0, text="hello")
        assert seg.start == 0.0
        assert seg.end == 5.0
        assert seg.text == "hello"

    def test_duration(self):
        seg = SubtitleSegment(start=1.5, end=4.5, text="test")
        assert seg.end - seg.start == 3.0


class TestSubtitleStyle:
    """字幕样式配置."""

    def test_default_values(self):
        style = SubtitleStyle()
        assert style.font_size > 0
        assert isinstance(style.font_color, str)
        assert isinstance(style.background_color, str)

    def test_ass_color_generation(self):
        style = SubtitleStyle(font_color="#FFFFFF")
        # 应该能生成 ASS 颜色格式
        color = style.ass_font_color
        assert isinstance(color, str)
        assert color.startswith("&H")

    def test_ass_background_color(self):
        style = SubtitleStyle(background_color="#000000", background_opacity=0.5)
        color = style.ass_background_color
        assert isinstance(color, str)
        assert color.startswith("&H")

    def test_opacity_affects_alpha(self):
        style1 = SubtitleStyle(background_opacity=1.0)
        style2 = SubtitleStyle(background_opacity=0.0)
        # 不透明度不同，alpha 应该不同
        assert style1.ass_background_color != style2.ass_background_color