"""
文本分块器单元测试
"""
from __future__ import annotations

import pytest
from app.services.text_chunker import chunk_text, _split_paragraphs, _split_long_paragraph, _merge_segments


class TestSplitParagraphs:
    """段落分割测试"""

    def test_empty_text(self):
        assert _split_paragraphs("") == []
        assert _split_paragraphs("   ") == []
        assert _split_paragraphs("\n\n\n") == []

    def test_single_paragraph(self):
        result = _split_paragraphs("Hello world")
        assert result == ["Hello world"]

    def test_multiple_paragraphs(self):
        text = "第一段内容。\n\n第二段内容。\n\n第三段内容。"
        result = _split_paragraphs(text)
        assert len(result) == 3
        assert "第一段" in result[0]
        assert "第二段" in result[1]
        assert "第三段" in result[2]

    def test_mixed_newlines(self):
        text = "段1\n\n\n段2\n\n段3"
        result = _split_paragraphs(text)
        assert len(result) == 3


class TestSplitLongParagraph:
    """超长段落分割测试"""

    def test_short_paragraph(self):
        result = _split_long_paragraph("短文本", chunk_size=500)
        assert result == ["短文本"]

    def test_long_paragraph_chinese(self):
        para = "第一句。" * 200  # 600 chars, exceeds 500
        result = _split_long_paragraph(para, chunk_size=500)
        assert len(result) >= 2
        assert all(len(c) <= 500 for c in result)

    def test_long_paragraph_english(self):
        para = "Sentence. " * 200
        result = _split_long_paragraph(para, chunk_size=500)
        assert len(result) >= 2
        assert all(len(c) <= 500 for c in result)

    def test_no_sentence_boundary(self):
        """无句号可分割时按字符硬切"""
        para = "a" * 1000
        result = _split_long_paragraph(para, chunk_size=500)
        assert len(result) == 2
        assert len(result[0]) == 500
        assert len(result[1]) == 500


class TestMergeSegments:
    """段落合并测试"""

    def test_empty(self):
        assert _merge_segments([], 500, 0) == []

    def test_single_segment(self):
        result = _merge_segments(["hello"], 500, 0)
        assert result == ["hello"]

    def test_merge_short_segments(self):
        segs = ["a" * 100, "b" * 100, "c" * 100]  # each < 500, total ~300 < 500
        result = _merge_segments(segs, 500, 0)
        assert len(result) == 1
        assert len(result[0]) > 200

    def test_split_large_segments(self):
        segs = ["a" * 300, "b" * 300, "c" * 300]  # 需要分为多个chunk
        result = _merge_segments(segs, 500, 0)
        assert len(result) >= 2

    def test_overlap(self):
        segs = ["a" * 300, "b" * 300]
        result = _merge_segments(segs, 500, 50)
        assert len(result) >= 1


class TestChunkText:
    """chunk_text 整体测试"""

    def test_empty_text(self):
        assert chunk_text("") == []
        assert chunk_text("   ") == []
        assert chunk_text(None) == []  # type: ignore

    def test_short_text(self):
        result = chunk_text("Hello world", chunk_size=500, chunk_overlap=0)
        assert len(result) == 1
        assert "Hello world" in result[0]

    def test_normal_text(self):
        text = """
这是第一段。它包含一些内容。

这是第二段。它也有一些内容。而且更长一些。

这是第三段。最后一段内容。
"""
        result = chunk_text(text, chunk_size=500, chunk_overlap=0)
        assert len(result) >= 1
        # 所有内容都应该在结果中
        all_text = "".join(result)
        assert "第一段" in all_text
        assert "第二段" in all_text
        assert "第三段" in all_text

    def test_chinese_text(self):
        """中文文本测试"""
        text = "我喜欢吃川菜。特别是麻辣火锅。还有水煮鱼。这些都很美味。"
        result = chunk_text(text, chunk_size=100, chunk_overlap=0)
        assert len(result) >= 1

    def test_overlap_between_chunks(self):
        """验证块间重叠"""
        para = "这是一个很长的段落。" * 50
        result = chunk_text(para, chunk_size=200, chunk_overlap=50)
        if len(result) > 1:
            # 相邻块应该有重叠内容
            assert len(result[0]) > 0
            assert len(result[1]) > 0

    @pytest.mark.unit
    def test_with_mixed_punctuation(self):
        text = "Hello! How are you? I am fine. Thank you. 你好！最近怎么样？我很好。谢谢。"
        result = chunk_text(text, chunk_size=200, chunk_overlap=0)
        assert len(result) >= 1