import pytest
from src.fuzzy_anchor import FuzzyAnchor


class TestFuzzyAnchor:
    def test_create_slice_basic(self):
        text = "line0\nline1\nline2\nline3\nline4\n"
        result = FuzzyAnchor.create_slice(text, 2, 4)
        assert "start_line" in result
        assert "end_line" in result
        assert "content_hash" in result
        assert "start_context" in result
        assert "end_context" in result
        assert result["start_line"] == 2
        assert result["end_line"] == 4
        assert result["start_context"] == result["end_context"]

    def test_resolve_slice_exact_match(self):
        text = "line0\nline1\nline2\nline3\nline4\n"
        slc = FuzzyAnchor.create_slice(text, 2, 4)
        result = FuzzyAnchor.resolve_slice(text, slc)
        assert result is not None
        start, end = result
        assert start == 2
        assert end == 4

    def test_resolve_slice_line_inserted_before(self):
        original = "line0\nline1\nline2\nline3\nline4\n"
        modified = "NEW\nline0\nline1\nline2\nline3\nline4\n"
        slc = FuzzyAnchor.create_slice(original, 2, 4)
        result = FuzzyAnchor.resolve_slice(modified, slc)
        assert result is not None
        start, end = result
        assert start == 3
        assert end == 5

    def test_resolve_slice_line_deleted_before_returns_none(self):
        original = "line0\nline1\nline2\nline3\nline4\n"
        modified = "line0\nline2\nline3\nline4\n"
        slc = FuzzyAnchor.create_slice(original, 2, 4)
        result = FuzzyAnchor.resolve_slice(modified, slc)
        assert result is None

    def test_resolve_slice_multiple_lines_changed(self):
        original = "line0\nline1\nline2\nline3\nline4\n"
        modified = "a\nb\nc\nd\ne\nline0\nline1\nline2\nline3\nline4\n"
        slc = FuzzyAnchor.create_slice(original, 1, 2)
        result = FuzzyAnchor.resolve_slice(modified, slc)
        assert result is not None
        start, end = result
        assert start == 6
        assert end == 7

    def test_resolve_slice_anchor_mismatch_returns_none(self):
        original = "alpha\nbeta\ngamma\ndelta\nepsilon\n"
        modified = "foo\nbar\nbaz\ndelta\nepsilon\n"
        slc = FuzzyAnchor.create_slice(original, 2, 3)
        result = FuzzyAnchor.resolve_slice(modified, slc)
        assert result is None