"""Tests for diff parser module."""

import pytest

from auto_commit_service.git.diff_parser import summarize_diff, DiffSummary


class TestSummarizeDiff:
    """Tests for summarize_diff function."""

    def test_empty_diff(self) -> None:
        """Test parsing empty diff."""
        summary = summarize_diff("")

        assert summary.files_modified == 0
        assert summary.files_added == 0
        assert summary.files_deleted == 0
        assert summary.additions == 0
        assert summary.deletions == 0

    def test_modified_file(self, sample_diff: str) -> None:
        """Test parsing diff with modified file."""
        summary = summarize_diff(sample_diff)

        assert summary.files_modified == 1  # src/app.py
        assert summary.files_added == 1  # src/utils.py
        assert summary.additions > 0
        assert "src/app.py" in summary.key_files
        assert "src/utils.py" in summary.key_files

    def test_file_types_tracking(self, sample_diff: str) -> None:
        """Test that file types are tracked."""
        summary = summarize_diff(sample_diff)

        assert ".py" in summary.file_types
        assert summary.file_types[".py"] == 2

    def test_diff_excerpt_truncation(self) -> None:
        """Test that large diffs are truncated."""
        # Create a large diff
        large_diff = "\n".join([f"+line {i}" for i in range(500)])
        large_diff = f"diff --git a/big.txt b/big.txt\n{large_diff}"

        summary = summarize_diff(large_diff, max_excerpt_lines=50)

        assert "truncated" in summary.diff_excerpt.lower()
        assert len(summary.diff_excerpt.split("\n")) <= 52  # 50 + truncation message

    def test_total_properties(self, sample_diff: str) -> None:
        """Test total_files and total_changes properties."""
        summary = summarize_diff(sample_diff)

        assert summary.total_files == summary.files_modified + summary.files_added + summary.files_deleted
        assert summary.total_changes == summary.additions + summary.deletions


class TestDiffSummary:
    """Tests for DiffSummary dataclass."""

    def test_default_values(self) -> None:
        """Test default values."""
        summary = DiffSummary()

        assert summary.files_modified == 0
        assert summary.file_types == {}
        assert summary.key_files == []
        assert summary.diff_excerpt == ""

    def test_total_files(self) -> None:
        """Test total_files property."""
        summary = DiffSummary(
            files_modified=5,
            files_added=3,
            files_deleted=2,
        )

        assert summary.total_files == 10