"""Tests for field extraction module."""

from cmdparse.extractors import extract_array_index, extract_fields, flatten_dict, get_nested_value


class TestGetNestedValue:
    def test_simple_dict_access(self):
        data = {"name": "John", "age": 30}
        assert get_nested_value(data, "name") == "John"
        assert get_nested_value(data, "age") == 30

    def test_nested_dict_access(self):
        data = {"user": {"address": {"city": "NYC"}}}
        assert get_nested_value(data, "user.address.city") == "NYC"

    def test_list_index_access(self):
        data = {"items": ["a", "b", "c"]}
        assert get_nested_value(data, "items.0") == "a"
        assert get_nested_value(data, "items.1") == "b"

    def test_missing_key_returns_none(self):
        data = {"name": "John"}
        assert get_nested_value(data, "age") is None

    def test_none_data_returns_none(self):
        assert get_nested_value(None, "name") is None


class TestExtractArrayIndex:
    def test_with_array_index(self):
        base, index, rest = extract_array_index("items[0].name")
        assert base == "items"
        assert index == 0
        assert rest == "name"

    def test_without_array_index(self):
        base, index, rest = extract_array_index("name")
        assert base == "name"
        assert index is None
        assert rest is None


class TestExtractFields:
    def test_extract_single_field(self):
        data = [{"name": "John", "age": 30, "city": "NYC"}]
        result = extract_fields(data, ["name"])
        assert result == [{"name": "John"}]

    def test_extract_multiple_fields(self):
        data = [{"name": "John", "age": 30, "city": "NYC"}]
        result = extract_fields(data, ["name", "city"])
        assert result == [{"name": "John", "city": "NYC"}]

    def test_extract_nested_fields(self):
        data = [{"user": {"name": "John", "age": 30}}]
        result = extract_fields(data, ["user.name"])
        assert result == [{"user.name": "John"}]

    def test_extract_from_multiple_rows(self):
        data = [{"name": "John", "age": 30}, {"name": "Jane", "age": 25}]
        result = extract_fields(data, ["name"])
        assert result == [{"name": "John"}, {"name": "Jane"}]

    def test_empty_fields_returns_original(self):
        data = [{"name": "John", "age": 30}]
        result = extract_fields(data, [])
        assert result == data

    def test_empty_data_returns_empty(self):
        result = extract_fields([], ["name"])
        assert result == []


class TestFlattenDict:
    def test_flatten_simple_dict(self):
        d = {"name": "John", "age": 30}
        result = flatten_dict(d)
        assert result == {"name": "John", "age": 30}

    def test_flatten_nested_dict(self):
        d = {"user": {"name": "John", "address": {"city": "NYC"}}}
        result = flatten_dict(d)
        assert "user.name" in result
        assert "user.address.city" in result
        assert result["user.name"] == "John"
        assert result["user.address.city"] == "NYC"