from __future__ import annotations

import copy
import json
from pathlib import Path

import pytest

from gcmd_classifier.errors import (
    DuplicateCanonicalPathError,
    DuplicateUUIDError,
    InvalidHierarchyTransitionError,
    MalformedHierarchyError,
    VocabularyLookupError,
)
from gcmd_classifier.vocabulary import build_vocabulary_index, calculate_file_hash, load_vocabulary

FIXTURE_PATH = Path("tests/fixtures/gcmd_hierarchy_small.json")
FULL_HIERARCHY_PATH = Path("data/gcmd_hierarchy.json")


def load_fixture_data() -> dict:
    return json.loads(FIXTURE_PATH.read_text())


def build_fixture_index():
    return load_vocabulary(FIXTURE_PATH)


def test_recursive_traversal_and_variable_depth_branches() -> None:
    index = build_fixture_index()

    assert len(index) == 10
    assert index.root_level == "Category"
    assert index.root_name == "EARTH SCIENCE"
    assert index.children_of(None) == ("topic-atmosphere", "topic-oceans")
    assert index.children_of("term-weather-events") == ()
    assert index.get("vl3-carbon-dioxide-profiles").level == "Variable_Level_3"


def test_uuid_preservation_and_record_fields() -> None:
    index = build_fixture_index()
    record = index.get("vl3-carbon-dioxide-profiles")

    assert record.UUID == "vl3-carbon-dioxide-profiles"
    assert record.name == "CARBON DIOXIDE PROFILES"
    assert record.level == "Variable_Level_3"
    assert record.topic == "ATMOSPHERE"
    assert record.term == "ATMOSPHERIC CHEMISTRY"
    assert record.path_components == (
        "ATMOSPHERE",
        "ATMOSPHERIC CHEMISTRY",
        "CARBON",
        "CARBON DIOXIDE",
        "CARBON DIOXIDE PROFILES",
    )
    assert (
        record.canonical_path == "ATMOSPHERE > ATMOSPHERIC CHEMISTRY > CARBON > CARBON DIOXIDE > "
        "CARBON DIOXIDE PROFILES"
    )
    assert record.parent_uuid == "vl2-carbon-dioxide"
    assert record.parent_name == "CARBON DIOXIDE"
    assert record.child_uuids == ()
    assert record.has_children is False
    assert record.assignable is True
    assert record.definition == "Vertical carbon dioxide profiles."
    assert record.vocabulary_version == calculate_file_hash(FIXTURE_PATH)


def test_topic_term_and_variable_records_are_assignable() -> None:
    index = build_fixture_index()

    topic = index.get("topic-atmosphere")
    term = index.get("term-atmospheric-chemistry")
    internal_variable = index.get("vl1-atmosphere-carbon")
    leaf_variable = index.get("vl2-methane")

    assert topic.level == "Topic"
    assert term.level == "Term"
    assert internal_variable.level == "Variable_Level_1"
    assert leaf_variable.level == "Variable_Level_2"
    assert topic.assignable is True
    assert term.assignable is True
    assert internal_variable.assignable is True
    assert leaf_variable.assignable is True
    assert internal_variable.has_children is True
    assert leaf_variable.has_children is False


def test_root_category_is_non_assignable_context() -> None:
    index = build_fixture_index()

    assert "EARTH SCIENCE" not in index.records_by_path
    assert all(record.level != "Category" for record in index.records_by_uuid.values())
    assert index.parent_of("topic-atmosphere") is None
    assert index.get("topic-atmosphere").parent_name == "EARTH SCIENCE"


def test_optional_and_missing_definitions() -> None:
    index = build_fixture_index()

    assert index.get("topic-atmosphere").definition == "Atmospheric science."
    assert index.get("vl2-methane").definition is None


def test_canonical_path_excludes_root_category() -> None:
    index = build_fixture_index()

    assert index.get("topic-atmosphere").canonical_path == "ATMOSPHERE"
    assert index.get("term-weather-events").canonical_path == "ATMOSPHERE > WEATHER EVENTS"
    assert not index.get("topic-atmosphere").canonical_path.startswith("EARTH SCIENCE")


def test_identical_names_in_different_branches_are_allowed_when_paths_differ() -> None:
    index = build_fixture_index()

    atmosphere_carbon = index.get("vl1-atmosphere-carbon")
    ocean_carbon = index.get("vl1-ocean-carbon")

    assert atmosphere_carbon.name == ocean_carbon.name == "CARBON"
    assert atmosphere_carbon.canonical_path != ocean_carbon.canonical_path


def test_duplicate_uuid_detection() -> None:
    data = load_fixture_data()
    data["children"][1]["UUID"] = "topic-atmosphere"

    with pytest.raises(DuplicateUUIDError):
        build_vocabulary_index(data, vocabulary_version="test")


def test_duplicate_canonical_path_detection() -> None:
    data = load_fixture_data()
    duplicate = copy.deepcopy(data["children"][0]["children"][1])
    duplicate["UUID"] = "term-weather-events-duplicate"
    data["children"][0]["children"].append(duplicate)

    with pytest.raises(DuplicateCanonicalPathError):
        build_vocabulary_index(data, vocabulary_version="test")


@pytest.mark.parametrize("field", ["level", "name"])
def test_missing_required_fields(field: str) -> None:
    data = load_fixture_data()
    del data["children"][0][field]

    with pytest.raises(MalformedHierarchyError):
        build_vocabulary_index(data, vocabulary_version="test")


def test_unexpected_uuidless_non_root_node() -> None:
    data = load_fixture_data()
    del data["children"][0]["UUID"]

    with pytest.raises(MalformedHierarchyError):
        build_vocabulary_index(data, vocabulary_version="test")


def test_valid_hierarchy_level_transitions() -> None:
    index = build_fixture_index()

    assert index.get("topic-atmosphere").child_uuids == (
        "term-atmospheric-chemistry",
        "term-weather-events",
    )
    assert index.get("term-atmospheric-chemistry").child_uuids == ("vl1-atmosphere-carbon",)
    assert index.get("vl1-atmosphere-carbon").child_uuids == (
        "vl2-carbon-dioxide",
        "vl2-methane",
    )
    assert index.get("vl2-carbon-dioxide").child_uuids == ("vl3-carbon-dioxide-profiles",)


def test_invalid_hierarchy_level_transition() -> None:
    data = load_fixture_data()
    data["children"][0]["children"][0]["level"] = "Variable_Level_1"

    with pytest.raises(InvalidHierarchyTransitionError):
        build_vocabulary_index(data, vocabulary_version="test")


def test_parent_and_direct_child_lookup() -> None:
    index = build_fixture_index()

    assert index.parent_of("vl2-carbon-dioxide") == "vl1-atmosphere-carbon"
    assert index.children_of("vl1-atmosphere-carbon") == (
        "vl2-carbon-dioxide",
        "vl2-methane",
    )
    with pytest.raises(VocabularyLookupError):
        index.parent_of("missing-uuid")


def test_topic_to_term_lookup() -> None:
    index = build_fixture_index()

    terms = index.terms_for_topic("topic-atmosphere")
    assert tuple(term.UUID for term in terms) == (
        "term-atmospheric-chemistry",
        "term-weather-events",
    )
    with pytest.raises(VocabularyLookupError):
        index.terms_for_topic("term-weather-events")


def test_term_to_variable_lookup() -> None:
    index = build_fixture_index()

    variables = index.variables_for_parent("term-atmospheric-chemistry")
    assert tuple(variable.UUID for variable in variables) == ("vl1-atmosphere-carbon",)
    assert index.variables_for_parent("vl2-methane") == ()
    with pytest.raises(VocabularyLookupError):
        index.variables_for_parent("topic-atmosphere")


def test_ancestor_and_descendant_checks() -> None:
    index = build_fixture_index()

    assert index.is_ancestor("topic-atmosphere", "vl3-carbon-dioxide-profiles") is True
    assert index.is_descendant("vl3-carbon-dioxide-profiles", "topic-atmosphere") is True
    assert index.is_ancestor("term-weather-events", "vl3-carbon-dioxide-profiles") is False
    assert index.ancestors_of("vl3-carbon-dioxide-profiles") == (
        "vl2-carbon-dioxide",
        "vl1-atmosphere-carbon",
        "term-atmospheric-chemistry",
        "topic-atmosphere",
    )


def test_vocabulary_file_hash_stability() -> None:
    assert calculate_file_hash(FIXTURE_PATH) == calculate_file_hash(FIXTURE_PATH)
    assert build_fixture_index().vocabulary_version == calculate_file_hash(FIXTURE_PATH)


def test_source_file_immutability() -> None:
    before = FULL_HIERARCHY_PATH.read_bytes()
    load_vocabulary(FULL_HIERARCHY_PATH)
    after = FULL_HIERARCHY_PATH.read_bytes()

    assert after == before


def test_every_current_topic_and_term_has_uuid() -> None:
    index = load_vocabulary(FULL_HIERARCHY_PATH)

    assert all(topic.UUID for topic in index.topics())
    assert all(term.UUID for topic in index.topics() for term in index.terms_for_topic(topic.UUID))


def test_full_data_smoke_counts_for_current_vocabulary() -> None:
    index = load_vocabulary(FULL_HIERARCHY_PATH)
    counts = index.count_by_level()

    assert counts["Topic"] == 14
    assert counts["Term"] == 144
    assert counts["Variable_Level_1"] == 1368
    assert counts["Variable_Level_2"] == 1456
    assert counts["Variable_Level_3"] == 553
    assert len(index) == 3535