"""
Tests for BaseCompletionEngine.

Uses a mock implementation to test the abstract base class functionality.
"""

import pytest
from typing import Any

from myfasthtml.core.dsl.types import Position, Suggestion, CompletionResult
from myfasthtml.core.dsl.base_completion import BaseCompletionEngine
from myfasthtml.core.dsl.base_provider import BaseMetadataProvider


class MockProvider:
    """Mock metadata provider for testing."""

    def get_style_presets(self) -> list[str]:
        return ["custom_highlight"]

    def get_format_presets(self) -> list[str]:
        return ["CHF"]


class MockCompletionEngine(BaseCompletionEngine):
    """Mock completion engine for testing base class functionality."""

    def __init__(self, provider: BaseMetadataProvider, suggestions: list[Suggestion] = None):
        super().__init__(provider)
        self._suggestions = suggestions or []
        self._scope = None
        self._context = "test_context"

    def detect_scope(self, text: str, current_line: int) -> Any:
        return self._scope

    def detect_context(self, text: str, cursor: Position, scope: Any) -> Any:
        return self._context

    def get_suggestions(self, context: Any, scope: Any, prefix: str) -> list[Suggestion]:
        return self._suggestions


# =============================================================================
# Filter Suggestions Tests
# =============================================================================


def test_i_can_filter_suggestions_by_prefix():
    """Test that _filter_suggestions filters case-insensitively."""
    provider = MockProvider()
    engine = MockCompletionEngine(provider)

    suggestions = [
        Suggestion("primary", "Primary color", "preset"),
        Suggestion("error", "Error color", "preset"),
        Suggestion("warning", "Warning color", "preset"),
        Suggestion("Error", "Title case error", "preset"),
    ]

    # Filter by "err" - should match "error" and "Error" (case-insensitive)
    filtered = engine._filter_suggestions(suggestions, "err")
    labels = [s.label for s in filtered]
    assert "error" in labels
    assert "Error" in labels
    assert "primary" not in labels
    assert "warning" not in labels


def test_i_can_filter_suggestions_empty_prefix():
    """Test that empty prefix returns all suggestions."""
    provider = MockProvider()
    engine = MockCompletionEngine(provider)

    suggestions = [
        Suggestion("a"),
        Suggestion("b"),
        Suggestion("c"),
    ]

    filtered = engine._filter_suggestions(suggestions, "")
    assert len(filtered) == 3


# =============================================================================
# Empty Result Tests
# =============================================================================


def test_i_can_get_empty_result():
    """Test that _empty_result returns a CompletionResult with no suggestions."""
    provider = MockProvider()
    engine = MockCompletionEngine(provider)

    cursor = Position(line=5, ch=10)
    result = engine._empty_result(cursor)

    assert result.from_pos == cursor
    assert result.to_pos == cursor
    assert result.suggestions == []
    assert result.is_empty is True


# =============================================================================
# Comment Skipping Tests
# =============================================================================


def test_i_can_skip_completion_in_comment():
    """Test that get_completions returns empty when cursor is in a comment."""
    provider = MockProvider()
    suggestions = [Suggestion("should_not_appear")]
    engine = MockCompletionEngine(provider, suggestions)

    text = "# This is a comment"
    cursor = Position(line=0, ch=15)  # Inside the comment

    result = engine.get_completions(text, cursor)

    assert result.is_empty is True
    assert len(result.suggestions) == 0


def test_i_can_get_completions_outside_comment():
    """Test that get_completions works when cursor is not in a comment."""
    provider = MockProvider()
    suggestions = [Suggestion("style"), Suggestion("format")]
    engine = MockCompletionEngine(provider, suggestions)

    # Cursor at space (ch=5) so prefix is empty and all suggestions are returned
    text = "text  # comment"
    cursor = Position(line=0, ch=5)  # At empty space, before comment

    result = engine.get_completions(text, cursor)

    assert result.is_empty is False
    assert len(result.suggestions) == 2