"""
Tests for token counting utilities.
"""
import pytest

from src.shared.tokens import count_tokens, count_message_tokens, estimate_tokens


class TestTokenCounting:
    """Tests for token counting functions."""

    def test_estimate_tokens_basic(self):
        """Test basic token estimation."""
        text = "Hello world"
        tokens = estimate_tokens(text)
        # ~4 chars per token
        assert tokens == len(text) // 4

    def test_estimate_tokens_empty(self):
        """Test estimation with empty string."""
        assert estimate_tokens("") == 0

    def test_estimate_tokens_long_text(self):
        """Test estimation with longer text."""
        text = "a" * 400
        tokens = estimate_tokens(text)
        assert tokens == 100

    def test_count_tokens_basic(self):
        """Test actual token counting."""
        text = "Hello, how are you today?"
        tokens = count_tokens(text)
        # Should return reasonable token count
        assert tokens > 0
        assert tokens < len(text)  # Should be fewer tokens than characters

    def test_count_tokens_empty(self):
        """Test counting empty string."""
        tokens = count_tokens("")
        assert tokens == 0

    def test_count_message_tokens_single(self):
        """Test counting tokens in single message."""
        messages = [{"role": "user", "content": "Hello"}]
        tokens = count_message_tokens(messages)
        assert tokens > 0

    def test_count_message_tokens_multiple(self):
        """Test counting tokens in multiple messages."""
        messages = [
            {"role": "user", "content": "Hello, how are you?"},
            {"role": "assistant", "content": "I'm doing well, thank you!"},
        ]
        tokens = count_message_tokens(messages)
        # Should be more than single message
        single_tokens = count_message_tokens([messages[0]])
        assert tokens > single_tokens

    def test_count_message_tokens_empty_list(self):
        """Test counting empty message list."""
        tokens = count_message_tokens([])
        # tiktoken returns small overhead for empty list (assistant priming)
        assert tokens < 10


class TestTokenCountingAccuracy:
    """Tests for token counting accuracy."""

    def test_code_tokens_reasonable(self):
        """Test that code is tokenized reasonably."""
        code = """
def hello_world():
    print("Hello, World!")
    return True
"""
        tokens = count_tokens(code)
        # Code should have reasonable token count
        assert 10 < tokens < 100

    def test_special_characters(self):
        """Test tokenization of special characters."""
        text = "Hello! @#$%^&*() World?"
        tokens = count_tokens(text)
        assert tokens > 0

    def test_unicode_text(self):
        """Test tokenization of unicode text."""
        text = "Hello 世界 🌍"
        tokens = count_tokens(text)
        assert tokens > 0