"""Tests for OpenAI-compatible API format handling."""

import json
import pytest
import sys
import os

# Add parent directory to path for imports
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from openai_compat import (
    ChatCompletionRequest,
    ChatMessage,
    InferenceParams,
    create_chat_response,
    create_error_response,
    create_stream_chunk,
    estimate_tokens,
    generate_completion_id,
    messages_to_dicts,
    stream_response_generator,
)


class TestChatCompletionRequest:
    """Test request parsing."""

    def test_parse_basic_request(self, sample_request_data):
        """Test parsing a basic chat completion request."""
        request = ChatCompletionRequest(**sample_request_data)

        assert request.model == "meta-llama/Llama-3.1-8B-Instruct"
        assert len(request.messages) == 2
        assert request.messages[0].role == "system"
        assert request.messages[1].role == "user"
        assert request.temperature == 0.7
        assert request.max_tokens == 512
        assert request.stream is False

    def test_parse_streaming_request(self, sample_streaming_request_data):
        """Test parsing a streaming request."""
        request = ChatCompletionRequest(**sample_streaming_request_data)

        assert request.stream is True
        assert request.max_tokens == 256

    def test_default_values(self):
        """Test that defaults are applied correctly."""
        minimal_request = {
            "model": "test-model",
            "messages": [{"role": "user", "content": "Hi"}],
        }
        request = ChatCompletionRequest(**minimal_request)

        assert request.temperature == 0.7
        assert request.top_p == 0.95
        assert request.max_tokens == 512
        assert request.stream is False
        assert request.stop is None

    def test_validation_temperature_bounds(self):
        """Test temperature validation."""
        with pytest.raises(ValueError):
            ChatCompletionRequest(
                model="test",
                messages=[{"role": "user", "content": "Hi"}],
                temperature=-0.5,
            )

        with pytest.raises(ValueError):
            ChatCompletionRequest(
                model="test",
                messages=[{"role": "user", "content": "Hi"}],
                temperature=2.5,
            )


class TestChatCompletionResponse:
    """Test response generation."""

    def test_create_basic_response(self):
        """Test creating a basic chat response."""
        response = create_chat_response(
            model="test-model",
            content="Hello! How can I help you?",
            prompt_tokens=10,
            completion_tokens=8,
        )

        assert response.model == "test-model"
        assert response.object == "chat.completion"
        assert len(response.choices) == 1
        assert response.choices[0].message.role == "assistant"
        assert response.choices[0].message.content == "Hello! How can I help you?"
        assert response.choices[0].finish_reason == "stop"
        assert response.usage.prompt_tokens == 10
        assert response.usage.completion_tokens == 8
        assert response.usage.total_tokens == 18

    def test_response_has_unique_id(self):
        """Test that each response has a unique ID."""
        response1 = create_chat_response(model="test", content="Hi")
        response2 = create_chat_response(model="test", content="Hi")

        assert response1.id != response2.id
        assert response1.id.startswith("chatcmpl-")

    def test_response_serialization(self):
        """Test that response can be serialized to JSON."""
        response = create_chat_response(
            model="test-model",
            content="Test",
        )

        json_str = response.model_dump_json()
        parsed = json.loads(json_str)

        assert parsed["model"] == "test-model"
        assert parsed["choices"][0]["message"]["content"] == "Test"


class TestStreamingResponse:
    """Test streaming response format."""

    def test_create_stream_chunk_with_content(self):
        """Test creating a streaming chunk with content."""
        chunk = create_stream_chunk(
            completion_id="test-id",
            model="test-model",
            content="Hello",
        )

        assert chunk.id == "test-id"
        assert chunk.object == "chat.completion.chunk"
        assert chunk.choices[0].delta.content == "Hello"
        assert chunk.choices[0].finish_reason is None

    def test_create_stream_chunk_with_role(self):
        """Test creating a streaming chunk with role (first chunk)."""
        chunk = create_stream_chunk(
            completion_id="test-id",
            model="test-model",
            role="assistant",
        )

        assert chunk.choices[0].delta.role == "assistant"
        assert chunk.choices[0].delta.content is None

    def test_create_stream_chunk_with_finish_reason(self):
        """Test creating a final streaming chunk."""
        chunk = create_stream_chunk(
            completion_id="test-id",
            model="test-model",
            finish_reason="stop",
        )

        assert chunk.choices[0].finish_reason == "stop"

    def test_stream_response_generator(self):
        """Test the full streaming response generator."""
        def token_gen():
            yield "Hello"
            yield " World"
            yield "!"

        chunks = list(stream_response_generator("test-model", token_gen()))

        # Should have: role chunk, 3 content chunks, finish chunk, [DONE]
        assert len(chunks) == 6

        # First chunk has role
        first_data = json.loads(chunks[0].replace("data: ", "").strip())
        assert first_data["choices"][0]["delta"]["role"] == "assistant"

        # Content chunks
        second_data = json.loads(chunks[1].replace("data: ", "").strip())
        assert second_data["choices"][0]["delta"]["content"] == "Hello"

        # Last data chunk has finish reason
        last_data = json.loads(chunks[4].replace("data: ", "").strip())
        assert last_data["choices"][0]["finish_reason"] == "stop"

        # Very last is [DONE]
        assert chunks[5] == "data: [DONE]\n\n"


class TestInferenceParams:
    """Test parameter extraction."""

    def test_extract_params_from_request(self, sample_request_data):
        """Test extracting inference parameters from request."""
        request = ChatCompletionRequest(**sample_request_data)
        params = InferenceParams.from_request(request)

        assert params.model_id == "meta-llama/Llama-3.1-8B-Instruct"
        assert len(params.messages) == 2
        assert params.max_new_tokens == 512
        assert params.temperature == 0.7
        assert params.stream is False

    def test_messages_to_dicts(self):
        """Test converting ChatMessage objects to dicts."""
        messages = [
            ChatMessage(role="user", content="Hello"),
            ChatMessage(role="assistant", content="Hi there!"),
        ]

        dicts = messages_to_dicts(messages)

        assert dicts == [
            {"role": "user", "content": "Hello"},
            {"role": "assistant", "content": "Hi there!"},
        ]


class TestErrorResponse:
    """Test error response format."""

    def test_create_error_response(self):
        """Test creating an error response."""
        error = create_error_response(
            message="Model not found",
            error_type="invalid_request_error",
            param="model",
        )

        assert error.error.message == "Model not found"
        assert error.error.type == "invalid_request_error"
        assert error.error.param == "model"

    def test_error_response_serialization(self):
        """Test error response JSON serialization."""
        error = create_error_response(
            message="Test error",
            error_type="server_error",
            code="internal_error",
        )

        parsed = json.loads(error.model_dump_json())

        assert parsed["error"]["message"] == "Test error"
        assert parsed["error"]["type"] == "server_error"
        assert parsed["error"]["code"] == "internal_error"


class TestUtilityFunctions:
    """Test utility functions."""

    def test_generate_completion_id_format(self):
        """Test completion ID format."""
        id1 = generate_completion_id()
        id2 = generate_completion_id()

        assert id1.startswith("chatcmpl-")
        assert len(id1) == len("chatcmpl-") + 24
        assert id1 != id2  # Should be unique

    def test_estimate_tokens(self):
        """Test rough token estimation."""
        # ~4 chars per token
        assert estimate_tokens("Hello World!") == 3  # 12 chars / 4 = 3
        assert estimate_tokens("A") == 1  # Min 1
        assert estimate_tokens("This is a longer piece of text.") == 8  # 32 / 4 = 8