from unittest.mock import MagicMock, patch
import pytest
from src import ai_client
from src import mma_prompts

def test_tier4_patch_prompt_exists() -> None:
  """Test that TIER4_PATCH_PROMPT is defined in mma_prompts.py."""
  assert hasattr(mma_prompts, "TIER4_PATCH_PROMPT")
  prompt = mma_prompts.TIER4_PATCH_PROMPT
  assert "unified diff" in prompt.lower() or "diff -u" in prompt.lower()
  assert "---" in prompt
  assert "+++" in prompt
  assert "@@" in prompt

def test_tier4_patch_prompt_format_instructions() -> None:
  """Test that the patch prompt includes format instructions for unified diff."""
  prompt = mma_prompts.TIER4_PATCH_PROMPT
  assert "--- a/" in prompt or "---" in prompt
  assert "+++ b/" in prompt or "+++" in prompt

def test_run_tier4_patch_generation_exists() -> None:
  """Test that run_tier4_patch_generation function exists in ai_client."""
  assert hasattr(ai_client, "run_tier4_patch_generation")
  assert callable(ai_client.run_tier4_patch_generation)

def test_run_tier4_patch_generation_empty_error() -> None:
  """Test that run_tier4_patch_generation returns empty string on empty error."""
  with patch("src.ai_client._ensure_gemini_client"), \
     patch("src.ai_client._gemini_client") as mock_client:
    mock_resp = MagicMock()
    mock_resp.text = ""
    mock_client.models.generate_content.return_value = mock_resp
    
    result = ai_client.run_tier4_patch_generation("", "file context")
    assert result == ""

def test_run_tier4_patch_generation_calls_ai() -> None:
  """Test that run_tier4_patch_generation calls the AI with the correct prompt."""
  with patch("src.ai_client._ensure_gemini_client"), \
     patch("src.ai_client._gemini_client", create=True) as mock_client, \
     patch("src.ai_client.types") as mock_types:
    mock_resp = MagicMock()
    mock_resp.text = "--- a/test.py\n+++ b/test.py\n@@ -1 +1 @@\n-old\n+new"
    mock_client.models.generate_content.return_value = mock_resp
    mock_types.GenerateContentConfig = MagicMock()
    
    error = "TypeError: unsupported operand"
    file_context = "def foo():\n    pass"
    result = ai_client.run_tier4_patch_generation(error, file_context)
    
    mock_client.models.generate_content.assert_called()

def test_run_tier4_patch_generation_returns_diff() -> None:
  """Test that run_tier4_patch_generation returns diff text."""
  with patch("src.ai_client._ensure_gemini_client"), \
     patch("src.ai_client._gemini_client", create=True) as mock_client, \
     patch("src.ai_client.types") as mock_types:
    expected_diff = "--- a/src/test.py\n+++ b/src/test.py\n@@ -10,5 +10,6 @@\n def test_func():\n-    old_value = 1\n+    old_value = 1\n+    new_value = 2"
    mock_resp = MagicMock()
    mock_resp.text = expected_diff
    mock_client.models.generate_content.return_value = mock_resp
    mock_types.GenerateContentConfig = MagicMock()
    
    result = ai_client.run_tier4_patch_generation("error", "context")
    assert "---" in result
    assert "+++" in result
    assert "@@" in result