import hashlib
import threading
import unittest
from unittest.mock import mock_open, patch

import src.utils.llm_utils as llm_utils
from src import config


class TestLLMUtils(unittest.TestCase):
    def setUp(self):
        self.filename = "test_file.txt"
        self.prompt = "This is a test prompt."
        self.response = "This is a test response."
        # Clear cache before each test
        llm_utils.claude_cache.clear()

    def tearDown(self):
        # Clear cache after each test
        llm_utils.claude_cache.clear()

    def test_get_cache_key_basic(self):
        """Test basic cache key generation (backward compatible)."""
        model_id = "test_model"
        expected_hash = hashlib.sha256(f"{model_id}:{self.prompt}".encode()).hexdigest()
        self.assertEqual(llm_utils.get_cache_key(self.prompt, model_id), expected_hash)

    def test_get_cache_key_with_instruction(self):
        """Test cache key includes instruction parameter."""
        model_id = "test_model"
        instruction = "You are a helpful assistant."
        
        key1 = llm_utils.get_cache_key(self.prompt, model_id, instruction=instruction)
        key2 = llm_utils.get_cache_key(self.prompt, model_id, instruction="Different instruction")
        
        # Keys should be different when instruction differs
        self.assertNotEqual(key1, key2)
        
        # Same instruction should produce same key
        key3 = llm_utils.get_cache_key(self.prompt, model_id, instruction=instruction)
        self.assertEqual(key1, key3)

    def test_get_cache_key_with_max_tokens(self):
        """Test cache key includes max_tokens parameter."""
        model_id = "test_model"
        
        key1 = llm_utils.get_cache_key(self.prompt, model_id, max_tokens=100)
        key2 = llm_utils.get_cache_key(self.prompt, model_id, max_tokens=200)
        
        # Keys should be different when max_tokens differs
        self.assertNotEqual(key1, key2)
        
        # Same max_tokens should produce same key
        key3 = llm_utils.get_cache_key(self.prompt, model_id, max_tokens=100)
        self.assertEqual(key1, key3)

    def test_get_cache_key_with_cache_flag(self):
        """Test cache key includes cache flag."""
        model_id = "test_model"
        
        key1 = llm_utils.get_cache_key(self.prompt, model_id, cache=False)
        key2 = llm_utils.get_cache_key(self.prompt, model_id, cache=True)
        
        # Keys should be different when cache flag differs
        self.assertNotEqual(key1, key2)

    def test_get_cache_key_all_parameters(self):
        """Test cache key with all parameters."""
        model_id = "test_model"
        instruction = "You are helpful"
        max_tokens = 100
        
        key1 = llm_utils.get_cache_key(
            self.prompt, model_id, instruction=instruction, max_tokens=max_tokens, cache=True
        )
        key2 = llm_utils.get_cache_key(
            self.prompt, model_id, instruction=instruction, max_tokens=max_tokens, cache=True
        )
        
        # Same parameters should produce same key
        self.assertEqual(key1, key2)
        
        # Different parameters should produce different keys
        key3 = llm_utils.get_cache_key(
            self.prompt, model_id, instruction="Different", max_tokens=max_tokens, cache=True
        )
        self.assertNotEqual(key1, key3)

    def test_get_cache_key_with_image_array(self):
        """Test cache key generation for image arrays."""
        model_id = "test_model"
        image_list = ["base64_image1", "base64_image2"]
        
        key1 = llm_utils.get_cache_key_with_image_array(
            self.prompt, model_id, image_list, max_tokens=100
        )
        key2 = llm_utils.get_cache_key_with_image_array(
            self.prompt, model_id, image_list, max_tokens=200
        )
        
        # Keys should be different when max_tokens differs
        self.assertNotEqual(key1, key2)
        
        # Same parameters should produce same key
        key3 = llm_utils.get_cache_key_with_image_array(
            self.prompt, model_id, image_list, max_tokens=100
        )
        self.assertEqual(key1, key3)

    def test_cache_thread_safety_concurrent_reads(self):
        """Test thread safety with concurrent cache reads."""
        model_id = "test_model"
        cache_key = llm_utils.get_cache_key(self.prompt, model_id)
        
        # Pre-populate cache
        llm_utils.claude_cache[cache_key] = self.response
        
        results = []
        errors = []
        
        def read_cache():
            try:
                # Simulate cache read
                with llm_utils._cache_lock:
                    if cache_key in llm_utils.claude_cache:
                        result = llm_utils.claude_cache[cache_key]
                        results.append(result)
            except Exception as e:
                errors.append(e)
        
        # Create multiple threads reading from cache
        threads = []
        for _ in range(10):
            thread = threading.Thread(target=read_cache)
            threads.append(thread)
            thread.start()
        
        for thread in threads:
            thread.join()
        
        # Verify no errors and all reads succeeded
        self.assertEqual(len(errors), 0)
        self.assertEqual(len(results), 10)
        self.assertTrue(all(r == self.response for r in results))

    def test_cache_thread_safety_concurrent_writes(self):
        """Test thread safety with concurrent cache writes."""
        model_id = "test_model"
        num_threads = 10
        
        def write_to_cache(thread_id):
            prompt = f"prompt_{thread_id}"
            response = f"response_{thread_id}"
            cache_key = llm_utils.get_cache_key(prompt, model_id)
            
            # Simulate cache write with lock
            with llm_utils._cache_lock:
                if len(llm_utils.claude_cache) >= llm_utils.CACHE_LIMIT:
                    llm_utils.claude_cache.popitem(last=False)
                llm_utils.claude_cache[cache_key] = response
                llm_utils.claude_cache.move_to_end(cache_key)
        
        threads = []
        for i in range(num_threads):
            thread = threading.Thread(target=write_to_cache, args=(i,))
            threads.append(thread)
            thread.start()
        
        for thread in threads:
            thread.join()
        
        # Verify all writes succeeded (cache should have entries)
        self.assertGreater(len(llm_utils.claude_cache), 0)
        self.assertLessEqual(len(llm_utils.claude_cache), num_threads)

    def test_cache_thread_safety_mixed_operations(self):
        """Test thread safety with mixed read/write operations."""
        model_id = "test_model"
        initial_key = llm_utils.get_cache_key("initial_prompt", model_id)
        llm_utils.claude_cache[initial_key] = "initial_response"
        
        read_count = [0]
        write_count = [0]
        
        def read_operation():
            with llm_utils._cache_lock:
                if initial_key in llm_utils.claude_cache:
                    _ = llm_utils.claude_cache[initial_key]
                    read_count[0] += 1
        
        def write_operation(thread_id):
            prompt = f"write_prompt_{thread_id}"
            response = f"write_response_{thread_id}"
            cache_key = llm_utils.get_cache_key(prompt, model_id)
            
            with llm_utils._cache_lock:
                if len(llm_utils.claude_cache) >= llm_utils.CACHE_LIMIT:
                    llm_utils.claude_cache.popitem(last=False)
                llm_utils.claude_cache[cache_key] = response
                write_count[0] += 1
        
        threads = []
        # Mix of read and write threads
        for i in range(5):
            threads.append(threading.Thread(target=read_operation))
        for i in range(5):
            threads.append(threading.Thread(target=write_operation, args=(i,)))
        
        for thread in threads:
            thread.start()
        
        for thread in threads:
            thread.join()
        
        # Verify operations completed without errors
        self.assertEqual(read_count[0], 5)
        self.assertEqual(write_count[0], 5)

    @patch("builtins.open", new_callable=mock_open)
    def test_invoke_claude_local_mode(self, mock_open_file):
        """Test invoke_claude in local mode."""
        original_run_mode = config.RUN_MODE
        try:
            config.RUN_MODE = "local"
            model_id = config.MODEL_ID_CLAUDE35_SONNET

            with patch("src.utils.llm_utils.local_claude_3_and_up", return_value=self.response):
                response = llm_utils.invoke_claude(self.prompt, model_id, self.filename)
                self.assertEqual(response, self.response)
        finally:
            config.RUN_MODE = original_run_mode

    @patch("builtins.open", new_callable=mock_open)
    def test_invoke_claude_uses_enhanced_cache_key(self, mock_open_file):
        """Test that invoke_claude uses enhanced cache key with all parameters."""
        original_run_mode = config.RUN_MODE
        try:
            config.RUN_MODE = "local"
            model_id = config.MODEL_ID_CLAUDE35_SONNET
            instruction = "Test instruction"
            max_tokens = 100
            cache = True

            with patch("src.utils.llm_utils.local_claude_3_and_up", return_value=self.response):
                # First call should not use cache (cache is empty)
                response1 = llm_utils.invoke_claude(
                    self.prompt, model_id, self.filename,
                    max_tokens=max_tokens, cache=cache, instruction=instruction
                )
                
                # Second call with same parameters should use cache
                with patch("src.utils.llm_utils.local_claude_3_and_up") as mock_local:
                    response2 = llm_utils.invoke_claude(
                        self.prompt, model_id, self.filename,
                        max_tokens=max_tokens, cache=cache, instruction=instruction
                    )
                    # Should not call local_claude_3_and_up again (cache hit)
                    mock_local.assert_not_called()
                    self.assertEqual(response1, response2)
        finally:
            config.RUN_MODE = original_run_mode
            llm_utils.claude_cache.clear()

    def test_token_tracking_uses_exact_api_counts(self):
        """Test that token tracking uses exact API response counts, not estimates."""
        # This test verifies that we're using usage_tracking.extract_usage_from_response()
        # which gets exact counts from API, not estimated counts like len(prompt.split())
        
        # Mock API response with exact token counts
        mock_response_body = {
            "usage": {
                "input_tokens": 150,
                "output_tokens": 75,
                "cache_creation_input_tokens": 20,
                "cache_read_input_tokens": 30,
            }
        }
        
        # Verify extract_usage_from_response extracts exact counts
        import src.utils.usage_tracking as usage_tracking
        input_tokens, output_tokens, cache_creation, cache_read = (
            usage_tracking.extract_usage_from_response(mock_response_body)
        )
        
        # Should match exact API response, not estimates
        self.assertEqual(input_tokens, 150)
        self.assertEqual(output_tokens, 75)
        self.assertEqual(cache_creation, 20)
        self.assertEqual(cache_read, 30)
        
        # Verify these are not estimated (e.g., len(prompt.split()))
        # Exact counts from API are integers, not based on string length
        self.assertIsInstance(input_tokens, int)
        self.assertIsInstance(output_tokens, int)

    def test_validate_model_support_deprecated_claude_2(self):
        """Test that deprecated Claude 2 models raise ValueError."""
        with self.assertRaises(ValueError) as context:
            llm_utils._validate_model_support(
                "anthropic.claude-instant-v1",
                "anthropic.claude-instant-v1"
            )
        self.assertIn("Claude 2 is no longer supported", str(context.exception))

    def test_validate_model_support_claude_3_haiku_supported(self):
        """Test that Claude 3 Haiku models are supported."""
        # Should not raise an exception
        try:
            llm_utils._validate_model_support(
                config.MODEL_ID_CLAUDE45_HAIKU,
                config.MODEL_ID_CLAUDE45_HAIKU
            )
        except ValueError:
            self.fail("_validate_model_support raised ValueError for supported Claude 3 Haiku model")

    def test_validate_model_support_supported_model(self):
        """Test that supported models pass validation."""
        # Should not raise an exception
        try:
            llm_utils._validate_model_support(
                config.MODEL_ID_CLAUDE35_SONNET,
                config.MODEL_ID_CLAUDE35_SONNET
            )
        except ValueError:
            self.fail("_validate_model_support raised ValueError for supported model")

    def test_validate_model_support_unsupported_model(self):
        """Test that unsupported models raise ValueError."""
        with self.assertRaises(ValueError) as context:
            llm_utils._validate_model_support(
                "unknown.model.id",
                "unknown.model.id"
            )
        self.assertIn("Only Claude 3+ models are supported", str(context.exception))
        self.assertIn("Haiku", str(context.exception))

    def test_validate_model_support_with_context(self):
        """Test that context parameter is included in error messages."""
        with self.assertRaises(ValueError) as context:
            llm_utils._validate_model_support(
                "unknown.model.id",
                "unknown.model.id",
                context="for image array"
            )
        self.assertIn("for image array", str(context.exception))

    def test_supports_prompt_cache_supported_models(self):
        """Test that models supporting prompt cache return True."""
        # Test Claude 3.7 Sonnet
        if config.MODEL_ID_CLAUDE37_SONNET:
            self.assertTrue(llm_utils._supports_prompt_cache(config.MODEL_ID_CLAUDE37_SONNET))
        
        # Test Claude 4 Sonnet
        if config.MODEL_ID_CLAUDE4_SONNET:
            self.assertTrue(llm_utils._supports_prompt_cache(config.MODEL_ID_CLAUDE4_SONNET))
        
        # Test Claude 4.5 Sonnet
        if config.MODEL_ID_CLAUDE45_SONNET:
            self.assertTrue(llm_utils._supports_prompt_cache(config.MODEL_ID_CLAUDE45_SONNET))

    def test_supports_prompt_cache_unsupported_models(self):
        """Test that models not supporting prompt cache return False."""
        # Claude 3.5 Sonnet v1 doesn't support caching (only v2+)
        if config.MODEL_ID_CLAUDE35_SONNET:
            self.assertFalse(llm_utils._supports_prompt_cache(config.MODEL_ID_CLAUDE35_SONNET))
        
        # Unknown model
        self.assertFalse(llm_utils._supports_prompt_cache("unknown.model.id"))

    def test_build_claude_3_request_body_basic(self):
        """Test building request body without instruction."""
        body = llm_utils._build_claude_3_request_body(
            "test prompt", max_tokens=100
        )
        
        self.assertEqual(body["anthropic_version"], "bedrock-2023-05-31")
        self.assertEqual(body["max_tokens"], 100)
        self.assertEqual(body["temperature"], 0.0)
        self.assertEqual(len(body["messages"]), 1)
        self.assertEqual(body["messages"][0]["role"], "user")
        self.assertNotIn("system", body)

    def test_build_claude_3_request_body_with_instruction_no_cache(self):
        """Test building request body with instruction but no caching."""
        instruction = "You are a helpful assistant."
        body = llm_utils._build_claude_3_request_body(
            "test prompt", max_tokens=100, instruction=instruction, cache=False
        )
        
        self.assertEqual(body["system"], instruction)
        self.assertNotIsInstance(body["system"], list)

    def test_build_claude_3_request_body_with_cache_supported_model(self):
        """Test building request body with caching enabled for supported model."""
        instruction = "You are a helpful assistant."
        model_id = config.MODEL_ID_CLAUDE37_SONNET or config.MODEL_ID_CLAUDE4_SONNET
        
        if model_id and llm_utils._supports_prompt_cache(model_id):
            body = llm_utils._build_claude_3_request_body(
                "test prompt", max_tokens=100, instruction=instruction, 
                cache=True, model_id=model_id
            )
            
            # Should use array format with cache_control
            self.assertIsInstance(body["system"], list)
            self.assertEqual(len(body["system"]), 1)
            self.assertEqual(body["system"][0]["type"], "text")
            self.assertEqual(body["system"][0]["text"], instruction)
            self.assertEqual(body["system"][0]["cache_control"]["type"], "ephemeral")

    def test_build_claude_3_request_body_with_cache_unsupported_model(self):
        """Test building request body with caching enabled for unsupported model."""
        instruction = "You are a helpful assistant."
        model_id = config.MODEL_ID_CLAUDE35_SONNET  # v1 doesn't support caching
        
        if model_id:
            body = llm_utils._build_claude_3_request_body(
                "test prompt", max_tokens=100, instruction=instruction,
                cache=True, model_id=model_id
            )
            
            # Should use simple string format (no cache_control)
            self.assertEqual(body["system"], instruction)
            self.assertNotIsInstance(body["system"], list)


if __name__ == "__main__":
    unittest.main()