/**
 * @file test_mcp_c_filter_chain_exception_safety.cc
 * @brief Tests for exception safety in MCP Filter Chain C API
 *
 * These tests verify that:
 * 1. No exceptions cross the C API boundary
 * 2. Functions return appropriate error codes on failure
 * 3. Resource cleanup happens correctly
 */

#include <memory>
#include <stdexcept>

#include <gmock/gmock.h>
#include <gtest/gtest.h>

#include "mcp/c_api/mcp_c_api.h"
#include "mcp/c_api/mcp_c_api_json.h"
#include "mcp/c_api/mcp_c_filter_chain.h"
#include "mcp/c_api/mcp_c_types.h"

using namespace testing;

namespace {

// Test fixture for exception safety tests
class FilterChainExceptionSafetyTest : public ::testing::Test {
 protected:
  void SetUp() override {
    // Initialize MCP API - no longer needed
    // mcp_result_t result = mcp_initialize(nullptr);
    // ASSERT_EQ(result, MCP_OK);

    // Create a dispatcher for testing
    dispatcher_ = mcp_dispatcher_create();
    ASSERT_NE(dispatcher_, nullptr);
  }

  void TearDown() override {
    if (dispatcher_) {
      mcp_dispatcher_destroy(dispatcher_);
      dispatcher_ = nullptr;
    }

    // mcp_cleanup() - no longer needed
    // mcp_cleanup();
  }

  mcp_dispatcher_t dispatcher_ = nullptr;
};

// Test that handle-returning functions return nullptr/0 on exception
TEST_F(FilterChainExceptionSafetyTest,
       HandleReturningFunctionsReturnNullOnException) {
  // Test mcp_chain_create_from_json with null json
  mcp_filter_chain_t chain = mcp_chain_create_from_json(dispatcher_, nullptr);
  EXPECT_EQ(chain, 0);

  // Test mcp_chain_export_to_json with invalid chain
  mcp_json_value_t json = mcp_chain_export_to_json(0);
  EXPECT_NE(json, nullptr);  // Returns null JSON, not nullptr
  mcp_json_free(json);

  // Test mcp_chain_clone with invalid chain
  mcp_filter_chain_t cloned = mcp_chain_clone(0);
  EXPECT_EQ(cloned, 0);

  // Test mcp_chain_merge with invalid chains
  mcp_filter_chain_t merged = mcp_chain_merge(0, 0, MCP_CHAIN_MODE_SEQUENTIAL);
  EXPECT_EQ(merged, 0);

  // Test mcp_chain_dump with invalid chain
  char* dump = mcp_chain_dump(0, "text");
  EXPECT_EQ(dump, nullptr);
}

// Test that status-returning functions return error codes on exception
TEST_F(FilterChainExceptionSafetyTest,
       StatusReturningFunctionsReturnErrorOnException) {
  // Test functions with invalid parameters
  mcp_result_t result;

  result = mcp_chain_validate_json(nullptr, nullptr);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);

  result = mcp_chain_validate_config(nullptr, nullptr);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);

  result = mcp_chain_assemble_from_json(dispatcher_, nullptr, nullptr);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);

  result = mcp_chain_assemble_from_config(dispatcher_, nullptr, nullptr);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);

  // Test mcp_chain_pause with invalid chain
  result = mcp_chain_pause(0);
  EXPECT_EQ(result, MCP_ERROR_NOT_FOUND);

  // Test mcp_chain_resume with invalid chain
  result = mcp_chain_resume(0);
  EXPECT_EQ(result, MCP_ERROR_NOT_FOUND);

  // Test mcp_chain_reset with invalid chain
  result = mcp_chain_reset(0);
  EXPECT_EQ(result, MCP_ERROR_NOT_FOUND);

  // Test mcp_chain_set_filter_enabled with null filter name
  result = mcp_chain_set_filter_enabled(0, nullptr, true);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);

  // Test mcp_chain_get_stats with null stats
  result = mcp_chain_get_stats(0, nullptr);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);

  // Test mcp_chain_set_event_callback with invalid chain
  result = mcp_chain_set_event_callback(0, nullptr, nullptr);
  EXPECT_EQ(result, MCP_ERROR_NOT_FOUND);
}

// Test that state-returning functions return error state on exception
TEST_F(FilterChainExceptionSafetyTest,
       StateReturningFunctionsReturnErrorStateOnException) {
  // Test mcp_chain_get_state with invalid chain
  mcp_chain_state_t state = mcp_chain_get_state(0);
  EXPECT_EQ(state, MCP_CHAIN_STATE_ERROR);
}

// Test that void functions don't crash on exception
TEST_F(FilterChainExceptionSafetyTest, VoidFunctionsNoCrashOnException) {
  // These should not crash even with invalid parameters

  // Test mcp_chain_router_destroy with null
  mcp_chain_router_destroy(nullptr);

  // Test mcp_chain_pool_return with null pool
  mcp_chain_pool_return(nullptr, 0);

  // Test mcp_chain_pool_destroy with null
  mcp_chain_pool_destroy(nullptr);
}

// Test router functions for exception safety
TEST_F(FilterChainExceptionSafetyTest, RouterFunctionsExceptionSafety) {
  // Create router with null config
  mcp_chain_router_t router = mcp_chain_router_create(nullptr);
  EXPECT_EQ(router, nullptr);

  // Test add_route with null router
  mcp_result_t result = mcp_chain_router_add_route(nullptr, nullptr, 0);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);

  // Test route with null router
  // TODO: Fix - mcp_chain_router_route requires mcp_buffer_handle_t not nullptr
  // mcp_filter_chain_t chain = mcp_chain_router_route(nullptr, 0, nullptr);
  // EXPECT_EQ(chain, 0);
}

// Test pool functions for exception safety
TEST_F(FilterChainExceptionSafetyTest, PoolFunctionsExceptionSafety) {
  // Create pool with invalid base chain
  mcp_chain_pool_t pool = mcp_chain_pool_create(0, 10, MCP_ROUTING_ROUND_ROBIN);
  // This may or may not return nullptr depending on implementation

  // Test get_next with null pool
  mcp_filter_chain_t chain = mcp_chain_pool_get_next(nullptr);
  EXPECT_EQ(chain, 0);

  // Test get_stats with null pool
  size_t active, idle;
  uint64_t processed;
  mcp_result_t result =
      mcp_chain_pool_get_stats(nullptr, &active, &idle, &processed);
  EXPECT_EQ(result, MCP_ERROR_INVALID_ARGUMENT);
}

// Test optimization functions for exception safety
TEST_F(FilterChainExceptionSafetyTest, OptimizationFunctionsExceptionSafety) {
  mcp_result_t result;

  // Test with invalid chain (should be safe)
  result = mcp_chain_optimize(0);
  EXPECT_EQ(result, MCP_OK);  // TODO functions return OK

  result = mcp_chain_reorder_filters(0);
  EXPECT_EQ(result, MCP_OK);  // TODO functions return OK

  // TODO: mcp_chain_profile API changed or removed
  // result = mcp_chain_profile(0, nullptr, 100, nullptr);
  // EXPECT_EQ(result, MCP_OK); // TODO functions return OK

  result = mcp_chain_set_trace_level(0, 1);
  EXPECT_EQ(result, MCP_OK);  // TODO functions return OK

  result = mcp_chain_validate(0, nullptr);
  EXPECT_EQ(result, MCP_OK);  // TODO functions return OK
}

// Test that complex operations with valid inputs don't throw
TEST_F(FilterChainExceptionSafetyTest, ValidOperationsNoThrow) {
  // Create a simple chain configuration
  mcp_json_value_t config = mcp_json_create_object();
  ASSERT_NE(config, nullptr);

  mcp_json_value_t name = mcp_json_create_string("test_chain");
  mcp_json_object_set(config, "name", name);

  mcp_json_value_t filters = mcp_json_create_array();
  mcp_json_object_set(config, "filters", filters);

  // This should handle any internal exceptions gracefully
  mcp_filter_chain_t chain = mcp_chain_create_from_json(dispatcher_, config);
  // Chain creation might fail but shouldn't crash

  if (chain != 0) {
    // Test various operations that should be exception-safe
    mcp_chain_state_t state = mcp_chain_get_state(chain);
    EXPECT_NE(state, MCP_CHAIN_STATE_ERROR);

    mcp_result_t result = mcp_chain_pause(chain);
    EXPECT_TRUE(result == MCP_OK || result == MCP_ERROR_NOT_FOUND);

    result = mcp_chain_resume(chain);
    EXPECT_TRUE(result == MCP_OK || result == MCP_ERROR_NOT_FOUND);

    // Clean up
    // Note: No direct destroy function for chains in the API
  }

  mcp_json_free(config);
}

}  // namespace
