/**
 * @file test_bgp_route_exchange.c
 * @brief Интеграционный тест обмена маршрутами между двумя инстансами
 * 
 * Тест проверяет:
 * - Создание двух инстансов с разными подсетями
 * - Установление ETCP соединения
 * - Обмен маршрутами через BGP
 * - Проверку таблиц роутинга (client -> server direction)
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/stat.h>
#include "../lib/platform_compat.h"
#include "test_utils.h"

#ifdef _WIN32
#include <windows.h>
#include <direct.h>
#define _mkdir(path) _mkdir(path)
#else
#include <unistd.h>
#endif

#include "../src/etcp.h"
#include "../src/etcp_connections.h"
#include "../src/config_parser.h"
#include "../src/utun_instance.h"
#include "../src/routing.h"
#include "../src/route_lib.h"
#include "../src/route_bgp.h"
#include "../src/tun_if.h"
#include "../src/secure_channel.h"
#include "../lib/u_async.h"
#include "../lib/debug_config.h"

#define TEST_TIMEOUT_MS 5000    // 5 seconds timeout
#define BGP_EXCHANGE_WAIT_MS 200 // Wait for BGP exchange (100ms + margin)

// Test state
static struct UTUN_INSTANCE* server_instance = NULL;
static struct UTUN_INSTANCE* client_instance = NULL;
static struct UASYNC* ua = NULL;
static int test_phase = 0;      // 0=init, 1=connected, 2=bgp_exchanged, 3=success, 4=failure
static void* monitor_timeout_id = NULL;
static void* test_timeout_id = NULL;

// Temp config file paths
#ifdef _WIN32
static char temp_dir[MAX_PATH];
#else
static char temp_dir[] = "/tmp/utun_bgp_test_XXXXXX";
#endif
static char server_config_path[256];
static char client_config_path[256];

// Cross-platform mkdtemp replacement
static int create_temp_directory(void) {
#ifdef _WIN32
    char tmp_path[MAX_PATH];
    GetTempPathA(MAX_PATH, tmp_path);
    
    // Generate unique directory name
    srand((unsigned int)GetTickCount());
    int attempts = 0;
    while (attempts < 100) {
        snprintf(temp_dir, sizeof(temp_dir), "%s\\utun_bgp_test_%08x", 
                 tmp_path, (unsigned int)rand());
        if (_mkdir(temp_dir) == 0) {
            return 0;  // Success
        }
        attempts++;
    }
    return -1;  // Failed after 100 attempts
#else
    return (test_mkdtemp(temp_dir) != 0) ? -1 : 0;
#endif
}

// Server config: 2 subnets - 192.168.10.0/24 and 192.168.11.0/24
static const char* server_config_content =
    "[global]\n"
    "my_node_id=0x1111111111111111\n"
    "my_private_key=67b705a92b41bcaae105af2d6a17743faa7b26ccebba8b3b9b0af05e9cd1d5fb\n"
    "my_public_key=1c55e4ccae7c4470707759086738b10681bf88b81f198cc2ab54a647d1556e17c65e6b1833e0c771e5a39382c03067c388915a4c732191bc130480f20f8e00b9\n"
    "tun_ip=10.99.0.1/24\n"
    "tun_ifname=tun99\n"
    "\n"
    "[routing]\n"
    "my_subnet=192.168.10.0/24\n"
    "my_subnet=192.168.11.0/24\n"
    "\n"
    "[server: test]\n"
    "addr=127.0.0.1:39011\n"
    "type=public\n";

// Client config: 2 subnets - 192.168.20.0/24 and 192.168.21.0/24
static const char* client_config_content =
    "[global]\n"
    "my_node_id=0x2222222222222222\n"
    "my_private_key=4813d31d28b7e9829247f488c6be7672f2bdf61b2508333128e386d1759afed2\n"
    "my_public_key=c594f33c91f3a2222795c2c110c527bf214ad1009197ce14556cb13df3c461b3c373bed8f205a8dd1fc0c364f90bf471d7c6f5db49564c33e4235d268569ac71\n"
    "tun_ip=10.99.0.2/24\n"
    "tun_ifname=tun98\n"
    "\n"
    "[routing]\n"
    "my_subnet=192.168.20.0/24\n"
    "my_subnet=192.168.21.0/24\n"
    "\n"
    "[server: test]\n"
    "addr=127.0.0.1:39012\n"
    "type=public\n"
    "\n"
    "[client: test_client]\n"
    "keepalive=1\n"
    "peer_public_key=1c55e4ccae7c4470707759086738b10681bf88b81f198cc2ab54a647d1556e17c65e6b1833e0c771e5a39382c03067c388915a4c732191bc130480f20f8e00b9\n"
    "link=test:127.0.0.1:39011\n";

// Create temp config files
static int create_temp_configs(void) {
    if (create_temp_directory() != 0) {
        fprintf(stderr, "Failed to create temp directory\n");
        return -1;
    }
    
    snprintf(server_config_path, sizeof(server_config_path), "%s/server.conf", temp_dir);
    snprintf(client_config_path, sizeof(client_config_path), "%s/client.conf", temp_dir);
    
    FILE* f = fopen(server_config_path, "w");
    if (!f) {
        fprintf(stderr, "Failed to create server config file\n");
        return -1;
    }
    fprintf(f, "%s", server_config_content);
    fclose(f);
    
    f = fopen(client_config_path, "w");
    if (!f) {
        fprintf(stderr, "Failed to create client config file\n");
        test_unlink(server_config_path);
        return -1;
    }
    fprintf(f, "%s", client_config_content);
    fclose(f);
    
    return 0;
}

// Cleanup temp config files
static void cleanup_temp_configs(void) {
#ifdef _WIN32
    if (server_config_path[0]) _unlink(server_config_path);
    if (client_config_path[0]) _unlink(client_config_path);
    if (temp_dir[0]) _rmdir(temp_dir);
#else
    if (server_config_path[0]) test_unlink(server_config_path);
    if (client_config_path[0]) test_unlink(client_config_path);
    if (temp_dir[0]) test_rmdir(temp_dir);
#endif
}

// Check if connection is established (link initialized)
static int is_connection_established(struct UTUN_INSTANCE* inst) {
    if (!inst) return 0;
    
    struct ETCP_CONN* conn = inst->connections;
    while (conn) {
        struct ETCP_LINK* link = conn->links;
        while (link) {
            if (link->initialized) {
                return 1;
            }
            link = link->next;
        }
        conn = conn->next;
    }
    return 0;
}

// Print routing table contents
static void print_routing_table(struct UTUN_INSTANCE* inst, const char* name) {
    if (!inst || !inst->rt) {
        DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "%s: No routing table\n", name);
        return;
    }
    
    DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "\n=== %s Routing Table (%zu routes) ===", name, inst->rt->count);
    
    for (size_t i = 0; i < inst->rt->count; i++) {
        struct ROUTE_ENTRY* entry = &inst->rt->entries[i];
        char network_str[16];
        struct in_addr addr;
        addr.s_addr = htonl(entry->network);
        inet_ntop(AF_INET, &addr, network_str, sizeof(network_str));
        
        const char* type_str = entry->v_node_info ? "LEARNED" : "LOCAL";
        
        uint64_t node_id = 0;
        if (entry->v_node_info) {
            node_id = be64toh(entry->v_node_info->node.node_id);
        }
        
        DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "  Route %zu: %s/%d [%s] node_id=%016llX", 
                   i + 1, network_str, entry->prefix_length, type_str,
                   (unsigned long long)node_id);
    }
    DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "=====================================\n");
}

// Check if specific learned route exists
static int check_learned_route(struct UTUN_INSTANCE* inst, uint32_t network, 
                                uint8_t prefix_len, uint64_t expected_node_id) {
    if (!inst || !inst->rt) {
        DEBUG_ERROR(DEBUG_CATEGORY_ROUTING, "check_learned_route: no instance or rt");
        return 0;
    }
    
    uint64_t expected_be = htobe64(expected_node_id);
    for (size_t i = 0; i < inst->rt->count; i++) {
        struct ROUTE_ENTRY* entry = &inst->rt->entries[i];
        if (entry->network == network && 
            entry->prefix_length == prefix_len &&
            entry->v_node_info != NULL &&
            entry->v_node_info->node.node_id == expected_be) {
            return 1;
        }
    }
    return 0;
}

// Verify BGP route exchange results
static int verify_bgp_exchange(void) {
    int success = 1;
    
    DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "\n=== Verifying BGP Route Exchange ===\n");
    
    // Print tables for debugging
    print_routing_table(server_instance, "SERVER");
    print_routing_table(client_instance, "CLIENT");
    
    // Check server learned client's routes (192.168.20.0/24, 192.168.21.0/24)
    DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "Checking server learned client's routes...");

    // Note: Routes are stored in host byte order, not network byte order
    if (!check_learned_route(server_instance,0x0014a8c0,24,0x2222222222222222ULL)) {
        DEBUG_ERROR(DEBUG_CATEGORY_ROUTING,"FAIL: Server missing learned route 192.168.20.0/24");
        success = 0;
    } else {
        DEBUG_INFO(DEBUG_CATEGORY_ROUTING,"PASS: Server has learned route 192.168.20.0/24");
    }

    if (!check_learned_route(server_instance,0x0015a8c0,24,0x2222222222222222ULL)) {
        DEBUG_ERROR(DEBUG_CATEGORY_ROUTING,"FAIL: Server missing learned route 192.168.21.0/24");
        success = 0;
    } else {
        DEBUG_INFO(DEBUG_CATEGORY_ROUTING,"PASS: Server has learned route 192.168.21.0/24");
    }
    
    // Check client learned server's routes (192.168.10.0/24, 192.168.11.0/24)
    // NOTE: For now we only test client -> server direction
    // This will be enabled after server -> client is implemented
    DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "Checking client learned server's routes (disabled - server->client not implemented)...");
    
    return success;
}

// Monitor callback - checks connection status and BGP exchange
static void monitor_connections(void* arg) {
    (void)arg;
    
    if (test_phase >= 3) {
        monitor_timeout_id = NULL;
        return;
    }
    
    switch (test_phase) {
        case 0: { // Waiting for connection
            int server_connected = is_connection_established(server_instance);
            int client_connected = is_connection_established(client_instance);
            
            if (server_connected && client_connected) {
                DEBUG_INFO(DEBUG_CATEGORY_ETCP, "=== Connection established! Waiting for BGP exchange... ===");
                test_phase = 1;
                // Schedule next check after BGP exchange time
                monitor_timeout_id = uasync_set_timeout(ua, BGP_EXCHANGE_WAIT_MS, NULL, monitor_connections);
                return;
            }
            break;
        }
        
        case 1: { // Connection established, wait for BGP exchange
            DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "=== Checking BGP route exchange ===");
            test_phase = 2;
            
            // Verify routes
            if (verify_bgp_exchange()) {
                DEBUG_INFO(DEBUG_CATEGORY_ROUTING, "=== BGP ROUTE EXCHANGE SUCCESS ===");
                test_phase = 3; // Success
            } else {
                DEBUG_ERROR(DEBUG_CATEGORY_ROUTING, "=== BGP ROUTE EXCHANGE FAILED ===");
                test_phase = 4; // Failure
            }
            
            // Cancel timeout for quick exit
            if (test_timeout_id) {
                uasync_cancel_timeout(ua, test_timeout_id);
                test_timeout_id = NULL;
            }
            return;
        }
        
        case 2: // Verification done
            return;
    }
    
    // Schedule next check
    if (test_phase < 3) {
        monitor_timeout_id = uasync_set_timeout(ua, 100, NULL, monitor_connections);
    }
}

static void test_timeout(void* arg) {
    (void)arg;
    if (test_phase < 3) {
        DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "\n=== TEST TIMEOUT ===");
        test_phase = 4; // Failure
        if (monitor_timeout_id) {
            uasync_cancel_timeout(ua, monitor_timeout_id);
            monitor_timeout_id = NULL;
        }
    }
}

int main() {
    printf("=== BGP Route Exchange Test ===\n");
    
    // Create temp config files
    if (create_temp_configs() != 0) {
        fprintf(stderr, "Failed to create temporary config files\n");
        return 1;
    }
    
    debug_config_init();
    debug_set_level(DEBUG_LEVEL_INFO);
    debug_set_categories(DEBUG_CATEGORY_ROUTING | DEBUG_CATEGORY_ETCP | DEBUG_CATEGORY_BGP);
    
    // Disable TUN for testing
    utun_instance_set_tun_init_enabled(0);
    
    // Create shared uasync context
    ua = uasync_create();
    if (!ua) {
        fprintf(stderr, "Failed to create uasync context\n");
        return 1;
    }
    
    // Create server instance
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Creating server instance...");
    server_instance = utun_instance_create(ua, server_config_path);
    if (!server_instance) {
        DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "Failed to create server instance");
        return 1;
    }
    
    // Initialize server instance (includes connections, routing, and BGP)
    if (utun_instance_init(server_instance) < 0) {
        DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "Failed to initialize server instance");
        return 1;
    }
    
    // BGP module is now initialized automatically in utun_instance_create
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Server instance ready (node_id=%016llX, bgp=%p)", 
               (unsigned long long)server_instance->node_id, (void*)server_instance->bgp);
    
    // Create client instance
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Creating client instance...");
    client_instance = utun_instance_create(ua, client_config_path);
    if (!client_instance) {
        DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "Failed to create client instance");
        return 1;
    }
    
    // Initialize client instance (includes connections, routing, and BGP)
    if (utun_instance_init(client_instance) < 0) {
        DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "Failed to initialize client instance");
        return 1;
    }
    
    // BGP module is now initialized automatically in utun_instance_create
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Client instance ready (node_id=%016llX, bgp=%p)", 
               (unsigned long long)client_instance->node_id, (void*)client_instance->bgp);
    
    // Give server time to initialize
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Waiting for server initialization...");
    for (int i = 0; i < 50; i++) {
        uasync_poll(ua, 10);
    }
    
    // Start monitoring
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Starting connection monitoring...");
    monitor_timeout_id = uasync_set_timeout(ua, 100, NULL, monitor_connections);
    test_timeout_id = uasync_set_timeout(ua, TEST_TIMEOUT_MS, NULL, test_timeout);
    
    // Main event loop - use uasync timers only, no artificial timing
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Running event loop...");
    
    while (test_phase < 3) {
        uasync_poll(ua, -1);  // Wait indefinitely for events/timeouts
    }
    
    // Cleanup
    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "\nCleaning up...");
    
    if (monitor_timeout_id) {
        uasync_cancel_timeout(ua, monitor_timeout_id);
        monitor_timeout_id = NULL;
    }
    if (test_timeout_id) {
        uasync_cancel_timeout(ua, test_timeout_id);
        test_timeout_id = NULL;
    }
    
    // Print final routing tables
    print_routing_table(server_instance, "SERVER (final)");
    print_routing_table(client_instance, "CLIENT (final)");
    
    // Destroy instances
    if (server_instance) {
        server_instance->running = 0;
        utun_instance_destroy(server_instance);
    }
    if (client_instance) {
        client_instance->running = 0;
        utun_instance_destroy(client_instance);
    }
    
    if (ua) {
        uasync_destroy(ua, 0);
        ua = NULL;
    }
    
    cleanup_temp_configs();
    
    // Test result
    if (test_phase == 3) {
        printf("\n=== TEST PASSED ===\n");
        printf("BGP route exchange working (client -> server direction)\n");
        return 0;
    } else {
        printf("\n=== TEST FAILED ===\n");
        if (test_phase == 4) {
            printf("BGP route exchange verification failed\n");
        } else {
            printf("Test timeout or connection failed\n");
        }
        return 1;
    }
}