/*
 * etcpmon_client.c - ETCP Monitor Client Network Implementation
 */

#include "etcpmon_client.h"
#include "etcpmon_graph.h"
#include <stdio.h>
#include <string.h>
#include <ws2tcpip.h>
#include <windows.h>

//#pragma comment(lib, "ws2_32.lib")

/* Log file name */
#define LOG_FILENAME "etcpmon.log"

/* Get current timestamp in milliseconds (Unix epoch) */
uint64_t get_timestamp_ms(void) {
    FILETIME ft;
    GetSystemTimeAsFileTime(&ft);
    
    /* Convert FILETIME (100-nanosecond intervals since 1601) to milliseconds */
    uint64_t time = ((uint64_t)ft.dwHighDateTime << 32) | ft.dwLowDateTime;
    /* Convert from 1601 to 1970 epoch (11644473600000 milliseconds) */
    return (time / 10000) - 11644473600000ULL;
}

/* Log hex data to file */
static void log_hex_data(FILE* log, const char* prefix, const uint8_t* data, size_t len) {
    if (!log || !data || len == 0) return;
    
    fprintf(log, "%llu: [%s] ", (unsigned long long)get_timestamp_ms(), prefix);
    for (size_t i = 0; i < len && i < 256; i++) {  /* Limit to 256 bytes per line */
        fprintf(log, "%02X ", data[i]);
    }
    if (len > 256) {
        fprintf(log, "... (%llu bytes total)", (unsigned long long)len);
    }
    fprintf(log, "\n");
    fflush(log);
}

void etcpmon_client_init(struct etcpmon_client* client) {
    if (!client) return;
    memset(client, 0, sizeof(*client));
    client->sock = INVALID_SOCKET;
    client->connected = 0;
    client->fully_connected = 0;
    client->log_file = NULL;
    memset(&client->history, 0, sizeof(client->history));
    for (int i = 0; i < GRAPH_METRICS_COUNT; i++) {
        client->history.min_val[i] = 1e9f;
        client->history.max_val[i] = -1e9f;
    }
    client->history.last_minmax_update = 0;   // ← добавь
}

void etcpmon_client_cleanup(struct etcpmon_client* client) {
    if (!client) return;
    
    etcpmon_client_disconnect(client);
    
    /* Close log file */
    if (client->log_file) {
        fprintf(client->log_file, "%llu: [LOG] Log closed\n", 
               (unsigned long long)get_timestamp_ms());
        fclose(client->log_file);
        client->log_file = NULL;
    }
    
    /* Free cached data */
    if (client->conn_list) {
        free(client->conn_list);
        client->conn_list = NULL;
    }
    if (client->last_metrics) {
        free(client->last_metrics);
        client->last_metrics = NULL;
    }
    if (client->last_links) {
        free(client->last_links);
        client->last_links = NULL;
    }
}

int etcpmon_client_connect(struct etcpmon_client* client, const char* addr, uint16_t port) {
    if (!client || !addr) return -1;
    
    if (client->connected) {
        etcpmon_client_disconnect(client);
    }
    
    /* Open log file (truncate on start) */
    if (!client->log_file) {
        client->log_file = fopen(LOG_FILENAME, "w");
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [LOG] ETCP Monitor communication log started\n", 
                   (unsigned long long)get_timestamp_ms());
            fprintf(client->log_file, "%llu: [LOG] Connecting to %s:%d\n", 
                   (unsigned long long)get_timestamp_ms(), addr, port);
            fflush(client->log_file);
        }
    }
    
    /* Create socket */
    client->sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (client->sock == INVALID_SOCKET) {
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [ERROR] Failed to create socket\n", 
                   (unsigned long long)get_timestamp_ms());
            fflush(client->log_file);
        }
        if (client->on_error) {
            client->on_error("Failed to create socket", client->user_data);
        }
        return -1;
    }
    
    /* Set non-blocking mode */
    u_long nonblock = 1;
    ioctlsocket(client->sock, FIONBIO, &nonblock);
    
    /* Setup address */
    struct sockaddr_in server_addr;
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);
    
    if (inet_pton(AF_INET, addr, &server_addr.sin_addr) != 1) {
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [ERROR] Invalid address: %s\n", 
                   (unsigned long long)get_timestamp_ms(), addr);
            fflush(client->log_file);
        }
        closesocket(client->sock);
        client->sock = INVALID_SOCKET;
        if (client->on_error) {
            client->on_error("Invalid address", client->user_data);
        }
        return -1;
    }
    
    /* Connect (non-blocking) */
    int result = connect(client->sock, (struct sockaddr*)&server_addr, sizeof(server_addr));
    if (result == SOCKET_ERROR) {
        int err = WSAGetLastError();
        if (err != WSAEWOULDBLOCK && err != WSAEINPROGRESS) {
            if (client->log_file) {
                fprintf(client->log_file, "%llu: [ERROR] Connection failed: %d\n", 
                       (unsigned long long)get_timestamp_ms(), err);
                fflush(client->log_file);
            }
            closesocket(client->sock);
            client->sock = INVALID_SOCKET;
            if (client->on_error) {
                char msg[256];
                snprintf(msg, sizeof(msg), "Connection failed: %d", err);
                client->on_error(msg, client->user_data);
            }
            return -1;
        }
        /* Connection in progress, will complete asynchronously */
    }
    
    strncpy(client->server_addr, addr, sizeof(client->server_addr) - 1);
    client->server_port = port;
    client->connected = 1;
    client->fully_connected = 0;
    
    if (client->log_file) {
        fprintf(client->log_file, "%llu: [LOG] Socket created, connection in progress\n", 
               (unsigned long long)get_timestamp_ms());
        fflush(client->log_file);
    }
    
    return 0;
}

void etcpmon_client_disconnect(struct etcpmon_client* client) {
    if (!client) return;
    
    if (client->sock != INVALID_SOCKET) {
        /* Send disconnect command */
        if (client->connected) {
            struct etcpmon_msg_header hdr;
            etcpmon_build_header(&hdr, 0, ETCPMON_CMD_DISCONNECT);
            
            if (client->log_file) {
                log_hex_data(client->log_file, "TX", (const uint8_t*)&hdr, sizeof(hdr));
                fprintf(client->log_file, "%llu: [LOG] Sending CMD_DISCONNECT\n", 
                       (unsigned long long)get_timestamp_ms());
            }
            
            send(client->sock, (const char*)&hdr, sizeof(hdr), 0);
        }
        
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [LOG] Connection closed\n", 
                   (unsigned long long)get_timestamp_ms());
            fflush(client->log_file);
        }
        
        closesocket(client->sock);
        client->sock = INVALID_SOCKET;
    }
    
    client->connected = 0;
    client->fully_connected = 0;
    client->recv_len = 0;
    client->selected_peer_id = 0;
}

int etcpmon_client_is_connected(const struct etcpmon_client* client) {
    return client ? client->connected : 0;
}

int etcpmon_client_request_list(struct etcpmon_client* client) {
    if (!client || client->sock == INVALID_SOCKET) return -1;
    
    struct etcpmon_msg_header hdr;
    etcpmon_build_header(&hdr, 0, ETCPMON_CMD_LIST_CONN);
    
    if (client->log_file) {
        log_hex_data(client->log_file, "TX", (const uint8_t*)&hdr, sizeof(hdr));
        fprintf(client->log_file, "%llu: [LOG] CMD_LIST_CONN\n", 
               (unsigned long long)get_timestamp_ms());
        fflush(client->log_file);
    }
    
    int sent = send(client->sock, (const char*)&hdr, sizeof(hdr), 0);
    if (sent != sizeof(hdr)) {
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [ERROR] Failed to send CMD_LIST_CONN: %d\n", 
                   (unsigned long long)get_timestamp_ms(), WSAGetLastError());
            fflush(client->log_file);
        }
        return -1;
    }
    
    return 0;
}

int etcpmon_client_select_connection(struct etcpmon_client* client, uint64_t peer_node_id) {
    if (!client || client->sock == INVALID_SOCKET) return -1;
    
    uint8_t buffer[sizeof(struct etcpmon_msg_header) + sizeof(struct etcpmon_cmd_select)];
    struct etcpmon_msg_header* hdr = (struct etcpmon_msg_header*)buffer;
    struct etcpmon_cmd_select* cmd = (struct etcpmon_cmd_select*)(buffer + sizeof(*hdr));
    
    etcpmon_build_header(hdr, sizeof(*cmd), ETCPMON_CMD_SELECT_CONN);
    cmd->peer_node_id = peer_node_id;
    
    if (client->log_file) {
        log_hex_data(client->log_file, "TX", buffer, sizeof(buffer));
        fprintf(client->log_file, "%llu: [LOG] CMD_SELECT_CONN peer_id=%016llX\n", 
               (unsigned long long)get_timestamp_ms(), (unsigned long long)peer_node_id);
        fflush(client->log_file);
    }
    
    int sent = send(client->sock, (const char*)buffer, sizeof(buffer), 0);
    if (sent != sizeof(buffer)) {
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [ERROR] Failed to send CMD_SELECT_CONN: %d\n", 
                   (unsigned long long)get_timestamp_ms(), WSAGetLastError());
            fflush(client->log_file);
        }
        return -1;
    }
    
    client->selected_peer_id = peer_node_id;
    return 0;
}

int etcpmon_client_request_metrics(struct etcpmon_client* client) {
    if (!client || client->sock == INVALID_SOCKET) return -1;
    
    struct etcpmon_msg_header hdr;
    etcpmon_build_header(&hdr, 0, ETCPMON_CMD_GET_METRICS);
    
    if (client->log_file) {
        log_hex_data(client->log_file, "TX", (const uint8_t*)&hdr, sizeof(hdr));
        fprintf(client->log_file, "%llu: [LOG] CMD_GET_METRICS\n", 
               (unsigned long long)get_timestamp_ms());
        fflush(client->log_file);
    }
    
    int sent = send(client->sock, (const char*)&hdr, sizeof(hdr), 0);
    if (sent != sizeof(hdr)) {
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [ERROR] Failed to send CMD_GET_METRICS: %d\n", 
                   (unsigned long long)get_timestamp_ms(), WSAGetLastError());
            fflush(client->log_file);
        }
        return -1;
    }
    
    return 0;
}

static void handle_response(struct etcpmon_client* client, uint8_t msg_type, 
                           const uint8_t* payload, uint16_t payload_size) {
    switch (msg_type) {
        case ETCPMON_RSP_CONN_LIST: {
            if (payload_size < sizeof(struct etcpmon_rsp_conn_list)) break;
            
            struct etcpmon_rsp_conn_list* rsp = (struct etcpmon_rsp_conn_list*)payload;
            uint8_t count = rsp->count;
            
            if (payload_size < sizeof(*rsp) + count * sizeof(struct etcpmon_conn_info)) break;
            
            /* Update cached list */
            if (client->conn_list) {
                free(client->conn_list);
            }
            client->conn_list = (struct etcpmon_conn_info*)malloc(count * sizeof(struct etcpmon_conn_info));
            if (client->conn_list) {
                memcpy(client->conn_list, payload + sizeof(*rsp), count * sizeof(struct etcpmon_conn_info));
                client->conn_count = count;
                
                if (client->log_file) {
                    fprintf(client->log_file, "%llu: [LOG] RSP_CONN_LIST count=%d\n", 
                           (unsigned long long)get_timestamp_ms(), count);
                    for (uint8_t i = 0; i < count; i++) {
                        fprintf(client->log_file, "%llu: [LOG]   [%d] peer_id=%016llX name='%s'\n", 
                               (unsigned long long)get_timestamp_ms(), i,
                               (unsigned long long)client->conn_list[i].peer_node_id,
                               client->conn_list[i].name);
                    }
                    fflush(client->log_file);
                }
                
                if (client->on_conn_list) {
                    client->on_conn_list(client->conn_list, count, client->user_data);
                }
            }
            break;
        }
        
        case ETCPMON_RSP_METRICS: {
            if (payload_size < sizeof(struct etcpmon_rsp_metrics)) break;
            
            struct etcpmon_rsp_metrics* rsp = (struct etcpmon_rsp_metrics*)payload;
            uint8_t links_count = rsp->etcp.links_count;
            
            if (payload_size < sizeof(*rsp) + links_count * sizeof(struct etcpmon_link_metrics)) break;
            
            /* Update cached metrics */
            if (client->last_metrics) {
                free(client->last_metrics);
            }
            if (client->last_links) {
                free(client->last_links);
            }
            
            client->last_metrics = (struct etcpmon_rsp_metrics*)malloc(sizeof(*rsp));
            client->last_links = (struct etcpmon_link_metrics*)malloc(links_count * sizeof(struct etcpmon_link_metrics));
            
            if (client->last_metrics && client->last_links) {
                memcpy(client->last_metrics, rsp, sizeof(*rsp));
                memcpy(client->last_links, payload + sizeof(*rsp), 
                       links_count * sizeof(struct etcpmon_link_metrics));
                client->last_links_count = links_count;
                
                if (client->log_file) {
                    fprintf(client->log_file, "%llu: [LOG] RSP_METRICS rtt=%u bytes=%llu links=%d\n", 
                           (unsigned long long)get_timestamp_ms(),
                           rsp->etcp.rtt_last,
                           (unsigned long long)rsp->etcp.bytes_sent_total,
                           links_count);
                    fflush(client->log_file);
                }
                
                if (client->on_metrics) {
                    client->on_metrics(client->last_metrics, client->last_links, 
                                        links_count, client->user_data);
                }
                
                etcpmon_client_add_to_history(client, client->last_metrics);
            }
            break;
        }
        
        case ETCPMON_RSP_ERROR: {
            if (payload_size >= sizeof(struct etcpmon_rsp_error)) {
                struct etcpmon_rsp_error* rsp = (struct etcpmon_rsp_error*)payload;
                const char* msg = (const char*)(payload + sizeof(*rsp));
                
                if (client->log_file) {
                    fprintf(client->log_file, "%llu: [LOG] RSP_ERROR code=%d msg='%s'\n", 
                           (unsigned long long)get_timestamp_ms(), rsp->error_code, msg);
                    fflush(client->log_file);
                }
                
                if (client->on_error) {
                    client->on_error(msg, client->user_data);
                }
            }
            break;
        }
    }
}

int etcpmon_client_process(struct etcpmon_client* client) {
    if (!client || client->sock == INVALID_SOCKET) return -1;

// Проверка завершения non-blocking connect
    if (client->connected && !client->fully_connected) {
        int error = 0;
        int len = sizeof(error);
        if (getsockopt(client->sock, SOL_SOCKET, SO_ERROR, (char*)&error, &len) == 0) {
            if (error == 0) {
                // Connect успешно завершён
                client->fully_connected = 1;
                if (client->log_file) {
                    fprintf(client->log_file, "%llu: [LOG] Connection established\n", 
                           (unsigned long long)get_timestamp_ms());
                    fflush(client->log_file);
                }
                if (client->on_connected) {
                    client->on_connected(client->user_data);  // Здесь вызов request_list
                }
                // Продолжаем к recv, т.к. подключены
            } else if (error == WSAEINPROGRESS || error == WSAEALREADY) {
                // Подключение ещё в процессе, ничего не делаем, ждём следующий вызов process
                if (client->log_file) {
                    fprintf(client->log_file, "%llu: [LOG] Connect in progress (polling)...\n", 
                           (unsigned long long)get_timestamp_ms());
                    fflush(client->log_file);
                }
                return 0;  // Важно: выходим, чтобы не идти в recv (оно провалится с ошибкой)
            } else {
                // Подключение провалилось по другой причине
                if (client->log_file) {
                    fprintf(client->log_file, "%llu: [ERROR] Connect failed: %d\n", 
                           (unsigned long long)get_timestamp_ms(), error);
                    fflush(client->log_file);
                }
                etcpmon_client_disconnect(client);
                if (client->on_disconnected) {
                    client->on_disconnected(client->user_data);
                }
                if (client->on_error) {
                    char msg[256];
                    snprintf(msg, sizeof(msg), "Connect failed: %d", error);
                    client->on_error(msg, client->user_data);
                }
                return -1;
            }
        } else {
            // getsockopt провалился (редко, но на всякий случай)
            if (client->log_file) {
                fprintf(client->log_file, "%llu: [ERROR] getsockopt failed: %d\n", 
                       (unsigned long long)get_timestamp_ms(), WSAGetLastError());
                fflush(client->log_file);
            }
            etcpmon_client_disconnect(client);
            if (client->on_disconnected) {
                client->on_disconnected(client->user_data);
            }
            return -1;
        }
    }

    // Если подключение в процессе, мы уже вышли выше. Здесь recv только для установленного соединения
    uint8_t* buf = client->recv_buffer + client->recv_len;
    int buf_space = ETCPMON_MAX_MSG_SIZE - client->recv_len;
    
    if (buf_space <= 0) {
        client->recv_len = 0;
        buf = client->recv_buffer;
        buf_space = ETCPMON_MAX_MSG_SIZE;
    }
    
    int received = recv(client->sock, (char*)buf, buf_space, 0);
    
    if (received == SOCKET_ERROR) {
        int err = WSAGetLastError();
        if (err == WSAEWOULDBLOCK) {
            return 0;  /* No data available */
        }
        /* Connection error */
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [ERROR] recv failed: %d\n", 
                   (unsigned long long)get_timestamp_ms(), err);
            fflush(client->log_file);
        }
        etcpmon_client_disconnect(client);
        if (client->on_disconnected) {
            client->on_disconnected(client->user_data);
        }
        return -1;
    }
    
    if (received == 0) {
        /* Connection closed by server */
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [LOG] Connection closed by server (recv returned 0)\n", 
                   (unsigned long long)get_timestamp_ms());
            fflush(client->log_file);
        }
        etcpmon_client_disconnect(client);
        if (client->on_disconnected) {
            client->on_disconnected(client->user_data);
        }
        return -1;
    }
    
    /* Log received data */
    if (client->log_file) {
        log_hex_data(client->log_file, "RX", buf, received);
    }
    
    client->recv_len += received;
    
    /* Process complete messages */
    int processed = 0;
    while (client->recv_len >= sizeof(struct etcpmon_msg_header)) {
        struct etcpmon_msg_header* hdr = (struct etcpmon_msg_header*)client->recv_buffer;
        
        if (etcpmon_validate_header(hdr) != 0) {
            /* Invalid header, skip byte */
            if (client->log_file) {
                fprintf(client->log_file, "%llu: [ERROR] Invalid header, skipping byte\n", 
                       (unsigned long long)get_timestamp_ms());
                fflush(client->log_file);
            }
            memmove(client->recv_buffer, client->recv_buffer + 1, client->recv_len - 1);
            client->recv_len--;
            continue;
        }
        
        if (client->recv_len < hdr->size) {
            break;  /* Wait for more data */
        }
        
        /* Handle message */
        uint8_t* payload = client->recv_buffer + sizeof(*hdr);
        uint16_t payload_size = hdr->size - sizeof(*hdr);
        
        if (client->log_file) {
            fprintf(client->log_file, "%llu: [LOG] Received message type=0x%02X size=%d\n", 
                   (unsigned long long)get_timestamp_ms(), hdr->type, hdr->size);
            fflush(client->log_file);
        }
        
        handle_response(client, hdr->type, payload, payload_size);
        processed++;
        
        /* Remove processed message */
        if (client->recv_len > hdr->size) {
            memmove(client->recv_buffer, client->recv_buffer + hdr->size,
                   client->recv_len - hdr->size);
        }
        client->recv_len -= hdr->size;
    }
    
    return processed;
}

void etcpmon_client_set_callbacks(struct etcpmon_client* client,
                                   void (*on_connected)(void*),
                                   void (*on_disconnected)(void*),
                                   void (*on_conn_list)(struct etcpmon_conn_info*, uint8_t, void*),
                                   void (*on_metrics)(struct etcpmon_rsp_metrics*, 
                                                     struct etcpmon_link_metrics*, 
                                                     uint8_t, void*),
                                   void (*on_error)(const char*, void*),
                                   void* user_data) {
    if (!client) return;
    
    client->on_connected = on_connected;
    client->on_disconnected = on_disconnected;
    client->on_conn_list = on_conn_list;
    client->on_metrics = on_metrics;
    client->on_error = on_error;
    client->user_data = user_data;
}

const char* etcpmon_client_get_conn_name(struct etcpmon_client* client, uint64_t peer_id) {
    if (!client || !client->conn_list) return NULL;
    
    for (uint8_t i = 0; i < client->conn_count; i++) {
        if (client->conn_list[i].peer_node_id == peer_id) {
            return client->conn_list[i].name;
        }
    }
    return NULL;
}

struct metrics_history* etcpmon_client_get_history(struct etcpmon_client* client) {
    if (!client) return NULL;
    return &client->history;
}

void etcpmon_client_add_to_history(struct etcpmon_client* client, struct etcpmon_rsp_metrics* metrics) {
    if (!client || !metrics) return;
    
    struct metrics_history* h = &client->history;
    int idx = h->head;
//    for (int m = 0; m < GRAPH_METRICS_COUNT; m++) {
//        float v = h->values[m][idx];
//        if (v < h->min_val[m]) h->min_val[m] = v;
//        if (v > h->max_val[m]) h->max_val[m] = v;
//    }
    
    if (client->log_file) {
        fprintf(client->log_file, "add_to_history: rtt_last=%u rtt_avg10=%u rtt_avg100=%u jitter=%u\n",
            metrics->etcp.rtt_last, metrics->etcp.rtt_avg_10, metrics->etcp.rtt_avg_100, metrics->etcp.jitter);
        fflush(client->log_file);
    }
    
    float scale = 0.1f;  // to ms (protocol: 0.1ms units)
    h->values[GRAPH_METRIC_RTT_LAST][idx] = (float)metrics->etcp.rtt_last * scale;
    h->values[GRAPH_METRIC_RTT_AVG10][idx] = (float)metrics->etcp.rtt_avg_10 * scale;
    h->values[GRAPH_METRIC_RTT_AVG100][idx] = (float)metrics->etcp.rtt_avg_100 * scale;
    h->values[GRAPH_METRIC_JITTER][idx] = (float)metrics->etcp.jitter * scale;

    uint32_t retrans_delta = 0;
    uint32_t acks_delta = 0;
    uint64_t bytes_delta = 0;
    
    if (h->count > 0) {
        if (metrics->etcp.retrans_count >= h->last_retrans) {
            retrans_delta = metrics->etcp.retrans_count - h->last_retrans;
        }
        if (metrics->etcp.ack_count >= h->last_acks) {
            acks_delta = metrics->etcp.ack_count - h->last_acks;
        }
        if (metrics->etcp.bytes_sent_total >= h->last_bytes_sent) {
            bytes_delta = metrics->etcp.bytes_sent_total - h->last_bytes_sent;
        }
    }
    
    h->last_retrans = metrics->etcp.retrans_count;
    h->last_acks = metrics->etcp.ack_count;
    h->last_bytes_sent = metrics->etcp.bytes_sent_total;
    
    h->values[GRAPH_METRIC_RETRANS][idx] = (float)retrans_delta;
    h->values[GRAPH_METRIC_ACKS][idx] = (float)acks_delta;
    h->values[GRAPH_METRIC_INFLIGHT][idx] = (float)metrics->etcp.unacked_bytes;
    h->values[GRAPH_METRIC_BYTES_SENT][idx] = (float)bytes_delta;
    
    h->head = (h->head + 1) % GRAPH_HISTORY_SIZE;
    if (h->count < GRAPH_HISTORY_SIZE) {
        h->count++;
    }
    
    if (client->log_file) {
        fprintf(client->log_file, "history updated: count=%d head=%d\n", h->count, h->head);
        fflush(client->log_file);
    }
}