#include "session_console.h"

#include <errno.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "esp_console.h"
#include "esp_err.h"
#include "session_broker.h"

#define CONSOLE_HEX_MAX_BYTES 48
#define CONSOLE_READ_MAX_BYTES 512

static void print_usage(void)
{
    printf("Usage:\n");
    printf("  broker status|clients|counters|clear-counters\n");
    printf("  broker connect <name>\n");
    printf("  broker disconnect <client-id>\n");
    printf("  broker request-writer <client-id>\n");
    printf("  broker release-writer <client-id>\n");
    printf("  broker force-writer <client-id|none>\n");
    printf("  broker send-hex <client-id> <hex-bytes>\n");
    printf("  broker read <client-id> [maximum-bytes]\n");
    printf("  broker events <client-id>\n");
}

static bool parse_u32(const char *text, uint32_t minimum, uint32_t maximum, uint32_t *value)
{
    if (text == NULL || *text == '\0') {
        return false;
    }
    for (const char *character = text; *character != '\0'; ++character) {
        if (*character < '0' || *character > '9') {
            return false;
        }
    }

    char *end = NULL;
    errno = 0;
    unsigned long parsed = strtoul(text, &end, 10);
    if (errno != 0 || end == text || *end != '\0' ||
        parsed < minimum || parsed > maximum) {
        return false;
    }
    *value = (uint32_t)parsed;
    return true;
}

static bool parse_client_id(const char *text, session_broker_client_id_t *client_id)
{
    uint32_t value;
    if (!parse_u32(text, 1, UINT32_MAX, &value)) {
        return false;
    }
    *client_id = value;
    return true;
}

static const char *client_type_name(session_broker_client_type_t type)
{
    switch (type) {
    case SESSION_BROKER_CLIENT_CONSOLE:
        return "console";
    case SESSION_BROKER_CLIENT_USB:
        return "usb";
    case SESSION_BROKER_CLIENT_WEB:
        return "web";
    case SESSION_BROKER_CLIENT_SSH:
        return "ssh";
    case SESSION_BROKER_CLIENT_INTERNAL:
        return "internal";
    default:
        return "unknown";
    }
}

static const char *event_type_name(session_broker_event_type_t type)
{
    switch (type) {
    case SESSION_BROKER_EVENT_CONNECT:
        return "connect";
    case SESSION_BROKER_EVENT_DISCONNECT:
        return "disconnect";
    case SESSION_BROKER_EVENT_WRITER_GRANTED:
        return "writer-granted";
    case SESSION_BROKER_EVENT_WRITER_RELEASED:
        return "writer-released";
    case SESSION_BROKER_EVENT_WRITER_REVOKED:
        return "writer-revoked";
    case SESSION_BROKER_EVENT_WRITER_DENIED:
        return "writer-denied";
    default:
        return "unknown";
    }
}

static int show_status(void)
{
    session_broker_global_snapshot_t snapshot;
    esp_err_t err = session_broker_get_global_snapshot(&snapshot);
    if (err != ESP_OK) {
        printf("Could not read broker status: %s\n", esp_err_to_name(err));
        return 1;
    }

    printf("Broker clients=%" PRIu32 " writer=%lu latest-event=%" PRIu64 "\n",
           snapshot.connected_clients,
           (unsigned long)snapshot.writer_id,
           snapshot.latest_event_sequence);
    printf("UART-RX=%" PRIu64 " unobserved=%" PRIu64
           " observer-queued=%" PRIu64 " observer-read=%" PRIu64
           " observer-dropped=%" PRIu64 "\n",
           snapshot.counters.uart_rx_bytes,
           snapshot.counters.unobserved_rx_bytes,
           snapshot.counters.output_queued_bytes,
           snapshot.counters.output_read_bytes,
           snapshot.counters.output_dropped_bytes);
    return 0;
}

static int show_clients(void)
{
    session_broker_client_snapshot_t clients[SESSION_BROKER_MAX_CLIENTS];
    size_t count = session_broker_list_clients(clients, SESSION_BROKER_MAX_CLIENTS);
    if (count == 0) {
        printf("No broker clients connected.\n");
        return 0;
    }

    printf("ID         type      writer pending events name\n");
    for (size_t index = 0; index < count; ++index) {
        const session_broker_client_snapshot_t *client = &clients[index];
        printf("%-10lu %-9s %-6s %-7u %-6" PRIu32 " %s\n",
               (unsigned long)client->id,
               client_type_name(client->type),
               client->is_writer ? "yes" : "no",
               (unsigned int)client->output_bytes_pending,
               client->events_pending,
               client->name);
    }
    return 0;
}

static int show_counters(void)
{
    session_broker_global_snapshot_t snapshot;
    esp_err_t err = session_broker_get_global_snapshot(&snapshot);
    if (err != ESP_OK) {
        printf("Could not read broker counters: %s\n", esp_err_to_name(err));
        return 1;
    }

    const session_broker_global_counters_t *counter = &snapshot.counters;
    printf("RX: UART=%" PRIu64 " unobserved=%" PRIu64
           " queued=%" PRIu64 " read=%" PRIu64 " dropped=%" PRIu64 "\n",
           counter->uart_rx_bytes,
           counter->unobserved_rx_bytes,
           counter->output_queued_bytes,
           counter->output_read_bytes,
           counter->output_dropped_bytes);
    printf("TX: accepted=%" PRIu64 " rejected=%" PRIu64 "\n",
           counter->tx_accepted_bytes,
           counter->tx_rejected_bytes);
    printf("Sessions: connect=%" PRIu64 " disconnect=%" PRIu64
           " writer-requests=%" PRIu64 " grants=%" PRIu64
           " releases=%" PRIu64 " revocations=%" PRIu64
           " denials=%" PRIu64 " changes=%" PRIu64 "\n",
           counter->connections,
           counter->disconnections,
           counter->writer_requests,
           counter->writer_grants,
           counter->writer_releases,
           counter->writer_revocations,
           counter->writer_denials,
           counter->writer_changes);
    printf("Events: generated=%" PRIu64 " queued=%" PRIu64
           " popped=%" PRIu64 " dropped=%" PRIu64 "\n",
           counter->events_generated,
           counter->events_queued,
           counter->events_popped,
           counter->event_drops);
    return 0;
}

static int connect_client(const char *name)
{
    session_broker_client_id_t client_id;
    esp_err_t err = session_broker_connect(
        SESSION_BROKER_CLIENT_CONSOLE,
        name,
        &client_id);
    if (err != ESP_OK) {
        printf("Could not connect broker client: %s\n", esp_err_to_name(err));
        return 1;
    }
    printf("Connected console client '%s' with ID %lu.\n", name, (unsigned long)client_id);
    return 0;
}

static int disconnect_client(const char *id_text)
{
    session_broker_client_id_t client_id;
    if (!parse_client_id(id_text, &client_id)) {
        printf("Invalid client ID.\n");
        return 1;
    }
    esp_err_t err = session_broker_disconnect(client_id);
    if (err != ESP_OK) {
        printf("Could not disconnect client %lu: %s\n", (unsigned long)client_id, esp_err_to_name(err));
        return 1;
    }
    printf("Disconnected client %lu.\n", (unsigned long)client_id);
    return 0;
}

static int change_writer(const char *operation, const char *id_text)
{
    session_broker_client_id_t client_id;
    if (!parse_client_id(id_text, &client_id)) {
        printf("Invalid client ID.\n");
        return 1;
    }

    esp_err_t err;
    if (strcmp(operation, "request-writer") == 0) {
        err = session_broker_request_writer(client_id);
    } else {
        err = session_broker_release_writer(client_id);
    }
    if (err != ESP_OK) {
        printf("Writer operation failed for client %lu: %s\n",
               (unsigned long)client_id, esp_err_to_name(err));
        return 1;
    }
    printf("Writer is now %lu.\n", (unsigned long)session_broker_get_writer_id());
    return 0;
}

static int force_writer(const char *id_text)
{
    session_broker_client_id_t client_id = SESSION_BROKER_NO_CLIENT;
    if (strcmp(id_text, "none") != 0 && !parse_client_id(id_text, &client_id)) {
        printf("Writer must be a connected client ID or 'none'.\n");
        return 1;
    }

    esp_err_t err = session_broker_force_writer(client_id);
    if (err != ESP_OK) {
        printf("Could not force writer: %s\n", esp_err_to_name(err));
        return 1;
    }
    printf("Writer is now %lu.\n", (unsigned long)session_broker_get_writer_id());
    return 0;
}

static int hexadecimal_value(char character)
{
    if (character >= '0' && character <= '9') {
        return character - '0';
    }
    if (character >= 'a' && character <= 'f') {
        return character - 'a' + 10;
    }
    if (character >= 'A' && character <= 'F') {
        return character - 'A' + 10;
    }
    return -1;
}

static int send_hexadecimal(const char *id_text, const char *text)
{
    session_broker_client_id_t client_id;
    if (!parse_client_id(id_text, &client_id)) {
        printf("Invalid client ID.\n");
        return 1;
    }

    uint8_t data[CONSOLE_HEX_MAX_BYTES];
    size_t text_length = strlen(text);
    if (text_length == 0 || (text_length % 2) != 0 || text_length > sizeof(data) * 2) {
        printf("Provide 1..%d bytes as hexadecimal digits without separators.\n", CONSOLE_HEX_MAX_BYTES);
        return 1;
    }

    size_t data_length = text_length / 2;
    for (size_t index = 0; index < data_length; ++index) {
        int high = hexadecimal_value(text[index * 2]);
        int low = hexadecimal_value(text[index * 2 + 1]);
        if (high < 0 || low < 0) {
            size_t invalid_index = index * 2 + (high < 0 ? 0 : 1);
            printf("Invalid hexadecimal digit at character %u.\n", (unsigned int)invalid_index);
            return 1;
        }
        data[index] = (uint8_t)((high << 4) | low);
    }

    size_t accepted = 0;
    esp_err_t err = session_broker_write(client_id, data, data_length, &accepted);
    if (err != ESP_OK) {
        printf("Client %lu could not write: %s\n", (unsigned long)client_id, esp_err_to_name(err));
        return 1;
    }
    printf("Broker accepted %u of %u bytes from client %lu.\n",
           (unsigned int)accepted,
           (unsigned int)data_length,
           (unsigned long)client_id);
    return accepted == data_length ? 0 : 1;
}

static int read_hexadecimal(int argc, char **argv)
{
    session_broker_client_id_t client_id;
    if (!parse_client_id(argv[2], &client_id)) {
        printf("Invalid client ID.\n");
        return 1;
    }

    uint32_t maximum = CONSOLE_READ_MAX_BYTES;
    if (argc == 4 && !parse_u32(argv[3], 1, CONSOLE_READ_MAX_BYTES, &maximum)) {
        printf("Read size must be 1..%d bytes.\n", CONSOLE_READ_MAX_BYTES);
        return 1;
    }

    uint8_t data[CONSOLE_READ_MAX_BYTES];
    size_t received = 0;
    esp_err_t err = session_broker_read(client_id, data, maximum, &received);
    if (err != ESP_OK) {
        printf("Could not read client %lu: %s\n", (unsigned long)client_id, esp_err_to_name(err));
        return 1;
    }

    printf("Client %lu read %u byte%s",
           (unsigned long)client_id,
           (unsigned int)received,
           received == 1 ? "" : "s");
    if (received > 0) {
        printf(": ");
        for (size_t index = 0; index < received; ++index) {
            printf("%02x", data[index]);
        }
    }
    printf("\n");
    return 0;
}

static int show_events(const char *id_text)
{
    session_broker_client_id_t client_id;
    if (!parse_client_id(id_text, &client_id)) {
        printf("Invalid client ID.\n");
        return 1;
    }

    session_broker_client_snapshot_t snapshot;
    esp_err_t err = session_broker_get_client_snapshot(client_id, &snapshot);
    if (err != ESP_OK) {
        printf("Unknown client %lu: %s\n", (unsigned long)client_id, esp_err_to_name(err));
        return 1;
    }

    unsigned int count = 0;
    session_broker_event_t event;
    while (true) {
        err = session_broker_pop_event(client_id, &event);
        if (err == ESP_ERR_TIMEOUT) {
            break;
        }
        if (err != ESP_OK) {
            printf("Could not pop events for client %lu: %s\n",
                   (unsigned long)client_id, esp_err_to_name(err));
            return 1;
        }
        printf("#%" PRIu64 " %-16s subject=%lu writer=%lu\n",
               event.sequence,
               event_type_name(event.type),
               (unsigned long)event.client_id,
               (unsigned long)event.writer_id);
        ++count;
    }
    if (count == 0) {
        printf("No pending events for client %lu.\n", (unsigned long)client_id);
    }
    return 0;
}

static int command_broker(int argc, char **argv)
{
    if (argc == 1 || (argc == 2 && strcmp(argv[1], "status") == 0)) {
        return show_status();
    }
    if (argc == 2 && strcmp(argv[1], "clients") == 0) {
        return show_clients();
    }
    if (argc == 2 && strcmp(argv[1], "counters") == 0) {
        return show_counters();
    }
    if (argc == 2 && strcmp(argv[1], "clear-counters") == 0) {
        esp_err_t err = session_broker_clear_counters();
        if (err != ESP_OK) {
            printf("Could not clear broker counters: %s\n", esp_err_to_name(err));
            return 1;
        }
        printf("Broker counters cleared.\n");
        return 0;
    }
    if (argc == 3 && strcmp(argv[1], "connect") == 0) {
        return connect_client(argv[2]);
    }
    if (argc == 3 && strcmp(argv[1], "disconnect") == 0) {
        return disconnect_client(argv[2]);
    }
    if (argc == 3 &&
        (strcmp(argv[1], "request-writer") == 0 ||
         strcmp(argv[1], "release-writer") == 0)) {
        return change_writer(argv[1], argv[2]);
    }
    if (argc == 3 && strcmp(argv[1], "force-writer") == 0) {
        return force_writer(argv[2]);
    }
    if (argc == 4 && strcmp(argv[1], "send-hex") == 0) {
        return send_hexadecimal(argv[2], argv[3]);
    }
    if ((argc == 3 || argc == 4) && strcmp(argv[1], "read") == 0) {
        return read_hexadecimal(argc, argv);
    }
    if (argc == 3 && strcmp(argv[1], "events") == 0) {
        return show_events(argv[2]);
    }

    print_usage();
    return 1;
}

esp_err_t session_console_register_commands(void)
{
    const esp_console_cmd_t command = {
        .command = "broker",
        .help = "Manage Phase 2 broker clients, writer ownership, events, and binary data",
        .hint = NULL,
        .func = &command_broker,
        .argtable = NULL,
    };
    return esp_console_cmd_register(&command);
}