/**
 * @file
 * @brief command line tool that uses BACnet AtomicReadFile service messages
 * to read a file object contents from another device, and save it locally.
 * @author Steve Karg <skarg@users.sourceforge.net>
 * @date 2006
 * @copyright SPDX-License-Identifier: MIT
 */
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h> /* for time */
/* BACnet Stack defines - first */
#include "bacnet/bacdef.h"
/* BACnet Stack API */
#include "bacnet/bactext.h"
#include "bacnet/iam.h"
#include "bacnet/arf.h"
#include "bacnet/npdu.h"
#include "bacnet/apdu.h"
#include "bacport.h"
#include "bacnet/whois.h"
#include "bacnet/version.h"
/* some demo stuff needed */
#include "bacnet/basic/binding/address.h"
#include "bacnet/basic/object/device.h"
#include "bacnet/basic/sys/filename.h"
#include "bacnet/basic/services.h"
#include "bacnet/basic/tsm/tsm.h"
#include "bacnet/datalink/datalink.h"
#include "bacnet/datalink/dlenv.h"

#if BACNET_SVC_SERVER
#error "App requires server-only features disabled! Set BACNET_SVC_SERVER=0"
#endif

/* buffer used for receive */
static uint8_t Rx_Buf[MAX_MPDU] = { 0 };

/* global variables used in this file */
static uint32_t Target_File_Object_Instance = BACNET_MAX_INSTANCE;
static uint32_t Target_Device_Object_Instance = BACNET_MAX_INSTANCE;
static BACNET_ADDRESS Target_Address;
static char *Local_File_Name = NULL;
static int Target_File_Start_Position;
static unsigned int Target_File_Requested_Octet_Count;
static bool End_Of_File_Detected = false;
static bool Error_Detected = false;
static uint8_t Request_Invoke_ID = 0;

static void Atomic_Read_File_Error_Handler(
    BACNET_ADDRESS *src,
    uint8_t invoke_id,
    BACNET_ERROR_CLASS error_class,
    BACNET_ERROR_CODE error_code)
{
    if (address_match(&Target_Address, src) &&
        (invoke_id == Request_Invoke_ID)) {
        printf(
            "BACnet Error: %s: %s\n",
            bactext_error_class_name((int)error_class),
            bactext_error_code_name((int)error_code));
        Error_Detected = true;
    }
}

static void MyAbortHandler(
    BACNET_ADDRESS *src, uint8_t invoke_id, uint8_t abort_reason, bool server)
{
    (void)server;
    if (address_match(&Target_Address, src) &&
        (invoke_id == Request_Invoke_ID)) {
        printf(
            "BACnet Abort: %s\n", bactext_abort_reason_name((int)abort_reason));
        Error_Detected = true;
    }
}

static void
MyRejectHandler(BACNET_ADDRESS *src, uint8_t invoke_id, uint8_t reject_reason)
{
    if (address_match(&Target_Address, src) &&
        (invoke_id == Request_Invoke_ID)) {
        printf(
            "BACnet Reject: %s\n",
            bactext_reject_reason_name((int)reject_reason));
        Error_Detected = true;
    }
}

static void AtomicReadFileAckHandler(
    uint8_t *service_request,
    uint16_t service_len,
    BACNET_ADDRESS *src,
    BACNET_CONFIRMED_SERVICE_ACK_DATA *service_data)
{
    int len = 0;
    int result = 0;
    BACNET_ATOMIC_READ_FILE_DATA data;
    FILE *pFile = NULL; /* stream pointer */
    size_t octets_written = 0;
    size_t octet_count = 0;
    uint8_t *octet_buffer = NULL;

    if (address_match(&Target_Address, src) &&
        (service_data->invoke_id == Request_Invoke_ID)) {
        len =
            arf_ack_decode_service_request(service_request, service_len, &data);
        if ((len > 0) && (data.access == FILE_STREAM_ACCESS)) {
            if (data.type.stream.fileStartPosition == 0) {
                pFile = fopen(Local_File_Name, "wb");
            } else {
                pFile = fopen(Local_File_Name, "rb+");
            }
            if (pFile) {
                octet_count = octetstring_length(&data.fileData[0]);
                if (octet_count == 0) {
                    /* asked for many octets, and got zero. Force EOF */
                    if (!data.endOfFile) {
                        fprintf(stderr, "Missing EOF!\n");
                        data.endOfFile = true;
                    }
                } else {
                    result = fseek(
                        pFile, data.type.stream.fileStartPosition, SEEK_SET);
                    if (result == 0) {
                        /* unit to write in bytes -
                           in our case, an octet is one byte */
                        octet_buffer = octetstring_value(&data.fileData[0]);
                        octets_written =
                            fwrite(octet_buffer, 1, octet_count, pFile);
                        if (octets_written != octet_count) {
                            fprintf(
                                stderr,
                                "Unable to write data to file \"%s\".\n",
                                Local_File_Name);
                        } else {
                            Target_File_Start_Position =
                                data.type.stream.fileStartPosition +
                                octets_written;
                            printf(
                                "\r%d bytes", (int)Target_File_Start_Position);
                        }
                        fflush(pFile);
                    } else {
                        fprintf(
                            stderr, "Unable to seek to %d!\n",
                            data.type.stream.fileStartPosition);
                    }
                }
                fclose(pFile);
            }
            if (data.endOfFile) {
                End_Of_File_Detected = true;
                printf("\n");
            }
        } else {
            fprintf(stderr, "Decode error! %d bytes decoded.\n", len);
        }
    } else {
        fprintf(
            stderr, "Address & Invoke ID mismatch! Invoke ID=%d\n",
            Request_Invoke_ID);
    }
}

static void LocalIAmHandler(
    uint8_t *service_request, uint16_t service_len, BACNET_ADDRESS *src)
{
    int len = 0;
    uint32_t device_id = 0;
    unsigned max_apdu = 0;
    int segmentation = 0;
    uint16_t vendor_id = 0;

    (void)src;
    (void)service_len;
    len = iam_decode_service_request(
        service_request, &device_id, &max_apdu, &segmentation, &vendor_id);
    if (len != -1) {
        address_add(device_id, max_apdu, src);
    } else {
        fprintf(stderr, "!\n");
    }

    return;
}

static void Init_Service_Handlers(void)
{
    Device_Init(NULL);
    /* we need to handle who-is
       to support dynamic device binding to us */
    apdu_set_unconfirmed_handler(SERVICE_UNCONFIRMED_WHO_IS, handler_who_is);
    /* handle i-am to support binding to other devices */
    apdu_set_unconfirmed_handler(SERVICE_UNCONFIRMED_I_AM, LocalIAmHandler);
    /* set the handler for all the services we don't implement
       It is required to send the proper reject message... */
    apdu_set_unrecognized_service_handler_handler(handler_unrecognized_service);
    /* we must implement read property - it's required! */
    apdu_set_confirmed_handler(
        SERVICE_CONFIRMED_READ_PROPERTY, handler_read_property);
    /* handle the data coming back from confirmed requests */
    apdu_set_confirmed_ack_handler(
        SERVICE_CONFIRMED_ATOMIC_READ_FILE, AtomicReadFileAckHandler);
    /* handle any errors coming back */
    apdu_set_error_handler(
        SERVICE_CONFIRMED_ATOMIC_READ_FILE, Atomic_Read_File_Error_Handler);
    apdu_set_abort_handler(MyAbortHandler);
    apdu_set_reject_handler(MyRejectHandler);
}

static void print_usage(const char *filename)
{
    printf("Usage: %s device-instance file-instance local-name\n", filename);
    printf("       [--version][--help]\n");
}

static void print_help(const char *filename)
{
    printf("Read a file from a BACnet device and save it locally.\n");
    printf("\n");
    printf(
        "device-instance:\n"
        "BACnet Device Object Instance number that you are trying to\n"
        "communicate to.  This number will be used to try and bind with\n"
        "the device using Who-Is and I-Am services.  For example, if you were\n"
        "reading from Device Object 123, the device-instance would be 123.\n");
    printf("\n");
    printf(
        "file-instance:\n"
        "This is the file object instance number that you are reading from.\n"
        "For example, if you were reading from File 2, \n"
        "the file-instance would be 2.\n");
    printf("\n");
    printf("local-name:\n"
           "The name of the file that will be stored locally.\n");
    printf("\n");
    printf(
        "Example:\n"
        "If you want read File 2 from Device 123 and save it to temp.txt,\n"
        "use the following command:\n"
        "%s 123 2 temp.txt\n",
        filename);
}

int main(int argc, char *argv[])
{
    BACNET_ADDRESS src = { 0 }; /* address where message came from */
    uint16_t pdu_len = 0;
    unsigned timeout = 100; /* milliseconds */
    unsigned max_apdu = 0;
    time_t elapsed_seconds = 0;
    time_t last_seconds = 0;
    time_t current_seconds = 0;
    time_t timeout_seconds = 0;
    uint8_t invoke_id = 0;
    bool found = false;
    uint16_t my_max_apdu = 0;
    int argi = 0;
    const char *filename = NULL;

    /* print help if requested */
    filename = filename_remove_path(argv[0]);
    for (argi = 1; argi < argc; argi++) {
        if (strcmp(argv[argi], "--help") == 0) {
            print_usage(filename);
            print_help(filename);
            return 0;
        }
        if (strcmp(argv[argi], "--version") == 0) {
            printf("%s %s\n", filename, BACNET_VERSION_TEXT);
            printf("Copyright (C) 2014 by Steve Karg and others.\n"
                   "This is free software; see the source for copying "
                   "conditions.\n"
                   "There is NO warranty; not even for MERCHANTABILITY or\n"
                   "FITNESS FOR A PARTICULAR PURPOSE.\n");
            return 0;
        }
    }
    if (argc < 4) {
        print_usage(filename);
        return 0;
    }
    /* decode the command line parameters */
    Target_Device_Object_Instance = strtol(argv[1], NULL, 0);
    Target_File_Object_Instance = strtol(argv[2], NULL, 0);
    Local_File_Name = argv[3];
    if (Target_Device_Object_Instance > BACNET_MAX_INSTANCE) {
        fprintf(
            stderr, "device-instance=%u - not greater than %u\n",
            Target_Device_Object_Instance, BACNET_MAX_INSTANCE);
        return 1;
    }
    if (Target_File_Object_Instance > BACNET_MAX_INSTANCE) {
        fprintf(
            stderr, "file-instance=%u - not greater than %u\n",
            Target_File_Object_Instance, BACNET_MAX_INSTANCE);
        return 1;
    }
    /* setup my info */
    Device_Set_Object_Instance_Number(BACNET_MAX_INSTANCE);
    address_init();
    Init_Service_Handlers();
    dlenv_init();
    atexit(datalink_cleanup);
    /* configure the timeout values */
    last_seconds = time(NULL);
    timeout_seconds = (apdu_timeout() / 1000) * apdu_retries();
    /* try to bind with the device */
    found = address_bind_request(
        Target_Device_Object_Instance, &max_apdu, &Target_Address);
    if (!found) {
        Send_WhoIs(
            Target_Device_Object_Instance, Target_Device_Object_Instance);
    }
    /* loop forever */
    for (;;) {
        /* increment timer - exit if timed out */
        current_seconds = time(NULL);

        /* returns 0 bytes on timeout */
        pdu_len = datalink_receive(&src, &Rx_Buf[0], MAX_MPDU, timeout);

        /* process */
        if (pdu_len) {
            npdu_handler(&src, &Rx_Buf[0], pdu_len);
        }
        /* at least one second has passed */
        if (current_seconds != last_seconds) {
            tsm_timer_milliseconds(((current_seconds - last_seconds) * 1000));
            datalink_maintenance_timer(current_seconds - last_seconds);
        }
        /* wait until the device is bound, or timeout and quit */
        if (!found) {
            found = address_bind_request(
                Target_Device_Object_Instance, &max_apdu, &Target_Address);
        }
        if (found) {
            /* calculate the smaller of our APDU size or theirs
               and remove the overhead of the APDU (about 16 octets max).
               note: we could fail if there is a bottle neck (router)
               and smaller MPDU in betweeen. */
            if (max_apdu < MAX_APDU) {
                my_max_apdu = max_apdu;
            } else {
                my_max_apdu = MAX_APDU;
            }
            /* Typical sizes are 50, 128, 206, 480, 1024, and 1476 octets */
            if (my_max_apdu <= 50) {
                Target_File_Requested_Octet_Count = my_max_apdu - 20;
            } else if (my_max_apdu <= 480) {
                Target_File_Requested_Octet_Count = my_max_apdu - 32;
            } else if (my_max_apdu <= 1476) {
                Target_File_Requested_Octet_Count = my_max_apdu - 64;
            } else {
                Target_File_Requested_Octet_Count = my_max_apdu / 2;
            }
            /* has the previous invoke id expired or returned?
               note: invoke ID = 0 is invalid, so it will be idle */
            if ((invoke_id == 0) || tsm_invoke_id_free(invoke_id)) {
                if (End_Of_File_Detected || Error_Detected) {
                    break;
                }
                /* the ACK will increment the start position if OK */
                /* we'll read the file in chunks
                   less than max_apdu to keep unsegmented */
                invoke_id = Send_Atomic_Read_File_Stream(
                    Target_Device_Object_Instance, Target_File_Object_Instance,
                    Target_File_Start_Position,
                    Target_File_Requested_Octet_Count);
                Request_Invoke_ID = invoke_id;
            } else if (tsm_invoke_id_failed(invoke_id)) {
                fprintf(stderr, "\rError: TSM Timeout!\n");
                tsm_free_invoke_id(invoke_id);
                /* try again or abort? */
                Error_Detected = true;
                break;
            }
        } else {
            /* increment timer - exit if timed out */
            elapsed_seconds += (current_seconds - last_seconds);
            if (elapsed_seconds > timeout_seconds) {
                fprintf(stderr, "\rError: APDU Timeout!\n");
                Error_Detected = true;
                break;
            }
        }
        /* keep track of time for next check */
        last_seconds = current_seconds;
    }

    if (Error_Detected) {
        return 1;
    }

    return 0;
}
