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

#ifdef __APPLE__
#include <PCSC/winscard.h>
#include <PCSC/wintypes.h>
#else
#include <winscard.h>
#endif

#ifndef FALSE
#define FALSE   0
#endif

#ifndef TRUE
#define TRUE    1
#endif

#ifndef SCARD_CTL_CODE
#define SCARD_CTL_CODE(code) (0x42000000 + (code))
#endif

#define IOCTL_SMARTCARD_TOGGLE_CARD_STATE   SCARD_CTL_CODE(2075)

LONG GetReaderNames(SCARDCONTEXT hContext, LPSTR **pReaderNames,
    LPDWORD pNumReaders);
void FreeReaderNames(LPSTR *readerNames, DWORD numReaders);

/**
 * The main function.
 * @param[in] argc the argument count
 * @param[in] argv the array of arguments
 */
int main(int argc, char *argv[])
{
    LONG err = SCARD_S_SUCCESS;
    SCARDCONTEXT hContext;
    BOOL established = FALSE;
    LPSTR *readerNames = NULL;
    DWORD numReaders = 0;
    int readerIndex = -1;
    SCARDHANDLE hCard;
    DWORD activeProtocol = 0;
    int i = 0;

    // Establish the context.
    printf("Establishing the context...\n");
    err = SCardEstablishContext(SCARD_SCOPE_USER, NULL, NULL, &hContext);
    if (err != SCARD_S_SUCCESS)
    {
        printf("Error: SCardEstablishContext failed with error 0x%08X\n", err);
        goto cleanup;
    }

    established = TRUE;

    // Get reader names.
    printf("Getting reader names...\n");
    err = GetReaderNames(hContext, &readerNames, &numReaders);
    if (err != SCARD_S_SUCCESS)
    {
        printf("Error: GetReaderNames failed with error 0x%08X\n", err);
        goto cleanup;
    }

    // Display reader names.
    for (i = 0; i < numReaders; i++)
    {
        printf("Reader %d: %s\n", i, readerNames[i]);
    }

    // Select reader.
    while ((readerIndex < 0) || (readerIndex >= numReaders))
    {
        printf("Select reader: ");
        scanf("%d", &readerIndex);
    }

    // Connect to the reader.
    printf("Connecting to the reader (shared, T=0 or T=1)...\n");
    err = SCardConnect(hContext, readerNames[readerIndex],
        SCARD_SHARE_SHARED, SCARD_PROTOCOL_T0 | SCARD_PROTOCOL_T1, &hCard,
        &activeProtocol);
    if (err != SCARD_S_SUCCESS)
    {
        printf("Error: SCardConnect failed with error 0x%08X\n", err);
        goto cleanup;
    }

    // Disconnect the reader.
    printf("Disconnecting the reader...\n");
    err = SCardDisconnect(hCard, SCARD_LEAVE_CARD);
    if (err != SCARD_S_SUCCESS)
    {
        printf("Error: SCardConnect failed with error 0x%08X\n", err);
        goto cleanup;
    }

    // Connect to the reader.
    printf("Connecting to the reader (direct, raw)...\n");
    err = SCardConnect(hContext, readerNames[readerIndex],
        SCARD_SHARE_DIRECT, SCARD_PROTOCOL_RAW, &hCard, &activeProtocol);
    if (err != SCARD_S_SUCCESS)
    {
        printf("Error: SCardConnect failed with error 0x%08X\n", err);
        goto cleanup;
    }

    // Disconnect the reader.
    printf("Disconnecting the reader...\n");
    err = SCardDisconnect(hCard, SCARD_LEAVE_CARD);
    if (err != SCARD_S_SUCCESS)
    {
        printf("Error: SCardConnect failed with error 0x%08X\n", err);
        goto cleanup;
    }

    for (i = 0; i < 10; i++)
    {
        // Connect to the reader.
        printf("Connecting to the reader (shared, T=0 or T=1)...\n");
        err = SCardConnect(hContext, readerNames[readerIndex],
            SCARD_SHARE_SHARED, SCARD_PROTOCOL_T0 | SCARD_PROTOCOL_T1, &hCard,
            &activeProtocol);
        if (err != SCARD_S_SUCCESS)
        {
            printf("Error: SCardConnect failed with error 0x%08X\n", err);
        }
        else
        {
            break;
        }
    }

    if (err != SCARD_S_SUCCESS)
    {
        goto cleanup;
    }

    // Disconnect the reader.
    printf("Disconnecting the reader...\n");
    err = SCardDisconnect(hCard, SCARD_LEAVE_CARD);
    if (err != SCARD_S_SUCCESS)
    {
        printf("Error: SCardConnect failed with error 0x%08X\n", err);
        goto cleanup;
    }

cleanup:
    // Free reader names.
    if (readerNames != NULL)
    {
        FreeReaderNames(readerNames, numReaders);
        readerNames = NULL;
    }

    if (established)
    {
        // Release the context.
        printf("Releasing the context...\n");
        err = SCardReleaseContext(hContext);
        if (err != SCARD_S_SUCCESS)
        {
            printf("Error: SCardReleaseContext failed with error 0x%08X\n",
                err);
        }

        established = FALSE;
    }

    return 0;
}

/**
 * Gets reader names.
 * @param[in]  hContext     the context
 * @param[out] pReaderNames the pointer to the array of reader names
 * @param[out] pNumReaders  the pointer to the number of readers
 * @return the error code
 */
LONG GetReaderNames(SCARDCONTEXT hContext, LPSTR **pReaderNames,
    LPDWORD pNumReaders)
{
    LONG err = SCARD_S_SUCCESS;
    LPSTR buffer = NULL;
    DWORD bufferLength = 0;
    LPSTR pReader = NULL;
    DWORD numReaders = 0;

    // Get the buffer length.
    SCardListReaders(hContext, NULL, NULL, &bufferLength);

    // Allocate the buffer.
    buffer = malloc(bufferLength);
    if (buffer == NULL)
    {
        err = SCARD_E_NO_MEMORY;
        goto cleanup;
    }

    // List readers.
    err = SCardListReaders(hContext, NULL, buffer, &bufferLength);
    if (err != SCARD_S_SUCCESS)
    {
        goto cleanup;
    }

    // Count the number of readers.
    pReader = buffer;
    while (*pReader != '\0')
    {
        pReader = pReader + strlen(pReader) + 1;
        numReaders++;
    }

    // Allocate the array.
    if ((numReaders > 0) && (pReaderNames != NULL))
    {
        int i = 0;

        *pReaderNames = (LPSTR *) calloc(numReaders, sizeof(LPSTR *));
        if (*pReaderNames == NULL)
        {
            err = SCARD_E_NO_MEMORY;
            goto cleanup;
        }

        pReader = buffer;
        while (*pReader != '\0')
        {
            (*pReaderNames)[i] = malloc(strlen(pReader) + 1);
            if ((*pReaderNames)[i] == NULL)
            {
                err = SCARD_E_NO_MEMORY;
                goto cleanup;
            }

            strcpy((*pReaderNames)[i], pReader);
            i++;

            pReader = pReader + strlen(pReader) + 1;
        }
    }

cleanup:
    if (err != SCARD_S_SUCCESS)
    {
        // Free reader names.
        if ((pReaderNames != NULL) && (*pReaderNames != NULL))
        {
            FreeReaderNames(*pReaderNames, numReaders);
            *pReaderNames = NULL;
        }
    }

    // Free the buffer.
    if (buffer != NULL)
    {
        free(buffer);
        buffer = NULL;
    }

    // Return the number of readers.
    if (pNumReaders != NULL)
    {
        *pNumReaders = numReaders;
    }

    return err;
}

/**
 * Frees reader names.
 * @param[in] readerNames the array of reader names
 * @param[in] numReaders  the number of readers
 */
void FreeReaderNames(LPSTR *readerNames, DWORD numReaders)
{
    if (readerNames != NULL)
    {
        int i = 0;

        for (i = 0; i < numReaders; i++)
        {
            if (readerNames[i] != NULL)
            {
                free(readerNames[i]);
                readerNames[i] = NULL;
            }
        }

        free(readerNames);
        readerNames = NULL;
    }
}