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

#include "psa/crypto.h"

/* This block is present to support Visual Studio builds prior to 2015 */
#if defined(_MSC_VER) && _MSC_VER < 1900
#include <stdarg.h>
int snprintf( char *s, size_t n, const char *fmt, ... )
{
    int ret;
    va_list argp;

    /* Avoid calling the invalid parameter handler by checking ourselves */
    if( s == NULL || n == 0 || fmt == NULL )
        return( -1 );

    va_start( argp, fmt );
#if defined(_TRUNCATE) && !defined(__MINGW32__)
    ret = _vsnprintf_s( s, n, _TRUNCATE, fmt, argp );
#else
    ret = _vsnprintf( s, n, fmt, argp );
    if( ret < 0 || (size_t) ret == n )
    {
        s[n-1] = '\0';
        ret = -1;
    }
#endif
    va_end( argp );

    return( ret );
}
#endif

/* There are different GET_HASH macros for different kinds of algorithms
 * built from hashes, but the values are all constructed on the
 * same model. */
#define PSA_ALG_GET_HASH(alg)                                   \
    (((alg) & PSA_ALG_HASH_MASK) | PSA_ALG_CATEGORY_HASH)

static void append(char **buffer, size_t buffer_size,
                   size_t *required_size,
                   const char *string, size_t length)
{
    *required_size += length;
    if (*required_size < buffer_size) {
        memcpy(*buffer, string, length);
        *buffer += length;
    }
}

static void append_integer(char **buffer, size_t buffer_size,
                           size_t *required_size,
                           const char *format /*printf format for value*/,
                           unsigned long value)
{
    size_t n = snprintf(*buffer, buffer_size - *required_size, format, value);
    if (n < buffer_size - *required_size) *buffer += n;
    *required_size += n;
}

/* The code of these function is automatically generated and included below. */
static const char *psa_ecc_curve_name(psa_ecc_curve_t curve);
static const char *psa_hash_algorithm_name(psa_algorithm_t hash_alg);

static void append_with_curve(char **buffer, size_t buffer_size,
                              size_t *required_size,
                              const char *string, size_t length,
                              psa_ecc_curve_t curve)
{
    const char *curve_name = psa_ecc_curve_name(curve);
    append(buffer, buffer_size, required_size, string, length);
    append(buffer, buffer_size, required_size, "(", 1);
    if (curve_name != NULL) {
        append(buffer, buffer_size, required_size,
               curve_name, strlen(curve_name));
    } else {
        append_integer(buffer, buffer_size, required_size,
                       "0x%04x", curve);
    }
    append(buffer, buffer_size, required_size, ")", 1);
}

static void append_with_hash(char **buffer, size_t buffer_size,
                             size_t *required_size,
                             const char *string, size_t length,
                             psa_algorithm_t hash_alg)
{
    const char *hash_name = psa_hash_algorithm_name(hash_alg);
    append(buffer, buffer_size, required_size, string, length);
    append(buffer, buffer_size, required_size, "(", 1);
    if (hash_name != NULL) {
        append(buffer, buffer_size, required_size,
               hash_name, strlen(hash_name));
    } else {
        append_integer(buffer, buffer_size, required_size,
                       "0x%08lx", hash_alg);
    }
    append(buffer, buffer_size, required_size, ")", 1);
}

#include "psa_constant_names_generated.c"

static int psa_snprint_status(char *buffer, size_t buffer_size,
                              psa_status_t status)
{
    const char *name = psa_strerror(status);
    if (name == NULL) {
        return snprintf(buffer, buffer_size, "%ld", (long) status);
    } else {
        size_t length = strlen(name);
        if (length < buffer_size) {
            memcpy(buffer, name, length + 1);
            return (int) length;
        } else {
            return (int) buffer_size;
        }
    }
}

static int psa_snprint_ecc_curve(char *buffer, size_t buffer_size,
                                 psa_ecc_curve_t curve)
{
    const char *name = psa_ecc_curve_name(curve);
    if (name == NULL) {
        return snprintf(buffer, buffer_size, "0x%04x", (unsigned) curve);
    } else {
        size_t length = strlen(name);
        if (length < buffer_size) {
            memcpy(buffer, name, length + 1);
            return (int) length;
        } else {
            return (int) buffer_size;
        }
    }
}

static void usage(const char *program_name)
{
    printf("Usage: %s TYPE VALUE [VALUE...]\n",
           program_name == NULL ? "psa_constant_names" : program_name);
    printf("Print the symbolic name whose numerical value is VALUE in TYPE.\n");
    printf("Supported types (with = between aliases):\n");
    printf("  alg=algorithm         Algorithm (psa_algorithm_t)\n");
    printf("  curve=ecc_curve       Elliptic curve identifier (psa_ecc_curve_t)\n");
    printf("  type=key_type         Key type (psa_key_type_t)\n");
    printf("  usage=key_usage       Key usage (psa_key_usage_t)\n");
    printf("  error=status          Status code (psa_status_t)\n");
}

typedef enum {
    TYPE_STATUS,
} signed_value_type;

int process_signed(signed_value_type type, long min, long max, char **argp)
{
    for (; *argp != NULL; argp++) {
        char buffer[200];
        char *end;
        long value = strtol(*argp, &end, 0);
        if (*end) {
            printf("Non-numeric value: %s\n", *argp);
            return EXIT_FAILURE;
        }
        if (value < min || (errno == ERANGE && value < 0)) {
            printf("Value too small: %s\n", *argp);
            return EXIT_FAILURE;
        }
        if (value > max || (errno == ERANGE && value > 0)) {
            printf("Value too large: %s\n", *argp);
            return EXIT_FAILURE;
        }

        switch (type) {
            case TYPE_STATUS:
                psa_snprint_status(buffer, sizeof(buffer),
                                   (psa_status_t) value);
                break;
        }
        puts(buffer);
    }

    return EXIT_SUCCESS;
}

typedef enum {
    TYPE_ALGORITHM,
    TYPE_ECC_CURVE,
    TYPE_KEY_TYPE,
    TYPE_KEY_USAGE,
} unsigned_value_type;

int process_unsigned(unsigned_value_type type, unsigned long max, char **argp)
{
    for (; *argp != NULL; argp++) {
        char buffer[200];
        char *end;
        unsigned long value = strtoul(*argp, &end, 0);
        if (*end) {
            printf("Non-numeric value: %s\n", *argp);
            return EXIT_FAILURE;
        }
        if (value > max || errno == ERANGE) {
            printf("Value out of range: %s\n", *argp);
            return EXIT_FAILURE;
        }

        switch (type) {
            case TYPE_ALGORITHM:
                psa_snprint_algorithm(buffer, sizeof(buffer),
                                      (psa_algorithm_t) value);
                break;
            case TYPE_ECC_CURVE:
                psa_snprint_ecc_curve(buffer, sizeof(buffer),
                                      (psa_ecc_curve_t) value);
                break;
            case TYPE_KEY_TYPE:
                psa_snprint_key_type(buffer, sizeof(buffer),
                                     (psa_key_type_t) value);
                break;
            case TYPE_KEY_USAGE:
                psa_snprint_key_usage(buffer, sizeof(buffer),
                                      (psa_key_usage_t) value);
                break;
        }
        puts(buffer);
    }

    return EXIT_SUCCESS;
}

int main(int argc, char *argv[])
{
    if (argc <= 1 ||
        !strcmp(argv[1], "help") ||
        !strcmp(argv[1], "--help"))
    {
        usage(argv[0]);
        return EXIT_FAILURE;
    }

    if (!strcmp(argv[1], "error") || !strcmp(argv[1], "status")) {
        /* There's no way to obtain the actual range of a signed type,
         * so hard-code it here: psa_status_t is int32_t. */
        return process_signed(TYPE_STATUS, INT32_MIN, INT32_MAX,
                              argv + 2);
    } else if (!strcmp(argv[1], "alg") || !strcmp(argv[1], "algorithm")) {
        return process_unsigned(TYPE_ALGORITHM, (psa_algorithm_t) (-1),
                                argv + 2);
    } else if (!strcmp(argv[1], "curve") || !strcmp(argv[1], "ecc_curve")) {
        return process_unsigned(TYPE_ECC_CURVE, (psa_ecc_curve_t) (-1),
                                argv + 2);
    } else if (!strcmp(argv[1], "type") || !strcmp(argv[1], "key_type")) {
        return process_unsigned(TYPE_KEY_TYPE, (psa_key_type_t) (-1),
                                argv + 2);
    } else if (!strcmp(argv[1], "usage") || !strcmp(argv[1], "key_usage")) {
        return process_unsigned(TYPE_KEY_USAGE, (psa_key_usage_t) (-1),
                                argv + 2);
    } else {
        printf("Unknown type: %s\n", argv[1]);
        return EXIT_FAILURE;
    }
}
