#include "dever_ffi.h"
#include <stdio.h>
#include <string.h>

extern long long fixture_triple(long long value);

static int invoke(void *context, dever_ffi_slice operation, dever_ffi_slice payload, dever_ffi_output *output) {
    (void)context;
    if (operation.size == 6 && memcmp(operation.data, "reject", 6) == 0) {
        const char *error = "{\"error\":\"example.Rejected\",\"payload\":null}";
        memcpy(output->data, error, strlen(error));
        output->size = strlen(error);
        return DEVER_FFI_ERROR;
    }
    if (operation.size == 10 && memcmp(operation.data, "bad_length", 10) == 0) {
        output->size = output->capacity + 1;
        return DEVER_FFI_OK;
    }
    if (operation.size == 5 && memcmp(operation.data, "fault", 5) == 0) return DEVER_FFI_FAULT;
    if (payload.size >= 64) return DEVER_FFI_FAULT;
    char input[64];
    memcpy(input, payload.data, (size_t)payload.size);
    input[payload.size] = 0;
    long long value = 0;
    if (sscanf(input, "{\"value\":%lld}", &value) != 1 || value > 1000000 || value < -1000000) return DEVER_FFI_FAULT;
    int size = snprintf(output->data, (size_t)output->capacity, "{\"value\":%lld}", fixture_triple(value));
    if (size < 0 || (uint64_t)size >= output->capacity) return DEVER_FFI_FAULT;
    output->size = (uint64_t)size;
    return DEVER_FFI_OK;
}

static void closed(void *context) {
    (void)context;
    fputs("closed\n", stderr);
}

int main(void) {
    const dever_ffi_handler handler = {DEVER_FFI_ABI_V1, NULL, NULL, invoke, closed};
    return dever_ffi_serve(&handler);
}