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

#define NAME        "multimax"
#define N_ARGS      2

#define ARG_MAX     0
#define ARG_VALUE   1

#define DATA(ptr)   ((Data *) ptr)

extern "C" {

#include "value.cc"

typedef struct {
	Value max;
	Value value;
}
Data;

void free_data(UDF_INIT *initid) {
	Data* data = (Data *) initid->ptr;
	value_set_null(&data->max);
	value_set_null(&data->value);
}

long long multimax(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error) {
	Value * value = &DATA(initid->ptr)->value;
	if (value->is_null) {
		*is_null = 1;
		return 0;
	}
	return value->val.i;
}

void multimax_add(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error) {
	Data *data = (Data *) initid->ptr;
	Value max;
	value_from_arg(&max, args, ARG_MAX);

	if (value_compare(&max, &data->max) >= 0) {
		value_copy_arg(&data->max, args, ARG_MAX);
		value_copy_arg(&data->value, args, ARG_VALUE);
	}
}

void multimax_clear(UDF_INIT *initid, char *is_null, char *error) {
	free_data(initid);
}

bool multimax_init(UDF_INIT *initid, UDF_ARGS *args, char *message) {
	if (args->arg_count == N_ARGS) {
		Data *data = DATA(malloc(sizeof(Data)));
		value_init(&data->max);
		value_init(&data->value);

		args->arg_type[ARG_VALUE] = INT_RESULT;
		initid->ptr = (char *) data;
		initid->maybe_null = 1;
		initid->const_item = 0;
		return 0;
	} else {
		sprintf(message, "%s must have %d parameters", NAME, N_ARGS);
		return 1;
	}
}

void multimax_deinit(UDF_INIT *initid) {
	free_data(initid);
	free(initid->ptr);
}

}