// SPDX-License-Identifier: GPL-2.0+

#define pr_fmt(fmt) "avm_kpi_test: " fmt

#include "avm_kpi.h"
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/random.h>

#define MAX_TEST_ATTR 32u
#define MAX_TEST_SAMPLER 16u

static struct kpi_node *test_node;
static struct kpi_attribute_absolute *attributes[MAX_TEST_ATTR];
static struct kpi_sampler *samplers[MAX_TEST_SAMPLER];

static u32 positive_sequence(__maybe_unused void *ctx)
{
	static u32 i;

	return i++;
}

static s32 negative_sequence(__maybe_unused void *ctx)
{
	static s32 i;

	return 0 - i++;
}

static s32 random_32(__maybe_unused void *ctx)
{
	s32 num;

	get_random_bytes(&num, sizeof(num));
	return num;
}

static s64 random_64(__maybe_unused void *ctx)
{
	s64 num;

	get_random_bytes(&num, sizeof(num));
	return num;
}

static void str_collect(__maybe_unused void *ctx, char *buf,
			__maybe_unused size_t buffer_len)
{
	strcpy(buf, "Hello, World!");
}

static int __init avm_kpi_test_init(void)
{
	const enum kpi_reducer reducers[] = {
		KPI_REDUCER_NONE,     KPI_REDUCER_MIN,      KPI_REDUCER_MAX,
		KPI_REDUCER_SUM,      KPI_REDUCER_AVG,      KPI_REDUCER_MEDIAN,
		KPI_REDUCER_VARIANCE, _KPI_REDUCER_BOTTOM_,
	};
	const struct kpi_sliding_window window = {
		.size_seconds = 60,
		.num_samples = 12,
	};
	struct kpi_node *system_node;
	unsigned int a, s;

	system_node = kpi_get_section("system");
	if (!system_node)
		return -EPERM;

	test_node = create_kpi_node("test", NULL);
	if (!test_node)
		return -EPERM;

	attributes[a++] = kpi_add_attr_u32("sessions", test_node,
					   positive_sequence, NULL);

	attributes[a++] = kpi_add_attr_string("version", test_node, str_collect,
					      NULL, 100u);

	attributes[a++] = kpi_add_attr_string("test", system_node, str_collect,
					      NULL, 100u);

	samplers[s++] =
		kpi_add_sampler_u32("psequence", test_node, positive_sequence,
				    NULL, window, reducers);

	samplers[s++] =
		kpi_add_sampler_s32("nsequence", test_node, negative_sequence,
				    NULL, window, reducers);

	samplers[s++] = kpi_add_sampler_s32("rand32", test_node, random_32,
					    NULL, window, reducers);

	samplers[s++] = kpi_add_sampler_s64("rand64", test_node, random_64,
					    NULL, window, reducers);

	WARN_ON(a > MAX_TEST_ATTR);
	WARN_ON(s > MAX_TEST_SAMPLER);

	return 0;
}
module_init(avm_kpi_test_init);

static void __exit avm_kpi_test_exit(void)
{
	unsigned int i;

	for (i = 0; attributes[i]; ++i)
		kpi_delete_attribute(attributes[i]);

	for (i = 0; samplers[i]; ++i)
		kpi_delete_sampler(samplers[i]);

	destroy_kpi_node(test_node);
}
module_exit(avm_kpi_test_exit);