#include <criterion/criterion.h>
#include <string.h>
#include "internal/icmp_packet_internal.h"
#include "internal/icmp_packet.h"

Test(packet_parse_icmp, echo_reply)
{
	uint8_t buffer[20 + 8 + 4] = {0}; // 20 bytes IP header, 8 ICMP, 4 payload
	size_t ip_hdr_len = 20;

	// fake ICMP header: type=0 (echo reply), code=0
	struct icmp_header *icmp = (struct icmp_header *)(buffer + ip_hdr_len);
	icmp->type = 0;
	icmp->code = 0;

	// payload: "PONG"
	memcpy(buffer + ip_hdr_len + 8, "PONG", 4);

	uint8_t type = 255, code = 255;
	const void *payload = NULL;
	size_t payload_len = 0;

	int ret = icmp_parse_icmp_payload(buffer, sizeof(buffer),
		ip_hdr_len, &type, &code, &payload, &payload_len);

	cr_assert_eq(ret, 0, "Should succeed for valid ICMP echo reply");
	cr_assert_eq(type, 0, "Type should be 0 (echo reply)");
	cr_assert_eq(code, 0, "Code should be 0");
	cr_assert_eq(payload_len, 4, "Payload length should be 4");
	cr_assert(memcmp(payload, "PONG", 4) == 0, "Payload should be 'PONG'");
}

Test(packet_parse_icmp, no_payload)
{
	// Only IP header + ICMP header (20+8=28)
	uint8_t buffer[28] = {0};
	size_t ip_hdr_len = 20;
	struct icmp_header *icmp = (struct icmp_header *)(buffer + ip_hdr_len);
	icmp->type = 8; // Echo request
	icmp->code = 1;

	uint8_t type = 0, code = 0;
	const void *payload = NULL;
	size_t payload_len = 123;

	int ret = icmp_parse_icmp_payload(buffer, sizeof(buffer),
			ip_hdr_len, &type, &code, &payload, &payload_len);

	cr_assert_eq(ret, 0, "Should succeed for ICMP with no payload");
	cr_assert_eq(payload_len, 0, "Payload length should be 0");
}

Test(packet_parse_icmp, extract_type_code)
{
	// Build with type=11 (time exceeded), code=0
	uint8_t buffer[20 + 8] = {0};
	size_t ip_hdr_len = 20;
	struct icmp_header *icmp = (struct icmp_header *)(buffer + ip_hdr_len);
	icmp->type = 11;
	icmp->code = 0;

	uint8_t type = 0, code = 100;
	const void *payload = NULL;
	size_t payload_len = 0;

	int ret = icmp_parse_icmp_payload(buffer, sizeof(buffer),
			ip_hdr_len, &type, &code, &payload, &payload_len);

	cr_assert_eq(ret, 0, "Should succeed for ICMP Time Exceeded");
	cr_assert_eq(type, 11, "Type should be 11");
	cr_assert_eq(code, 0, "Code should be 0");
}

Test(packet_parse_icmp, buffer_too_small)
{
	// Only enough for IP header + 4 bytes of ICMP header (need 8)
	uint8_t buffer[20 + 4] = {0};
	size_t ip_hdr_len = 20;

	uint8_t type = 0, code = 0;
	const void *payload = NULL;
	size_t payload_len = 0;

	int ret = icmp_parse_icmp_payload(buffer, sizeof(buffer),
			ip_hdr_len, &type, &code, &payload, &payload_len);

	cr_assert_eq(ret, -1,
				"Should fail when buffer is too small for ICMP header");
}