#include "parcer.h"
#include "server_structs.h"
#include <netinet/in.h>
#include <sys/types.h>
#include <arpa/inet.h>

int ensure(size_t recv_len, size_t offset, size_t need) {
	return (offset + need <= recv_len);
}

u_int8_t read_uint8(const u_int8_t *buf, size_t recv_len, size_t *offset, int *ok) {
	if (!ensure(recv_len, *offset, sizeof(uint8_t))) {
		*ok = 0;
		return 0;
	}
	u_int8_t v;
	memcpy(&v, buf + *offset, sizeof(v));
	*offset += sizeof(v);
	return v;
}

u_int16_t read_uint16(const u_int8_t *buf, size_t recv_len, size_t *offset, int *ok) {
	if (!ensure(recv_len, *offset, sizeof(uint16_t))) {
		*ok = 0;
		return 0;
	}
	u_int16_t v;
	memcpy(&v, buf + *offset, sizeof(v));
	*offset += sizeof(v);
	return (u_int16_t)ntohs(v);
}

u_int32_t read_uint32(const u_int8_t *buf, size_t recv_len, size_t *offset, int *ok) {
	if (!ensure(recv_len, *offset, sizeof(uint32_t))) {
		*ok = 0;
		return 0;
	}
	u_int32_t v;
	memcpy(&v, buf + *offset, sizeof(v));
	*offset += sizeof(v);
	return (u_int32_t)ntohl(v);
}

int32_t read_int32(const u_int8_t *buf, size_t recv_len, size_t *offset, int *ok) {
	if (!ensure(recv_len, *offset, sizeof(int32_t))) {
		*ok = 0;
		return 0;
	}
	int32_t v;
	memcpy(&v, buf + *offset, sizeof(v));
	*offset += sizeof(v);
	return (int32_t)ntohl((u_int32_t)v);
}

float read_float(const u_int8_t *buf, size_t recv_len, size_t *offset, int *ok) {
	if (!ensure(recv_len, *offset, sizeof(float))) {
		*ok = 0;
		return 0.0f;
	}
	u_int32_t v_int;
	memcpy(&v_int, buf + *offset, sizeof(v_int));
	*offset += sizeof(v_int);
	v_int = ntohl(v_int);
	float v_float;
	memcpy(&v_float, &v_int, sizeof(v_float));
	return v_float;
}

void read_bytes(const u_int8_t *buf, size_t recv_len, size_t *offset, u_int8_t *out, size_t len, int *ok) {
	if (!ensure(recv_len, *offset, len)) {
		*ok = 0;
		return;
	}
	memcpy(out, buf + *offset, len);
	*offset += len;
}

void read_utf32le_string(const uint8_t *buffer, size_t buf_size, size_t *offset, char *dest, size_t max_len, int *ok) {
	size_t i = *offset;
	size_t j = 0;

	while (i + 3 < buf_size && j < max_len) {
		uint32_t codeunit = buffer[i] | (buffer[i + 1] << 8) | (buffer[i + 2] << 16) | (buffer[i + 3] << 24);

		if (codeunit == 0) {
			i += 4; // termina a string
			break;
		}

		if (codeunit < 0x80) {
			dest[j++] = (char)codeunit;
		} else {
			dest[j++] = '?'; // substitui caracteres fora de ASCII
		}

		i += 4;
	}

	dest[j] = '\0';
	*offset = i;
	*ok = 1;
}

void read_utf16le_string(const uint8_t *buffer, size_t buf_size, size_t *offset, char *dest, size_t max_len, int *ok) {
	size_t i = *offset;
	size_t j = 0;

	while (i + 1 < buf_size && j < max_len - 1) {
		uint16_t codeunit = buffer[i] | (buffer[i + 1] << 8);

		if (codeunit == 0) {
			i += 2; // termina a string
			break;
		}

		if (codeunit < 0x80) {
			dest[j++] = (char)codeunit;
		} else {
			dest[j++] = '?'; // substitui caracteres fora de ASCII
		}

		i += 2;
	}

	dest[j] = '\0';
	*offset = i;
	*ok = 1;
}

void read_string(const u_int8_t *buf, size_t recv_len, size_t *offset, char *out, size_t len, int *ok) {
	if (!ensure(recv_len, *offset, len)) {
		*ok = 0;
		return;
	}

	for (size_t i = 0; i <= len; i++) {
		out[i] = (char)buf[*offset + i];
	}
	out[len] = '\0'; // Ensure null termination
	*offset += len;
	*ok = 1;
}