#include <stdint.h>
#include <string.h>

/**
 * @brief Write a 8 bit unsigned int to the buffer
 *
 * @param buf The buffer to write to
 * @param value The 8 bit unsigned int to write
 * @param index The index read/write pointer
 */
void buf_append_u8(uint8_t *buf, uint8_t value, size_t *index) {
    buf[(*index)++] = value;
}

/**
 * @brief Write a 16 bit signed int to the buffer
 *
 * @param buf The buffer to write to
 * @param value The 16 bit signed int to write
 * @param index The index read/write pointer
 */
void buf_append_i16(uint8_t *buf, int16_t value, size_t *index) {
    buf[(*index)++] = (value >> 8) & 0xFF;
    buf[(*index)++] = value & 0xFF;
}

/**
 * @brief Write a 32 bit signed int to the buffer
 *
 * @param buf The buffer to write to
 * @param value The 32 bit signed int to write
 * @param index The index read/write pointer
 */
void buf_append_i32(uint8_t *buf, int32_t value, size_t *index) {
    buf[(*index)++] = (value >> 24) & 0xFF;
    buf[(*index)++] = (value >> 16) & 0xFF;
    buf[(*index)++] = (value >> 8) & 0xFF;
    buf[(*index)++] = value & 0xFF;
}

/**
 * @brief Write a 32 bit float to the buffer
 *
 * @param buf The buffer to write to
 * @param value The 32 bit float to write
 * @param index The index read/write pointer
 */
void buf_append_f32(uint8_t *buf, float value, size_t *index) {
    uint32_t u;
    memcpy(&u, &value, sizeof(float)); // Safe conversion
    buf_append_i32(buf, (int32_t)u, index);
}

/**
 * @brief Read a 8 bit unsigned int from the buffer
 *
 * @param buf The buffer to read from
 * @param index The index read/write pointer
 * @return 8 bit unsigned int
 */
uint8_t buf_read_u8(const uint8_t *buf, size_t *index) {
    return buf[(*index)++];
}

/**
 * @brief Read a 16 bit int from the buffer
 *
 * @param buf The buffer to read from
 * @param index The index read/write pointer
 * @return 16 bit signed int
 */
uint8_t buf_read_i16(const uint8_t *buf, size_t *index) {
    int16_t val = 0;
    val |= ((int16_t)buf[(*index)++]) << 8;
    val |= ((int16_t)buf[(*index)++]);
    return val;
}

/**
 * @brief Read a 32 bit int from the buffer
 *
 * @param buf The buffer to read from
 * @param index The index read/write pointer
 * @return 32 bit signed int
 */
int32_t buf_read_i32(const uint8_t *buf, size_t *index) {
    int32_t val = 0;
    val |= ((int32_t)buf[(*index)++]) << 24;
    val |= ((int32_t)buf[(*index)++]) << 16;
    val |= ((int32_t)buf[(*index)++]) << 8;
    val |= ((int32_t)buf[(*index)++]);
    return val;
}

/**
 * @brief Read a 32 bit float from the buffer
 *
 * @param buf The buffer to read from
 * @param index The index read/write pointer
 * @return 32 bit float
 */
float buf_read_f32(const uint8_t *buf, size_t *index) {
    uint32_t u = (uint32_t)buf_read_i32(buf, index);
    float    f;
    memcpy(&f, &u, sizeof(float));
    return f;
}