/* I²C 占用核算的实现。**两个目标编的是同一份**（和 hal_err.c 一样放在组件根下），
   所以宿主机上算出来的占用率就是上板会打印的那个数。 */
#include "hal_i2c_acct.h"

static uint64_t s_bits;
static uint32_t s_txns;
static uint32_t s_freq_hz = HAL_I2C_FREQ_HZ_DEFAULT;

uint32_t hal_i2c_txn_bits(size_t wr_len, size_t rd_len)
{
    if (wr_len == 0 && rd_len == 0) {
        return 1u + 9u + 1u; /* 探测：START + 地址字节 + STOP */
    }

    uint32_t bits = 1u; /* START */
    if (wr_len > 0) {
        bits += 9u * (uint32_t)(1u + wr_len); /* 地址 + 载荷 */
    }
    if (rd_len > 0) {
        if (wr_len > 0) {
            bits += 1u; /* 重复 START */
        }
        bits += 9u * (uint32_t)(1u + rd_len);
    }
    bits += 1u; /* STOP */
    return bits;
}

void hal_i2c_acct_add(size_t wr_len, size_t rd_len)
{
    s_bits += hal_i2c_txn_bits(wr_len, rd_len);
    s_txns++;
}

uint64_t hal_i2c_acct_bits(void) { return s_bits; }
uint32_t hal_i2c_acct_txns(void) { return s_txns; }

void hal_i2c_acct_set_freq(uint32_t hz)
{
    s_freq_hz = (hz == 0) ? HAL_I2C_FREQ_HZ_DEFAULT : hz;
}

uint32_t hal_i2c_acct_freq(void) { return s_freq_hz; }

uint64_t hal_i2c_bits_to_us(uint64_t bits)
{
    /* 先乘后除，别先算「每位多少 µs」—— 400 kHz 下那是 2.5 µs，整数除法会抹平。 */
    return (bits * 1000000ull) / (uint64_t)s_freq_hz;
}

uint32_t hal_i2c_acct_window_us(uint64_t *cursor_bits)
{
    const uint64_t now = s_bits;
    const uint64_t was = (cursor_bits != NULL) ? *cursor_bits : 0;
    if (cursor_bits != NULL) {
        *cursor_bits = now;
    }
    return (uint32_t)hal_i2c_bits_to_us(now - was);
}

void hal_i2c_acct_reset(void)
{
    s_bits = 0;
    s_txns = 0;
    s_freq_hz = HAL_I2C_FREQ_HZ_DEFAULT;
}