/* CH224A 运行期轮询。契约见 pdmon.h。 */
#include "pdmon.h"

#include <stddef.h>

#include "ch224a.h"
#include "evlog.h"
#include "i2cbus.h"
#include "slot.h"
#include "tca9548a.h"

typedef struct {
    uint8_t  status;
    uint32_t ma;
} pd_read_t;

static pdmon_snap_t s_snap;
static int          s_ch = I2CBUS_CH_TRUNK; /* 上次应答的支路 */
static uint32_t     s_logged_ma;            /* 最近一次进了日志的档位 */
static uint32_t     s_prev_ma;              /* 上一拍读到的（去抖用） */

static hal_err_t read_fn(void *arg)
{
    pd_read_t      *r = (pd_read_t *)arg;
    const hal_err_t err = ch224a_read_status(CH224A_ADDR_DEFAULT, &r->status);
    return (err == HAL_OK) ? ch224a_read_max_ma(CH224A_ADDR_DEFAULT, &r->ma) : err;
}

void pdmon_init(uint32_t boot_ma)
{
    s_snap = (pdmon_snap_t){ 0 };
    s_ch = I2CBUS_CH_TRUNK;
    s_logged_ma = boot_ma;
    s_prev_ma = boot_ma;
}

void pdmon_poll(void)
{
    pd_read_t r = { 0 };
    hal_err_t err = i2cbus_xact(s_ch, SLOT_LOCK_TIMEOUT_MS, read_fn, &r);
    if (err != HAL_OK) {
        const int other = (s_ch == I2CBUS_CH_TRUNK) ? TCA9548A_CH_PD : I2CBUS_CH_TRUNK;
        err = i2cbus_xact(other, SLOT_LOCK_TIMEOUT_MS, read_fn, &r);
        if (err == HAL_OK) {
            s_ch = other;
        }
    }
    s_snap.polls++;
    if (err != HAL_OK) {
        s_snap.ok = false; /* 值留着：旧的档位比一个 0 可信（ch224a.h 同一条） */
        s_snap.errors++;
        return;
    }
    s_snap.status = r.status;
    s_snap.ma = r.ma;
    s_snap.ok = true;

    /* 换档：连续两拍读到同一个非零值、且和日志里最后那条不一样。0 = 协商中途 / 没协商上，不记。 */
    if (r.ma != 0 && r.ma == s_prev_ma && r.ma != s_logged_ma) {
        s_logged_ma = r.ma;
        evlog_put(0, LOG_EV_PD_LIMIT, PDMON_EV_ARG_CHANGED,
                  (int32_t)(ch224a_power_limit_mw(r.ma) / 100u), (int32_t)r.ma);
    }
    s_prev_ma = r.ma;
}

void pdmon_get(pdmon_snap_t *out)
{
    if (out != NULL) {
        *out = s_snap;
    }
}