/* 一片刀片的 I/O 门面。契约见 slot.h。 */
#include "slot.h"

#include <assert.h>
#include <stddef.h>

#include "hal_gpio.h"
#include "i2cbus.h"
#include "rail_cfg.h"

/* `PRSNT#` 的缓存（见 slot.h：读失败保留上一次的值）。 */
static bool s_present[PHONERAIL_RAIL_COUNT] = { true, true, true, true, true };

static bool rail_valid(int rail) { return rail >= 1 && rail <= PHONERAIL_RAIL_COUNT; }

int slot_mux_ch(int rail)
{
    assert(rail_valid(rail));
    return (int)rail_cfg(rail)->mux_ch;
}

/* ---- PRSNT# -------------------------------------------------------------- */

hal_err_t slot_prsnt_init(void)
{
    for (int rail = 1; rail <= PHONERAIL_RAIL_COUNT; rail++) {
        const hal_err_t err =
            hal_gpio_config(rail_cfg(rail)->prsnt_n, HAL_GPIO_INPUT_PULLUP);
        if (err != HAL_OK) {
            return err;
        }
    }
    slot_prsnt_poll();
    return HAL_OK;
}

void slot_prsnt_poll(void)
{
    for (int rail = 1; rail <= PHONERAIL_RAIL_COUNT; rail++) {
        int level = 0;
        if (hal_gpio_read(rail_cfg(rail)->prsnt_n, &level) == HAL_OK) {
            s_present[rail - 1] = (level == 0); /* 低 = 在位 */
        }
        /* 读失败：保留上一次的值（slot.h 里的理由）。 */
    }
}

bool slot_present(int rail)
{
    return rail_valid(rail) && s_present[rail - 1];
}

/* ---- 一次 xact 的正文们 --------------------------------------------------
   每个都是「通道已选好、锁已持有」的状态下被调一次。 */

typedef struct {
    int     rail;
    uint8_t mask;
    uint8_t value;
} out0_arg_t;

static hal_err_t do_out0(void *arg)
{
    const out0_arg_t *a = (const out0_arg_t *)arg;
    return pca9555_write_out0(a->rail - 1, a->mask, a->value);
}

static hal_err_t do_init(void *arg)
{
    const int rail = *(const int *)arg;
    return pca9555_init(rail - 1);
}

static hal_err_t do_init_keep_vbus(void *arg)
{
    const int rail = *(const int *)arg;
    return pca9555_init_keep(rail - 1, (uint8_t)(1u << PCA9555_BIT_VBUS_EN));
}

/* ---- 输出 ---------------------------------------------------------------- */

/* 已持锁版本：影子下标与通道由调用方保证一致 —— 调用方只可能是
   `t_safety`，而它是拿 `slot_mux_ch(rail)` 去开的 `xact`。 */
static hal_err_t out0_locked(int rail, uint8_t mask, uint8_t value)
{
    if (!rail_valid(rail)) {
        return HAL_ERR_ARG;
    }
    return pca9555_write_out0(rail - 1, mask, value);
}

static hal_err_t out0_xact(int rail, uint8_t mask, uint8_t value)
{
    if (!rail_valid(rail)) {
        return HAL_ERR_ARG;
    }
    out0_arg_t a = { rail, mask, value };
    return i2cbus_xact(slot_mux_ch(rail), SLOT_LOCK_TIMEOUT_MS, do_out0, &a);
}

hal_err_t slot_init(int rail)
{
    if (!rail_valid(rail)) {
        return HAL_ERR_ARG;
    }
    int r = rail;
    return i2cbus_xact(slot_mux_ch(rail), SLOT_LOCK_TIMEOUT_MS, do_init, &r);
}

hal_err_t slot_init_keep_vbus(int rail)
{
    if (!rail_valid(rail)) {
        return HAL_ERR_ARG;
    }
    int r = rail;
    return i2cbus_xact(slot_mux_ch(rail), SLOT_LOCK_TIMEOUT_MS, do_init_keep_vbus, &r);
}

hal_err_t slot_out0_write(int rail, uint8_t mask, uint8_t value)
{
    return out0_xact(rail, mask, value);
}

uint8_t slot_shadow(int rail)
{
    assert(rail_valid(rail));
    return pca9555_shadow(rail - 1);
}

/* VBUS 的极性：**高 = 通**（TPS22918 的 ON 脚，板上 R701 100 kΩ 下拉 ⇒
   PCA9555 复位为高阻时 VBUS 必断）。极性只在这两个函数里各出现一次。 */
#define SLOT_VBUS_BIT ((uint8_t)(1u << PCA9555_BIT_VBUS_EN))

hal_err_t slot_vbus_enable(int rail, bool on)
{
    return out0_xact(rail, SLOT_VBUS_BIT, on ? SLOT_VBUS_BIT : 0u);
}

hal_err_t slot_vbus_enable_locked(int rail, bool on)
{
    return out0_locked(rail, SLOT_VBUS_BIT, on ? SLOT_VBUS_BIT : 0u);
}

bool slot_vbus_is_on(int rail)
{
    /* 影子就在驱动里（写成功才更新），这里不另存一份 —— 两处影子迟早会分家。 */
    return rail_valid(rail) && (pca9555_shadow(rail - 1) & SLOT_VBUS_BIT) != 0;
}

/* ---- 输入 ---------------------------------------------------------------- */

hal_err_t slot_read_inputs_locked(int rail, pca9555_in_t *out)
{
    if (!rail_valid(rail) || out == NULL) {
        return HAL_ERR_ARG;
    }
    return pca9555_read_inputs(out);
}