/* 刷机模式的窗口表。契约与线程约定在 chgmode.h。 */
#include "chgmode.h"

#include "phonerail.h"

typedef struct {
    volatile uint32_t until; /* 窗口截止时刻（ms，回绕安全比较） */
    volatile uint8_t  set;   /* 1 = 窗口或宽限期还没被 tick 清掉 */
    uint8_t           by_cmd; /* 1 = 命令关掉的（已记过事件，tick 不再报「到期」）；只有执行器任务读写 */
} chg_t;

static chg_t s_chg[PHONERAIL_RAIL_COUNT];

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

/* `a` 在 `b` 之前（回绕安全）。 */
static bool before(uint32_t a, uint32_t b) { return (int32_t)(a - b) < 0; }

bool chgmode_active(int rail, uint32_t now)
{
    return rail_ok(rail) && s_chg[rail - 1].set && before(now, s_chg[rail - 1].until);
}

bool chgmode_relaxed(int rail, uint32_t now)
{
    return rail_ok(rail) && s_chg[rail - 1].set &&
           before(now, s_chg[rail - 1].until + CHG_MODE_GRACE_MS);
}

uint32_t chgmode_left_s(int rail, uint32_t now)
{
    if (!chgmode_active(rail, now)) {
        return 0;
    }
    return (s_chg[rail - 1].until - now + 999u) / 1000u;
}

int chgmode_count(uint32_t now)
{
    int n = 0;
    for (int r = 1; r <= PHONERAIL_RAIL_COUNT; r++) {
        n += chgmode_active(r, now) ? 1 : 0;
    }
    return n;
}

hal_err_t chgmode_set(int rail, uint32_t minutes, uint32_t now)
{
    if (!rail_ok(rail) || minutes > CHG_MODE_MAX_MIN) {
        return HAL_ERR_ARG;
    }
    chg_t *c = &s_chg[rail - 1];
    if (minutes == 0) {
        if (chgmode_active(rail, now)) {
            c->until = now; /* 立刻结束窗口，宽限期从现在算 */
            c->by_cmd = 1;
        }
        return HAL_OK;
    }
    if (!chgmode_active(rail, now) && chgmode_count(now) >= CHG_MODE_MAX_RAILS) {
        return HAL_ERR_STATE;
    }
    /* 先写时刻、后置标志：巡检任务读到 set=1 时 until 一定是新的。 */
    c->until = now + minutes * 60000u;
    c->by_cmd = 0;
    c->set = 1;
    return HAL_OK;
}

hal_err_t chgmode_extend(int rail, uint32_t minutes, uint32_t now)
{
    if (!rail_ok(rail) || minutes < 1 || minutes > CHG_MODE_MAX_MIN) {
        return HAL_ERR_ARG;
    }
    if (!chgmode_active(rail, now)) {
        return HAL_ERR_STATE;
    }
    chg_t         *c = &s_chg[rail - 1];
    const uint32_t cap = CHG_MODE_MAX_MIN * 60000u;
    uint32_t       left = c->until - now + minutes * 60000u; /* 窗口内 until − now 为正 */
    if (left > cap) {
        left = cap;
    }
    c->until = now + left; /* set 已是 1；单字写，巡检看到的要么旧要么新 */
    return HAL_OK;
}

uint32_t chgmode_tick(uint32_t now)
{
    uint32_t ended = 0;
    for (int r = 1; r <= PHONERAIL_RAIL_COUNT; r++) {
        chg_t *c = &s_chg[r - 1];
        if (c->set && !before(now, c->until + CHG_MODE_GRACE_MS)) {
            c->set = 0;
            if (!c->by_cmd) {
                ended |= 1u << (r - 1);
            }
        }
    }
    return ended;
}

void chgmode_reset(void)
{
    for (int r = 0; r < PHONERAIL_RAIL_COUNT; r++) {
        s_chg[r].set = 0;
        s_chg[r].until = 0;
        s_chg[r].by_cmd = 0;
    }
}