/******************************************************************************
 * @file    app_battery.c
 * @brief   电量算法实现：电压滤波、充放电基准记录、突变防抖、缓冲平滑显示
 * @author  cyWu <1917507415@qq.com>
 * @date    2026.08.27
 * @version V1.0.1
 * @history
 * - V1.0.0, 2026.08.26, cyWu, 首次发布，实现电压滤波、充放电基准、突变防抖与缓冲平滑
 * - V1.0.1, 2026.08.27, cyWu, 补充函数内部注释
 ******************************************************************************/

#include "app_battery.h"
#include "board_pin.h"
#include <string.h>

#define LOG_TAG_CONST APP
#define LOG_TAG       "[APP_BAT]"
#define LOG_INFO_ENABLE
#include "debug.h"

/*========================= 时间/阈值配置 =========================*/
#define BAT_SWITCH_WAIT_CHARGE_MS      60000u   /**< 切到充电后等 60s 才记基准 */
#define BAT_SWITCH_WAIT_DISCHARGE_MS   60000u   /**< 切到放电后等 60s 才记基准 */
#define BAT_CHARGE_BUFFER_MS           60000u  /**< 充电缓冲：1 分钟走 1% */
#define BAT_DISCHARGE_BUFFER_MS        20000u   /**< 放电缓冲：20 秒走 1% */
#define BAT_DISCHARGE_FILTER_W         90       /**< 放电指数滤波权重(/100)，压掉电机拉载噪声 */
#define BAT_SUDDEN_DROP_PCT            1        /**< 突变阈值：单次超过 1% 判定为突变 */
#define BAT_DROP_RECOVERY_MS           60000u   /**< 突变超过此时长强制接受新电量 */
#define BAT_RECOVERY_WAIT_MS           30000u   /**< 突变后电量回升，需稳定这么久才解除 */

#if APP_BATTERY_AUTO_INCREMENT_EN
#define BAT_AUTO_INC_INTERVAL_MS       (3u * 60u * 1000u) /**< 自增间隔：3 分钟 */
#define BAT_AUTO_INC_TRIGGER_MV        2        /**< 距历史满电压 2mV 内触发自增模式 */
#endif

/** 充/放电各自的基准电压——记录"状态切换稳定后"的真实电压与当时电量，
 *  之后按这个基准重新拟合电压-电量曲线，而不是死用出厂固定曲线 */
typedef struct {
    uint16_t base_mv;
    uint8_t  base_percent;
    uint8_t  recorded;
} AppBatteryBase_t;

/** 模块状态，所有跟时间相关的字段都用 dt 累加，不依赖系统绝对时钟 */
typedef struct {
    uint8_t  initialized;
    uint16_t voltage_mv;      /**< 滤波后电压 */
    uint8_t  percent;         /**< 当前对外显示的电量（已缓冲平滑） */
    uint8_t  target_percent;  /**< 电压当下换算出的目标电量 */
    uint8_t  charging;

    uint8_t  is_switching;    /**< 充放电状态刚切换，等稳定后才记基准 */
    uint32_t switch_ms;

    uint8_t  is_buffering;    /**< percent 正在按缓冲节奏逼近 target_percent */
    uint32_t buffer_ms;

    uint8_t  drop_detected;   /**< 放电时检测到电量单次跳变过大，先当噪声处理 */
    uint8_t  recovery_waiting;
    uint8_t  pre_drop_percent;
    uint32_t drop_ms;
    uint32_t recovery_ms;

#if APP_BATTERY_AUTO_INCREMENT_EN
    uint8_t  auto_inc_active;
    uint8_t  was_full;
    uint32_t auto_inc_ms;
    uint16_t max_charge_mv;      /**< 本次充电周期内记录到的最高电压 */
    uint16_t full_charge_mv;     /**< 历史上电量到过 100% 时记录的电压，用于下次提前触发自增 */
#endif
} AppBatteryCtx_t;

static AppBatteryCtx_t  s_batt;
static AppBatteryBase_t s_charge_base;
static AppBatteryBase_t s_discharge_base;

static uint8_t battery_mv_to_percent_discharge(uint16_t mv);
static uint8_t battery_mv_to_percent_charge(uint16_t mv);
static void    battery_update_voltage_filter(uint16_t mv);
static void    battery_start_buffer(uint8_t target_percent);
static void    battery_update_buffer(uint16_t dt);
static uint8_t battery_check_sudden_drop(uint16_t dt, uint8_t target_percent);

#if APP_BATTERY_AUTO_INCREMENT_EN
static void battery_update_charge_max_mv(uint16_t mv);
static void battery_check_auto_increment(uint16_t mv);
static void battery_handle_auto_increment(uint16_t dt);
static void battery_learn_full_charge_mv(void);
#endif

/**
 * @brief  初始化电量模块状态
 * @return 无
 */
void app_battery_init(void)
{
    memset(&s_batt, 0, sizeof(s_batt));
    memset(&s_charge_base, 0, sizeof(s_charge_base));
    memset(&s_discharge_base, 0, sizeof(s_discharge_base));
}

/**
 * @brief  查询当前显示用电量百分比
 * @return 0~100
 */
uint8_t app_battery_get_percent(void)
{
    return s_batt.percent;
}

/**
 * @brief  外部强制刷新电量，立即生效，清掉正在进行的缓冲，避免被缓冲拉回去
 * @param  percent 目标百分比，超过 100 会被钳到 100
 * @return 无
 */
void app_battery_set_percent(uint8_t percent)
{
    AppBatteryCtx_t *b = &s_batt;

    if (percent > 100) {
        percent = 100;
    }
    b->initialized = 1;
    b->percent = percent;
    b->target_percent = percent;
    b->is_buffering = 0;   /* 立刻生效，清掉正在走的缓冲，避免被拉回去 */
    b->buffer_ms = 0;
    log_info("battery percent forced to %d%%\n", percent);
}

/**
 * @brief  按最新采样电压推进电量算法
 * @param  dt       距上次调用的毫秒数
 * @param  mv       本次采样均值电压，单位 mV
 * @param  charging 1=充电中，0=放电
 * @return 无
 */
void app_battery_tick(uint16_t dt, uint16_t mv, uint8_t charging)
{
    AppBatteryCtx_t *b = &s_batt;
    int32_t new_percent;
    uint8_t target;

    /* 第一次进来：用当前电压直接算出显示电量，后面才走滤波/缓冲 */
    if (!b->initialized) {
        b->voltage_mv = mv;
        b->charging = charging;
        b->percent = charging ? battery_mv_to_percent_charge(mv)
                               : battery_mv_to_percent_discharge(mv);
        b->target_percent = b->percent;
        b->initialized = 1;
        return;
    }

    /* 充放电状态刚切：先等电压稳定再记基准，这段时间显示电量维持原值 */
    if (charging != b->charging) {
        b->charging = charging;
        b->is_switching = 1;
        b->switch_ms = 0;
        b->is_buffering = 0;
        b->drop_detected = 0;
        b->recovery_waiting = 0;
#if APP_BATTERY_AUTO_INCREMENT_EN
        if (charging) {
            b->max_charge_mv = 0;
            b->auto_inc_active = 0;
        }
#endif
        log_info("battery switching to %s\n", charging ? "charge" : "discharge");
    }

    if (b->is_switching) {
        uint32_t wait_ms = b->charging ? BAT_SWITCH_WAIT_CHARGE_MS : BAT_SWITCH_WAIT_DISCHARGE_MS;

        b->switch_ms += dt;
        if (b->switch_ms < wait_ms) {
            return; /* 基准没记完前，显示电量维持原值，不参与后面的计算 */
        }
        {
            AppBatteryBase_t *base = b->charging ? &s_charge_base : &s_discharge_base;
            base->base_mv = mv;
            base->base_percent = b->percent;
            base->recorded = 1;
            log_info("battery %s base %dmV %d%%\n",
                     b->charging ? "charge" : "discharge", mv, b->percent);
        }
        b->is_switching = 0;
        b->voltage_mv = mv;
    }

    battery_update_voltage_filter(mv);

    /* 电压换算成目标电量：放电只减不增，充电只增不减，避免噪声来回跳 */
    if (!b->charging) {
        new_percent = battery_mv_to_percent_discharge(b->voltage_mv);
        if (new_percent > b->target_percent) {
            new_percent = b->target_percent;
        }
    } else {
#if APP_BATTERY_AUTO_INCREMENT_EN
        battery_update_charge_max_mv(mv);
        battery_check_auto_increment(mv);
#endif
        new_percent = battery_mv_to_percent_charge(b->voltage_mv);
        if (new_percent < b->target_percent) {
            new_percent = b->target_percent;
        }
    }
    if (new_percent > 100) {
        new_percent = 100;
    } else if (new_percent < 0) {
        new_percent = 0;
    }
    target = (uint8_t)new_percent;

    /* 放电时单次跳变过大先当噪声，稳住后再更新 */
    if (!b->charging && battery_check_sudden_drop(dt, target)) {
        return;
    }

    if (target != b->target_percent) {
        b->target_percent = target;
        battery_start_buffer(target);
    }
    battery_update_buffer(dt);

#if APP_BATTERY_AUTO_INCREMENT_EN
    if (b->charging) {
        if (b->auto_inc_active) {
            battery_handle_auto_increment(dt);
        }
        battery_learn_full_charge_mv();
    }
#endif
}

/*========================= 私有函数实现 =========================*/

/**
 * @brief  放电时电压转百分比：有基准用基准拟合，没有就用出厂固定曲线
 */
static uint8_t battery_mv_to_percent_discharge(uint16_t mv)
{
    int32_t pct;
    int32_t span;

    /* 有放电基准：从当时记下的电压/电量，线性拟合到空电电压 */
    if (s_discharge_base.recorded) {
        uint16_t v0 = s_discharge_base.base_mv;

        if (mv > v0) {
            mv = v0; /* 放电电压不应比基准还高，高出的当噪声钳掉 */
        }
        span = (int32_t)v0 - BOARD_VBAT_EMPTY_MV;
        if (span <= 0) {
            return s_discharge_base.base_percent;
        }
        pct = (int32_t)(mv - BOARD_VBAT_EMPTY_MV) * s_discharge_base.base_percent / span;
        if (pct < 0) {
            pct = 0;
        } else if (pct > s_discharge_base.base_percent) {
            pct = s_discharge_base.base_percent;
        }
        return (uint8_t)pct;
    }

    /* 没有基准：用出厂固定曲线 空电~满电 线性换算 */
    if (mv <= BOARD_VBAT_EMPTY_MV) {
        return 0;
    }
    if (mv >= BOARD_VBAT_FULL_MV) {
        return 100;
    }
    pct = (int32_t)(mv - BOARD_VBAT_EMPTY_MV) * 100 / (BOARD_VBAT_FULL_MV - BOARD_VBAT_EMPTY_MV);
    return (uint8_t)pct;
}

/**
 * @brief  充电时电压转百分比：有基准用基准拟合，没有就用出厂固定曲线
 */
static uint8_t battery_mv_to_percent_charge(uint16_t mv)
{
    int32_t pct;
    int32_t span;
    int32_t remain;

    /* 有充电基准：从当时记下的电压/电量，线性拟合到充满电压 */
    if (s_charge_base.recorded) {
        uint16_t v0 = s_charge_base.base_mv;

        if (mv < v0) {
            mv = v0; /* 充电电压不应比基准还低，低出的当噪声钳掉 */
        }
        span = (int32_t)BOARD_VBAT_CHARGE_FULL_MV - v0;
        remain = 100 - s_charge_base.base_percent;
        if (span <= 0) {
            return 100;
        }
        pct = (int32_t)(mv - v0) * remain / span + s_charge_base.base_percent;
        if (pct < s_charge_base.base_percent) {
            pct = s_charge_base.base_percent;
        } else if (pct > 100) {
            pct = 100;
        }
        return (uint8_t)pct;
    }

    /* 没有基准：用出厂充电曲线线性换算 */
    if (mv <= BOARD_VBAT_CHARGE_EMPTY_MV) {
        return 0;
    }
    if (mv >= BOARD_VBAT_CHARGE_FULL_MV) {
        return 100;
    }
    pct = (int32_t)(mv - BOARD_VBAT_CHARGE_EMPTY_MV) * 100
          / (BOARD_VBAT_CHARGE_FULL_MV - BOARD_VBAT_CHARGE_EMPTY_MV);
    return (uint8_t)pct;
}

/**
 * @brief  更新电压滤波值：放电用指数滤波压噪声，充电直接用采样值（充电曲线本身平缓）
 */
static void battery_update_voltage_filter(uint16_t mv)
{
    if (!s_batt.charging) {
        /* 放电：指数滤波压掉电机拉载噪声，权重越大越平滑、越滞后 */
        s_batt.voltage_mv = (uint16_t)(((uint32_t)s_batt.voltage_mv * BAT_DISCHARGE_FILTER_W
                                         + (uint32_t)mv * (100 - BAT_DISCHARGE_FILTER_W)) / 100);
    } else {
        s_batt.voltage_mv = mv; /* 充电曲线本身平缓，直接用采样值 */
    }
}

/**
 * @brief  启动电量缓冲：目标变了就重新计时，percent 后面按固定节奏逼近 target
 */
static void battery_start_buffer(uint8_t target_percent)
{
    if (target_percent == s_batt.percent) {
        s_batt.is_buffering = 0;
        return;
    }
    s_batt.is_buffering = 1;
    s_batt.buffer_ms = 0;
}

/**
 * @brief  推进电量缓冲：满一个步进周期就 ±1%，保留余数不清零，避免长期漂移
 */
static void battery_update_buffer(uint16_t dt)
{
    AppBatteryCtx_t *b = &s_batt;
    uint32_t step_ms;

    if (!b->is_buffering) {
        return;
    }
    step_ms = b->charging ? BAT_CHARGE_BUFFER_MS : BAT_DISCHARGE_BUFFER_MS;
    b->buffer_ms += dt;
    if (b->buffer_ms < step_ms) {
        return;
    }
    b->buffer_ms -= step_ms; /* 减一个周期而不是清零，余数留给下次，避免长期漂移 */

    if (b->charging) {
        if (b->percent < b->target_percent) {
            b->percent++;
        }
    } else {
        if (b->percent > b->target_percent) {
            b->percent--;
        }
    }
    if (b->percent == b->target_percent) {
        b->is_buffering = 0;
        b->buffer_ms = 0;
    }
}

/**
 * @brief  放电突变检测：单次跳变超过阈值先当噪声，回升稳定一段时间才解除；
 *         若一直没回升，超时后强制接受，避免误判卡死电量不更新
 * @param  dt             距上次调用的毫秒数
 * @param  target_percent 本次电压算出来的目标电量
 * @return 1=仍在突变检测中（不更新电量），0=正常
 */
static uint8_t battery_check_sudden_drop(uint16_t dt, uint8_t target_percent)
{
    AppBatteryCtx_t *b = &s_batt;

    if (b->drop_detected) {
        int16_t recovery_diff;

        b->drop_ms += dt;
        recovery_diff = (int16_t)target_percent - (int16_t)b->pre_drop_percent;

        /* 电量已经回升到突变阈值以内：再稳一段时间才真正解除 */
        if (recovery_diff >= -(int16_t)BAT_SUDDEN_DROP_PCT) {
            if (!b->recovery_waiting) {
                b->recovery_waiting = 1;
                b->recovery_ms = 0;
            } else {
                b->recovery_ms += dt;
            }
            if (b->recovery_ms >= BAT_RECOVERY_WAIT_MS) {
                b->drop_detected = 0;
                b->recovery_waiting = 0;
                return 0;
            }
            return 1;
        }
        b->recovery_waiting = 0;

        /* 一直没回升：超时后强制接受新电量，避免卡死不更新 */
        if (b->drop_ms >= BAT_DROP_RECOVERY_MS) {
            b->drop_detected = 0;
            return 0;
        }
        return 1;
    }

    /* 单次跳变超过阈值，先当噪声，锁住显示电量 */
    if ((int16_t)b->percent - (int16_t)target_percent > BAT_SUDDEN_DROP_PCT) {
        b->drop_detected = 1;
        b->pre_drop_percent = b->percent;
        b->drop_ms = 0;
        b->recovery_waiting = 0;
        return 1;
    }
    return 0;
}

#if APP_BATTERY_AUTO_INCREMENT_EN
/**
 * @brief  记录本次充电周期内的最高电压，用作下次提前触发自增的参考
 */
static void battery_update_charge_max_mv(uint16_t mv)
{
    if (mv > s_batt.max_charge_mv) {
        s_batt.max_charge_mv = mv;
    }
}

/**
 * @brief  接近历史满电压时提前启动自增模式，避免曲线末期平台期卡住不动
 */
static void battery_check_auto_increment(uint16_t mv)
{
    AppBatteryCtx_t *b = &s_batt;
    uint16_t trigger_mv;

    if (b->auto_inc_active || b->full_charge_mv == 0 || b->percent >= 99) {
        return;
    }
    trigger_mv = b->full_charge_mv - BAT_AUTO_INC_TRIGGER_MV;
    if (mv >= trigger_mv) {
        b->auto_inc_active = 1;
        b->auto_inc_ms = 0;
        log_info("battery auto-inc start %dmV trigger=%dmV full=%dmV\n",
                 mv, trigger_mv, b->full_charge_mv);
    }
}

/**
 * @brief  自增模式下每隔固定间隔 +1%，最多到 99%（100% 交给真实电压判定）
 */
static void battery_handle_auto_increment(uint16_t dt)
{
    AppBatteryCtx_t *b = &s_batt;

    if (b->percent >= 99) {
        b->auto_inc_active = 0;
        return;
    }
    b->auto_inc_ms += dt;
    if (b->auto_inc_ms >= BAT_AUTO_INC_INTERVAL_MS) {
        b->auto_inc_ms = 0;
        b->percent++;
        b->target_percent = b->percent;
        log_info("battery auto-inc +1%% -> %d%%\n", b->percent);
        if (b->percent >= 99) {
            b->auto_inc_active = 0;
        }
    }
}

/**
 * @brief  电量首次到达 100% 时记下当时电压，供下次充电提前触发自增
 */
static void battery_learn_full_charge_mv(void)
{
    AppBatteryCtx_t *b = &s_batt;

    if (b->percent == 100) {
        if (!b->was_full && b->max_charge_mv > 0) {
            b->full_charge_mv = b->max_charge_mv;
            log_info("battery full-charge voltage learned: %dmV\n", b->full_charge_mv);
            b->auto_inc_active = 0;
        }
        b->was_full = 1;
    } else {
        b->was_full = 0;
    }
}
#endif /* APP_BATTERY_AUTO_INCREMENT_EN */