/**
 * @file button_manager.cpp
 * @brief 三按钮管理器实现 - 双向去抖 + 长按/短按 + 超时自愈
 *
 * 核心改进 (v2):
 *   1. 按下沿和释放沿都经过 BTN_DEBOUNCE_MS 稳定确认
 *   2. 长按期间持续检测 (不再等到松手才触发)
 *   3. 按下超过 BTN_STUCK_TIMEOUT_MS 自动复位, 防止状态机卡死
 *   4. 用 stableState 替代瞬时 raw 驱动状态, 消除噪声误触发
 */

#include "button_manager.h"

// ============================================================
// 构造
// ============================================================

ButtonManager::ButtonManager()
    : _cbProvision(nullptr)
    , _cbDismiss(nullptr)
    , _cbPage(nullptr)
{
    auto initBtn = [](ButtonState& s, uint8_t pin) {
        s.pin           = pin;
        s.stableState   = false;
        s.rawState      = false;
        s.changeTime    = 0;
        s.pressTime     = 0;
        s.longTriggered = false;
        s.shortPending  = false;
    };

    initBtn(_btnProvision, BTN_PROVISION_PIN);
    initBtn(_btnDismiss,   BTN_ALARM_DISMISS_PIN);
    initBtn(_btnPage,      BTN_PAGE_SWITCH_PIN);
}

// ============================================================
// 初始化
// ============================================================

void ButtonManager::begin() {
    pinMode(BTN_PROVISION_PIN,     INPUT_PULLUP);
    pinMode(BTN_ALARM_DISMISS_PIN, INPUT_PULLUP);
    pinMode(BTN_PAGE_SWITCH_PIN,   INPUT_PULLUP);

    // 强制初始化为未按下 (PCB 上电 GPIO 不稳, 忽略初始状态)
    _btnProvision.rawState    = false;
    _btnProvision.stableState  = false;
    _btnDismiss.rawState      = false;
    _btnDismiss.stableState    = false;
    _btnPage.rawState         = false;
    _btnPage.stableState       = false;

    Serial.println(F("[按钮] ✅ 三按钮初始化完成 (双向去抖+超时自愈)"));
    Serial.printf("  配网: GPIO%d | 解除报警: GPIO%d | 翻页: GPIO%d\n",
                  BTN_PROVISION_PIN, BTN_ALARM_DISMISS_PIN, BTN_PAGE_SWITCH_PIN);
    Serial.printf("  去抖:%dms | 长按:%dms | 卡死超时:%dms\n",
                  BTN_DEBOUNCE_MS, BTN_LONG_PRESS_MS, BTN_STUCK_TIMEOUT_MS);
}

// ============================================================
// 主循环轮询
// ============================================================

void ButtonManager::loop() {
    // 开机 10 秒静默 (PCB 上电 GPIO 不稳 + 强制初始未按下)
    if (millis() < 10000) return;

    // 按钮1: 配网 (仅长按)
    _processButton(_btnProvision, false, true);

    // 按钮2: 解除报警 (仅短按)
    _processButton(_btnDismiss, true, false);

    // 按钮3: 翻页 (仅短按)
    _processButton(_btnPage, true, false);
}

// ============================================================
// 单按钮状态机 (基于稳定状态, 非瞬时边沿)
// ============================================================

void ButtonManager::_processButton(ButtonState& btn, bool hasShort, bool hasLong) {
    uint32_t now = millis();
    bool raw = _readPin(btn.pin);  // true = 按下 (LOW)

    // ── 第1步: raw 状态变化时启动去抖计时 ──
    if (raw != btn.rawState) {
        btn.rawState = raw;
        btn.changeTime = now;
        // 不立即改变 stableState — 等稳定确认
    }

    // ── 第2步: 去抖确认 — raw 保持稳定超过 BTN_DEBOUNCE_MS 才生效 ──
    bool debounced = (now - btn.changeTime >= BTN_DEBOUNCE_MS);
    bool stateChanged = (btn.rawState != btn.stableState);

    if (debounced && stateChanged) {
        // 状态正式切换
        btn.stableState = btn.rawState;

        if (btn.stableState) {
            // ── 确认按下 ──
            btn.pressTime     = now;
            btn.longTriggered = false;
            btn.shortPending  = hasShort;  // 只有支持短按的按钮才标记待判定
        } else {
            // ── 确认释放 ──
            uint32_t holdTime = now - btn.pressTime;

            // 短按判定: 按下时长在去抖和长按阈值之间
            if (btn.shortPending && holdTime >= BTN_DEBOUNCE_MS
                && holdTime < BTN_LONG_PRESS_MS && !btn.longTriggered) {
                // 根据引脚分发短按回调
                if (btn.pin == BTN_ALARM_DISMISS_PIN && _cbDismiss) {
                    _cbDismiss();
                }
                if (btn.pin == BTN_PAGE_SWITCH_PIN && _cbPage) {
                    _cbPage();
                }
            }

            btn.shortPending  = false;
            btn.longTriggered = false;
        }
    }

    // ── 第3步: 长按检测 (在按下稳定期间持续检查) ──
    if (hasLong && btn.stableState && !btn.longTriggered) {
        uint32_t holdTime = now - btn.pressTime;
        if (holdTime >= BTN_LONG_PRESS_MS) {
            btn.longTriggered = true;
            btn.shortPending  = false;  // 长按已触发, 不再判定短按
            if (_cbProvision) {
                _cbProvision();
            }
        }
    }

    // ── 第4步: 卡死自愈 — 按下超时强制复位 ──
    if (btn.stableState && (now - btn.pressTime >= BTN_STUCK_TIMEOUT_MS)) {
        Serial.printf("[按钮] ⚠️ GPIO%d 按下超时 %lums, 强制复位\n",
                      btn.pin, now - btn.pressTime);
        _resetButton(btn);
    }
}

// ============================================================
// 强制复位
// ============================================================

void ButtonManager::_resetButton(ButtonState& btn) {
    btn.stableState   = false;
    btn.rawState      = _readPin(btn.pin);  // 重新同步真实硬件状态
    btn.changeTime    = 0;
    btn.pressTime     = 0;
    btn.longTriggered = false;
    btn.shortPending  = false;
}

// ============================================================
// 读引脚 (INPUT_PULLUP → LOW = 按下)
// ============================================================

bool ButtonManager::_readPin(uint8_t pin) {
    return digitalRead(pin) == LOW;
}