/**
 ****************************************************************************************************
 * @file        app.c
 * @author      HiFi Player Project
 * @version     V1.2
 * @date        2026-01-01
 * @brief       应用管理器 + 全局按键服务
 *
 * 模块职责：
 *   1. 唯一持有 XL9555 按键的扫描权（其它模块不再直接读按键，避免重复扫描/漏键）。
 *   2. 按键去抖 + 区分短按/长按，统一投递到事件队列（消费者是 ui.c）。
 *   3. 维护当前应用模式、主界面应用表与选择项，并提供“返回 / 切换应用”接口。
 ****************************************************************************************************
 */

#include "app.h"

#include <string.h>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"

#include "esp_log.h"
#include "lvgl.h"

#include "xl9555.h"

#define TAG                 "app"

/* ---------------- 按键服务参数 ---------------- */
#define KEY_SCAN_PERIOD_MS  10              /* 扫描周期 */
#define KEY_DEBOUNCE_COUNT  3               /* 连续 3 次一致才确认（约 30ms） */
#define KEY_LONG_PRESS_MS   700             /* 长按阈值 */
#define KEY_TASK_STACK      (3 * 1024)
#define KEY_TASK_PRIO       5               /* 低于播放器(6)，高于 LVGL(4) */
#define EVENT_QUEUE_LEN     16

/* ---------------- 主界面应用表（新增应用只需在这里加一条） ---------------- */
static const app_entry_t s_apps[] = {
    {
        .icon       = LV_SYMBOL_AUDIO,          /* 音符：音乐播放器 */
        .title      = "MUSIC",
        .subtitle   = "WAV files in SD /MUSIC",
        .mode       = APP_MODE_PLAYER,
        .enabled    = true,
        .color_from = 0x8E5BFF,
        .color_to   = 0x3FB6F5,
    },
    {
        .icon       = LV_SYMBOL_DIRECTORY,      /* 文件夹：SD 卡文件浏览 */
        .title      = "FILES",
        .subtitle   = "Browse files on SD card",
        .mode       = APP_MODE_NONE,
        .enabled    = false,
        .color_from = 0x31C27C,
        .color_to   = 0x1E9C6B,
    },
    {
        .icon       = LV_SYMBOL_SETTINGS,       /* 齿轮：设置 */
        .title      = "SETTINGS",
        .subtitle   = "Display, audio and keys",
        .mode       = APP_MODE_NONE,
        .enabled    = false,
        .color_from = 0x9AA3B5,
        .color_to   = 0x6A7183,
    },
    {
        .icon       = LV_SYMBOL_LIST,           /* 列表：关于 */
        .title      = "ABOUT",
        .subtitle   = "HiFi Player V1.2",
        .mode       = APP_MODE_NONE,
        .enabled    = false,
        .color_from = 0xFFB020,
        .color_to   = 0xF07C18,
    },
};

#define APP_COUNT   ((int)(sizeof(s_apps) / sizeof(s_apps[0])))

/* ---------------- 内部状态 ---------------- */
typedef struct {
    uint8_t    last_raw;            /* 上次原始电平（1=按下） */
    uint8_t    stable;              /* 已确认的稳定状态 */
    uint8_t    counter;             /* 连续一致计数 */
    TickType_t press_tick;          /* 按下时刻 */
    bool       long_sent;           /* 本次按住是否已上报长按 */
} key_state_t;

static const uint16_t s_key_mask[APP_KEY_NUM] = { KEY0_IO, KEY1_IO, KEY2_IO, KEY3_IO };
static key_state_t    s_keys[APP_KEY_NUM];

static QueueHandle_t  s_event_queue = NULL;
static app_mode_t     s_mode = APP_MODE_HOME;
static int            s_selection = 0;

/* ---------------- 按键事件投递 ---------------- */
static void key_post(uint8_t key, uint8_t type)
{
    app_event_t ev = { .key = key, .type = type };

    if (s_event_queue != NULL)
    {
        /* 队列满时丢弃新事件，绝不阻塞按键任务 */
        (void)xQueueSend(s_event_queue, &ev, 0);
    }
}

/**
 * @brief  按键扫描任务（非阻塞去抖 + 长短按识别）
 */
static void key_task(void *arg)
{
    (void)arg;

    memset(s_keys, 0, sizeof(s_keys));

    while (1)
    {
        uint8_t data[2] = {0, 0};

        if (xl9555_read_byte(data, 2) == ESP_OK)
        {
            uint16_t level  = (uint16_t)(((uint16_t)data[1] << 8) | data[0]);
            TickType_t now  = xTaskGetTickCount();

            for (int i = 0; i < APP_KEY_NUM; i++)
            {
                key_state_t *k = &s_keys[i];
                uint8_t raw = ((level & s_key_mask[i]) == 0) ? 1 : 0;   /* 低电平有效 */

                /* --- 1. 去抖计数 --- */
                if (raw != k->last_raw)
                {
                    k->last_raw = raw;
                    k->counter  = 0;
                }
                else if (k->counter < KEY_DEBOUNCE_COUNT)
                {
                    k->counter++;
                }

                if (k->counter < KEY_DEBOUNCE_COUNT)
                {
                    continue;                   /* 尚未稳定 */
                }

                /* --- 2. 状态变化 --- */
                if (raw != k->stable)
                {
                    k->stable = raw;

                    if (raw)                    /* 刚按下：记录时刻 */
                    {
                        k->press_tick = now;
                        k->long_sent  = false;
                    }
                    else if (!k->long_sent)     /* 松开且从未上报长按 → 短按 */
                    {
                        key_post((uint8_t)i, APP_KEY_SHORT);
                    }
                }
                /* --- 3. 按住不放 → 长按 --- */
                else if (raw && !k->long_sent &&
                         ((now - k->press_tick) >= pdMS_TO_TICKS(KEY_LONG_PRESS_MS)))
                {
                    k->long_sent = true;
                    key_post((uint8_t)i, APP_KEY_LONG);
                }
            }
        }

        vTaskDelay(pdMS_TO_TICKS(KEY_SCAN_PERIOD_MS));
    }
}

/* ---------------- 对外接口 ---------------- */
void app_start(void)
{
    if (s_event_queue == NULL)
    {
        s_event_queue = xQueueCreate(EVENT_QUEUE_LEN, sizeof(app_event_t));
        if (s_event_queue == NULL)
        {
            ESP_LOGE(TAG, "create event queue failed");
            return;
        }
    }

    s_mode      = APP_MODE_HOME;
    s_selection = 0;

    if (xTaskCreate(key_task, "key_svc", KEY_TASK_STACK, NULL, KEY_TASK_PRIO, NULL) != pdPASS)
    {
        ESP_LOGE(TAG, "create key task failed");
    }
    else
    {
        ESP_LOGI(TAG, "app manager started, %d app(s) in launcher", APP_COUNT);
    }
}

app_mode_t app_get_mode(void)
{
    return s_mode;
}

void app_set_mode(app_mode_t mode)
{
    if (mode == s_mode)
    {
        return;
    }

    s_mode = mode;

    /* 丢弃切换过程中的残留事件，避免“上一个界面的按键”触发新界面的动作 */
    app_event_flush();

    ESP_LOGI(TAG, "switch to mode %d", (int)mode);
}

void app_back(void)
{
    if (s_mode != APP_MODE_HOME)
    {
        app_set_mode(APP_MODE_HOME);
    }
}

bool app_switch_next(void)
{
    int count = 0;
    const app_entry_t *apps = app_get_entries(&count);

    if (count <= 0)
    {
        return false;
    }

    /* 找到当前模式的表项下标（找不到则视为 -1，从第 1 个开始找） */
    int start = -1;
    for (int i = 0; i < count; i++)
    {
        if (apps[i].mode == s_mode)
        {
            start = i;
            break;
        }
    }

    /* 向后找下一个“可用且已实现”的应用 */
    for (int step = 1; step <= count; step++)
    {
        int idx = (start + step + count) % count;

        if (apps[idx].enabled && (apps[idx].mode < APP_MODE_NUM))
        {
            s_selection = idx;
            app_set_mode(apps[idx].mode);
            return true;
        }
    }

    return false;
}

const app_entry_t *app_get_entries(int *count)
{
    if (count != NULL)
    {
        *count = APP_COUNT;
    }

    return s_apps;
}

int app_get_selection(void)
{
    if ((s_selection < 0) || (s_selection >= APP_COUNT))
    {
        s_selection = 0;
    }

    return s_selection;
}

void app_select_move(int delta)
{
    if (APP_COUNT <= 0)
    {
        return;
    }

    s_selection = (app_get_selection() + delta) % APP_COUNT;
    if (s_selection < 0)
    {
        s_selection += APP_COUNT;
    }
}

bool app_event_poll(app_event_t *ev)
{
    if ((s_event_queue == NULL) || (ev == NULL))
    {
        return false;
    }

    return (xQueueReceive(s_event_queue, ev, 0) == pdTRUE);
}

bool app_event_wait(app_event_t *ev, uint32_t timeout_ms)
{
    if ((s_event_queue == NULL) || (ev == NULL))
    {
        return false;
    }

    TickType_t ticks = (timeout_ms == 0) ? 0 : pdMS_TO_TICKS(timeout_ms);

    return (xQueueReceive(s_event_queue, ev, ticks) == pdTRUE);
}

void app_event_flush(void)
{
    if (s_event_queue != NULL)
    {
        (void)xQueueReset(s_event_queue);
    }
}