#include "iot_board.h"
#include "dac.h"
#include "dac_njw1195.h"
#include "driver/gpio.h"
#include "esp_adc/adc_oneshot.h"
#include "esp_log.h"
#include "esp_check.h"
#include "esp_sleep.h"

static const char TAG[] = "MusicBoxBoard";

#define DAC_XSMT_GPIO 19
#define BAT_ADC_GPIO  36
#define BAT_ADC_CHAN  ADC_CHANNEL_0
#define CHG_FULL_GPIO 34
#define CHG_ING_GPIO  35

#define BAT_CAL_K     0.008635f // Empirically calibrated: Raw 2103 -> 18.16V (18.16 / 2103)
#define BAT_CELLS     5
#define BAT_VCELL_MIN 3.0f
#define BAT_VCELL_MAX 4.2f

static bool s_board_initialized = false;
static adc_oneshot_unit_handle_t s_adc_handle = NULL;

typedef struct {
    float voltage;
    int percentage;
} bat_curve_t;

// Professional Li-ion 18650 discharge curve mapping (light load)
// 已根据常见的 18650 锂电池放电平台进行了优化修正
static const bat_curve_t s_bat_curve[] = {
    {4.15f, 100}, // 满电 (预留一点电压降)
    {4.08f, 90},
    {4.00f, 80},
    {3.93f, 70},
    {3.87f, 60},
    {3.82f, 50},  // 常见的 50% 放电平台中点
    {3.79f, 40},
    {3.75f, 30},
    {3.70f, 20},
    {3.60f, 10},  // 低于 3.6V 电量下降极快
    {3.40f, 5},
    {3.20f, 0}    // 保护板关断临界点
};
#define BAT_CURVE_POINTS (sizeof(s_bat_curve) / sizeof(s_bat_curve[0]))

esp_err_t iot_board_init(void) {
    if (s_board_initialized) {
        return ESP_OK;
    }

    ESP_LOGI(TAG, "Initializing Music Box board...");

    // 1. Initialize DAC_XSMT GPIO
    gpio_config_t xsmt_conf = {
        .pin_bit_mask = (1ULL << DAC_XSMT_GPIO),
        .mode = GPIO_MODE_OUTPUT,
        .pull_up_en = GPIO_PULLUP_DISABLE,
        .pull_down_en = GPIO_PULLDOWN_DISABLE,
        .intr_type = GPIO_INTR_DISABLE,
    };
    ESP_ERROR_CHECK(gpio_config(&xsmt_conf));
    gpio_set_level(DAC_XSMT_GPIO, 1); // Unmute external ES/DAC

    // 2. Register and initialize NJW1195AV DAC
    dac_register(&dac_njw1195_ops);
    esp_err_t err = dac_init(NULL);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Failed to initialize NJW1195AV DAC: %s", esp_err_to_name(err));
        return err;
    }

    // 3. Initialize Battery ADC
    adc_oneshot_unit_init_cfg_t unit_cfg = {
        .unit_id = ADC_UNIT_1,
    };
    ESP_ERROR_CHECK(adc_oneshot_new_unit(&unit_cfg, &s_adc_handle));

    adc_oneshot_chan_cfg_t chan_cfg = {
        .atten = ADC_ATTEN_DB_12,
        .bitwidth = ADC_BITWIDTH_12,
    };
    ESP_ERROR_CHECK(adc_oneshot_config_channel(s_adc_handle, BAT_ADC_CHAN, &chan_cfg));

    s_board_initialized = true;
    ESP_LOGI(TAG, "Music Box board initialized successfully");
    return ESP_OK;
}

esp_err_t iot_board_deinit(void) {
    if (!s_board_initialized) {
        return ESP_OK;
    }
    dac_deinit();
    if (s_adc_handle) {
        adc_oneshot_del_unit(s_adc_handle);
        s_adc_handle = NULL;
    }
    s_board_initialized = false;
    return ESP_OK;
}

bool iot_board_is_init(void) {
    return s_board_initialized;
}

board_res_handle_t iot_board_get_handle(int id) {
    (void)id;
    return NULL;
}

const char *iot_board_get_info(void) {
    return BOARD_NAME;
}

void iot_board_init_lvgl_resources(void) {
    // No LVGL/Display
}

void board_power_off(void) {
    dac_njw1195_set_mute(true);
    esp_deep_sleep_start();
}

bool board_battery_read(int *percent, bool *charging) {
    if (!s_board_initialized || s_adc_handle == NULL) {
        return false;
    }

    // 5-sample median filter
    int samples[5];
    for (int i = 0; i < 5; i++) {
        adc_oneshot_read(s_adc_handle, BAT_ADC_CHAN, &samples[i]);
    }
    
    // Bubble sort
    for (int i = 0; i < 4; i++) {
        for (int j = 0; j < 4 - i; j++) {
            if (samples[j] > samples[j+1]) {
                int temp = samples[j];
                samples[j] = samples[j+1];
                samples[j+1] = temp;
            }
        }
    }
    int raw = samples[2]; // Median value

    bool is_charging = false;
    // Read real-time charger GPIOs (平时上拉高1，插入充电/充满触发为低0)
    int full = gpio_get_level(CHG_FULL_GPIO);
    int ing = gpio_get_level(CHG_ING_GPIO);
    // 只要有任意引脚被拉低(0)，即代表接上了充电器 (充电中: full=1, ing=0; 充满: full=0, ing=1)
    is_charging = (full == 0 || ing == 0);
    
    if (charging) {
        *charging = is_charging;
    }

    float vbat = raw * BAT_CAL_K;
    float vcell_raw = vbat / BAT_CELLS;
    float vcell = vcell_raw;
    
    // Compensate for internal resistance voltage jump during fast charging
    if (is_charging && vcell > 3.0f && vcell < 4.2f) {
        vcell -= 0.1f; // Deduct approx 0.1V per cell charging offset (0.5V total)
    }

    // ESP_LOGI(TAG, "Battery Read -> Raw: %d, V_bat: %.2fV, V_cell: %.2fV (Compensated: %.2fV), Chg: %d", 
    //         raw, vbat, vcell_raw, vcell, is_charging);
    
    int pct = 0;
    if (vcell >= s_bat_curve[0].voltage) {
        pct = 100;
    } else if (vcell <= s_bat_curve[BAT_CURVE_POINTS - 1].voltage) {
        pct = 0;
    } else {
        for (int i = 0; i < BAT_CURVE_POINTS - 1; i++) {
            if (vcell <= s_bat_curve[i].voltage && vcell > s_bat_curve[i + 1].voltage) {
                float v_range = s_bat_curve[i].voltage - s_bat_curve[i + 1].voltage;
                float p_range = s_bat_curve[i].percentage - s_bat_curve[i + 1].percentage;
                float v_diff = vcell - s_bat_curve[i + 1].voltage;
                pct = s_bat_curve[i + 1].percentage + (int)(v_diff / v_range * p_range + 0.5f);
                break;
            }
        }
    }

    if (percent) {
        *percent = pct;
    }

    return true;
}