#include "ntc.h"

#define TABLE_SIZE 181
#define NTC_SERIES_RESISTOR 10000 // 10K
#define BASE_TEMP -55
// NTC-10K-3950-B值
//-55~125°C对应的电阻阻值表(单位: Ω)
static uint32_t _table[TABLE_SIZE] = {
    739500, 705664, 669165, 631466, 593686,                                         //-55~-51
    556644, 520911, 486858, 454704, 424553, 396426, 370283, 346049, 323623, 302890, //-50~-41
    283730, 266022, 249649, 234498, 220466, 207454, 195372, 184139, 173681, 163931, //-40~-31
    154827, 146315, 138347, 130877, 123866, 117280, 111084, 105252, 99756, 94573,   //-30~-21
    89682, 85063, 80699, 76574, 72672, 68982, 65489, 62183, 59052, 56087,           //-20~-11
    53280, 50620, 48100, 45712, 43450, 41306, 39274, 37349, 35524, 33795,           //-10~-1
    32116,                                                                          // 0
    30601, 29128, 27732, 26408, 25152, 23962, 22833, 21762, 20746, 19783,           // 1~10
    18868, 18000, 17177, 16395, 15652, 14947, 14277, 13641, 13036, 12461,           // 11~20
    11915, 11395, 10901, 10431, 10000, 9557, 9151, 8765, 8397, 8047,                // 21~30
    7712, 7394, 7090, 6800, 6523, 6259, 6008, 5767, 5537, 5318,                     // 31~40
    5108, 4907, 4716, 4532, 4357, 4189, 4029, 3875, 3728, 3588,                     // 41~50
    3453, 3324, 3200, 3081, 2968, 2859, 2754, 2654, 2558, 2466,                     // 51~60
    2377, 2293, 2211, 2133, 2058, 1986, 1917, 1850, 1786, 1725,                     // 61~70
    1666, 1610, 1555, 1503, 1452, 1404, 1358, 1313, 1270, 1228,                     // 71~80
    1189, 1150, 1113, 1078, 1044, 1011, 979, 948, 919, 890,                         // 81~90
    863, 837, 811, 787, 763, 740, 718, 697, 676, 657,                               // 91~100
    637, 619, 601, 584, 567, 551, 535, 520, 505, 491,                               // 101~110
    478, 464, 451, 439, 427, 415, 404, 393, 382, 371,                               // 111~120
    361, 351, 342, 333, 324,                                                        // 121~125
};

static uint8_t ntc_lookup(const uint32_t *list, uint16_t adc)
{
    uint8_t middle = 0;
    uint8_t indexL = 0;
    uint8_t indexR = TABLE_SIZE - 1;
    if (adc >= *(list + 0))
        return 0;
    if (adc <= *(list + TABLE_SIZE - 1))
        return TABLE_SIZE - 1;

    while ((indexR - indexL) > 1)
    {
        middle = (indexL + indexR) >> 1;
        if (adc == *(list + middle))
            return middle;
        else if (adc > *(list + middle))
            indexR = middle;
        else if (adc < *(list + middle))
            indexL = middle;
    }
    return indexL;
}

void ntc_init(void)
{
}

/**
 * @brief 获取温度值，单位为0.1摄氏度
 * @param {uint16_t} adc采集值
 * @return {float32_t} 温度值
 * @note
 */
float32_t ntc_get_temp(uint16_t adc)
{

    uint8_t index = 0;
    int16_t data = 0;
    int16_t t = 0;
    int16_t result = 0;
    uint32_t rt = 0;
    const int16_t base = BASE_TEMP * 10;
    float32_t res;
    res.f = BASE_TEMP;

    /**
     * ad = (4095*rt)/(rt+10000)
     * rt = (ad*100)/(4095-ad)
     */
    rt = (adc * NTC_SERIES_RESISTOR) / (4095 - adc);
    index = ntc_lookup(_table, rt);
    if (rt >= _table[0])
        return res;
    if (rt <= *(_table + TABLE_SIZE - 1))
    {
        result = (TABLE_SIZE - 1) * 10 + base;
    }
    else
    {
        data = _table[index] - _table[index + 1];
        t = 10 * (_table[index] - rt) / data;
        result = base + index * 10 + t;
    }
    res.f = result / 10.0;
    return res;
}