#include "fpga.h"
#include "hw.h"
#include "led.h"
#include "rtc.h"
#include "task.h"


#define RTC_I2C_ADDRESS             (0xDE)

#define RTC_ADDRESS_RTCSEC          (0x00)
#define RTC_ADDRESS_RTCMIN          (0x01)
#define RTC_ADDRESS_RTCHOUR         (0x02)
#define RTC_ADDRESS_RTCWKDAY        (0x03)
#define RTC_ADDRESS_RTCDATE         (0x04)
#define RTC_ADDRESS_RTCMTH          (0x05)
#define RTC_ADDRESS_RTCYEAR         (0x06)
#define RTC_ADDRESS_CONTROL         (0x07)
#define RTC_ADDRESS_OSCTRIM         (0x08)
#define RTC_ADDRESS_SRAM_MAGIC      (0x20)
#define RTC_ADDRESS_SRAM_REGION     (0x24)
#define RTC_ADDRESS_SRAM_VERSION    (0x28)
#define RTC_ADDRESS_SRAM_SETTINGS   (0x2C)

#define RTC_RTCSEC_ST               (1 << 7)

#define RTC_RTCWKDAY_VBATEN         (1 << 3)
#define RTC_RTCWKDAY_OSCRUN         (1 << 5)

#define RTC_SETTINGS_VERSION        (1)


static rtc_time_t rtc_time = {
    .second     = 0x00,
    .minute     = 0x00,
    .hour       = 0x12,
    .weekday    = 0x02,
    .day        = 0x01,
    .month      = 0x03,
    .year       = 0x22
};
static bool rtc_time_valid = false;
static volatile bool rtc_time_pending = false;

static uint8_t rtc_region = 0xFF;
static volatile bool rtc_region_pending = false;

static rtc_settings_t rtc_settings = {
    .led_enabled    = true,
};
static volatile bool rtc_settings_pending = false;
static volatile bool rtc_initialized = false;

static const uint8_t rtc_regs_bit_mask[7] = {
    0b01111111,
    0b01111111,
    0b00111111,
    0b00000111,
    0b00111111,
    0b00011111,
    0b11111111
};


static void rtc_task_resume (void) {
    task_set_ready(TASK_ID_RTC);
}

static void rtc_on_error (void) {
    rtc_time_valid = false;
    led_blink_error(LED_ERROR_RTC);
    task_yield();
}

static void rtc_read (uint8_t address, uint8_t *data, uint8_t length) {
    hw_i2c_read(RTC_I2C_ADDRESS, address, data, length, rtc_task_resume);
    task_yield();
    if (hw_i2c_get_error()) {
        rtc_on_error();
    }
}

static void rtc_write (uint8_t address, uint8_t *data, uint8_t length) {
    hw_i2c_write(RTC_I2C_ADDRESS, address, data, length, rtc_task_resume);
    task_yield();
    if (hw_i2c_get_error()) {
        rtc_on_error();
    }
}

static void rtc_sanitize_time (uint8_t *regs) {
    for (int i = 0; i < 7; i++) {
        regs[i] &= rtc_regs_bit_mask[i];
    }
}

static void rtc_wait_osc (bool running) {
    uint8_t rtcwkday;

    while (1) {
        rtc_read(RTC_ADDRESS_RTCWKDAY, &rtcwkday, 1);

        if (running && (rtcwkday & RTC_RTCWKDAY_OSCRUN)) {
            return;
        } else if (!running && (!(rtcwkday & RTC_RTCWKDAY_OSCRUN))) {
            return;
        }
    }
}

static void rtc_read_time (void) {
    uint8_t regs[7];

    rtc_read(RTC_ADDRESS_RTCSEC, regs, 7);

    rtc_sanitize_time(regs);

    if (!rtc_time_pending) {
        rtc_time.second = regs[0];
        rtc_time.minute = regs[1];
        rtc_time.hour = regs[2];
        rtc_time.weekday = regs[3];
        rtc_time.day = regs[4];
        rtc_time.month = regs[5];
        rtc_time.year = regs[6];

        rtc_time_valid = true;
    }
}

static void rtc_write_time (void) {
    uint8_t regs[7];

    regs[0] = 0x00;

    rtc_write(RTC_ADDRESS_RTCSEC, regs, 1);

    rtc_wait_osc(false);

    regs[0] = rtc_time.second;
    regs[1] = rtc_time.minute;
    regs[2] = rtc_time.hour;
    regs[3] = rtc_time.weekday;
    regs[4] = rtc_time.day;
    regs[5] = rtc_time.month;
    regs[6] = rtc_time.year;

    rtc_sanitize_time(regs);

    regs[0] |= RTC_RTCSEC_ST;
    regs[3] |= (RTC_RTCWKDAY_OSCRUN | RTC_RTCWKDAY_VBATEN);

    rtc_write(RTC_ADDRESS_RTCSEC, regs, 7);

    rtc_wait_osc(true);
}

static void rtc_read_region (void) {
    rtc_read(RTC_ADDRESS_SRAM_REGION, &rtc_region, 1);
}

static void rtc_write_region (void) {
    rtc_write(RTC_ADDRESS_SRAM_REGION, &rtc_region, 1);
}

static void rtc_read_settings (void) {
    rtc_read(RTC_ADDRESS_SRAM_SETTINGS, (uint8_t *) (&rtc_settings), sizeof(rtc_settings));
}

static void rtc_write_settings (void) {
    rtc_write(RTC_ADDRESS_SRAM_SETTINGS, (uint8_t *) (&rtc_settings), sizeof(rtc_settings));
}

static void rtc_init (void) {
    bool uninitialized = false;
    const char *magic = "SC64";
    uint8_t buffer[4];
    uint32_t settings_version;

    rtc_read(RTC_ADDRESS_SRAM_MAGIC, buffer, 4);

    for (int i = 0; i < 4; i++) {
        if (buffer[i] != magic[i]) {
            uninitialized = true;
            break;
        }
    }

    if (uninitialized) {
        buffer[0] = 0;
        rtc_write(RTC_ADDRESS_SRAM_MAGIC, (uint8_t *) (magic), 4);
        rtc_write(RTC_ADDRESS_OSCTRIM, buffer, 1);
        rtc_write_time();
        rtc_write_region();
    }

    rtc_read(RTC_ADDRESS_SRAM_VERSION, (uint8_t *) (&settings_version), 4);

    if (uninitialized || (settings_version != RTC_SETTINGS_VERSION)) {
        settings_version = RTC_SETTINGS_VERSION;
        rtc_write(RTC_ADDRESS_SRAM_VERSION, (uint8_t *) (&settings_version), 4);
        rtc_write_settings();
    }
}


bool rtc_is_initialized (void) {
    return rtc_initialized;
}

bool rtc_get_time (rtc_time_t *time) {
    bool vaild;

    hw_i2c_disable_irq();
    hw_tim_disable_irq(TIM_ID_RTC);

    time->second = rtc_time.second;
    time->minute = rtc_time.minute;
    time->hour = rtc_time.hour;
    time->weekday = rtc_time.weekday;
    time->day = rtc_time.day;
    time->month = rtc_time.month;
    time->year = rtc_time.year;
    vaild = rtc_time_valid;

    hw_tim_enable_irq(TIM_ID_RTC);
    hw_i2c_enable_irq();

    return vaild;
}

void rtc_set_time (rtc_time_t *time) {
    hw_i2c_disable_irq();
    hw_tim_disable_irq(TIM_ID_RTC);

    rtc_time.second = time->second;
    rtc_time.minute = time->minute;
    rtc_time.hour = time->hour;
    rtc_time.weekday = time->weekday;
    rtc_time.day = time->day;
    rtc_time.month = time->month;
    rtc_time.year = time->year;
    rtc_time_pending = true;

    hw_tim_enable_irq(TIM_ID_RTC);
    hw_i2c_enable_irq();
}

uint8_t rtc_get_region (void) {
    return rtc_region;
}

void rtc_set_region (uint8_t region) {
    rtc_region = region;
    rtc_region_pending = true;
}

rtc_settings_t *rtc_get_settings (void) {
    return (&rtc_settings);
}

void rtc_set_settings (rtc_settings_t *settings) {
    hw_tim_disable_irq(TIM_ID_LED);

    rtc_settings = *settings;
    rtc_settings_pending = true;

    hw_tim_enable_irq(TIM_ID_LED);
}

void rtc_task (void) {
    rtc_init();

    rtc_read_region();
    rtc_read_settings();

    rtc_initialized = true;

    while (1) {
        if (rtc_time_pending) {
            rtc_time_pending = false;
            rtc_write_time();
        }

        if (rtc_region_pending) {
            rtc_region_pending = false;
            rtc_write_region();
        }

        if (rtc_settings_pending) {
            rtc_settings_pending = false;
            rtc_write_settings();
        }

        rtc_read_time();

        hw_tim_setup(TIM_ID_RTC, 50, rtc_task_resume);

        task_yield();
    }
}

void rtc_process (void) {
    rtc_time_t time;
    uint32_t data[2];
    uint32_t scr = fpga_reg_get(REG_RTC_SCR);

    if ((scr & RTC_SCR_PENDING) && ((scr & RTC_SCR_MAGIC_MASK) == RTC_SCR_MAGIC)) {
        data[0] = fpga_reg_get(REG_RTC_TIME_0);
        data[1] = fpga_reg_get(REG_RTC_TIME_1);

        time.weekday = ((data[0] >> 24) & 0xFF) + 1;
        time.hour = ((data[0] >> 16) & 0xFF);
        time.minute = ((data[0] >> 8) & 0xFF);
        time.second = ((data[0] >> 0) & 0xFF);
        time.year = ((data[1] >> 16) & 0xFF);
        time.month = ((data[1] >> 8) & 0xFF);
        time.day = ((data[1] >> 0) & 0xFF);

        rtc_set_time(&time);

        fpga_reg_set(REG_RTC_TIME_0, data[0]);
        fpga_reg_set(REG_RTC_TIME_1, data[1]);
        fpga_reg_set(REG_RTC_SCR, RTC_SCR_DONE);
    }

    rtc_get_time(&time);

    data[0] = (
        ((time.weekday - 1) << 24) |
        (time.hour << 16) |
        (time.minute << 8) |
        (time.second << 0)
    );
    data[1] = (
        (time.year << 16) |
        (time.month << 8) |
        (time.day << 0)
    );

    fpga_reg_set(REG_RTC_TIME_0, data[0]);
    fpga_reg_set(REG_RTC_TIME_1, data[1]);
}