#include "app_no_disturb.h"
#include "usr_rtc.h"
#include "system/includes.h"

#define APP_MINUTES_PER_DAY  (24U * 60U)
#define APP_NO_DISTURB_VM_MAGIC    0x444e4431UL
#define APP_NO_DISTURB_VM_VERSION  1U

typedef struct {
    uint8_t enabled;
    uint8_t weekdays_mask;
    uint16_t start_minute;
    uint16_t end_minute;
} AppNoDisturbCtx_t;

typedef struct {
    uint32_t magic;
    uint8_t version;
    uint8_t length;
    uint16_t checksum;
    uint8_t data[APP_NO_DISTURB_DATA_LEN];
} AppNoDisturbVm_t;

static AppNoDisturbCtx_t s_no_disturb;
static uint8_t s_saved_data[APP_NO_DISTURB_DATA_LEN];
static uint8_t s_saved_valid;

static uint16_t app_no_disturb_checksum(const uint8_t *data)
{
    uint16_t checksum = 0xa55aU;
    uint8_t i;

    for (i = 0; i < APP_NO_DISTURB_DATA_LEN; i++) {
        checksum = (uint16_t)((checksum << 5) | (checksum >> 11));
        checksum ^= data[i];
    }
    return checksum;
}

static uint8_t app_no_disturb_vm_valid(const AppNoDisturbVm_t *vm)
{
    return vm->magic == APP_NO_DISTURB_VM_MAGIC &&
           vm->version == APP_NO_DISTURB_VM_VERSION &&
           vm->length == APP_NO_DISTURB_DATA_LEN &&
           vm->checksum == app_no_disturb_checksum(vm->data);
}

static uint8_t app_no_disturb_weekday_monday0(const struct sys_time *time)
{
    static const uint8_t month_offset[12] = {
        0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4
    };
    uint32_t year = time->year;
    uint8_t sunday0;

    if (time->month < 3U) {
        year--;
    }
    sunday0 = (uint8_t)((year + year / 4U - year / 100U + year / 400U +
                         month_offset[time->month - 1U] + time->day) % 7U);
    return (uint8_t)((sunday0 + 6U) % 7U);
}

static uint8_t app_no_disturb_day_selected(uint8_t weekday)
{
    return (uint8_t)((s_no_disturb.weekdays_mask & (1U << weekday)) != 0U);
}

void app_no_disturb_configure(uint8_t enable, uint8_t weekdays_mask,
                              uint16_t start_minute, uint16_t end_minute)
{
    s_no_disturb.enabled = !!enable;
    s_no_disturb.weekdays_mask = weekdays_mask & 0x7fU;
    s_no_disturb.start_minute = start_minute;
    s_no_disturb.end_minute = end_minute;
}

uint8_t app_no_disturb_is_active_at(const struct sys_time *time)
{
    uint8_t weekday;
    uint16_t now_minute;

    if (!time || !s_no_disturb.enabled || !s_no_disturb.weekdays_mask ||
        s_no_disturb.start_minute >= APP_MINUTES_PER_DAY ||
        s_no_disturb.end_minute >= APP_MINUTES_PER_DAY ||
        time->month < 1U || time->month > 12U ||
        time->day < 1U || time->day > 31U ||
        time->hour > 23U || time->min > 59U) {
        return 0;
    }

    weekday = app_no_disturb_weekday_monday0(time);
    now_minute = (uint16_t)(time->hour * 60U + time->min);

    if (s_no_disturb.start_minute == s_no_disturb.end_minute) {
        return app_no_disturb_day_selected(weekday);
    }
    if (s_no_disturb.start_minute < s_no_disturb.end_minute) {
        return app_no_disturb_day_selected(weekday) &&
               now_minute >= s_no_disturb.start_minute &&
               now_minute < s_no_disturb.end_minute;
    }
    if (now_minute >= s_no_disturb.start_minute) {
        return app_no_disturb_day_selected(weekday);
    }
    if (now_minute < s_no_disturb.end_minute) {
        return app_no_disturb_day_selected((uint8_t)((weekday + 6U) % 7U));
    }
    return 0;
}

uint8_t app_no_disturb_is_active(void)
{
    struct sys_time time;

    if (!usr_rtc_get_time(&time)) {
        return 0;
    }
    return app_no_disturb_is_active_at(&time);
}

uint8_t app_no_disturb_storage_load(uint8_t data[APP_NO_DISTURB_DATA_LEN])
{
    AppNoDisturbVm_t vm;
    int ret;

    if (!data) {
        return 0;
    }
    memset(&vm, 0, sizeof(vm));
    ret = syscfg_read(CFG_USER_NO_DISTURB, (uint8_t *)&vm, sizeof(vm));
    if (ret != (int)sizeof(vm) || !app_no_disturb_vm_valid(&vm)) {
        s_saved_valid = 0;
        return 0;
    }
    memcpy(data, vm.data, APP_NO_DISTURB_DATA_LEN);
    memcpy(s_saved_data, vm.data, APP_NO_DISTURB_DATA_LEN);
    s_saved_valid = 1;
    return 1;
}

uint8_t app_no_disturb_storage_save(const uint8_t data[APP_NO_DISTURB_DATA_LEN])
{
    AppNoDisturbVm_t vm;
    int ret;

    if (!data) {
        return 0;
    }
    if (s_saved_valid &&
        !memcmp(s_saved_data, data, APP_NO_DISTURB_DATA_LEN)) {
        return 1;
    }

    memset(&vm, 0, sizeof(vm));
    vm.magic = APP_NO_DISTURB_VM_MAGIC;
    vm.version = APP_NO_DISTURB_VM_VERSION;
    vm.length = APP_NO_DISTURB_DATA_LEN;
    memcpy(vm.data, data, APP_NO_DISTURB_DATA_LEN);
    vm.checksum = app_no_disturb_checksum(vm.data);
    ret = syscfg_write(CFG_USER_NO_DISTURB, (uint8_t *)&vm, sizeof(vm));
    if (ret != (int)sizeof(vm)) {
        return 0;
    }
    memcpy(s_saved_data, data, APP_NO_DISTURB_DATA_LEN);
    s_saved_valid = 1;
    return 1;
}