#include <nds.h>
#include <time.h>
#include "clock.h"
#include "../bang.h"

// Uptime is the number of 1/256th second ticks since the emulator began.
static u32 uptime;
u32 get_uptime(void) { return uptime; }
void uptime_handler(void) { uptime++; }

// Check if any timer has expired.
bool check_timers(ClockDevice *clk) {
    bool output = FALSE;
    if (clk->t1.end && clk->t1.end <= uptime) { clk->t1.end = 0; output = TRUE; }
    if (clk->t2.end && clk->t2.end <= uptime) { clk->t2.end = 0; output = TRUE; }
    if (clk->t3.end && clk->t3.end <= uptime) { clk->t3.end = 0; output = TRUE; }
    if (clk->t4.end && clk->t4.end <= uptime) { clk->t4.end = 0; output = TRUE; }
    return output;
}

u8 get_timer_high(ClockTimer *t) {
    if (t->end > uptime) {
        t->read = t->end - uptime;
    } else {
        t->end = 0; t->read = 0;
    }
    return HIGH(t->read);
}

u8 get_timer_low(ClockTimer *t) {
    return LOW(t->read);
}

void set_timer_high(ClockTimer *t, u8 high) {
    SET_HIGH(t->write, high);
}
void set_timer_low(ClockTimer *t, u8 low) {
    SET_LOW(t->write, low);
    if (t->write) {
        t->end = uptime + t->write;
    } else {
        t->end = 0;
    }
}

void init_clock(void) {
    // Start a 256Hz timer to increment the uptime value.
    timerStart(0, ClockDivider_1024, TIMER_FREQ_1024(256), uptime_handler);
}

struct tm* get_datetime(void) {
    time_t timestamp = time(NULL);
    struct tm* datetime = localtime(&timestamp);
    return datetime;
}