pub struct Timer {

    /// Address of the timer
    base: *mut u8,

    /// Number of clock cycles before the timer fires
    period: u32,

    /// Current count of the timer, in milliseconds
    time_ms: u32,
}

impl Timer {
    pub fn new() -> Timer {
        Timer {
            base: 0xE0002800 as *mut u8,
            period: 12_000_000 / 1000, // 12 MHz, 1 ms timer
            time_ms: 0,
        }
    }

    pub fn enable(&self) {
        unsafe {
            // Disable, so we can update it
            self.base.add(0x20).write_volatile(0);

            // Update "reload" register
            self.base.add(0x10).write_volatile((self.period >> 24) as u8);
            self.base.add(0x14).write_volatile((self.period >> 16) as u8);
            self.base.add(0x18).write_volatile((self.period >> 8) as u8);
            self.base.add(0x1c).write_volatile((self.period >> 0) as u8);

            // Update "load" register
            self.base.add(0x00).write_volatile((self.period >> 24) as u8);
            self.base.add(0x04).write_volatile((self.period >> 16) as u8);
            self.base.add(0x08).write_volatile((self.period >> 8) as u8);
            self.base.add(0x0c).write_volatile((self.period >> 0) as u8);

            // Enable ISR
            self.base.add(0x40).write_volatile(1);

            // Set "pending" as well to clear it
            self.base.add(0x38).write_volatile(1);

            // Finally, enable it
            self.base.add(0x20).write_volatile(1);
        }
    }

    pub fn elapsed_ms(&self) -> u32 {
        return self.time_ms;
    }
}

// pub fn irq(_irq_number: usize) {
//     let timer_base = 0xE0002800 as *mut u8;
//     unsafe {
//         TIME_MS = TIME_MS + 1;
//         timer_base.add(0x3c).write_volatile(1);
//     };
// }

// pub fn get_time() -> u32 {
//     unsafe { TIME_MS }
// }

// pub fn time_init() {
//     let timer_base = 0xE0002800 as *mut u8;
//     let period = 12_000_000 / 1000; // 12 MHz, 1 ms timer
// }