use crate::memory_mapped::MemoryMapped;

pub enum Interrupt {
    VBlank = 0,
    HBlank = 1,
    VCounter = 2,
    Timer0 = 3,
    Timer1 = 4,
    Timer2 = 5,
    Timer3 = 6,
    Serial = 7,
    Dma0 = 8,
    Dma1 = 9,
    Dma2 = 10,
    Dma3 = 11,
    Keypad = 12,
    Gamepak = 13,
}

const ENABLED_INTERRUPTS: MemoryMapped<u16> = unsafe { MemoryMapped::new(0x04000200) };
const INTERRUPTS_ENABLED: MemoryMapped<u16> = unsafe { MemoryMapped::new(0x04000208) };

pub fn enable(interrupt: Interrupt) {
    let _interrupt_token = temporary_interrupt_disable();
    let interrupt = interrupt as usize;
    let enabled = ENABLED_INTERRUPTS.get() | (1 << (interrupt as u16));
    ENABLED_INTERRUPTS.set(enabled);
}

pub fn disable(interrupt: Interrupt) {
    let _interrupt_token = temporary_interrupt_disable();
    let interrupt = interrupt as usize;
    let enabled = ENABLED_INTERRUPTS.get() & !(1 << (interrupt as u16));
    ENABLED_INTERRUPTS.set(enabled);
}

pub struct Disable {}

impl Drop for Disable {
    fn drop(&mut self) {
        enable_interrupts();
    }
}

pub fn temporary_interrupt_disable() -> Disable {
    disable_interrupts();
    Disable {}
}

pub fn enable_interrupts() {
    INTERRUPTS_ENABLED.set(1);
}

pub(crate) fn disable_interrupts() {
    INTERRUPTS_ENABLED.set(0);
}