use std::borrow::Cow;
use std::fmt::{self, Display, Formatter};
use std::sync::atomic::AtomicU32;

pub type DebugMsg = Cow<'static, str>;

/// Immediate value
pub type Value = u64;

pub fn is_positive(val: Value) -> bool {
    0 == (val & 0x8000_0000_0000_0000)
}

pub fn is_negative(val: Value) -> bool {
    0 != (val & 0x8000_0000_0000_0000)
}

pub fn as_signed(val: Value) -> i64 {
    i64::from_ne_bytes(val.to_ne_bytes())
}

/// Immediate address
#[derive(Default, Debug, Clone, Copy, Eq, PartialEq, Ord, PartialOrd)]
pub struct Addr(pub u64);

impl Addr {
    pub fn advance(&mut self, add: i64) {
        if add < 0 {
            self.0 = self.0.wrapping_sub(-add as u64);
        } else {
            self.0 = self.0.wrapping_add(add as u64);
        }
    }
}

impl Display for Addr {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        if self.0 > 0x7fff_ffff_ffff_ffff {
            write!(f, "{}", i64::from_ne_bytes(self.0.to_ne_bytes()))
        } else {
            write!(f, "{}", self.0)
        }
    }
}

impl From<u64> for Addr {
    fn from(n: u64) -> Self {
        Self(n)
    }
}

impl From<usize> for Addr {
    fn from(n: usize) -> Self {
        Self(n as u64)
    }
}

impl From<Addr> for u64 {
    fn from(addr: Addr) -> Self {
        addr.0
    }
}

/// Label name
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub enum Label {
    Named(String),
    Numbered(u32),
}

impl Label {
    /// Generate a unique numbered label from a counter
    pub fn unique(counter: &AtomicU32) -> Self {
        Label::Numbered(counter.fetch_add(1, std::sync::atomic::Ordering::Relaxed))
    }
}

impl Display for Label {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self {
            Label::Named(name) => write!(f, ":{}", name),
            Label::Numbered(num) => write!(f, ":#{}", num),
        }
    }
}

impl From<&str> for Label {
    fn from(n: &str) -> Self {
        Self::Named(n.to_string())
    }
}

impl From<String> for Label {
    fn from(n: String) -> Self {
        Self::Named(n)
    }
}

/// Routine name
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct RoutineName(pub String);

impl Display for RoutineName {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.0)
    }
}

impl From<&str> for RoutineName {
    fn from(n: &str) -> Self {
        Self(n.to_string())
    }
}

impl From<String> for RoutineName {
    fn from(n: String) -> Self {
        Self(n)
    }
}