use std::{ops::{Add, Sub, Mul, Div, Shl, Shr, BitOr, BitAnd, BitXor, Neg, Not}, cmp::Ordering};
use crate::prelude::*;

fn ratio_to_f64(r: Rational64) -> f64 {
	*r.numer() as f64 / *r.denom() as f64
}

macro_rules! error {
    ($($arg:tt)*) => {
        exception!(VALUE_EXCEPTION, $($arg)*)
    };
}

///
/// MATH OPERATIONS
///

fn ipow(n: i64, d: i64, p: i64) -> Result<(i64, i64)> {
	Ok(match (n, d, p) {
		(0, _, 0) => Err(error!("cannot exponent 0 ** 0"))?,
		(0, _, _) => (0, 1),
		(_, _, 0) => (1, 1),
		(1, 1, _) => (1, 1),
		(n, d, p) if p < 0 => (d.pow((-p) as u32), n.pow((-p) as u32)),
		(n, d, p) => (n.pow(p as u32), d.pow(p as u32)),
	})
}

fn promote(a: Value, b: Value) -> (Value, Value) {
	use Value as V;
	match (&a, &b) {
		(V::Int(x),      V::Ratio(..))   => (V::Ratio((*x).into()), b),
		(V::Int(x),      V::Float(..))   => (V::Float(*x as f64), b),
		(V::Int(x),      V::Complex(..)) => (V::Complex((*x as f64).into()), b),
		(V::Ratio(x),    V::Float(..))   => (V::Float(ratio_to_f64(*x)), b),
		(V::Ratio(x),    V::Complex(..)) => (V::Complex(ratio_to_f64(*x).into()), b),
		(V::Float(x),    V::Complex(..)) => (V::Complex((*x).into()), b),
		(V::Ratio(..),   V::Int(y))      => (a, V::Ratio((*y).into())),
		(V::Float(..),   V::Int(y))      => (a, V::Float(*y as f64)),
		(V::Complex(..), V::Int(y))      => (a, V::Complex((*y as f64).into())),
		(V::Float(..),   V::Ratio(y))    => (a, V::Float(ratio_to_f64(*y))),
		(V::Complex(..), V::Ratio(y))    => (a, V::Complex(ratio_to_f64(*y).into())),
		(V::Complex(..), V::Float(y))    => (a, V::Complex((*y).into())),
        (V::List(l1),    V::List(l2)) if l1.len() > 0 && l2.len() > 0
            => (V::Matrix(Matrix::from_list(l1.to_vec()).into()), V::Matrix(Matrix::from_list(l2.to_vec()).into())),
        (_, V::List(l)) if l.len() > 0
            => (a, V::Matrix(Matrix::from_list(l.to_vec()).into())),
        (V::List(l), _) if l.len() > 0
            => (V::Matrix(Matrix::from_list(l.to_vec()).into()), b),
		_ => (a, b),
	}
}


impl Add for Value {
    type Output = Result<Self>;
    fn add(self, rhs: Self) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x + y)),
			(Float(x), Float(y)) => Ok(Float(x + y)),
			(Ratio(x), Ratio(y)) => Ok(Ratio(x + y)),
			(Complex(x), Complex(y)) => Ok(Complex(x + y)),
            (Matrix(x), Matrix(y)) => Ok(Matrix((x + y)?.into())),
            (Matrix(x), r) => Ok(Matrix(x.increment(r)?.into())),
            (l, Matrix(y)) => Ok(Matrix(y.increment(l)?.into())),
            (String(str), value) => Ok(String(Rc::from(
                format!("{str}{value}")
            ))),
            (value, String(str)) => Ok(String(Rc::from(
                format!("{value}{str}")
            ))),
			(List(mut l1), List(l2)) => {
				l1.extend_from_slice(&l2);
				Ok(List(l1))
			},
            (l, r) => Err(error!("cannot add {l:?} + {r:?}"))
		}
    }
}

impl Sub for Value {
    type Output = Result<Self>;
    fn sub(self, rhs: Self) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x - y)),
			(Float(x), Float(y)) => Ok(Float(x - y)),
			(Ratio(x), Ratio(y)) => Ok(Ratio(x - y)),
			(Complex(x), Complex(y)) => Ok(Complex(x - y)),
            (Matrix(x), Matrix(y)) => Ok(Matrix((x - y)?.into())),
            (Matrix(x), r) => Ok(Matrix(x.decrement(r)?.into())),
            (l, r) => Err(error!("cannot subtract {l:?} - {r:?}"))
		}
    }
}

impl Mul for Value {
	type Output = Result<Self>;
	fn mul(self, rhs: Value) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x * y)),
			(Float(x), Float(y)) => Ok(Float(x * y)),
			(Ratio(x), Ratio(y)) => Ok(Ratio(x * y)),
			(Complex(x), Complex(y)) => Ok(Complex(x * y)),
            (Matrix(x), Matrix(y)) => Ok(Matrix((x * y)?.into())),
            (Matrix(x), r) => Ok(Matrix(x.scale(r)?.into())),
            (l, Matrix(y)) => Ok(Matrix(y.scale(l)?.into())),
            (l, r) => Err(error!("cannot multiply {l:?} * {r:?}"))
		}
	}
}

impl Div for Value {
	type Output = Result<Self>;
	fn div(self, rhs: Value) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
            (Int(_), Int(0)) => Err(error!("cannot divide by zero")),
			(Int(x), Int(y)) => Ok(Ratio(Rational64::new(x, y))),
			(Float(x), Float(y)) => Ok(Float(x / y)),
			(Ratio(x), Ratio(y)) => Ok(Ratio(x / y)),
			(Complex(x), Complex(y)) => Ok(Complex(x / y)),
            (l, r) => Err(error!("cannot divide {l:?} / {r:?}"))
        }
	}
}

impl BitOr for Value {
	type Output = Result<Self>;
	fn bitor(self, rhs: Value) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x | y)),
            (l, r) => Err(error!("cannot bitwise or {l:?} | {r:?}"))
		}
	}
}

impl BitAnd for Value {
	type Output = Result<Self>;
	fn bitand(self, rhs: Value) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x & y)),
            (l, r) => Err(error!("cannot bitwise and {l:?} & {r:?}"))
		}
	}
}

impl BitXor for Value {
	type Output = Result<Self>;
	fn bitxor(self, rhs: Value) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x ^ y)),
            (l, r) => Err(error!("cannot bitwise xor {l:?} ^ {r:?}"))
		}
	}
}

impl Shl for Value {
	type Output = Result<Self>;
	fn shl(self, rhs: Value) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x << y)),
            (l, r) => Err(error!("cannot bitwise shift left {l:?} << {r:?}"))
		}
	}
}

impl Shr for Value {
	type Output = Result<Self>;
	fn shr(self, rhs: Value) -> Self::Output {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x >> y)),
            (l, r) => Err(error!("cannot bitwise shift right {l:?} >> {r:?}"))
		}
	}
}

impl PartialEq for Value {
	fn eq(&self, other: &Self) -> bool {
		use Value::*;
		match (self, other) {
			(Nil, Nil) => true,
			(Bool(a), Bool(b)) => a == b,
			(Int(a), Int(b)) => *a == *b,
			(Ratio(a), Ratio(b)) => *a == *b,
			(Float(a), Float(b)) => *a == *b,
			(Complex(a), Complex(b)) => *a == *b,
			(Int(a), Ratio(b)) => Rational64::from(*a) == *b,
			(Ratio(a), Int(b)) => *a == Rational64::from(*b),
			(Int(a), Float(b)) => *a as f64 == *b,
			(Float(a), Int(b)) => *a == *b as f64,
			(Int(a), Complex(b)) => Complex64::from(*a as f64) == *b,
			(Complex(a), Int(b)) => *a == Complex64::from(*b as f64),
			(Ratio(a), Float(b)) => ratio_to_f64(*a) == *b,
			(Float(a), Ratio(b)) => *a == ratio_to_f64(*b),
			(Ratio(a), Complex(b)) => Complex64::from(ratio_to_f64(*a)) == *b,
			(Complex(a), Ratio(b)) => *a == Complex64::from(ratio_to_f64(*b)),
			(Float(a), Complex(b)) => Complex64::from(*a) == *b,
			(Complex(a), Float(b)) => *a == Complex64::from(*b),
			(String(a), String(b)) => *a == *b,
			(List(a), List(b)) => *a == *b,
            (Matrix(a), Matrix(b)) => a == b,
			_ => false,
		}
	}
}

impl PartialOrd for Value {
	fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
		use Value::*;
		match (self, other) {
			(Nil, Nil) => Some(Ordering::Equal),
			(Bool(a), Bool(b)) => a.partial_cmp(b),
			(Int(a), Int(b)) => a.partial_cmp(b),
			(Ratio(a), Ratio(b)) => a.partial_cmp(b),
			(Float(a), Float(b)) => a.partial_cmp(b),
			(Int(a), Ratio(b)) => Rational64::from(*a).partial_cmp(b),
			(Ratio(a), Int(b)) => a.partial_cmp(&Rational64::from(*b)),
			(Int(a), Float(b)) => (*a as f64).partial_cmp(b),
			(Float(a), Int(b)) => a.partial_cmp(&(*b as f64)),
			(Ratio(a), Float(b)) => ratio_to_f64(*a).partial_cmp(b),
			(Float(a), Ratio(b)) => a.partial_cmp(&ratio_to_f64(*b)),
			(String(a), String(b)) => a.partial_cmp(b),
			(List(a), List(b)) => a.partial_cmp(b),
            (Matrix(a), Matrix(b)) => a.values.partial_cmp(&b.values),
			_ => None,
		}
	}
}

impl Neg for Value {
    type Output = Value;

    fn neg(self) -> Self::Output {
        use Value::*;
        match self {
            Bool(b) => Bool(!b),
            Int(i) => Int(-i),
            Float(f) => Float(-f),
            Ratio(r) => Ratio(-r),
            Complex(c) => Complex(-c),
            _ => return Float(f64::NAN)
        }
    }
}

impl Not for Value {
    type Output = bool;

    fn not(self) -> Self::Output {
        use Value as V;
        match self {
            V::Nil => true,
            V::Bool(b) => !b,
            V::Int(i) => i == 0,
            V::Float(f) => f == 0.0,
            V::Ratio(r) => *(r.numer()) == 0 || *(r.denom()) == 0,
            V::Complex(c) => !c.is_normal(),
            V::Regex(_) => false,
            V::List(_) => false,
            V::Matrix(_) => false,
            V::Table(_) => false,
            V::String(s) => s.as_ref() == "",
            V::Function(_) => false,
            V::Iter(_) => false,
            V::Range(_) => false,
            V::File(_) => false,
            V::Exception(_) => false,
        }
    }
}


impl Value {

	pub fn modulo(self, rhs: Value) -> Result<Self> {
		use Value::*;
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Int(x % y)),
			(Float(x), Float(y)) => Ok(Float(x % y)),
			(Ratio(x), Ratio(y)) => Ok(Ratio(x % y)),
			(Complex(x), Complex(y)) => Ok(Complex(x % y)),
            (l, r) => Err(error!("cannot modulo: {l:?} % {r:?}"))
		}
	}

	pub fn pow(self, rhs: Value) -> Result<Self> {
		use Value::*;
		if let (Ratio(x), Int(y)) = (&self, &rhs) {
		    return Ok(Ratio(ipow(*(*x).numer(), *(*x).denom(), *y)?.into()));
		}
		match promote(self, rhs) {
			(Int(x), Int(y)) => Ok(Ratio(ipow(x, 1, y)?.into())),
			(Float(x), Float(y)) => Ok(Float(x.powf(y))),
			(Ratio(x), Ratio(y)) => Ok(Float(ratio_to_f64(x).powf(ratio_to_f64(y)))),
			(Complex(x), Complex(y)) => Ok(Complex(x.powc(y))),
            (l, r) => Err(error!("cannot exponent: {l:?} ** {r:?}"))
		}
	}

    pub fn floaty(self) -> Self {
        use Value as V;
        match self {
            V::Int(i) => V::Float(i as f64),
            V::Ratio(r) => V::Float(ratio_to_f64(r)),
            a => a
        }
    }

	pub fn is_zero(&self) -> bool {
        use Value as V;
        match self {
            V::Int(i) => *i == 0,
            V::Float(f) => *f == 0.0 || *f == -0.0,
            V::Ratio(r) => *r.numer() == 0,
            _ => false,
        }
    }

	pub fn binary_op(op: BinaryOp, lhs: Value, rhs: Value) -> Result<Self> {
        use BinaryOp::*;
        match op {
            Add => lhs + rhs,
            Subtract => lhs - rhs,
            Multiply => lhs * rhs,
            Divide => lhs / rhs,
            Modulo => lhs.modulo(rhs),
            Power => lhs.pow(rhs),
            BitwiseAnd => lhs & rhs,
            BitwiseOr => lhs | rhs,
            BitwiseXor => lhs ^ rhs,
            BitwiseShiftLeft => lhs << rhs,
            BitwiseShiftRight => lhs >> rhs,
            Equals => Ok(Self::Bool(lhs == rhs)),
            NotEquals => Ok(Self::Bool(lhs != rhs)),
            GreaterEquals => Ok(Self::Bool(lhs >= rhs)),
            LessEquals => Ok(Self::Bool(lhs <= rhs)),
            GreaterThan => Ok(Self::Bool(lhs > rhs)),
            LessThan => Ok(Self::Bool(lhs < rhs)),
            Range | RangeEq => {
                let Value::Int(lhs) = lhs else {
                    return Err(error!("range can only take [Int]'s"))
                };
                let Value::Int(rhs) = rhs else {
                    return Err(error!("range can only take [Int]'s"))
                };
                Ok(Self::Range(Rc::new((lhs, rhs, op == RangeEq))))
            },
        }
    }

    pub fn unary_op(op: UnaryOp, val: Value) -> Value {
        use UnaryOp::*;
        match op {
            Negate => -val,
            Not => Self::Bool(!val),
        }
    }

    pub fn to_regex(value: &str) -> Result<Self> {
        match Regex::new(value) {
            Ok(r) => Ok(Self::Regex(r.into())),
            Err(e) => Err(error!("{e}")),
        }
    }
}