use crate::value::*;
use imbl::*;
use std::rc::Rc;
// use std::fmt;

#[derive(Clone, Debug)]
pub enum Base<'src> {
    Unary(fn(&Value<'src>) -> Value<'src>),
    Binary(fn(&Value<'src>, &Value<'src>) -> Value<'src>),
    Ternary(fn(&Value<'src>, &Value<'src>, &Value<'src>) -> Value<'src>),
}

pub fn eq<'src>(x: &Value<'src>, y: &Value<'src>) -> Value<'src> {
    Value::Boolean(x == y)
}

pub fn add<'src>(x: &Value<'src>, y: &Value<'src>) -> Value<'src> {
    match (x, y) {
        (Value::Number(x), Value::Number(y)) => Value::Number(x + y),
        _ => unreachable!("internal Ludus error"),
    }
}

pub fn sub<'src>(x: &Value<'src>, y: &Value<'src>) -> Value<'src> {
    match (x, y) {
        (Value::Number(x), Value::Number(y)) => Value::Number(x - y),
        _ => unreachable!("internal Ludus error"),
    }
}

pub fn unbox<'src>(x: &Value<'src>) -> Value<'src> {
    match x {
        Value::Box(_, cell) => cell.borrow().clone(),
        _ => unreachable!("internal Ludus error"),
    }
}

pub fn store<'src>(b: &Value<'src>, val: &Value<'src>) -> Value<'src> {
    if let Value::Box(_, cell) = b {
        cell.replace(val.clone());
        val.clone()
    } else {
        unreachable!("internal Ludus error")
    }
}

// TODO: do better than returning just the docstr
// name, patterns, AND docstring
pub fn doc<'src>(f: &Value<'src>) -> Value<'src> {
    match f {
        Value::Fn(f) => {
            let Fn { name, doc, .. } = **f;
            if let Some(docstr) = doc {
                Value::AllocatedString(Rc::new(format!("{name}: {docstr}")))
            } else {
                Value::InternedString(doc.unwrap_or("no documentation found"))
            }
        }
        _ => Value::InternedString("no documentation found"),
    }
}

pub fn and<'src>(x: &Value<'src>, y: &Value<'src>) -> Value<'src> {
    Value::Boolean(x.bool() && y.bool())
}

pub fn assoc<'src>(dict: &Value<'src>, key: &Value<'src>, value: &Value<'src>) -> Value<'src> {
    match (dict, key) {
        (Value::Dict(d), Value::Keyword(k)) => Value::Dict(d.update(k, value.clone())),
        _ => unreachable!("internal Ludus error"),
    }
}

pub fn r#bool<'src>(x: &Value<'src>) -> Value<'src> {
    Value::Boolean(x.bool())
}

pub fn chars<'src>(x: &Value<'src>) -> Value<'src> {
    match x {
        Value::InternedString(s) => {
            let chars = s.chars();

            let mut charlist = vector![];
            for char in chars {
                if char.is_ascii() {
                    charlist.push_back(Value::AllocatedString(Rc::new(char.to_string())))
                } else {
                    return Value::Tuple(Rc::new(vec![
                        Value::Keyword("err"),
                        Value::AllocatedString(Rc::new(format!(
                            "{char} is not an ascii character"
                        ))),
                    ]));
                }
            }
            Value::Tuple(Rc::new(vec![Value::Keyword("ok"), Value::List(charlist)]))
        }
        Value::AllocatedString(s) => {
            let chars = s.chars();

            let mut charlist = vector![];
            for char in chars {
                if char.is_ascii() {
                    charlist.push_back(Value::AllocatedString(Rc::new(char.to_string())))
                } else {
                    return Value::Tuple(Rc::new(vec![
                        Value::Keyword("err"),
                        Value::AllocatedString(Rc::new(format!(
                            "{char} is not an ascii character"
                        ))),
                    ]));
                }
            }
            Value::Tuple(Rc::new(vec![Value::Keyword("ok"), Value::List(charlist)]))
        }
        _ => unreachable!("internal Ludus error"),
    }
}

// TODO: figure out how to get to opportunistic mutation here
pub fn concat<'src>(x: &Value<'src>, y: &Value<'src>) -> Value<'src> {
    match (x, y) {
        (Value::InternedString(x), Value::InternedString(y)) => {
            Value::AllocatedString(Rc::new(format!("{x}{y}")))
        }
        (Value::AllocatedString(x), Value::AllocatedString(y)) => {
            Value::AllocatedString(Rc::new(format!("{x}{y}")))
        }
        (Value::AllocatedString(x), Value::InternedString(y)) => {
            Value::AllocatedString(Rc::new(format!("{x}{y}")))
        }
        (Value::InternedString(x), Value::AllocatedString(y)) => {
            Value::AllocatedString(Rc::new(format!("{x}{y}")))
        }
        (Value::List(x), Value::List(y)) => {
            let mut newlist = x.clone();
            newlist.append(y.clone());
            Value::List(newlist)
        }
        _ => unreachable!("internal Ludus error"),
    }
}

pub fn base<'src>() -> Vec<(&'src str, Value<'src>)> {
    vec![
        ("eq?", Value::Base(Base::Binary(eq))),
        ("add", Value::Base(Base::Binary(add))),
        ("sub", Value::Base(Base::Binary(sub))),
        ("unbox", Value::Base(Base::Unary(unbox))),
        ("store!", Value::Base(Base::Binary(store))),
        ("doc!", Value::Base(Base::Unary(doc))),
        ("and", Value::Base(Base::Binary(and))),
        ("assoc", Value::Base(Base::Ternary(assoc))),
        ("bool", Value::Base(Base::Unary(r#bool))),
        ("chars", Value::Base(Base::Unary(chars))),
        ("concat", Value::Base(Base::Binary(concat))),
    ]
}

// * [x] and (x, y) -> value
// * [x] assoc (x, y) -> dict
// * [ ] atan_2 (x) -> number
// * [x] bool (x) -> bool
// * [ ] ceil (x) -> number
// * [x] chars (x) -> list
// * [ ] concat (x, y) -> value
// * [ ] conj (x, y) -> list
// * [ ] cos (x) -> number
// * [ ] dec (x) -> number
// * [ ] disj (x) -> set
// * [ ] dissoc (x, y) -> dict
// * [ ] div (x, y) -> number
// * [ ] doc (x) -> string
// * [ ] downcase (x) -> string
// * [ ] first (x) -> value
// * [ ] floor (x) -> number
// * [ ] get (x, y) -> value
// * [ ] gt (x, y) -> bool
// * [ ] gte! (x, y) -> bool
// * [ ] inc (x) -> number
// * [ ] last (x) -> value
// * [ ] lt (x) -> bool
// * [ ] lte (x) -> bool
// * [ ] mod (x, y) -> number
// * [ ] or (x, y) -> value
// * [ ] pi
// * [ ] print! (x) -> :ok
// * [ ] prn (x) -> value
// * [ ] push (x) -> list
// * [ ] random () -> number
// * [ ] range () -> list
// * [ ] rest (x) -> coll
// * [ ] round (x) -> number
// * [ ] show (x) -> string
// * [ ] sin (x) -> number
// * [ ] slice (x, y, z) -> list
// * [ ] split (x, y) -> list(string)
// * [ ] sqrt (x) -> number
// * [ ] str_slice (x, y, z) -> string
// * [ ] stringify (x) -> string
// * [ ] sub (x, y) -> number
// * [ ] tan (x) -> number
// * [ ] to_list (x) -> list
// * [ ] to_number (x) -> number
// * [ ] trim (x) -> string
// * [ ] triml (x) -> string
// * [ ] trimr (x) -> string
// * [ ] type (x) -> keyword
// * [ ] upcase (x) -> string
// * [x] add (x, y) -> number
// * [x] eq (x, y) -> bool
// * [x] store! (x, y) -> value
// * [x] unbox (x) -> value