use crate::base::BaseFn;
use crate::compiler::Chunk;
use crate::parser::Ast;
use crate::spans::Spanned;
use imbl::{HashMap, Vector};
use std::cell::RefCell;
use std::rc::Rc;

#[derive(Clone, Debug)]
pub enum LFn {
    Declared {
        name: &'static str,
    },
    Defined {
        name: &'static str,
        doc: Option<&'static str>,
        chunks: Vec<(u8, Chunk)>,
        closed: RefCell<Vec<Value>>,
    },
}

impl LFn {
    pub fn close(&self, value: Value) {
        match self {
            LFn::Declared { .. } => unreachable!(),
            LFn::Defined { closed, .. } => {
                closed.borrow_mut().push(value);
            }
        }
    }

    pub fn doc(&self) -> Value {
        match self {
            LFn::Declared { name } => {
                Value::String(Rc::new(format!("fn {name}: undefined function")))
            }
            LFn::Defined {
                name,
                doc: Some(doc),
                ..
            } => Value::String(Rc::new(format!("fn {name}\n{doc}"))),
            LFn::Defined { name, .. } => {
                Value::String(Rc::new(format!("fn {name}: no documentation")))
            }
        }
    }

    pub fn name(&self) -> &'static str {
        match self {
            LFn::Declared { name } | LFn::Defined { name, .. } => name,
        }
    }

    pub fn chunk(&self, arity: u8) -> &Chunk {
        // println!("Getting chunk of {arity} from {:?}", self);
        match self {
            LFn::Declared { .. } => unreachable!(),
            LFn::Defined { chunks, .. } => &chunks.iter().find(|(a, _)| *a == arity).unwrap().1,
        }
    }

    pub fn upvalue(&self, idx: u8) -> Value {
        match self {
            LFn::Declared { .. } => unreachable!(),
            LFn::Defined { closed, .. } => closed.borrow()[idx as usize].clone(),
        }
    }
}

#[derive(Clone, Debug, PartialEq)]
pub struct Partial {
    pub args: Vec<Value>,
    pub name: &'static str,
    pub function: Value,
}

#[derive(Clone, Debug)]
pub enum Value {
    Nothing,
    Nil,
    True,
    False,
    Keyword(&'static str),
    Interned(&'static str),
    String(Rc<String>),
    Number(f64),
    Tuple(Rc<Vec<Value>>),
    List(Box<Vector<Value>>),
    Dict(Box<HashMap<&'static str, Value>>),
    Box(Rc<RefCell<Value>>),
    Fn(Rc<LFn>),
    BaseFn(BaseFn),
    Partial(Rc<Partial>),
}

impl PartialEq for Value {
    fn eq(&self, other: &Value) -> bool {
        use Value::*;
        match (self, other) {
            (Nothing, Nothing) | (Nil, Nil) | (True, True) | (False, False) => true,
            (Keyword(str1), Keyword(str2)) | (Interned(str1), Interned(str2)) => str1 == str2,
            (String(x), String(y)) => x == y,
            (String(x), Interned(y)) => x.as_ref() == y,
            (Interned(x), String(y)) => x == y.as_ref(),
            (Number(x), Number(y)) => x == y,
            (Tuple(x), Tuple(y)) => x == y,
            (List(x), List(y)) => x == y,
            (Dict(x), Dict(y)) => x == y,
            (Box(x), Box(y)) => std::ptr::eq(x.as_ref().as_ptr(), y.as_ref().as_ptr()),
            (Fn(x), Fn(y)) => std::ptr::eq(x, y),
            (BaseFn(x), BaseFn(y)) => std::ptr::eq(x, y),
            (Partial(x), Partial(y)) => x == y,
            _ => false,
        }
    }
}

impl std::fmt::Display for Value {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        use Value::*;
        match self {
            Nothing => write!(f, "_"),
            Nil => write!(f, "nil"),
            True => write!(f, "true"),
            False => write!(f, "false"),
            Keyword(str) => write!(f, ":{str}"),
            Interned(str) => write!(f, "\"{str}\""),
            String(str) => write!(f, "\"{str}\""),
            Number(n) => write!(f, "{n}"),
            Tuple(members) => write!(
                f,
                "({})",
                members
                    .iter()
                    .map(|x| x.to_string())
                    .collect::<Vec<_>>()
                    .join(", ")
            ),
            List(members) => write!(
                f,
                "[{}]",
                members
                    .iter()
                    .map(|x| x.to_string())
                    .collect::<Vec<_>>()
                    .join(", ")
            ),
            Dict(members) => write!(
                f,
                "#{{{}}}",
                members
                    .iter()
                    .map(|(k, v)| format!("{k} {v}"))
                    .collect::<Vec<_>>()
                    .join(", ")
            ),
            Box(value) => write!(f, "box {{ {} }}", value.as_ref().borrow()),
            Fn(lfn) => write!(f, "fn {}", lfn.name()),
            BaseFn(_) => write!(f, "base fn"),
            Partial(partial) => write!(f, "fn {}/partial", partial.name),
        }
    }
}

impl Value {
    pub fn show(&self) -> String {
        use Value::*;
        match &self {
            Nil => "nil".to_string(),
            True => "true".to_string(),
            False => "false".to_string(),
            Number(n) => format!("{n}"),
            Interned(str) => format!("\"{str}\""),
            String(str) => {
                let str_str = str.to_string();
                format!("\"{str_str}\"")
            }
            Keyword(str) => format!(":{str}"),
            Tuple(t) => {
                let members = t.iter().map(|e| e.show()).collect::<Vec<_>>().join(", ");
                format!("({members})")
            }
            List(l) => {
                let members = l.iter().map(|e| e.show()).collect::<Vec<_>>().join(", ");
                format!("[{members}]")
            }
            Dict(d) => {
                let members = d
                    .iter()
                    .map(|(k, v)| {
                        let key_show = Value::Keyword(k).show();
                        let value_show = v.show();
                        format!("{key_show} {value_show}")
                    })
                    .collect::<Vec<_>>()
                    .join(", ");
                format!("#{{{members}}}")
            }
            Box(x) => format!("box {{ {} }}", x.as_ref().borrow().show()),
            Fn(lfn) => format!("fn {}", lfn.name()),
            Partial(partial) => format!("fn {}/partial", partial.name),
            BaseFn(_) => "base fn".to_string(),
            Nothing => unreachable!(),
        }
    }

    pub fn stringify(&self) -> String {
        use Value::*;
        match &self {
            Nil => "nil".to_string(),
            True => "true".to_string(),
            False => "false".to_string(),
            Number(n) => format!("{n}"),
            Interned(str) => str.to_string(),
            Keyword(str) => str.to_string(),
            Tuple(t) => {
                let members = t
                    .iter()
                    .map(|e| e.stringify())
                    .collect::<Vec<_>>()
                    .join(", ");
                members.to_string()
            }
            List(l) => {
                let members = l
                    .iter()
                    .map(|e| e.stringify())
                    .collect::<Vec<_>>()
                    .join(", ");
                members.to_string()
            }
            Dict(d) => {
                let members = d
                    .iter()
                    .map(|(k, v)| {
                        let key_show = Value::Keyword(k).stringify();
                        let value_show = v.stringify();
                        format!("{key_show} {value_show}")
                    })
                    .collect::<Vec<_>>()
                    .join(", ");
                members.to_string()
            }
            String(s) => s.as_ref().clone(),
            Box(x) => x.as_ref().borrow().stringify(),
            Fn(lfn) => format!("fn {}", lfn.name()),
            _ => todo!(),
        }
    }

    pub fn type_of(&self) -> &'static str {
        use Value::*;
        match self {
            Nothing => unreachable!(),
            Nil => "nil",
            True => "bool",
            False => "bool",
            Keyword(..) => "keyword",
            Interned(..) => "string",
            String(..) => "string",
            Number(..) => "number",
            Tuple(..) => "tuple",
            List(..) => "list",
            Dict(..) => "dict",
            Box(..) => "box",
            Fn(..) => "fn",
            BaseFn(..) => "fn",
            Partial(..) => "fn",
        }
    }
}