use std::rc::Rc;
use std::collections::HashMap;
use std::str::FromStr;

use crate::tokenizing::TokenKind;
use crate::typechecking::{TypeConst, Type};

#[derive(Debug, Clone, Copy, PartialEq)]
pub enum Builtin {
  Add,
  Subtract,
  Multiply,
  Divide,
  Quotient,
  Modulo,
  Exponentiation,
  BitwiseAnd,
  BitwiseOr,
  BooleanAnd,
  BooleanOr,
  BooleanNot,
  Equality,
  LessThan,
  LessThanOrEqual,
  GreaterThan,
  GreaterThanOrEqual,
  Comparison,
  FieldAccess,
  IOPrint,
  IOPrintLn,
  IOGetLine,
  Assignment,
  Concatenate,
}

impl Builtin {
  pub fn get_type(&self) -> Type {
    ty!(Nat -> Nat -> Nat)
  }
}

impl FromStr for Builtin {
  type Err = ();

  fn from_str(s: &str) -> Result<Self, Self::Err> {
    use Builtin::*;
    Ok(match s {
      "+" => Add,
      "-" => Subtract,
      "*" => Multiply,
      "/" => Divide,
      "quot" => Quotient,
      "%" => Modulo,
      "++" => Concatenate,
      "^" =>  Exponentiation,
      "&" => BitwiseAnd,
      "&&" => BooleanAnd,
      "|" => BitwiseOr,
      "||" => BooleanOr,
      "!" => BooleanNot,
      ">" => GreaterThan,
      ">=" => GreaterThanOrEqual,
      "<" => LessThan,
      "<=" => LessThanOrEqual,
      "==" => Equality,
      "=" => Assignment,
      "<=>" => Comparison,
      "." => FieldAccess,
      "print" => IOPrint,
      "println" => IOPrintLn,
      "getline" => IOGetLine,
      _ => return Err(())
    })
  }
}

#[derive(Debug, PartialEq, Clone)]
pub struct BinOp {
  sigil: Rc<String>
}

impl BinOp {
  pub fn from_sigil(sigil: &str) -> BinOp {
    BinOp { sigil: Rc::new(sigil.to_string()) }
  }
  pub fn sigil(&self) -> &Rc<String> {
    &self.sigil
  }
  pub fn from_sigil_token(tok: &TokenKind) -> Option<BinOp> {
    use self::TokenKind::*;
    let s = match tok {
      Operator(op) => op,
      Period => ".",
      Pipe => "|",
      Slash => "/",
      LAngleBracket => "<",
      RAngleBracket => ">",
      Equals => "=",
      _ => return None
    };
    Some(BinOp::from_sigil(s))
  }

  pub fn get_type(&self) -> Result<Type, String> {
    let s = self.sigil.as_str();
    BINOPS.get(s).map(|x| x.0.clone()).ok_or(format!("Binop {} not found", s))
  }

  pub fn min_precedence() -> i32 {
    i32::min_value()
  }
  pub fn get_precedence_from_token(op: &TokenKind) -> Option<i32> {
    use self::TokenKind::*;
    let s = match op {
      Operator(op) => op,
      Period => ".",
      Pipe => "|",
      Slash => "/",
      LAngleBracket => "<",
      RAngleBracket => ">",
      Equals => "=",
      _ => return None
    };
    let default = 10_000_000;
    Some(BINOPS.get(s).map(|x| x.2.clone()).unwrap_or_else(|| {
      default
    }))
  }

  pub fn get_precedence(&self) -> i32 {
    let s: &str = &self.sigil;
    let default = 10_000_000;
    BINOPS.get(s).map(|x| x.2.clone()).unwrap_or_else(|| {
      default
    })
  }
}


//TODO mapping between sigil string and precedence should live in ast.rs
//mapping between operation and type should live here in builtins.rs

/* the second tuple member is a placeholder for when I want to make evaluation rules tied to the
 * binop definition */
//TODO some of these types are going to have to be adjusted
lazy_static! {
  static ref BINOPS: HashMap<&'static str, (Type, (), i32)> =
    hashmap! {
      "+" => (ty!(Nat -> Nat -> Nat), (), 10),
      "-" => (ty!(Nat -> Nat -> Nat), (), 10),
      "*" => (ty!(Nat -> Nat -> Nat), (), 20),
      "/" => (ty!(Nat -> Nat -> Float), (), 20),
      "quot" => (ty!(Nat -> Nat -> Nat), (), 20),
      "%" => (ty!(Nat -> Nat -> Nat), (), 20),
      "++" => (ty!(StringT -> StringT -> StringT), (), 30),
      "^" => (ty!(Nat -> Nat -> Nat), (), 20),
      "&" => (ty!(Nat -> Nat -> Nat), (), 20),
      "|" => (ty!(Nat -> Nat -> Nat), (), 20),
      ">" => (ty!(Nat -> Nat -> Bool), (), 20),
      ">=" => (ty!(Nat -> Nat -> Bool), (), 20),
      "<" => (ty!(Nat -> Nat -> Bool), (), 20),
      "<=" => (ty!(Nat -> Nat -> Bool), (), 20),
      "==" => (ty!(Nat -> Nat -> Bool), (), 20),
      "=" => (ty!(Unit), (), 20), //TODO not sure what the type of this should be b/c special fmr
      "<=>" => (ty!(Nat -> Nat -> Ordering), (), 20), //TODO figure out how to treat Order
    };
}