use core::panic;
use std::fmt::Display;

use crate::parser::ast::expr::Path;

#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Ident(pub String);

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

impl Ident {
    pub fn as_path(self) -> Path {
        Path(vec![self])
    }
}


#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Number {
    pub val: usize,
    pub base: u8,
    pub signed: bool,
}

impl Display for Number {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self.base {
            2 => write!(f, "{:#b}", self.val),
            8 => write!(f, "{:#o}", self.val),
            10 => {
                if self.signed {
                    write!(f, "{}", self.val as isize)
                } else {
                    write!(f, "{}", self.val as usize)
                }
            }
            16 => write!(f, "{:#x}", self.val),
            _ => unreachable!()
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
pub struct TString {
    pub val: String,
    pub cstr: bool,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Char(pub char);

impl Into<char> for Char {
    fn into(self) -> char {
        self.0
    }
}

impl From<char> for Char {
    fn from(value: char) -> Self {
        Char(value)
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Keyword {
    Fn, If, Else, Struct, Enum, 
    Type, While, For, Break, Continue,
    Let, Const, Mut, Static,
    True, False, Include, Extern, Return, 
    As, Loop
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Delimiter {
    CurlyL, CurlyR,
    SquareL, SquareR,
    ParenL, ParenR,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Punctuation {
    Semi, Colon, Pathsep, Comma,
    Arrow, FatArrow, Plus, Minus,
    Ampersand, Star, Div,
    Mod, Shl, Shr, AndAnd,
    OrOr, Or, Xor, Not,
    AddEq, SubEq,
    DivEq, MulEq,
    ModEq, ShlEq,
    ShrEq, AndEq,
    OrEq, XorEq,
    Eq, EqEq, Fieldaccess,
    Pathaccess, Lt, Gt, Le, Ge, Neq

}

impl Punctuation {

    // pls help
    pub fn precedence(&self) -> Option<(usize, usize)> {
        match self {
                Punctuation::AddEq |
                Punctuation::SubEq |
                Punctuation::DivEq |
                Punctuation::MulEq |
                Punctuation::ModEq |
                Punctuation::ShlEq |
                Punctuation::ShrEq |
                Punctuation::AndEq |
                Punctuation::OrEq |
                Punctuation::XorEq |
                Punctuation::Eq => Some((1, 2)),
                
                Punctuation::EqEq |
                Punctuation::Neq => Some((3, 4)),

                Punctuation::Div  |
                Punctuation::Star |
                Punctuation::Mod  => Some((5,6)),

                Punctuation::Plus |
                Punctuation::Minus => Some((7,8)),
                
                Punctuation::Shl |
                Punctuation::Shr  => Some((9,10)),
                
                Punctuation::Lt |
                Punctuation::Gt |
                Punctuation::Le |
                Punctuation::Ge  => Some((11, 12)),

                Punctuation::Ampersand => Some((13, 14)),
                Punctuation::Xor => Some((15, 16)),
                Punctuation::Or => Some((17, 18)),
                Punctuation::AndAnd => Some((19, 20)),
                Punctuation::OrOr => Some((21, 22)),
                
                _ => None
            }

    }
}

#[derive(Debug, Clone, Hash, PartialEq, PartialOrd, Ord, Eq)]
pub enum TokenType {
    Ident(Ident),
    Number(Number),
    String(TString),
    Char(Char),
    Keyword(Keyword), 
    Delim(Delimiter), 
    Punct(Punctuation),
    Comment(Comment),
}

#[derive(Debug, Clone, Hash, PartialEq, PartialOrd, Ord, Eq)]
pub enum Comment {
    Line(String),
    Block(String)
}

impl TokenType {
    pub fn unwrap_ident(&self) -> Ident {
        match self {
            Self::Ident(i) => i.clone(),
            _ => panic!("Expected {}, got {self}", Self::ident(""))
        }
    } 
    pub fn ident(s: &str) -> Self {
        Self::Ident(Ident(s.to_string()))
    }
    pub fn number(val: usize, base: u8, signed: bool) -> Self {
        Self::Number(Number { val, base, signed })
    }
    pub fn string(s: &str, cstr: bool) -> Self{
        Self::String(TString { val: s.to_string(), cstr })
    }
    pub fn char(v: char) -> Self {
        Self::Char(Char(v))
    }
    pub fn from_str(s: &str) -> Option<Self> {
        super::TT.get(s).cloned()
    }
    pub fn to_str(&self) -> String {
        for (k, v) in super::TT.iter() {
            if v == self {
                return k.to_string();
            }
        }

        match self {
            TokenType::Ident(s) => {
                return format!("Ident(\"{}\")", s.to_string());
            },
            TokenType::Number(num) => {
                match num.base {
                    2 => {
                        assert!(!num.signed, "base 2 (binary) numbers physically cannot be signed");
                        format!("{:#b}", num.val)
                    }
                    8 => {
                        assert!(!num.signed, "base 8 (octal) numbers physically cannot be signed");
                        format!("{:#o}", num.val)
                    }
                    10 => {
                        if num.signed {
                            format!("{}", num.val as isize)
                        } else {
                            format!("{}", num.val)
                        }
                    }
                    16 => {
                        assert!(!num.signed, "base 16 (hex) numbers physically cannot be signed");
                        format!("{:#x}", num.val)
                    }
                    _ => panic!("Invalid base for number, {}", num.base),
                }
            },
            TokenType::String(s) => {
                if s.cstr {
                    format!("\"{}\\0\"", s.val)
                } else {
                    format!("\"{}\"", s.val)
                }
            },
            TokenType::Char(c) => {
                format!("'{}'", c.0)
            }
            _ => unreachable!("Unreachable, did you add a new token and forget to add reverse lookup?"),
        }
    }
}

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