use std::fmt;
use std::fmt::{Debug, Formatter};
use track::{Span, Posn};
use word::{Reserved, Name};

#[derive(Debug, PartialEq)]
pub struct Token {
    pub location: Span,
    pub newline: bool,    // was there a newline between the preceding token and this one?
    pub value: TokenData
}

impl Token {
    pub fn new(start: Posn, end: Posn, value: TokenData) -> Token {
        Token {
            location: Span { start: start, end: end },
            newline: false,
            value: value
        }
    }
}

#[derive(Debug, PartialEq)]
pub enum TokenData {
    Reserved(Reserved),

    // 11.7 Punctuators
    LBrace,
    RBrace,
    LParen,
    RParen,
    LBrack,
    RBrack,
    Dot,
    //Ellipsis,
    Semi,
    Comma,
    LAngle,
    RAngle,
    LEq,
    GEq,
    Eq,
    NEq,
    StrictEq,
    StrictNEq,
    Plus,
    Minus,
    Star,
    Mod,
    Slash,
    Inc,
    Dec,
    LShift,
    RShift,
    URShift,
    BitAnd,
    BitOr,
    BitXor,
    Bang,
    Tilde,
    LogicalAnd,
    LogicalOr,
    Question,
    Colon,
    Assign,
    PlusAssign,
    MinusAssign,
    StarAssign,
    SlashAssign,
    ModAssign,
    LShiftAssign,
    RShiftAssign,
    URShiftAssign,
    BitAndAssign,
    BitOrAssign,
    BitXorAssign,
    Arrow,

    Number(NumberLiteral),
    String(StringLiteral),
    RegExp(RegExpLiteral),

    Identifier(Name),

    EOF
}

pub struct RegExpLiteral {
    pub pattern: String,
    pub flags: Vec<char>
}

trait CharsEx {
    fn alphabetize(&self) -> Vec<char>;
}

impl CharsEx for Vec<char> {
    fn alphabetize(&self) -> Vec<char> {
        let mut x: Vec<char> = self.to_vec();
        x.sort();
        x
    }
}

impl Debug for RegExpLiteral {
    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        fmt.debug_struct("RegExpLiteral")
            .field("pattern", &self.pattern)
            .field("flags", &self.flags.alphabetize())
            .finish()
    }
}

impl PartialEq for RegExpLiteral {
    fn eq(&self, other: &Self) -> bool {
        (self.pattern == other.pattern) &&
        (self.flags.alphabetize() == other.flags.alphabetize())
    }
}

pub struct StringLiteral {
    pub source: Option<String>,
    pub value: String
}

impl Debug for StringLiteral {
    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        fmt.debug_struct("StringLiteral")
            .field("value", &self.value)
            .finish()
    }
}

impl PartialEq for StringLiteral {
    fn eq(&self, other: &Self) -> bool {
        self.value == other.value
    }
}

pub struct NumberLiteral {
    pub source: Option<NumberSource>,
    pub value: f64
}

impl Debug for NumberLiteral {
    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        fmt.debug_struct("NumberLiteral")
            .field("value", &self.value)
            .finish()
    }
}

impl PartialEq for NumberLiteral {
    fn eq(&self, other: &Self) -> bool {
        self.value == other.value
    }
}

#[derive(Debug, PartialEq)]
pub enum NumberSource {
    DecimalInt(String, Option<Exp>),
    RadixInt(Radix, String),
    Float(Option<String>, Option<String>, Option<Exp>)
}

fn format_sign(sign: &Option<Sign>) -> String {
    match *sign {
        Some(Sign::Minus) => "-",
        _ => ""
    }.to_string()
}

fn format_int(src: &Option<String>) -> String {
    match *src {
        None        => "".to_string(),
        Some(ref s) => s.to_string()
    }
}

impl NumberSource {
    pub fn value(&self) -> f64 {
        match *self {
            NumberSource::DecimalInt(ref mantissa, None) => {
                let i: i64 = mantissa.parse().ok().unwrap();
                i as f64
            }
            NumberSource::DecimalInt(ref mantissa, Some(Exp { ref sign, ref value, .. })) => {
                let mantissa: i64 = mantissa.parse().ok().unwrap();
                let mantissa: f64 = mantissa as f64;
                let exp: i32 = value.parse().ok().unwrap();
                mantissa * (10 as f64).powi(if *sign == Some(Sign::Minus) { -exp } else { exp })
            }
            NumberSource::RadixInt(ref radix, ref src) => {
                let i = i64::from_str_radix(&src[..], radix.value()).ok().unwrap();
                i as f64
            }
            NumberSource::Float(ref ip, ref fp, None) => {
                format!("{}.{}", format_int(ip), format_int(fp)).parse().ok().unwrap()
            }
            NumberSource::Float(ref ip, ref fp, Some(Exp { ref sign, ref value, .. })) => {
                format!("{}.{}e{}{}", format_int(ip), format_int(fp), format_sign(sign), value).parse().ok().unwrap()
            }
        }
    }

    pub fn into_token_data(self) -> TokenData {
        let value = self.value();
        TokenData::Number(NumberLiteral {
            source: Some(self),
            value: value
        })
    }
}

#[derive(Debug, PartialEq)]
pub struct Exp {
    pub e: CharCase,
    pub sign: Option<Sign>,
    pub value: String
}

#[derive(Debug, PartialEq, Copy, Clone)]
pub enum Radix {
    Bin(CharCase),
    Oct(Option<CharCase>),
    Hex(CharCase)
}

impl Radix {
    pub fn value(&self) -> u32 {
        match *self {
            Radix::Bin(_) => 2,
            Radix::Oct(_) => 8,
            Radix::Hex(_) => 16
        }
    }
}

#[derive(Debug, PartialEq, Copy, Clone)]
pub enum CharCase {
    LowerCase,
    UpperCase
}

#[derive(Debug, PartialEq, Copy, Clone)]
pub enum Sign {
    Plus,
    Minus
}