use internal::{IResult,Err};
use std::collections::HashMap;

pub trait HexDisplay {
  fn offset(&self, second:&[u8]) -> usize;

  /// Converts the value of `self` to a hex value, returning the owned
  /// string.
  fn to_hex(&self, chunk_size: usize) -> String;

  fn to_hex_from(&self, chunk_size: usize, from: usize) -> String;
}

static CHARS: &'static[u8] = b"0123456789abcdef";


impl HexDisplay for [u8] {
  fn offset(&self, second:&[u8]) -> usize {
    let fst = self.as_ptr();
    let snd = second.as_ptr();

    snd as usize - fst as usize
  }

  #[allow(unused_variables)]
  fn to_hex(&self, chunk_size: usize) -> String {
    self.to_hex_from(chunk_size, 0)
  }

  #[allow(unused_variables)]
  fn to_hex_from(&self, chunk_size: usize, from: usize) -> String {
    let mut v = Vec::with_capacity(self.len() * 3);
    let mut i = from;
    for chunk in self.chunks(chunk_size) {
      let s = format!("{:08x}", i);
      for &ch in s.as_bytes().iter() {
        v.push(ch);
      }
      v.push('\t' as u8);

      i = i + chunk_size;

      for &byte in chunk {
        v.push(CHARS[(byte >> 4) as usize]);
        v.push(CHARS[(byte & 0xf) as usize]);
        v.push(' ' as u8);
      }
      if chunk_size > chunk.len() {
        for j in 0..(chunk_size - chunk.len()) {
          v.push(' ' as u8);
          v.push(' ' as u8);
          v.push(' ' as u8);
        }
      }
      v.push('\t' as u8);

      for &byte in chunk {
        if (byte >=32 && byte <= 126) || byte >= 128 {
          v.push(byte);
        } else {
          v.push('.' as u8);
        }
      }
      v.push('\n' as u8);
    }

    unsafe {
      String::from_utf8_unchecked(v)
    }
  }
}

/// Prints a message if the parser fails
///
/// The message prints the `Error` or `Incomplete`
/// and the parser's calling code
///
/// ```
/// # #[macro_use] extern crate nom;
/// # fn main() {
///    named!(f, dbg!( tag!( "abcd" ) ) );
///
///    let a = &b"efgh"[..];
///
///    // Will print the following message:
///    // Error(Position(0, [101, 102, 103, 104])) at l.5 by ' tag ! ( "abcd" ) '
///    f(a);
/// # }
/// ```
#[macro_export]
macro_rules! dbg (
  ($i: expr, $submac:ident!( $($args:tt)* )) => (
    {
      let l = line!();
      match $submac!($i, $($args)*) {
        $crate::IResult::Error(a) => {
          println!("Error({:?}) at l.{} by ' {} '", a, l, stringify!($submac!($($args)*)));
          $crate::IResult::Error(a)
        },
        $crate::IResult::Incomplete(a) => {
          println!("Incomplete({:?}) at {} by ' {} '", a, l, stringify!($submac!($($args)*)));
          $crate::IResult::Incomplete(a)
        },
        a => a
      }
    }
  );
);

/// Prints a message and the input if the parser fails
///
/// The message prints the `Error` or `Incomplete`
/// and the parser's calling code.
///
/// It also displays the input in hexdump format
///
/// ```
/// # #[macro_use] extern crate nom;
/// # fn main() {
///    named!(f, dbg_dmp!( tag!( "abcd" ) ) );
///
///    let a = &b"efghijkl"[..];
///
///    // Will print the following message:
///    // Error(Position(0, [101, 102, 103, 104, 105, 106, 107, 108])) at l.5 by ' tag ! ( "abcd" ) '
///    // 00000000        65 66 67 68 69 6a 6b 6c         efghijkl
///    f(a);
/// # }
#[macro_export]
macro_rules! dbg_dmp (
  ($i: expr, $submac:ident!( $($args:tt)* )) => (
    {
      use $crate::util::HexDisplay;
      let l = line!();
      match $submac!($i, $($args)*) {
        $crate::IResult::Error(a) => {
          println!("Error({:?}) at l.{} by ' {} '\n{}", a, l, stringify!($submac!($($args)*)), $i.to_hex(8));
          $crate::IResult::Error(a)
        },
        $crate::IResult::Incomplete(a) => {
          println!("Incomplete({:?}) at {} by ' {} '\n{}", a, l, stringify!($submac!($($args)*)), $i.to_hex(8));
          $crate::IResult::Incomplete(a)
        },
        a => a
      }
    }
  );
);

pub fn error_to_list(e:Err) -> Vec<u32> {
  let mut v:Vec<u32> = Vec::new();
  let mut err = e;
  loop {
    match err {
      Err::Code(i) | Err::Position(i,_)                  => {
        v.push(i);
        return v;
      },
      Err::Node(i, next) | Err::NodePosition(i, _, next) => {
        v.push(i);
        err = *next;
      }
    }
  }
}

pub fn compare_error_paths(e1:Err, e2:Err) -> bool {
  return error_to_list(e1) == error_to_list(e2)
}

pub fn add_error_pattern<'a,'b,I,O>(h: &mut HashMap<Vec<u32>, &'b str>, res: IResult<'a,I,O>, message: &'b str) -> bool {
  if let IResult::Error(e) = res {
    h.insert(error_to_list(e), message);
    true
  } else {
    false
  }
}

pub trait AsBytes {
  fn as_bytes(&self) -> &[u8];
}

impl<'a> AsBytes for &'a str {
  #[inline(always)]
  fn as_bytes(&self) -> &[u8] {
    str::as_bytes(self)
  }
}

impl AsBytes for str {
  #[inline(always)]
  fn as_bytes(&self) -> &[u8] {
    str::as_bytes(self)
  }
}

impl<'a> AsBytes for &'a [u8] {
  #[inline(always)]
  fn as_bytes(&self) -> &[u8] {
    *self
  }
}

impl AsBytes for [u8] {
  #[inline(always)]
  fn as_bytes(&self) -> &[u8] {
    self
  }
}

pub enum ErrorCode {
  Tag,
  MapRes,
  MapOpt,
  Alt,
  IsNot,
  IsA,
  Filter,
  SeparatedList,
  SeparatedNonEmptyList,
  Many1,
  Count,
  TakeUntilAndConsume,
  TakeUntil,
  TakeUntilEitherAndConsume,
  TakeUntilEither,
  LengthValue,
  TagClosure,
  Alpha,
  Digit,
  AlphaNumeric,
  Space,
  MultiSpace,
  LengthValueFn,
  Eof
}