import { memory: Memory, STRING_BYTE_LENGTH : i32, log : Log } from 'env';
import { setBaseAddress, align } from '../malloc';
import { getStringIterator, next, decodeLEB, done } from '../string';
import { StringIterator } from '../string';

type Log = (i32) => void;

let EOL : i32;
let EOF : i32;

let byteOffset : i32 = 0;
let pos : i32 = 0;
let col : i32 = 0;
let line : i32 = 0;
let iterator : StringIterator = 0;
let linesArray : i32;

export function _newLine() {
  line += 1;
  col = 0;
}

// Get next character in the stream
export function _next() : i32 {
  next(iterator);

  const character : i32 = iterator.value;

  if (character == EOL) {
    _newLine();
  } else {
    col += 1;
  }

  return character;
}

// Get current column number
export function _column() : i32 {
  return col;
}

// Get current line number
export function _line() : i32 {
  return line;
}

// Peek at the next character in the stream
export function _peek() : i32 {
  if (iterator.length == 0 || iterator.index == iterator.length) {
    return 0;
  }
  // decodeLEB gives a i64 so that it can return an updated address and value
  // we only need the value, since the address is not changed for the iterator
  const result : i64 = decodeLEB(iterator.addr);
  return (result : i32);
}

// Is the charater a whitespace
export function whitespace(char : i32) : i32 {
  return (
    char == '\n' ||
    char == ' ' ||
    char == '\t' ||
    char == '\v' ||
    char == '\r' ||
    char == '\f'
  );
}

// Initializer
function start() {
  // Fix this once global strings work
  EOL = '\n';
  EOF = 0;

  setBaseAddress(align(STRING_BYTE_LENGTH));
  iterator = getStringIterator(0);

  _newLine();
}