import { bind } from 'lodash';

// This is auto generated from the unicode tables.
// The tables are at:
// http://www.fileformat.info/info/unicode/category/Lu/list.htm
// http://www.fileformat.info/info/unicode/category/Ll/list.htm
// http://www.fileformat.info/info/unicode/category/Lt/list.htm
// http://www.fileformat.info/info/unicode/category/Lm/list.htm
// http://www.fileformat.info/info/unicode/category/Lo/list.htm
// http://www.fileformat.info/info/unicode/category/Nl/list.htm

const unicodeLetterTable = [
  170, 170, 181, 181, 186, 186, 192, 214, 216, 246, 248, 705, 710, 721, 736, 740, 748, 748, 750, 750, 880, 884, 886,
  887, 890, 893, 902, 902, 904, 906, 908, 908, 910, 929, 931, 1013, 1015, 1153, 1162, 1319, 1329, 1366, 1369, 1369,
  1377, 1415, 1488, 1514, 1520, 1522, 1568, 1610, 1646, 1647, 1649, 1747, 1749, 1749, 1765, 1766, 1774, 1775, 1786,
  1788, 1791, 1791, 1808, 1808, 1810, 1839, 1869, 1957, 1969, 1969, 1994, 2026, 2036, 2037, 2042, 2042, 2048, 2069,
  2074, 2074, 2084, 2084, 2088, 2088, 2112, 2136, 2308, 2361, 2365, 2365, 2384, 2384, 2392, 2401, 2417, 2423, 2425,
  2431, 2437, 2444, 2447, 2448, 2451, 2472, 2474, 2480, 2482, 2482, 2486, 2489, 2493, 2493, 2510, 2510, 2524, 2525,
  2527, 2529, 2544, 2545, 2565, 2570, 2575, 2576, 2579, 2600, 2602, 2608, 2610, 2611, 2613, 2614, 2616, 2617, 2649,
  2652, 2654, 2654, 2674, 2676, 2693, 2701, 2703, 2705, 2707, 2728, 2730, 2736, 2738, 2739, 2741, 2745, 2749, 2749,
  2768, 2768, 2784, 2785, 2821, 2828, 2831, 2832, 2835, 2856, 2858, 2864, 2866, 2867, 2869, 2873, 2877, 2877, 2908,
  2909, 2911, 2913, 2929, 2929, 2947, 2947, 2949, 2954, 2958, 2960, 2962, 2965, 2969, 2970, 2972, 2972, 2974, 2975,
  2979, 2980, 2984, 2986, 2990, 3001, 3024, 3024, 3077, 3084, 3086, 3088, 3090, 3112, 3114, 3123, 3125, 3129, 3133,
  3133, 3160, 3161, 3168, 3169, 3205, 3212, 3214, 3216, 3218, 3240, 3242, 3251, 3253, 3257, 3261, 3261, 3294, 3294,
  3296, 3297, 3313, 3314, 3333, 3340, 3342, 3344, 3346, 3386, 3389, 3389, 3406, 3406, 3424, 3425, 3450, 3455, 3461,
  3478, 3482, 3505, 3507, 3515, 3517, 3517, 3520, 3526, 3585, 3632, 3634, 3635, 3648, 3654, 3713, 3714, 3716, 3716,
  3719, 3720, 3722, 3722, 3725, 3725, 3732, 3735, 3737, 3743, 3745, 3747, 3749, 3749, 3751, 3751, 3754, 3755, 3757,
  3760, 3762, 3763, 3773, 3773, 3776, 3780, 3782, 3782, 3804, 3805, 3840, 3840, 3904, 3911, 3913, 3948, 3976, 3980,
  4096, 4138, 4159, 4159, 4176, 4181, 4186, 4189, 4193, 4193, 4197, 4198, 4206, 4208, 4213, 4225, 4238, 4238, 4256,
  4293, 4304, 4346, 4348, 4348, 4352, 4680, 4682, 4685, 4688, 4694, 4696, 4696, 4698, 4701, 4704, 4744, 4746, 4749,
  4752, 4784, 4786, 4789, 4792, 4798, 4800, 4800, 4802, 4805, 4808, 4822, 4824, 4880, 4882, 4885, 4888, 4954, 4992,
  5007, 5024, 5108, 5121, 5740, 5743, 5759, 5761, 5786, 5792, 5866, 5870, 5872, 5888, 5900, 5902, 5905, 5920, 5937,
  5952, 5969, 5984, 5996, 5998, 6000, 6016, 6067, 6103, 6103, 6108, 6108, 6176, 6263, 6272, 6312, 6314, 6314, 6320,
  6389, 6400, 6428, 6480, 6509, 6512, 6516, 6528, 6571, 6593, 6599, 6656, 6678, 6688, 6740, 6823, 6823, 6917, 6963,
  6981, 6987, 7043, 7072, 7086, 7087, 7104, 7141, 7168, 7203, 7245, 7247, 7258, 7293, 7401, 7404, 7406, 7409, 7424,
  7615, 7680, 7957, 7960, 7965, 7968, 8005, 8008, 8013, 8016, 8023, 8025, 8025, 8027, 8027, 8029, 8029, 8031, 8061,
  8064, 8116, 8118, 8124, 8126, 8126, 8130, 8132, 8134, 8140, 8144, 8147, 8150, 8155, 8160, 8172, 8178, 8180, 8182,
  8188, 8305, 8305, 8319, 8319, 8336, 8348, 8450, 8450, 8455, 8455, 8458, 8467, 8469, 8469, 8473, 8477, 8484, 8484,
  8486, 8486, 8488, 8488, 8490, 8493, 8495, 8505, 8508, 8511, 8517, 8521, 8526, 8526, 8544, 8584, 11264, 11310, 11312,
  11358, 11360, 11492, 11499, 11502, 11520, 11557, 11568, 11621, 11631, 11631, 11648, 11670, 11680, 11686, 11688, 11694,
  11696, 11702, 11704, 11710, 11712, 11718, 11720, 11726, 11728, 11734, 11736, 11742, 11823, 11823, 12293, 12295, 12321,
  12329, 12337, 12341, 12344, 12348, 12353, 12438, 12445, 12447, 12449, 12538, 12540, 12543, 12549, 12589, 12593, 12686,
  12704, 12730, 12784, 12799, 13312, 13312, 19893, 19893, 19968, 19968, 40907, 40907, 40960, 42124, 42192, 42237, 42240,
  42508, 42512, 42527, 42538, 42539, 42560, 42606, 42623, 42647, 42656, 42735, 42775, 42783, 42786, 42888, 42891, 42894,
  42896, 42897, 42912, 42921, 43002, 43009, 43011, 43013, 43015, 43018, 43020, 43042, 43072, 43123, 43138, 43187, 43250,
  43255, 43259, 43259, 43274, 43301, 43312, 43334, 43360, 43388, 43396, 43442, 43471, 43471, 43520, 43560, 43584, 43586,
  43588, 43595, 43616, 43638, 43642, 43642, 43648, 43695, 43697, 43697, 43701, 43702, 43705, 43709, 43712, 43712, 43714,
  43714, 43739, 43741, 43777, 43782, 43785, 43790, 43793, 43798, 43808, 43814, 43816, 43822, 43968, 44002, 44032, 44032,
  55203, 55203, 55216, 55238, 55243, 55291, 63744, 64045, 64048, 64109, 64112, 64217, 64256, 64262, 64275, 64279, 64285,
  64285, 64287, 64296, 64298, 64310, 64312, 64316, 64318, 64318, 64320, 64321, 64323, 64324, 64326, 64433, 64467, 64829,
  64848, 64911, 64914, 64967, 65008, 65019, 65136, 65140, 65142, 65276, 65313, 65338, 65345, 65370, 65382, 65470, 65474,
  65479, 65482, 65487, 65490, 65495, 65498, 65500, 65536, 65547, 65549, 65574, 65576, 65594, 65596, 65597, 65599, 65613,
  65616, 65629, 65664, 65786, 65856, 65908, 66176, 66204, 66208, 66256, 66304, 66334, 66352, 66378, 66432, 66461, 66464,
  66499, 66504, 66511, 66513, 66517, 66560, 66717, 67584, 67589, 67592, 67592, 67594, 67637, 67639, 67640, 67644, 67644,
  67647, 67669, 67840, 67861, 67872, 67897, 68096, 68096, 68112, 68115, 68117, 68119, 68121, 68147, 68192, 68220, 68352,
  68405, 68416, 68437, 68448, 68466, 68608, 68680, 69635, 69687, 69763, 69807, 73728, 74606, 74752, 74850, 77824, 78894,
  92160, 92728, 110592, 110593, 119808, 119892, 119894, 119964, 119966, 119967, 119970, 119970, 119973, 119974, 119977,
  119980, 119982, 119993, 119995, 119995, 119997, 120003, 120005, 120069, 120071, 120074, 120077, 120084, 120086,
  120092, 120094, 120121, 120123, 120126, 120128, 120132, 120134, 120134, 120138, 120144, 120146, 120485, 120488,
  120512, 120514, 120538, 120540, 120570, 120572, 120596, 120598, 120628, 120630, 120654, 120656, 120686, 120688,
  120712, 120714, 120744, 120746, 120770, 120772, 120779, 131072, 131072, 173782, 173782, 173824, 173824, 177972,
  177972, 177984, 177984, 178205, 178205, 194560, 195101,
];

const identifierStartTable: any[] = [];

for (let i = 0; i < 128; i++) {
  identifierStartTable[i] =
    (i >= 48 && i <= 57) || // 0-9
    i === 36 || // $
    i === 126 || // ~
    i === 124 || // |
    (i >= 65 && i <= 90) || // A-Z
    i === 95 || // _
    i === 45 || // -
    i === 42 || // *
    i === 58 || // :
    i === 91 || // templateStart [
    i === 93 || // templateEnd ]
    i === 63 || // ?
    i === 37 || // %
    i === 35 || // #
    i === 61 || // =
    (i >= 97 && i <= 122); // a-z
}

const identifierPartTable = identifierStartTable;

export class Lexer {
  input: any;
  char: number;
  from: number;

  constructor(expression: any) {
    this.input = expression;
    this.char = 1;
    this.from = 1;
  }

  peek(i?: number) {
    return this.input.charAt(i || 0);
  }

  skip(i?: number) {
    i = i || 1;
    this.char += i;
    this.input = this.input.slice(i);
  }

  tokenize() {
    const list = [];
    let token = this.next();
    while (token) {
      list.push(token);
      token = this.next();
    }
    return list;
  }

  next() {
    this.from = this.char;

    // Move to the next non-space character.
    if (/\s/.test(this.peek())) {
      while (/\s/.test(this.peek())) {
        this.from += 1;
        this.skip();
      }

      if (this.peek() === '') {
        // EOL
        return null;
      }
    }

    let match = this.scanStringLiteral();
    if (match) {
      return match;
    }

    match = this.scanPunctuator() || this.scanNumericLiteral() || this.scanIdentifier() || this.scanTemplateSequence();

    if (match) {
      this.skip(match.value.length);
      return match;
    }

    // No token could be matched, give up.
    return null;
  }

  scanTemplateSequence() {
    if (this.peek() === '[' && this.peek(1) === '[') {
      return {
        type: 'templateStart',
        value: '[[',
        pos: this.char,
      };
    }

    if (this.peek() === ']' && this.peek(1) === ']') {
      return {
        type: 'templateEnd',
        value: '[[',
        pos: this.char,
      };
    }

    return null;
  }

  /*
   * Extract a JavaScript identifier out of the next sequence of
   * characters or return 'null' if its not possible. In addition,
   * to Identifier this method can also produce BooleanLiteral
   * (true/false) and NullLiteral (null).
   */
  scanIdentifier() {
    let id = '';
    let index = 0;
    let type, char;

    // Detects any character in the Unicode categories "Uppercase
    // letter (Lu)", "Lowercase letter (Ll)", "Titlecase letter
    // (Lt)", "Modifier letter (Lm)", "Other letter (Lo)", or
    // "Letter number (Nl)".
    //
    // Both approach and unicodeLetterTable were borrowed from
    // Google's Traceur.

    function isUnicodeLetter(code: number) {
      for (let i = 0; i < unicodeLetterTable.length; ) {
        if (code < unicodeLetterTable[i++]) {
          return false;
        }

        if (code <= unicodeLetterTable[i++]) {
          return true;
        }
      }

      return false;
    }

    function isHexDigit(str: string) {
      return /^[0-9a-fA-F]$/.test(str);
    }

    const readUnicodeEscapeSequence = bind(function (this: any) {
      index += 1;

      if (this.peek(index) !== 'u') {
        return null;
      }

      const ch1 = this.peek(index + 1);
      const ch2 = this.peek(index + 2);
      const ch3 = this.peek(index + 3);
      const ch4 = this.peek(index + 4);
      let code;

      if (isHexDigit(ch1) && isHexDigit(ch2) && isHexDigit(ch3) && isHexDigit(ch4)) {
        code = parseInt(ch1 + ch2 + ch3 + ch4, 16);

        if (isUnicodeLetter(code)) {
          index += 5;
          return '\\u' + ch1 + ch2 + ch3 + ch4;
        }

        return null;
      }

      return null;
    }, this);

    const getIdentifierStart = bind(function (this: any) {
      const chr = this.peek(index);
      const code = chr.charCodeAt(0);

      if (chr === '*') {
        index += 1;
        return chr;
      }

      if (code === 92) {
        return readUnicodeEscapeSequence();
      }

      if (code < 128) {
        if (identifierStartTable[code]) {
          index += 1;
          return chr;
        }

        return null;
      }

      if (isUnicodeLetter(code)) {
        index += 1;
        return chr;
      }

      return null;
    }, this);

    const getIdentifierPart = bind(function (this: any) {
      const chr = this.peek(index);
      const code = chr.charCodeAt(0);

      if (code === 92) {
        return readUnicodeEscapeSequence();
      }

      if (code < 128) {
        if (identifierPartTable[code]) {
          index += 1;
          return chr;
        }

        return null;
      }

      if (isUnicodeLetter(code)) {
        index += 1;
        return chr;
      }

      return null;
    }, this);

    char = getIdentifierStart();
    if (char === null) {
      return null;
    }

    id = char;
    for (;;) {
      char = getIdentifierPart();

      if (char === null) {
        break;
      }

      id += char;
    }

    switch (id) {
      case 'true': {
        type = 'bool';
        break;
      }
      case 'false': {
        type = 'bool';
        break;
      }
      default:
        type = 'identifier';
    }

    return {
      type: type,
      value: id,
      pos: this.char,
    };
  }

  /*
   * Extract a numeric literal out of the next sequence of
   * characters or return 'null' if its not possible. This method
   * supports all numeric literals described in section 7.8.3
   * of the EcmaScript 5 specification.
   *
   * This method's implementation was heavily influenced by the
   * scanNumericLiteral function in the Esprima parser's source code.
   */
  scanNumericLiteral(): any {
    let index = 0;
    let value = '';
    const length = this.input.length;
    let char = this.peek(index);
    let bad;

    function isDecimalDigit(str: string) {
      return /^[0-9]$/.test(str);
    }

    function isOctalDigit(str: string) {
      return /^[0-7]$/.test(str);
    }

    function isHexDigit(str: string) {
      return /^[0-9a-fA-F]$/.test(str);
    }

    function isIdentifierStart(ch: string) {
      return ch === '$' || ch === '_' || ch === '\\' || (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z');
    }

    // handle negative num literals
    if (char === '-') {
      value += char;
      index += 1;
      char = this.peek(index);
    }

    // Numbers must start either with a decimal digit or a point.
    if (char !== '.' && !isDecimalDigit(char)) {
      return null;
    }

    if (char !== '.') {
      value += this.peek(index);
      index += 1;
      char = this.peek(index);

      if (value === '0') {
        // Base-16 numbers.
        if (char === 'x' || char === 'X') {
          index += 1;
          value += char;

          while (index < length) {
            char = this.peek(index);
            if (!isHexDigit(char)) {
              break;
            }
            value += char;
            index += 1;
          }

          if (value.length <= 2) {
            // 0x
            return {
              type: 'number',
              value: value,
              isMalformed: true,
              pos: this.char,
            };
          }

          if (index < length) {
            char = this.peek(index);
            if (isIdentifierStart(char)) {
              return null;
            }
          }

          return {
            type: 'number',
            value: value,
            base: 16,
            isMalformed: false,
            pos: this.char,
          };
        }

        // Base-8 numbers.
        if (isOctalDigit(char)) {
          index += 1;
          value += char;
          bad = false;

          while (index < length) {
            char = this.peek(index);

            // Numbers like '019' (note the 9) are not valid octals
            // but we still parse them and mark as malformed.

            if (isDecimalDigit(char)) {
              bad = true;
            }
            if (!isOctalDigit(char)) {
              // if the char is a non punctuator then its not a valid number
              if (!this.isPunctuator(char)) {
                return null;
              }
              break;
            }
            value += char;
            index += 1;
          }

          if (index < length) {
            char = this.peek(index);
            if (isIdentifierStart(char)) {
              return null;
            }
          }

          return {
            type: 'number',
            value: value,
            base: 8,
            isMalformed: bad,
          };
        }

        // Decimal numbers that start with '0' such as '09' are illegal
        // but we still parse them and return as malformed.

        if (isDecimalDigit(char)) {
          index += 1;
          value += char;
        }
      }

      while (index < length) {
        char = this.peek(index);
        if (!isDecimalDigit(char)) {
          break;
        }
        value += char;
        index += 1;
      }
    }

    // Decimal digits.

    if (char === '.') {
      value += char;
      index += 1;

      while (index < length) {
        char = this.peek(index);
        if (!isDecimalDigit(char)) {
          break;
        }
        value += char;
        index += 1;
      }
    }

    // Exponent part.

    if (char === 'e' || char === 'E') {
      value += char;
      index += 1;
      char = this.peek(index);

      if (char === '+' || char === '-') {
        value += this.peek(index);
        index += 1;
      }

      char = this.peek(index);
      if (isDecimalDigit(char)) {
        value += char;
        index += 1;

        while (index < length) {
          char = this.peek(index);
          if (!isDecimalDigit(char)) {
            break;
          }
          value += char;
          index += 1;
        }
      } else {
        return null;
      }
    }

    if (index < length) {
      char = this.peek(index);
      if (!this.isPunctuator(char)) {
        return null;
      }
    }

    return {
      type: 'number',
      value: value,
      base: 10,
      pos: this.char,
      isMalformed: !isFinite(+value),
    };
  }

  isPunctuator(ch1: string) {
    switch (ch1) {
      case '.':
      case '(':
      case ')':
      case ',':
      case '{':
      case '}':
        return true;
    }

    return false;
  }

  scanPunctuator() {
    const ch1 = this.peek();

    if (this.isPunctuator(ch1)) {
      return {
        type: ch1,
        value: ch1,
        pos: this.char,
      };
    }

    return null;
  }

  /*
   * Extract a string out of the next sequence of characters and/or
   * lines or return 'null' if its not possible. Since strings can
   * span across multiple lines this method has to move the char
   * pointer.
   *
   * This method recognizes pseudo-multiline JavaScript strings:
   *
   *   var str = "hello\
   *   world";
   */
  scanStringLiteral() {
    const quote = this.peek();

    // String must start with a quote.
    if (quote !== '"' && quote !== "'") {
      return null;
    }

    let value = '';

    this.skip();

    while (this.peek() !== quote) {
      if (this.peek() === '') {
        // End Of Line
        return {
          type: 'string',
          value: value,
          isUnclosed: true,
          quote: quote,
          pos: this.char,
        };
      }

      const char = this.peek();
      const jump = 1; // A length of a jump, after we're done
      // parsing this character.

      value += char;
      this.skip(jump);
    }

    this.skip();
    return {
      type: 'string',
      value: value,
      isUnclosed: false,
      quote: quote,
      pos: this.char,
    };
  }
}