var _utils = require('../utils');
var noop = _utils.noop;

var block = require('../rules/block');
var defaultOptions = require('./options');

/**
 * Block Lexer
 */

function Lexer(options) {
  this.tokens = [];
  this.tokens.links = {};
  this.options = options || defaultOptions;
  this.rules = block.normal;

  if (this.options.gfm) {
    if (this.options.tables) {
      this.rules = block.tables;
    } else {
      this.rules = block.gfm;
    }
  }

  // Is mathjax disabled ?
  if (!this.options.mathjax) {
    this.rules.math = noop;
  }
}

/**
 * Expose Block Rules
 */

Lexer.rules = block;

/**
 * Static Lex Method
 */

Lexer.lex = function(src, options) {
  var lexer = new Lexer(options);
  return lexer.lex(src);
};

/**
 * Preprocessing
 */

Lexer.prototype.lex = function(src) {
  src = src
    .replace(/\r\n|\r/g, '\n')
    .replace(/\t/g, '    ')
    .replace(/\u00a0/g, ' ')
    .replace(/\u2424/g, '\n');

  return this.token(src, true);
};

/**
 * Lexing
 */

Lexer.prototype.token = function(src, top, bq) {
  var src = src.replace(/^ +$/gm, '')
    , next
    , loose
    , cap
    , bull
    , b
    , item
    , space
    , i
    , l;

  while (src) {
    // newline
    if (cap = this.rules.newline.exec(src)) {
      src = src.substring(cap[0].length);
      if (cap[0].length > 1) {
        this.tokens.push({
          type: 'space'
        });
      }
    }

    // code
    if (cap = this.rules.code.exec(src)) {
      src = src.substring(cap[0].length);
      cap = cap[0].replace(/^ {4}/gm, '');
      this.tokens.push({
        type: 'code',
        text: !this.options.pedantic
          ? cap.replace(/\n+$/, '')
          : cap
      });
      continue;
    }

    // fences (gfm)
    if (cap = this.rules.fences.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'code',
        lang: cap[2],
        text: cap[3]
      });
      continue;
    }

    // footnote
    if (cap = this.rules.footnote.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'footnote',
        refname: cap[1],
        text: cap[2]
      });
      continue;
    }

    // math
    if (cap = this.rules.math.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'math',
        text: cap[2]
      });
      continue;
    }

    // heading
    if (cap = this.rules.heading.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'heading',
        depth: cap[1].length,
        text: cap[2]
      });
      continue;
    }

    // table no leading pipe (gfm)
    if (top && (cap = this.rules.nptable.exec(src))) {
      src = src.substring(cap[0].length);

      item = {
        type: 'table',
        header: cap[1].replace(/^ *| *\| *$/g, '').split(/ *\| */),
        align: cap[2].replace(/^ *|\| *$/g, '').split(/ *\| */),
        cells: cap[3].replace(/\n$/, '').split('\n')
      };

      for (i = 0; i < item.align.length; i++) {
        if (/^ *-+: *$/.test(item.align[i])) {
          item.align[i] = 'right';
        } else if (/^ *:-+: *$/.test(item.align[i])) {
          item.align[i] = 'center';
        } else if (/^ *:-+ *$/.test(item.align[i])) {
          item.align[i] = 'left';
        } else {
          item.align[i] = null;
        }
      }

      for (i = 0; i < item.cells.length; i++) {
        item.cells[i] = item.cells[i].split(/ *\| */);
      }

      this.tokens.push(item);

      continue;
    }

    // lheading
    if (cap = this.rules.lheading.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'heading',
        depth: cap[2] === '=' ? 1 : 2,
        text: cap[1]
      });
      continue;
    }

    // hr
    if (cap = this.rules.hr.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'hr'
      });
      continue;
    }

    // blockquote
    if (cap = this.rules.blockquote.exec(src)) {
      src = src.substring(cap[0].length);

      this.tokens.push({
        type: 'blockquote_start'
      });

      cap = cap[0].replace(/^ *> ?/gm, '');

      // Pass `top` to keep the current
      // "toplevel" state. This is exactly
      // how markdown.pl works.
      this.token(cap, top, true);

      this.tokens.push({
        type: 'blockquote_end'
      });

      continue;
    }

    // list
    if (cap = this.rules.list.exec(src)) {
      src = src.substring(cap[0].length);
      bull = cap[2];

      this.tokens.push({
        type: 'list_start',
        ordered: bull.length > 1
      });

      // Get each top-level item.
      cap = cap[0].match(this.rules._item);

      next = false;
      l = cap.length;
      i = 0;

      for (; i < l; i++) {
        item = cap[i];

        // Remove the list item's bullet
        // so it is seen as the next token.
        space = item.length;
        item = item.replace(/^ *([*+-]|\d+\.) +/, '');

        // Outdent whatever the
        // list item contains. Hacky.
        if (~item.indexOf('\n ')) {
          space -= item.length;
          item = !this.options.pedantic
            ? item.replace(new RegExp('^ {1,' + space + '}', 'gm'), '')
            : item.replace(/^ {1,4}/gm, '');
        }

        // Determine whether the next list item belongs here.
        // Backpedal if it does not belong in this list.
        if (this.options.smartLists && i !== l - 1) {
          b = block._bullet.exec(cap[i + 1])[0];
          if (bull !== b && !(bull.length > 1 && b.length > 1)) {
            src = cap.slice(i + 1).join('\n') + src;
            i = l - 1;
          }
        }

        // Determine whether item is loose or not.
        // Use: /(^|\n)(?! )[^\n]+\n\n(?!\s*$)/
        // for discount behavior.
        loose = next || /\n\n(?!\s*$)/.test(item);
        if (i !== l - 1) {
          next = item.charAt(item.length - 1) === '\n';
          if (!loose) loose = next;
        }

        this.tokens.push({
          type: loose
            ? 'loose_item_start'
            : 'list_item_start'
        });

        // Recurse.
        this.token(item, false, bq);

        this.tokens.push({
          type: 'list_item_end'
        });
      }

      this.tokens.push({
        type: 'list_end'
      });

      continue;
    }

    // html
    if (cap = this.rules.html.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: this.options.sanitize
          ? 'paragraph'
          : 'html',
        pre: cap[1] === 'pre' || cap[1] === 'script' || cap[1] === 'style',
        text: cap[0]
      });
      continue;
    }

    // def
    if ((!bq && top) && (cap = this.rules.def.exec(src))) {
      src = src.substring(cap[0].length);
      this.tokens.links[cap[1].toLowerCase()] = {
        href: cap[2],
        title: cap[3]
      };
      continue;
    }

    // table (gfm)
    if (top && (cap = this.rules.table.exec(src))) {
      src = src.substring(cap[0].length);

      item = {
        type: 'table',
        header: cap[1].replace(/^ *| *\| *$/g, '').split(/ *\| */),
        align: cap[2].replace(/^ *|\| *$/g, '').split(/ *\| */),
        cells: cap[3].replace(/(?: *\| *)?\n$/, '').split('\n').slice(0),
      };

      for (i = 0; i < item.align.length; i++) {
        if (/^ *-+: *$/.test(item.align[i])) {
          item.align[i] = 'right';
        } else if (/^ *:-+: *$/.test(item.align[i])) {
          item.align[i] = 'center';
        } else if (/^ *:-+ *$/.test(item.align[i])) {
          item.align[i] = 'left';
        } else {
          item.align[i] = null;
        }
      }

      for (i = 0; i < item.cells.length; i++) {
        item.cells[i] = item.cells[i]
          .replace(/^ *\| *| *\| *$/g, '')
          .split(/ *\| */);
      }

      this.tokens.push(item);

      continue;
    }

    // top-level paragraph
    if (top && (cap = this.rules.paragraph.exec(src))) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'paragraph',
        text: cap[1].charAt(cap[1].length - 1) === '\n'
          ? cap[1].slice(0, -1)
          : cap[1]
      });
      continue;
    }

    // text
    if (cap = this.rules.text.exec(src)) {
      // Top-level should never reach here.
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'text',
        text: cap[0]
      });
      continue;
    }

    if (src) {
      throw new
        Error('Infinite loop on byte: ' + src.charCodeAt(0));
    }
  }

  return this.tokens;
};

module.exports = Lexer;