'use strict';

var Node = require('snapdragon-node');
var utils = require('./utils');

/**
 * Braces parsers
 */

module.exports = function(braces, options) {
  function update(parent, val) {
    if (parent && parent.type === 'brace') {
      parent.text = parent.text || '';
      parent.text += val;
    }
  }

  braces.parser
    .set('bos', function() {
      if (!this.parsed) {
        this.ast = this.nodes[0] = new Node(this.ast);
      }
    })

    /**
     * Character parsers
     */

    .set('escape', function() {
      var pos = this.position();
      var m = this.match(/^(?:\\(.)|\$\{)/);
      if (!m) return;

      var prev = this.prev();
      var last = utils.last(prev.nodes);
      update(prev, m[0]);

      var node = pos(new Node({
        type: 'text',
        multiplier: 1,
        val: m[0]
      }));

      if (node.val === '\\\\') {
        return node;
      }

      if (node.val === '${') {
        var str = this.input;
        var idx = -1;
        var ch;

        while ((ch = str[++idx])) {
          this.consume(1);
          node.val += ch;
          if (ch === '\\') {
            node.val += str[++idx];
            continue;
          }
          if (ch === '}') {
            break;
          }
        }
      }

      if (last.val === '"' && this.input.charAt(0) === '"') {
        last.val = node.val;
        this.consume(1);
        return;
      }

      return concatNodes.call(this, pos, node, prev, options);
    })

    /**
     * Brackets: "[...]" (basic, this is overridden by
     * other parsers in more advanced implementations)
     */

    .set('bracket', function() {
      var pos = this.position();
      var m = this.match(/^(?!\\)(?:\[([!^]?)([^\]]{2,}|\]\-)(\]|[^*+?]+)|\[)/);
      if (!m) return;

      var prev = this.prev();
      var val = m[0];
      var negated = m[1] ? '^' : '';
      var inner = m[2] || '';
      var close = m[3] || '';

      update(prev, m[0]);

      if (this.input[0] === ']') {
        this.consume(1);
        inner = '\\]';
        val = '\\[';
      }

      if (this.input.slice(0, 2) === '\\]') {
        this.consume(2);
        inner = '\\]';
        val = '\\[';
      }

      var node = pos(new Node({
        type: 'bracket',
        val: val,
        escaped: close !== ']',
        negated: negated,
        inner: inner,
        close: close
      }));

      return node;
    })

    /**
     * Empty braces (we capture these early to
     * speed up processing in the compiler)
     */

    .set('multiplier', function() {
      var pos = this.position();
      var m = this.match(/^\{(,+(?:(\{,+\})*),*|,*(?:(\{,+\})*),+)\}/);
      if (!m) return;

      this.multiplier = true;
      var prev = this.prev();
      var val = m[0];
      var node = pos(new Node({
        type: 'text',
        multiplier: 1,
        match: m,
        val: val
      }));

      update(prev, m[0]);
      return concatNodes.call(this, pos, node, prev, options);
    })

    /**
     * Paren open: "("
     */

    .set('paren.open', function() {
      var pos = this.position();
      var m = this.match(/^\(/);
      if (!m) return;

      var prev = this.prev();
      update(prev, m[0]);

      var node = pos(new Node({
        type: 'paren',
        nodes: []
      }));

      var open = pos(new Node({
        type: 'paren.open',
        val: m[0]
      }));

      node.push(open);
      prev.push(node);
      this.push('paren', node);
    })

    /**
     * Paren close: ")"
     */

    .set('paren.close', function() {
      var pos = this.position();
      var m = this.match(/^\)/);
      if (!m) return;

      var paren = this.pop('paren');
      var node = pos(new Node({
        type: 'paren.close',
        val: m[0]
      }));

      if (!this.isType(paren, 'paren')) {
        if (this.options.strict) {
          throw new Error('missing opening "("');
        }
        node.type = 'text';
        node.escaped = true;
        return node;
      }

      update(this.prev(), m[0]);
      paren.push(node);

      paren.type = 'text';
      paren.val = '';

      // visit(paren, function(n) {
      //   if (n.type === 'bracket') {
      //     paren.val += n.val;
      //     if (n.inner === '\\]') {
      //       paren.val += n.inner;
      //     }
      //     paren.val += n.close;
      //   } else if (n.type === 'paren.open' || n.type === 'paren.close') {
      //     paren.val += n.val;
      //     paren.unescape = false;
      //   } else if (n.val) {
      //     paren.val += n.val;
      //   }
      // });

      delete paren.nodes;
    })

    /**
     * Brace open: "{"
     */

    .set('brace.open', function() {
      var pos = this.position();
      var m = this.match(/^\{(?!(?:[^\\}]?|,+)\})/);
      if (!m) return;

      var prev = this.prev();
      var last = utils.last(prev.nodes);
      var open = pos(new Node({
        type: 'brace.open',
        val: m[0]
      }));

      update(prev, m[0]);

      var node = pos(new Node({
        type: 'brace',
        nodes: []
      }));

      var lastChar = (last && last.val) ? last.val.slice(-1) : '';
      node.isExtglob = utils.isExtglobChar(lastChar);

      // if the last parsed character was an extglob character
      // we need to _not optimize_ the brace pattern because
      // it might be mistaken for an extglob by a downstream parser
      if (lastChar && node.isExtglob && !this.options.toExtglob) {
        last.optimize = false;
      }

      if (this.options.toExtglob) {
        node.lastChar = node.isExtglob ? lastChar : '';
        node.toExtglob = true;
      }

      node.push(open);
      prev.push(node);
      this.push('brace', node);
    })

    /**
     * Brace close: "}"
     */

    .set('brace.close', function() {
      var pos = this.position();
      var m = this.match(/^\}/);
      if (!m || !m[0]) return;

      var brace = this.pop('brace');
      var node = pos(new Node({
        type: 'brace.close',
        val: m[0]
      }));

      if (!this.isType(brace, 'brace')) {
        if (this.options.strict) {
          throw new Error('missing opening "{"');
        }
        node.type = 'text';
        node.multiplier = 0;
        node.escaped = true;
        return node;
      }

      var prev = this.prev();
      update(prev, node.val);

      var last = utils.last(prev.nodes);
      if (last.type === 'brace') {
        var lastNode = utils.last(last.nodes);
        var lastVal = lastNode.val ? lastNode.val[0] : null;
        if (lastVal === ')') {
          if (/[!@*?+]\(/.test(last.text)) {
            var open = last.nodes[0];
            var text = last.nodes[1];
            if (open.type === 'brace.open' && text && text.type === 'text') {
              text.optimize = false;
            }
          }
        }
      }

      if (brace.nodes.length > 2) {
        var first = brace.nodes[1];
        if (first.type === 'text' && first.val === ',') {
          brace.nodes.splice(1, 1);
          brace.nodes.push(first);
        }
      }

      brace.push(node);
    })

    /**
     * Capture boundary characters
     */

    .set('boundary', function() {
      var pos = this.position();
      var m = this.match(/^[$^](?!\{)/);
      if (!m) return;

      update(this.prev(), m[0]);
      return pos(new Node({
        type: 'text',
        val: m[0]
      }));
    })

    /**
     * One or zero, non-comma characters wrapped in braces
     */

    .set('nobrace', function() {
      var pos = this.position();
      var m = this.match(/^\{[^,]?\}/);
      if (!m) return;

      var prev = this.prev();
      var val = m[0];

      update(prev, val);
      return pos(new Node({
        type: 'text',
        multiplier: 0,
        val: val
      }));
    })

    /**
     * Text
     */

    .set('text', function() {
      var parsed = this.parsed;
      var pos = this.position();
      var m = this.match(/^((?!\\)[^${}()\[\]])+/);
      if (!m) return;

      var prev = this.prev();
      var val = m[0];

      if (utils.isExtglobChar(m[1]) && this.input[0] === '{') {
        val = val.slice(0, val.length - 1) + '\\' + val.slice(-1);
      }

      var node = pos(new Node({
        type: 'text',
        multiplier: 1,
        val: val
      }));

      update(prev, val);
      return concatNodes.call(this, pos, node, prev, options);
    });
};

/**
 * Combine text nodes, and calculate empty sets (`{,,}`)
 * @param {Function} `pos` Function to calculate node position
 * @param {Object} `node` AST node
 * @return {Object}
 */

function concatNodes(pos, node, parent, options) {
  node.orig = node.val;
  var prev = this.prev();
  var last = utils.last(prev.nodes);
  var isEscaped = false;

  if (node.val.length > 1) {
    var a = node.val.charAt(0);
    var b = node.val.slice(-1);

    isEscaped = (a === '"' && b === '"')
      || (a === "'" && b === "'")
      || (a === '`' && b === '`');
  }

  if (isEscaped && options.unescape !== false) {
    node.val = node.val.slice(1, node.val.length - 1);
    node.escaped = true;
  }

  if (node.match) {
    var match = node.match[1];
    if (!match || match.indexOf('}') === -1) {
      match = node.match[0];
    }

    // replace each set with a single ","
    var val = match.replace(/\{/g, ',').replace(/\}/g, '');
    node.multiplier *= val.length;
    node.val = '';
  }

  var simpleText = last.type === 'text'
    && last.multiplier === 1
    && node.multiplier === 1
    && node.val;

  if (simpleText) {
    last.val += node.val;
    return;
  }

  prev.push(node);
}

function visit(node, fn) {
  fn(node);
  return node.nodes ? mapVisit(node, fn) : node;
}

function mapVisit(node, fn) {
  for (let i = 0; i < node.nodes.length; i++) {
    visit(node.nodes[i], fn);
  }
  return node;
}