exports.parse = exports.decode = decode;

exports.stringify = exports.encode = encode;

exports.safe = safe;
exports.unsafe = unsafe;

var eol =
  typeof process !== 'undefined' && process.platform === 'win32' ?
    '\r\n'
  : '\n';

function encode(obj, opt) {
  var children = [];
  var out = '';

  if (typeof opt === 'string') {
    opt = {
      section: opt,
      whitespace: false,
    };
  } else {
    opt = opt || {};
    opt.whitespace = opt.whitespace === true;
  }

  var separator = opt.whitespace ? ' = ' : '=';

  Object.keys(obj).forEach(function (k, _, __) {
    var val = obj[k];
    if (val && Array.isArray(val)) {
      val.forEach(function (item) {
        out += safe(k + '[]') + separator + safe(item) + '\n';
      });
    } else if (val && typeof val === 'object') children.push(k);
    else out += safe(k) + separator + safe(val) + eol;
  });

  if (opt.section && out.length)
    out = '[' + safe(opt.section) + ']' + eol + out;

  children.forEach(function (k, _, __) {
    var nk = dotSplit(k).join('\\.');
    var section = (opt.section ? opt.section + '.' : '') + nk;
    var child = encode(obj[k], {
      section: section,
      whitespace: opt.whitespace,
    });
    if (out.length && child.length) out += eol;

    out += child;
  });

  return out;
}

function dotSplit(str) {
  return str
    .replace(/\1/g, '\u0002LITERAL\\1LITERAL\u0002')
    .replace(/\\\./g, '\u0001')
    .split(/\./)
    .map(function (part) {
      return part
        .replace(/\1/g, '\\.')
        .replace(/\2LITERAL\\1LITERAL\2/g, '\u0001');
    });
}

function decode(str) {
  var out = {};
  var p = out;
  var section = null;
  //          section     |key      = value
  var re = /^\[([^\]]*)\]$|^([^=]+)(=(.*))?$/i;
  var lines = str.split(/[\r\n]+/g);

  lines.forEach(function (line, _, __) {
    if (!line || line.match(/^\s*[;#]/)) return;
    var match = line.match(re);
    if (!match) return;
    if (match[1] !== undefined) {
      section = unsafe(match[1]);
      if (section === '__proto__') {
        // not allowed
        // keep parsing the section, but don't attach it.
        p = {};
        return;
      }
      p = out[section] = out[section] || {};
      return;
    }
    var key = unsafe(match[2]);
    if (key === '__proto__') return;
    var value = match[3] ? unsafe(match[4]) : true;
    switch (value) {
      case 'true':
      case 'false':
      case 'null':
        value = JSON.parse(value);
    }

    // Convert keys with '[]' suffix to an array
    if (key.length > 2 && key.slice(-2) === '[]') {
      key = key.substring(0, key.length - 2);
      if (key === '__proto__') return;
      if (!p[key]) p[key] = [];
      else if (!Array.isArray(p[key])) p[key] = [p[key]];
    }

    // safeguard against resetting a previously defined
    // array by accidentally forgetting the brackets
    if (Array.isArray(p[key])) p[key].push(value);
    else p[key] = value;
  });

  // {a:{y:1},"a.b":{x:2}} --> {a:{y:1,b:{x:2}}}
  // use a filter to return the keys that have to be deleted.
  Object.keys(out)
    .filter(function (k, _, __) {
      if (!out[k] || typeof out[k] !== 'object' || Array.isArray(out[k]))
        return false;

      // see if the parent section is also an object.
      // if so, add it to that, and mark this one for deletion
      var parts = dotSplit(k);
      var p = out;
      var l = parts.pop();
      var nl = l.replace(/\\\./g, '.');
      parts.forEach(function (part, _, __) {
        if (part === '__proto__') return;
        if (!p[part] || typeof p[part] !== 'object') p[part] = {};
        p = p[part];
      });
      if (p === out && nl === l) return false;

      p[nl] = out[k];
      return true;
    })
    .forEach(function (del, _, __) {
      delete out[del];
    });

  return out;
}

function isQuoted(val) {
  return (
    (val.charAt(0) === '"' && val.slice(-1) === '"') ||
    (val.charAt(0) === "'" && val.slice(-1) === "'")
  );
}

function safe(val) {
  return (
      typeof val !== 'string' ||
        val.match(/[=\r\n]/) ||
        val.match(/^\[/) ||
        (val.length > 1 && isQuoted(val)) ||
        val !== val.trim()
    ) ?
      JSON.stringify(val)
    : val.replace(/;/g, '\\;').replace(/#/g, '\\#');
}

function unsafe(val, doUnesc) {
  val = (val || '').trim();
  if (isQuoted(val)) {
    // remove the single quotes before calling JSON.parse
    if (val.charAt(0) === "'") val = val.substr(1, val.length - 2);

    try {
      val = JSON.parse(val);
    } catch (_) {}
  } else {
    // walk the val to find the first not-escaped ; character
    var esc = false;
    var unesc = '';
    for (var i = 0, l = val.length; i < l; i++) {
      var c = val.charAt(i);
      if (esc) {
        if ('\\;#'.indexOf(c) !== -1) unesc += c;
        else unesc += '\\' + c;

        esc = false;
      } else if (';#'.indexOf(c) !== -1) break;
      else if (c === '\\') esc = true;
      else unesc += c;
    }
    if (esc) unesc += '\\';

    return unesc.trim();
  }
  return val;
}