var assignInWith = require('./assignInWith'),

attempt = require('./attempt'),
baseValues = require('./_baseValues'),
customDefaultsAssignIn = require('./_customDefaultsAssignIn'),
escapeStringChar = require('./_escapeStringChar'),
isError = require('./isError'),
isIterateeCall = require('./_isIterateeCall'),
keys = require('./keys'),
reInterpolate = require('./_reInterpolate'),
templateSettings = require('./templateSettings'),
toString = require('./toString');

/** Used to match empty string literals in compiled template source. */ var reEmptyStringLeading = /b__p += '';/g,

reEmptyStringMiddle = /\b(__p \+=) '' \+/g,
reEmptyStringTrailing = /(__e\(.*?\)|\b__t\)) \+\n'';/g;

/**

* Used to match
* [ES template delimiters](http://ecma-international.org/ecma-262/7.0/#sec-template-literal-lexical-components).
*/

var reEsTemplate = /${([^\}]*(?:\.[^\}]*)*)}/g;

/** Used to ensure capturing order of template delimiters. */ var reNoMatch = /($^)/;

/** Used to match unescaped characters in compiled string literals. */ var reUnescapedString = /['nru2028u2029\]/g;

/** Used for built-in method references. */ var objectProto = Object.prototype;

/** Used to check objects for own properties. */ var hasOwnProperty = objectProto.hasOwnProperty;

/**

* Creates a compiled template function that can interpolate data properties
* in "interpolate" delimiters, HTML-escape interpolated data properties in
* "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
* properties may be accessed as free variables in the template. If a setting
* object is given, it takes precedence over `_.templateSettings` values.
*
* **Note:** In the development build `_.template` utilizes
* [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
* for easier debugging.
*
* For more information on precompiling templates see
* [lodash's custom builds documentation](https://lodash.com/custom-builds).
*
* For more information on Chrome extension sandboxes see
* [Chrome's extensions documentation](https://developer.chrome.com/extensions/sandboxingEval).
*
* @static
* @since 0.1.0
* @memberOf _
* @category String
* @param {string} [string=''] The template string.
* @param {Object} [options={}] The options object.
* @param {RegExp} [options.escape=_.templateSettings.escape]
*  The HTML "escape" delimiter.
* @param {RegExp} [options.evaluate=_.templateSettings.evaluate]
*  The "evaluate" delimiter.
* @param {Object} [options.imports=_.templateSettings.imports]
*  An object to import into the template as free variables.
* @param {RegExp} [options.interpolate=_.templateSettings.interpolate]
*  The "interpolate" delimiter.
* @param {string} [options.sourceURL='templateSources[n]']
*  The sourceURL of the compiled template.
* @param {string} [options.variable='obj']
*  The data object variable name.
* @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
* @returns {Function} Returns the compiled template function.
* @example
*
* // Use the "interpolate" delimiter to create a compiled template.
* var compiled = _.template('hello <%= user %>!');
* compiled({ 'user': 'fred' });
* // => 'hello fred!'
*
* // Use the HTML "escape" delimiter to escape data property values.
* var compiled = _.template('<b><%- value %></b>');
* compiled({ 'value': '<script>' });
* // => '<b>&lt;script&gt;</b>'
*
* // Use the "evaluate" delimiter to execute JavaScript and generate HTML.
* var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
* compiled({ 'users': ['fred', 'barney'] });
* // => '<li>fred</li><li>barney</li>'
*
* // Use the internal `print` function in "evaluate" delimiters.
* var compiled = _.template('<% print("hello " + user); %>!');
* compiled({ 'user': 'barney' });
* // => 'hello barney!'
*
* // Use the ES template literal delimiter as an "interpolate" delimiter.
* // Disable support by replacing the "interpolate" delimiter.
* var compiled = _.template('hello ${ user }!');
* compiled({ 'user': 'pebbles' });
* // => 'hello pebbles!'
*
* // Use backslashes to treat delimiters as plain text.
* var compiled = _.template('<%= "\\<%- value %\\>" %>');
* compiled({ 'value': 'ignored' });
* // => '<%- value %>'
*
* // Use the `imports` option to import `jQuery` as `jq`.
* var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
* var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
* compiled({ 'users': ['fred', 'barney'] });
* // => '<li>fred</li><li>barney</li>'
*
* // Use the `sourceURL` option to specify a custom sourceURL for the template.
* var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
* compiled(data);
* // => Find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector.
*
* // Use the `variable` option to ensure a with-statement isn't used in the compiled template.
* var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
* compiled.source;
* // => function(data) {
* //   var __t, __p = '';
* //   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
* //   return __p;
* // }
*
* // Use custom template delimiters.
* _.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
* var compiled = _.template('hello {{ user }}!');
* compiled({ 'user': 'mustache' });
* // => 'hello mustache!'
*
* // Use the `source` property to inline compiled templates for meaningful
* // line numbers in error messages and stack traces.
* fs.writeFileSync(path.join(process.cwd(), 'jst.js'), '\
*   var JST = {\
*     "main": ' + _.template(mainText).source + '\
*   };\
* ');
*/

function template(string, options, guard) {

// Based on John Resig's `tmpl` implementation
// (http://ejohn.org/blog/javascript-micro-templating/)
// and Laura Doktorova's doT.js (https://github.com/olado/doT).
var settings = templateSettings.imports._.templateSettings || templateSettings;

if (guard && isIterateeCall(string, options, guard)) {
  options = undefined;
}
string = toString(string);
options = assignInWith({}, options, settings, customDefaultsAssignIn);

var imports = assignInWith({}, options.imports, settings.imports, customDefaultsAssignIn),
    importsKeys = keys(imports),
    importsValues = baseValues(imports, importsKeys);

var isEscaping,
    isEvaluating,
    index = 0,
    interpolate = options.interpolate || reNoMatch,
    source = "__p += '";

// Compile the regexp to match each delimiter.
var reDelimiters = RegExp(
  (options.escape || reNoMatch).source + '|' +
  interpolate.source + '|' +
  (interpolate === reInterpolate ? reEsTemplate : reNoMatch).source + '|' +
  (options.evaluate || reNoMatch).source + '|$'
, 'g');

// Use a sourceURL for easier debugging.
// The sourceURL gets injected into the source that's eval-ed, so be careful
// with lookup (in case of e.g. prototype pollution), and strip newlines if any.
// A newline wouldn't be a valid sourceURL anyway, and it'd enable code injection.
var sourceURL = hasOwnProperty.call(options, 'sourceURL')
  ? ('//# sourceURL=' +
     (options.sourceURL + '').replace(/[\r\n]/g, ' ') +
     '\n')
  : '';

string.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
  interpolateValue || (interpolateValue = esTemplateValue);

  // Escape characters that can't be included in string literals.
  source += string.slice(index, offset).replace(reUnescapedString, escapeStringChar);

  // Replace delimiters with snippets.
  if (escapeValue) {
    isEscaping = true;
    source += "' +\n__e(" + escapeValue + ") +\n'";
  }
  if (evaluateValue) {
    isEvaluating = true;
    source += "';\n" + evaluateValue + ";\n__p += '";
  }
  if (interpolateValue) {
    source += "' +\n((__t = (" + interpolateValue + ")) == null ? '' : __t) +\n'";
  }
  index = offset + match.length;

  // The JS engine embedded in Adobe products needs `match` returned in
  // order to produce the correct `offset` value.
  return match;
});

source += "';\n";

// If `variable` is not specified wrap a with-statement around the generated
// code to add the data object to the top of the scope chain.
// Like with sourceURL, we take care to not check the option's prototype,
// as this configuration is a code injection vector.
var variable = hasOwnProperty.call(options, 'variable') && options.variable;
if (!variable) {
  source = 'with (obj) {\n' + source + '\n}\n';
}
// Cleanup code by stripping empty strings.
source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
  .replace(reEmptyStringMiddle, '$1')
  .replace(reEmptyStringTrailing, '$1;');

// Frame code as the function body.
source = 'function(' + (variable || 'obj') + ') {\n' +
  (variable
    ? ''
    : 'obj || (obj = {});\n'
  ) +
  "var __t, __p = ''" +
  (isEscaping
     ? ', __e = _.escape'
     : ''
  ) +
  (isEvaluating
    ? ', __j = Array.prototype.join;\n' +
      "function print() { __p += __j.call(arguments, '') }\n"
    : ';\n'
  ) +
  source +
  'return __p\n}';

var result = attempt(function() {
  return Function(importsKeys, sourceURL + 'return ' + source)
    .apply(undefined, importsValues);
});

// Provide the compiled function's source by its `toString` method or
// the `source` property as a convenience for inlining compiled templates.
result.source = source;
if (isError(result)) {
  throw result;
}
return result;

}

module.exports = template;