* Copyright (C) 2010-2014 Morgner UG (haftungsbeschränkt)

*

* This file is part of Structr <http://structr.org>.

*

* Structr is free software: you can redistribute it and/or modify

* it under the terms of the GNU General Public License as

* published by the Free Software Foundation, either version 3 of the

* License, or (at your option) any later version.

*

* Structr is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

* GNU General Public License for more details.

*

* You should have received a copy of the GNU General Public License

* along with Structr.  If not, see <http://www.gnu.org/licenses/>.

*/

*

* @author Christian Morgner

*/

  private static final Logger logger = Logger.getLogger(Functions.class.getName());

  public static final Map<String, Function<Object, Object>> functions = new LinkedHashMap<>();

  public static final String NULL_STRING                       = "___NULL___";

  public static final String ERROR_MESSAGE_MD5                 = "Usage: ${md5(string)}. Example: ${md5(this.email)}";

  public static final String ERROR_MESSAGE_ERROR               = "Usage: ${error(...)}. Example: ${error(\"base\", \"must_equal\", int(5))}";

  public static final String ERROR_MESSAGE_UPPER               = "Usage: ${upper(string)}. Example: ${upper(this.nickName)}";

  public static final String ERROR_MESSAGE_LOWER               = "Usage: ${lower(string)}. Example: ${lower(this.email)}";

  public static final String ERROR_MESSAGE_JOIN                = "Usage: ${join(collection, separator)}. Example: ${join(this.names, \",\")}";

  public static final String ERROR_MESSAGE_CONCAT              = "Usage: ${concat(values...)}. Example: ${concat(this.firstName, this.lastName)}";

  public static final String ERROR_MESSAGE_SPLIT               = "Usage: ${split(value)}. Example: ${split(this.commaSeparatedItems)}";

  public static final String ERROR_MESSAGE_ABBR                = "Usage: ${abbr(longString, maxLength)}. Example: ${abbr(this.title, 20)}";

  public static final String ERROR_MESSAGE_CAPITALIZE          = "Usage: ${capitalize(string)}. Example: ${capitalize(this.nickName)}";

  public static final String ERROR_MESSAGE_TITLEIZE            = "Usage: ${titleize(string, separator}. Example: ${titleize(this.lowerCamelCaseString, \"_\")}";

  public static final String ERROR_MESSAGE_NUM                 = "Usage: ${num(string)}. Example: ${num(this.numericalStringValue)}";

  public static final String ERROR_MESSAGE_INT                 = "Usage: ${int(string)}. Example: ${int(this.numericalStringValue)}";

  public static final String ERROR_MESSAGE_RANDOM              = "Usage: ${random(num)}. Example: ${set(this, \"password\", random(8))}";

  public static final String ERROR_MESSAGE_RINT                = "Usage: ${rint(range)}. Example: ${rint(1000)}";

  public static final String ERROR_MESSAGE_INDEX_OF            = "Usage: ${index_of(string, word)}. Example: ${index_of(this.name, \"the\")}";

  public static final String ERROR_MESSAGE_CONTAINS            = "Usage: ${contains(string, word)}. Example: ${contains(this.name, \"the\")}";

  public static final String ERROR_MESSAGE_SUBSTRING           = "Usage: ${substring(string, start, length)}. Example: ${substring(this.name, 19, 3)}";

  public static final String ERROR_MESSAGE_LENGTH              = "Usage: ${length(string)}. Example: ${length(this.name)}";

  public static final String ERROR_MESSAGE_REPLACE             = "Usage: ${replace(template, source)}. Example: ${replace(\"${this.id}\", this)}";

  public static final String ERROR_MESSAGE_CLEAN               = "Usage: ${clean(string)}. Example: ${clean(this.stringWithNonWordChars)}";

  public static final String ERROR_MESSAGE_URLENCODE           = "Usage: ${urlencode(string)}. Example: ${urlencode(this.email)}";

  public static final String ERROR_MESSAGE_ESCAPE_JS           = "Usage: ${escape_javascript(string)}. Example: ${escape_javascript(this.name)}";

  public static final String ERROR_MESSAGE_IF                  = "Usage: ${if(condition, trueValue, falseValue)}. Example: ${if(empty(this.name), this.nickName, this.name)}";

  public static final String ERROR_MESSAGE_EMPTY               = "Usage: ${empty(string)}. Example: ${if(empty(possibleEmptyString), \"empty\", \"non-empty\")}";

  public static final String ERROR_MESSAGE_EQUAL               = "Usage: ${equal(value1, value2)}. Example: ${equal(this.children.size, 0)}";

  public static final String ERROR_MESSAGE_ADD                 = "Usage: ${add(values...)}. Example: ${add(1, 2, 3, this.children.size)}";

  public static final String ERROR_MESSAGE_INT_SUM             = "Usage: ${int_sum(list)}. Example: ${int_sum(extract(this.children, \"number\"))}";

  public static final String ERROR_MESSAGE_DOUBLE_SUM          = "Usage: ${double_sum(list)}. Example: ${double_sum(extract(this.children, \"amount\"))}";

  public static final String ERROR_MESSAGE_IS_COLLECTION       = "Usage: ${is_collection(value)}. Example: ${is_collection(this)}";

  public static final String ERROR_MESSAGE_IS_ENTITY           = "Usage: ${is_entity(value)}. Example: ${is_entity(this)}";

  public static final String ERROR_MESSAGE_EXTRACT             = "Usage: ${extract(list, propertyName)}. Example: ${extract(this.children, \"amount\")}";

  public static final String ERROR_MESSAGE_FILTER              = "Usage: ${filter(list, expression)}. Example: ${filter(this.children, gt(size(data.children), 0))}";

  public static final String ERROR_MESSAGE_MERGE               = "Usage: ${merge(list1, list2, list3, ...)}. Example: ${merge(this.children, this.siblings)}";

  public static final String ERROR_MESSAGE_UNWIND              = "Usage: ${unwind(list1, ...)}. Example: ${unwind(this.children)}";

  public static final String ERROR_MESSAGE_SORT                = "Usage: ${sort(list1, key [, true])}. Example: ${sort(this.children, \"name\")}";

  public static final String ERROR_MESSAGE_LT                  = "Usage: ${lt(value1, value2)}. Example: ${if(lt(this.children, 2), \"Less than two\", \"Equal to or more than two\")}";

  public static final String ERROR_MESSAGE_GT                  = "Usage: ${gt(value1, value2)}. Example: ${if(gt(this.children, 2), \"More than two\", \"Equal to or less than two\")}";

  public static final String ERROR_MESSAGE_LTE                 = "Usage: ${lte(value1, value2)}. Example: ${if(lte(this.children, 2), \"Equal to or less than two\", \"More than two\")}";

  public static final String ERROR_MESSAGE_GTE                 = "Usage: ${gte(value1, value2)}. Example: ${if(gte(this.children, 2), \"Equal to or more than two\", \"Less than two\")}";

  public static final String ERROR_MESSAGE_SUBT                = "Usage: ${subt(value1, value)}. Example: ${subt(5, 2)}";

  public static final String ERROR_MESSAGE_MULT                = "Usage: ${mult(value1, value)}. Example: ${mult(5, 2)}";

  public static final String ERROR_MESSAGE_QUOT                = "Usage: ${quot(value1, value)}. Example: ${quot(5, 2)}";

  public static final String ERROR_MESSAGE_ROUND               = "Usage: ${round(value1 [, decimalPlaces])}. Example: ${round(2.345678, 2)}";

  public static final String ERROR_MESSAGE_MAX                 = "Usage: ${max(value1, value2)}. Example: ${max(this.children, 10)}";

  public static final String ERROR_MESSAGE_MIN                 = "Usage: ${min(value1, value2)}. Example: ${min(this.children, 5)}";

  public static final String ERROR_MESSAGE_CONFIG              = "Usage: ${config(keyFromStructrConf)}. Example: ${config(\"base.path\")}";

  public static final String ERROR_MESSAGE_DATE_FORMAT         = "Usage: ${date_format(value, pattern)}. Example: ${date_format(this.creationDate, \"yyyy-MM-dd'T'HH:mm:ssZ\")}";

  public static final String ERROR_MESSAGE_PARSE_DATE          = "Usage: ${parse_date(value, pattern)}. Example: ${parse_format(\"2014-01-01\", \"yyyy-MM-dd\")}";

  public static final String ERROR_MESSAGE_NUMBER_FORMAT       = "Usage: ${number_format(value, ISO639LangCode, pattern)}. Example: ${number_format(12345.6789, 'en', '#,##0.00')}";

  public static final String ERROR_MESSAGE_TEMPLATE            = "Usage: ${template(name, locale, source)}. Example: ${template(\"TEXT_TEMPLATE_1\", \"en_EN\", this)}";

  public static final String ERROR_MESSAGE_NOT                 = "Usage: ${not(bool1, bool2)}. Example: ${not(\"true\", \"true\")}";

  public static final String ERROR_MESSAGE_AND                 = "Usage: ${and(bool1, bool2)}. Example: ${and(\"true\", \"true\")}";

  public static final String ERROR_MESSAGE_OR                  = "Usage: ${or(bool1, bool2)}. Example: ${or(\"true\", \"true\")}";

  public static final String ERROR_MESSAGE_GET                 = "Usage: ${get(entity, propertyKey)}. Example: ${get(this, \"children\")}";

  public static final String ERROR_MESSAGE_GET_ENTITY          = "Cannot evaluate first argument to entity, must be entity or single element list of entities.";

  public static final String ERROR_MESSAGE_SIZE                = "Usage: ${size(collection)}. Example: ${size(this.children)}";

  public static final String ERROR_MESSAGE_FIRST               = "Usage: ${first(collection)}. Example: ${first(this.children)}";

  public static final String ERROR_MESSAGE_LAST                = "Usage: ${last(collection)}. Example: ${last(this.children)}";

  public static final String ERROR_MESSAGE_NTH                 = "Usage: ${nth(collection)}. Example: ${nth(this.children, 2)}";

  public static final String ERROR_MESSAGE_GET_COUNTER         = "Usage: ${get_counter(level)}. Example: ${get_counter(1)}";

  public static final String ERROR_MESSAGE_INC_COUNTER         = "Usage: ${inc_counter(level, [resetLowerLevels])}. Example: ${inc_counter(1, true)}";

  public static final String ERROR_MESSAGE_RESET_COUNTER       = "Usage: ${reset_counter(level)}. Example: ${reset_counter(1)}";

  public static final String ERROR_MESSAGE_MERGE_PROPERTIES    = "Usage: ${merge_properties(source, target , mergeKeys...)}. Example: ${merge_properties(this, parent, \"eMail\")}";

  public static final String ERROR_MESSAGE_KEYS                = "Usage: ${keys(entity, viewName)}. Example: ${keys(this, \"ui\")}";

  public static final String ERROR_MESSAGE_EACH                = "Usage: ${each(collection, expression)}. Example: ${each(this.children, \"set(this, \"email\", lower(get(this.email))))\")}";

  public static final String ERROR_MESSAGE_STORE               = "Usage: ${store(key, value)}. Example: ${store('tmpUser', this.owner)}";

  public static final String ERROR_MESSAGE_RETRIEVE            = "Usage: ${retrieve(key)}. Example: ${retrieve('tmpUser')}";

  public static final String ERROR_MESSAGE_PRINT               = "Usage: ${print(objects...)}. Example: ${print(this.name, \"test\")}";

  public static final String ERROR_MESSAGE_READ                = "Usage: ${read(filename)}. Example: ${read(\"text.xml\")}";

  public static final String ERROR_MESSAGE_WRITE               = "Usage: ${write(filename, value)}. Example: ${write(\"text.txt\", this.name)}";

  public static final String ERROR_MESSAGE_APPEND              = "Usage: ${append(filename, value)}. Example: ${append(\"test.txt\", this.name)}";

  public static final String ERROR_MESSAGE_XML                 = "Usage: ${xml(xmlSource)}. Example: ${xpath(xml(this.xmlSource), \"/test/testValue\")}";

  public static final String ERROR_MESSAGE_XPATH               = "Usage: ${xpath(xmlDocument, expression)}. Example: ${xpath(xml(this.xmlSource), \"/test/testValue\")}";

  public static final String ERROR_MESSAGE_SET                 = "Usage: ${set(entity, propertyKey, value)}. Example: ${set(this, \"email\", lower(this.email))}";

  public static final String ERROR_MESSAGE_SEND_PLAINTEXT_MAIL = "Usage: ${send_plaintext_mail(fromAddress, fromName, toAddress, toName, subject, content)}.";

  public static final String ERROR_MESSAGE_SEND_HTML_MAIL      = "Usage: ${send_html_mail(fromAddress, fromName, toAddress, toName, subject, content)}.";

  public static final String ERROR_MESSAGE_GEOCODE             = "Usage: ${geocode(street, city, country)}. Example: ${set(this, geocode(this.street, this.city, this.country))}";

  public static final String ERROR_MESSAGE_FIND                = "Usage: ${find(type, key, value)}. Example: ${find(\"User\", \"email\", \"tester@test.com\"}";

  public static final String ERROR_MESSAGE_CREATE              = "Usage: ${create(type, key, value)}. Example: ${create(\"Feedback\", \"text\", this.text)}";

  public static final String ERROR_MESSAGE_DELETE              = "Usage: ${delete(entity)}. Example: ${delete(this)}";

  public static final String ERROR_MESSAGE_CACHE               = "Usage: ${cache(key, timeout, valueExpression)}. Example: ${cache('value', 60, GET('http://rate-limited-URL.com'))}";

  public static Function<Object, Object> get(final String name) {

    return functions.get(name);

  }

  public static Object evaluate(final SecurityContext securityContext, final ActionContext actionContext, final GraphObject entity, final String expression) throws FrameworkException {

    final String expressionWithoutNewlines = expression.replace('\n', ' ');

    final StreamTokenizer tokenizer        = new StreamTokenizer(new StringReader(expressionWithoutNewlines));

    tokenizer.eolIsSignificant(true);

    tokenizer.wordChars('_', '_');

    tokenizer.wordChars('.', '.');

    tokenizer.wordChars('!', '!');

    Expression root    = new RootExpression();

    Expression current = root;

    Expression next    = null;

    String lastToken   = null;

    int token          = 0;

    int level          = 0;

    while (token != StreamTokenizer.TT_EOF) {

      token = nextToken(tokenizer);

      switch (token) {

        case StreamTokenizer.TT_EOF:

          break;

        case StreamTokenizer.TT_EOL:

          break;

        case StreamTokenizer.TT_NUMBER:

          if (current == null) {

            throw new FrameworkException(422, "Invalid expression: mismatched opening bracket before NUMBER");

          }

          next = new ConstantExpression(tokenizer.nval);

          current.add(next);

          lastToken += "NUMBER";

          break;

        case StreamTokenizer.TT_WORD:

          if (current == null) {

            throw new FrameworkException(422, "Invalid expression: mismatched opening bracket before " + tokenizer.sval);

          }

          next = checkReservedWords(tokenizer.sval);

          current.add(next);

          lastToken = tokenizer.sval;

          break;

        case '(':

          if (((current == null || current instanceof RootExpression) && next == null) || current == next) {

            // an additional bracket without a new function,

            // this can only be an execution group.

            next = new GroupExpression();

            current.add(next);

          }

          current = next;

          lastToken += "(";

          level++;

          break;

        case ')':

          if (current == null) {

            throw new FrameworkException(422, "Invalid expression: mismatched opening bracket before " + lastToken);

          }

          current = current.getParent();

          if (current == null) {

            throw new FrameworkException(422, "Invalid expression: mismatched closing bracket after " + lastToken);

          }

          lastToken += ")";

          level--;

          break;

        case ';':

          next = null;

          lastToken += ";";

          break;

        case ',':

          next = current;

          lastToken += ",";

          break;

        default:

          if (current == null) {

            throw new FrameworkException(422, "Invalid expression: mismatched opening bracket before " + tokenizer.sval);

          }

          current.add(new ConstantExpression(tokenizer.sval));

          lastToken = tokenizer.sval;

      }

    }

    if (level > 0) {

      throw new FrameworkException(422, "Invalid expression: mismatched closing bracket after " + lastToken);

    }

    return root.evaluate(securityContext, actionContext, entity);

  }

  private static Expression checkReservedWords(final String word) throws FrameworkException {

    if (word == null) {

      return new NullExpression();

    }

    switch (word) {

      case "cache":

        return new CacheExpression();

      case "true":

        return new ConstantExpression(true);

      case "false":

        return new ConstantExpression(false);

      case "if":

        return new IfExpression();

      case "each":

        return new EachExpression();

      case "filter":

        return new FilterExpression();

      case "data":

        return new ValueExpression("data");

      case "null":

        return new ConstantExpression(NULL_STRING);

    }

    // no match, try functions

    final Function<Object, Object> function = Functions.get(word);

    if (function != null) {

      return new FunctionExpression(word, function);

    } else {

      return new ValueExpression(word);

    }

  }

  private static int nextToken(final StreamTokenizer tokenizer) {

    try {

      return tokenizer.nextToken();

    } catch (IOException ioex) { }

    return StreamTokenizer.TT_EOF;

  }

  static {

    functions.put("error", new Function<Object, Object>() {

      @Override

      public Object apply(final ActionContext ctx, final GraphObject entity, final Object[] sources) throws FrameworkException {

        if (arrayHasLengthAndAllElementsNotNull(sources, 2)) {

          final PropertyKey key = StructrApp.getConfiguration().getPropertyKeyForJSONName(entity.getClass(), sources[0].toString());

          ctx.raiseError(entity.getType(), new ErrorToken(422, key) {

            @Override

            public JsonElement getContent() {

              return new JsonPrimitive(getErrorToken());

            }

            @Override

            public String getErrorToken() {

              return sources[1].toString();

            }

          });

        } else if (arrayHasLengthAndAllElementsNotNull(sources, 3)) {

          final PropertyKey key = StructrApp.getConfiguration().getPropertyKeyForJSONName(entity.getClass(), sources[0].toString());

          ctx.raiseError(entity.getType(), new SemanticErrorToken(key) {

            @Override

            public JsonElement getContent() {

              JsonObject obj = new JsonObject();

              if (sources[2] instanceof Number) {

                obj.add(getErrorToken(), new JsonPrimitive((Number)sources[2]));

              } else if (sources[2] instanceof Boolean) {

                obj.add(getErrorToken(), new JsonPrimitive((Boolean)sources[2]));

              } else {

                obj.add(getErrorToken(), new JsonPrimitive(sources[2].toString()));

              }

              return obj;

            }

            @Override

            public String getErrorToken() {

              return sources[1].toString();

            }

          });

        }

        return null;

      }

      @Override

      public String usage() {

        return ERROR_MESSAGE_ERROR;

      }

    });

    functions.put("md5", new Function<Object, Object>() {

      @Override

      public Object apply(final ActionContext ctx, final GraphObject entity, final Object[] sources) throws FrameworkException {

        return (arrayHasMinLengthAndAllElementsNotNull(sources, 1))

          ? DigestUtils.md5Hex(sources[0].toString())

          : "";

      }

      @Override

      public String usage() {

        return ERROR_MESSAGE_MD5;

      }

    });

    functions.put("upper", new Function<Object, Object>() {

      @Override

      public Object apply(final ActionContext ctx, final GraphObject entity, final Object[] sources) throws FrameworkException {

        return (arrayHasMinLengthAndAllElementsNotNull(sources, 1))

          ? sources[0].toString().toUpperCase()

          : "";

      }

      @Override

      public String usage() {

        return ERROR_MESSAGE_UPPER;

      }

    });

    functions.put("lower", new Function<Object, Object>() {

      @Override

      public Object apply(final ActionContext ctx, final GraphObject entity, final Object[] sources) throws FrameworkException {

        return (arrayHasMinLengthAndAllElementsNotNull(sources, 1))

          ? sources[0].toString().toLowerCase()

          : "";

      }

      @Override

      public String usage() {

        return ERROR_MESSAGE_LOWER;

      }