/*
 * Copyright 2013 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.template.soy.basicfunctions;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSet;
import com.google.template.soy.data.SanitizedContent;
import com.google.template.soy.data.SoyValue;
import com.google.template.soy.data.restricted.IntegerData;
import com.google.template.soy.data.restricted.StringData;
import com.google.template.soy.jssrc.restricted.JsExpr;
import com.google.template.soy.jssrc.restricted.JsExprUtils;
import com.google.template.soy.jssrc.restricted.SoyJsSrcFunction;
import com.google.template.soy.pysrc.restricted.PyExpr;
import com.google.template.soy.pysrc.restricted.SoyPySrcFunction;
import com.google.template.soy.shared.restricted.SoyJavaFunction;
import com.google.template.soy.shared.restricted.SoyPureFunction;

import java.util.List;
import java.util.Set;

import javax.inject.Inject;
import javax.inject.Singleton;

/**
 * A function that determines the index of the first occurrence of a string
 * within another string.
 *
 * <p><code>strIndexOf(expr1, expr2)</code> requires <code>expr1</code> and
 * <code>expr2</code> to be of type string or
 * {@link com.google.template.soy.data.SanitizedContent}.
 * <p>It returns the index within the string <code>expr1</code> of the first
 * occurrence of the specified substring <code>expr2</code>.
 * If no such index exists, then <code>-1</code>is returned.
 * <code>strIndexOf</code> is case sensitive and the string indices are
 * zero based.
 *
 */
@Singleton
@SoyPureFunction
final class StrIndexOfFunction implements SoyJavaFunction, SoyJsSrcFunction, SoyPySrcFunction {


  @Inject
  StrIndexOfFunction() {}


  @Override public String getName() {
    return "strIndexOf";
  }

  @Override public Set<Integer> getValidArgsSizes() {
    return ImmutableSet.of(2);
  }

  @Override public SoyValue computeForJava(List<SoyValue> args) {
    SoyValue arg0 = args.get(0);
    SoyValue arg1 = args.get(1);

    Preconditions.checkArgument(arg0 instanceof StringData || arg0 instanceof SanitizedContent,
        "First argument to strIndexOf() function is not StringData or SanitizedContent: %s", arg0);

    Preconditions.checkArgument(arg1 instanceof StringData || arg1 instanceof SanitizedContent,
        "Second argument to strIndexOf() function is not StringData or SanitizedContent: %s", arg1);

    String strArg0 = arg0.coerceToString();
    String strArg1 = arg1.coerceToString();

    return IntegerData.forValue(strArg0.indexOf(strArg1));
  }

  @Override public JsExpr computeForJsSrc(List<JsExpr> args) {
    // Coerce SanitizedContent args to strings.
    String arg0 = JsExprUtils.toString(args.get(0)).getText();
    String arg1 = JsExprUtils.toString(args.get(1)).getText();

    return new JsExpr("(" + arg0 + ").indexOf(" + arg1 + ")", Integer.MAX_VALUE);
  }

  @Override public PyExpr computeForPySrc(List<PyExpr> args) {
    // Coerce SanitizedContent args to strings.
    String arg0 = args.get(0).toPyString().getText();
    String arg1 = args.get(1).toPyString().getText();

    return new PyExpr("(" + arg0 + ").find(" + arg1 + ")", Integer.MAX_VALUE);
  }
}