/*
 * Copyright 2018 OpenAPI-Generator Contributors (https://openapi-generator.tech)
 * Copyright 2018 SmartBear Software
 *
 * 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
 *
 *     https://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 org.openapitools.codegen.templating.mustache;

import com.samskivert.mustache.Mustache;
import com.samskivert.mustache.Template;
import org.openapitools.codegen.CodegenConfig;
import org.openapitools.codegen.utils.CamelizeOption;

import java.io.IOException;
import java.io.Writer;

import static org.openapitools.codegen.utils.CamelizeOption.LOWERCASE_FIRST_LETTER;
import static org.openapitools.codegen.utils.CamelizeOption.UPPERCASE_FIRST_CHAR;
import static org.openapitools.codegen.utils.StringUtils.camelize;

/**
 * Converts text in a fragment to camelCase.
 *
 * Register:
 * <pre>
 * additionalProperties.put("camelcase", new CamelCaseLambda());
 * </pre>
 *
 * Use:
 * <pre>
 * {{#camelcase}}{{name}}{{/camelcase}}
 * </pre>
 */
public class CamelCaseLambda implements Mustache.Lambda {
    private CodegenConfig generator = null;
    private Boolean escapeParam = false;
    private CamelizeOption option = LOWERCASE_FIRST_LETTER;

    public CamelCaseLambda(boolean lowercaseFirstLetter) {
        if (lowercaseFirstLetter) {
            option = LOWERCASE_FIRST_LETTER;
        } else {
            option = UPPERCASE_FIRST_CHAR;
        }
    }

    public CamelCaseLambda() {}

    public CamelCaseLambda generator(final CodegenConfig generator) {
        this.generator = generator;
        return this;
    }

    public CamelCaseLambda escapeAsParamName(final Boolean escape) {
        this.escapeParam = escape;
        return this;
    }

    @Override
    public void execute(Template.Fragment fragment, Writer writer) throws IOException {
        String text = camelize(fragment.execute().replace(" ", "_"), option);
        if (generator != null) {
            text = generator.sanitizeName(text);
            if (generator.reservedWords().contains(text)) {
                // Escaping must be done *after* camelize, because generators may escape using characters removed by camelize function.
                text = generator.escapeReservedWord(text);
            }

            if (escapeParam) {
                // NOTE: many generators call escapeReservedWord in toParamName, but we can't assume that's always the case.
                //       Here, we'll have to accept that we may be duplicating some work.
                text = generator.toParamName(text);
            }
        }
        writer.write(text);
    }
}
