/*
 * Copyright 2012-2017 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat 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 2, or (at your
 * option) any later version.
 *
 * Thermostat 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 Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.common.swaggercombine;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * build a context object from command line arguements
 */
public class SwaggerCombineContextBuilder {

    /**
     * build a context object from command line arguements
     * @param args input arg list
     * @return new context object reflecting the input arguments
     * @throws IOException if @file doesn't exist
     */
    public SwaggerCombineContext buildContext(String[] args) throws IOException {

        final List<String> expandedArgs = expandArgs(args);

        final SwaggerCombineContext ctx = new SwaggerCombineContext();
        for (final String arg : expandedArgs) {
            if (arg == null) {
                System.err.println("null argument: (ignored)");
            } else if ("--quiet".equals(arg)) {
                ctx.quiet(true);
            } else if ("--pretty".equals(arg)) {
                ctx.prettyPrint(true);
            } else if ("--json".equals(arg)) {
                ctx.produce(SwaggerCombineContext.OutputFormat.JSON);
            } else if ("--yaml".equals(arg)) {
                ctx.produce(SwaggerCombineContext.OutputFormat.YAML);
            } else if (arg.startsWith("--output=")) {
                final String outFn = arg.substring(arg.indexOf('=') + 1);
                if ("-".equals(outFn)) {
                    ctx.setOutputFile(null);
                } else {
                    ctx.setOutputFile(outFn);
                }
                if (ctx.getFmt() == SwaggerCombineContext.OutputFormat.NONE) {
                    if (outFn.endsWith(".yaml")) {
                        ctx.produce(SwaggerCombineContext.OutputFormat.YAML);
                    } else if (outFn.endsWith(".json")) {
                        ctx.produce(SwaggerCombineContext.OutputFormat.JSON);
                    } else {
                        System.err.println("unable to determine output format from output extension - assuming YAML");
                        ctx.produce(SwaggerCombineContext.OutputFormat.YAML);
                    }
                }
            } else if ("--help".equals(arg)) {
                ctx.usage(true);
            } else if ("--lint".equals(arg)) {
                ctx.lint(true);
            } else if ("--use-template".equals(arg)) {
                ctx.useTemplate(true);
            } else if (arg.endsWith(".yaml") || arg.endsWith(".json")) {
                ctx.addMicroAPI(new File(arg));
            } else {
                System.err.println("invalid argument: " + arg);
                return null;
            }
        }
        return ctx;
    }

    /**
     * replace @filename with arguments from file (one line == one argument)
     * @param inargs input arg list
     * @return revices arglist with file contents inline
     * @throws IOException if file does not exist or can't be read
     */
    private List<String> expandArgs(String inargs[]) throws IOException {
        List<String> xargs = new ArrayList<>(inargs.length * 2);
        for (String arg : inargs) {
            if (arg == null || arg.length() < 2 || !arg.startsWith("@")) {
                xargs.add(arg);
            } else {
                BufferedReader in = new BufferedReader(new FileReader(arg.substring(1)));
                for (String line = in.readLine(); line != null; line = in.readLine()) {
                    xargs.add(line);
                }
            }
        }
        return xargs;
    }

}