/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * 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.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;

/**
 * An out of process executable.
 */
class Command {

    private final List<String> args;
    private final boolean permitNonZeroExitStatus;

    Command(String... args) {
        this(Arrays.asList(args));
    }

    Command(List<String> args) {
        this.args = new ArrayList<String>(args);
        this.permitNonZeroExitStatus = false;
    }

    private Command(Builder builder) {
        this.args = new ArrayList<String>(builder.args);
        this.permitNonZeroExitStatus = builder.permitNonZeroExitStatus;
    }

    static class Builder {
        private final List<String> args = new ArrayList<String>();
        private boolean permitNonZeroExitStatus = false;

        public Builder args(String... args) {
            return args(Arrays.asList(args));
        }

        public Builder args(Collection<String> args) {
            this.args.addAll(args);
            return this;
        }

        public Builder permitNonZeroExitStatus() {
            permitNonZeroExitStatus = true;
            return this;
        }

        public Command build() {
            return new Command(this);
        }

        public List<String> execute() {
            return build().execute();
        }
    }

    public List<String> execute() {
        try {
            Process process = new ProcessBuilder()
                    .command(args)
                    .redirectErrorStream(true)
                    .start();

            BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
            List<String> outputLines = new ArrayList<String>();
            String outputLine;
            while ((outputLine = in.readLine()) != null) {
                outputLines.add(outputLine);
            }

            if (process.waitFor() != 0 && !permitNonZeroExitStatus) {
                StringBuilder message = new StringBuilder();
                for (String line : outputLines) {
                    message.append("\n").append(line);
                }
                throw new RuntimeException("Process failed: " + args + message);
            }

            return outputLines;
        } catch (IOException e) {
            throw new RuntimeException("Process failed: " + args, e);
        } catch (InterruptedException e) {
            throw new RuntimeException("Process failed: " + args, e);
        }
    }

}