package com.google.ara.app.manager.util;

import java.util.List;

public final class ModuleNameJoiner {
    private ModuleNameJoiner() { }

    private static final String DEFAULT_SEPARATOR = ", ";

    public static String join(List<String> moduleNames, String conjoiner) {
        return join(moduleNames, conjoiner, DEFAULT_SEPARATOR);
    }

    public static String join(List<String> moduleNames, String conjoiner, String separator) {
        if (moduleNames == null) {
            return "";
        }

        switch (moduleNames.size()) {
            case 0:
                return "";

            case 1:
                return moduleNames.get(0);

            case 2:
                return simpleJoin(moduleNames, separator);

            default:
                return conjoin(
                        conjoiner,
                        simpleJoin(moduleNames.subList(0, moduleNames.size() - 1), separator),
                        moduleNames.get(moduleNames.size() - 1)
                );
        }
    }

    public static String simpleJoin(List<String> moduleNames, String separator) {
        if (moduleNames == null) {
            return "";
        }

        boolean first = true;
        StringBuffer sb = new StringBuffer(moduleNames.get(0));
        for (String s : moduleNames) {
            if (first) {
                first = false;
                continue;
            }
            sb.append(separator).append(s);
        }

        return sb.toString();
    }

    private static String conjoin(String conjoiner, String prefix, String postfix) {
        return prefix + conjoiner + postfix;
    }
}