/*
 * Copyright (c) 2006-2017 DMDirc Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
 * OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.dmdirc.addons.tabcompletion_bash;

import com.dmdirc.interfaces.WindowModel;
import com.dmdirc.ui.input.AdditionalTabTargets;
import com.dmdirc.ui.input.TabCompleter;
import com.dmdirc.ui.input.tabstyles.TabCompletionResult;
import com.dmdirc.ui.input.tabstyles.TabCompletionStyle;

import java.awt.Toolkit;
import java.util.List;
import java.util.Locale;

public class BashStyle implements TabCompletionStyle {

    /** The last position the user tab-completed at. */
    private int lastPosition = -1;
    /** The number of times the user has tab-completed the same position. */
    private int tabCount = 0;
    /** The last word that was tab completed. */
    private String lastWord = "";
    /** The tab completer that we use. */
    protected final TabCompleter tabCompleter;
    /** The input window that we use. */
    protected final WindowModel window;

    /**
     * Creates a new Bash-style tab completer.
     *
     * @param completer The tab completer this style is for
     * @param window    The window this tab style is for
     */
    public BashStyle(final TabCompleter completer, final WindowModel window) {
        this.tabCompleter = completer;
        this.window = window;
    }

    @Override
    public TabCompletionResult getResult(final String original, final int start,
            final int end, final boolean shiftPressed,
            final AdditionalTabTargets additional) {
        final String word = original.substring(start, end);
        final List<String> res = tabCompleter.complete(word, additional);

        if (start == lastPosition && word.equals(lastWord)) {
            tabCount++;
        } else {
            lastPosition = start;
            lastWord = word;
            tabCount = 1;
        }

        if (res.isEmpty()) {
            Toolkit.getDefaultToolkit().beep();

            return null;
        } else if (res.size() == 1) {
            // One result, just replace it

            final String result = res.get(0);

            return new TabCompletionResult(
                    original.substring(0, start) + result + original.substring(end),
                    start + result.length());
        } else {
            // Multiple results

            final String sub = getBestSubstring(res);
            if (sub.equalsIgnoreCase(word) && tabCount >= 2) {
                window.getEventBus().publishAsync(
                        new BashDisambiguationEvent(window, res.toString()));
                return null;
            } else {
                return new TabCompletionResult(
                        original.substring(0, start) + sub + original.substring(end),
                        start + sub.length());
            }
        }
    }

    /**
     * Returns the longest substring that matches all results.
     *
     * @return longest possible substring matching all results
     */
    private String getBestSubstring(final List<String> res) {
        if (res.isEmpty()) {
            return "";
        }

        final boolean caseSensitive = window.getConfigManager()
                .getOptionBool("tabcompletion", "casesensitive");

        String substring = res.get(0);
        for (String entry : res) {
            if (caseSensitive) {
                while (!entry.startsWith(substring)) {
                    substring = substring.substring(0, substring.length() - 1);
                }
            } else {
                while (!entry.toLowerCase(Locale.getDefault()).startsWith(
                        substring.toLowerCase(Locale.getDefault()))) {
                    substring = substring.substring(0, substring.length() - 1);
                }
            }
        }

        return substring;
    }

}