/**
 * indicator.ts
 *
 * Copyright (C) 2020,2021,2024  CismonX <admin@cismon.net>
 *
 * This file is part of vscode-texinfo.
 *
 * vscode-texinfo 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 3 of the License, or (at your option)
 * any later version.
 *
 * vscode-texinfo 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
 * vscode-texinfo.  If not, see <https://www.gnu.org/licenses/>.
 */

import * as vscode from 'vscode';
import GlobalContext from './global_context';
import { exec } from './utils/misc';

/**
 * Shows whether GNU Texinfo is properly installed and configured.
 */
export default class Indicator implements vscode.Disposable
{
    get canDisplayPreview() {
        return this._canDisplayPreview;
    }

    dispose() {
        this._statusBarItem.dispose();
    }

    constructor(private readonly _globalContext: GlobalContext) {
        _globalContext.subscribe(
            vscode.commands.registerCommand(
                'texinfo.indicator.click',
                this._click.bind(this),
            ),
            vscode.window.onDidChangeActiveTextEditor(
                this._refresh.bind(this),
            ),
        );
        this._updateStatus()
            .then(() => this._refresh(vscode.window.activeTextEditor));
    }

    private _canDisplayPreview = false;

    private readonly _statusBarItem = vscode.window.createStatusBarItem(
        vscode.StatusBarAlignment.Right, 100);

    /**
     * Calls when the status bar item is clicked.
     */
    private async _click() {
        await this._updateStatus();
        this._refresh(vscode.window.activeTextEditor);
    }

    /**
     * Refresh the show/hide status of the indicator based on given editor.
     * 
     * @param editor 
     */
    private _refresh(editor?: vscode.TextEditor) {
        if (editor?.document.languageId === 'texinfo') {
            this._statusBarItem.show();
        } else {
            this._statusBarItem.hide();
        }
    }

    /**
     * Update the installation status of GNU Texinfo,
     * by checking `makeinfo --version`.
     */
    private async _updateStatus() {
        const options = this._globalContext.options;
        const output
            = await exec(options.makeinfo, ['--version'], options.maxSize);
        const result = output.data?.match(/\(GNU texinfo\) (.*)\n/);
        const version = result?.[1] ?? '';
        let tooltip = '', icon: string;
        if (version) {
            icon = '$(check)';
            const verArr = version.split('.');
            if (version.length >= 2) {
                const verMajor = parseInt(verArr[0], 10);
                const verMinor = parseInt(verArr[1], 10);
                if (verMajor < 7 || verMinor < 1) {
                    icon = '$(warning)';
                    tooltip = `GNU Texinfo (${options.makeinfo}) ` +
                        `is outdated (${version} < 7.1).`;
                }
            }
            this._canDisplayPreview = true;
        } else {
            icon = '$(close)';
            tooltip = `GNU Texinfo (${options.makeinfo}) ` +
                `is not correctly installed or configured.`;
            this._canDisplayPreview = false;
        }
        this._statusBarItem.command = 'texinfo.indicator.click';
        this._statusBarItem.text = `${icon} GNU Texinfo ${version}`;
        this._statusBarItem.tooltip = tooltip;
    }
}