Iavra Battle Retry

/*:
 * @plugindesc Creates an invisible savegame before every fight and optionally reloads it after a defeat.
 * <Iavra Battle Retry>
 * @author Iavra
 *
 * @param Label Retry
 * @desc Label to be used for the "retry" option of the command window. Default: Retry
 * @default Retry
 *
 * @param Label Title
 * @desc Label to be used for the "title" option of the command window. Default: To Title
 * @default To Title
 *
 * @param Window Position
 * @desc Y coordinate of the command window, that gets displayed during the gameover scene after a battle. Default: 400
 * @default 400
 *
 * @param Disable Switch
 * @desc Id of an optional switch, that can be set ON to (temporarily) disable battle retry. Default: 0
 * @default 0
 *
 * @help
 * Note: Please place this below every other plugin, that deals with the battle system.
 *
 * If the plugin is active and the switch defined under "Disable Switch" is set to OFF, every lost fight (that will
 * redirect to the gameover screen) offers the option to retry the battle.
 */

var Imported = Imported || {};
Imported.iavra_quickselect = true;

//=============================================================================
// namespace IAVRA
//=============================================================================

var IAVRA = IAVRA || {};

(function() {
    "use strict";

    /**
     * Retrieve plugin parameters independant from the plugin's actual filename.
     */
    var _params = $plugins.filter(function(p) { return p.description.contains('<Iavra Battle Retry>'); })[0].parameters;
    var _param_labelRetry = _params['Label Retry'];
    var _param_labelTitle = _params['Label Title'];
    var _param_position = parseInt(_params['Window Position']) || 0;
    var _param_disableSwitch = parseInt(_params['Disable Switch']) || 0;

    /**
     * Contains the saved data.
     */
    var _data;

    /**
     * Creates a new save, which is stored in a variable, instead of being written to a file.
     */
    var _save = function() {
        var contents = DataManager.makeSaveContents();
        contents.troop = $gameTroop;
        _data = JsonEx.stringify(contents);
    }

    /**
     * Loads the current save from the variable.
     */
    var _load = function() {
        var contents = JsonEx.parse(_data)
        DataManager.extractSaveContents(contents);
        $gameTroop = contents.troop;
    };

    //=============================================================================
    // module IAVRA.BATTLERETRY
    //=============================================================================

    IAVRA.BATTLERETRY = {
        Scene_Gameover: function() { this.initialize.apply(this, arguments); },
        Window_Command: function() { this.initialize.apply(this, arguments); }
    };

    //=============================================================================
    // class IAVRA.BATTLERETRY.Scene_Gameover
    //=============================================================================

    (function($) {
        ($.prototype = Object.create(Scene_Gameover.prototype)).constructor = $;

        /**
         * Unlike the normal gameover scene, we display a command window, that can be used to retry the battle.
         */
        $.prototype.create = function() {
            Scene_Gameover.prototype.create.call(this);
            this.createCommandWindow();
        };

        /**
         * On start, open the command window for a small visual touch.
         */
        $.prototype.start = function() {
            Scene_Gameover.prototype.start.call(this);
            this._commandWindow.open();
        }

        /**
         * Add 2 command handler to either redirect to the title screen or back to the battle.
         */
        $.prototype.createCommandWindow = function() {
            this.addChild(this._commandWindow = new IAVRA.BATTLERETRY.Window_Command());
            this._commandWindow.setHandler('retry', this.retryBattle.bind(this));
            this._commandWindow.setHandler('title', this.gotoTitle.bind(this));
        };

        /**
         * On retry, load the stored savegame and go to the battle scene.
         */
        $.prototype.retryBattle = function() {
            _load();
            SceneManager.goto(Scene_Battle);
        };

        /**
         * We have a window, so we override the default behaviour of Scene_Gameover, that redirects to the title scene,
         * when the "ok" button is pressed.
         */
        $.prototype.isTriggered = function() { return false; }

    })(IAVRA.BATTLERETRY.Scene_Gameover);

    //=============================================================================
    // class IAVRA.BATTLEENTRY.Window_Retry
    //=============================================================================

    (function($) {
        ($.prototype = Object.create(Window_Command.prototype)).constructor = $;

        /**
         * Horizontally center the window and start closed, to it can be opened by the scene, when it starts.
         */
        $.prototype.initialize = function() {
            Window_Command.prototype.initialize.call(this, 0, _param_position);
            this.x = (Graphics.boxWidth - this.width) / 2;
            this.openness = 0;
        };

        /**
         * Add 2 commands, to either retry the battle or to go to the title screen (normal gameover behaviour).
         */
        $.prototype.makeCommandList = function() {
            this.addCommand(_param_labelRetry, 'retry', true);
            this.addCommand(_param_labelTitle, 'title', true);
        };

    })(IAVRA.BATTLERETRY.Window_Command);

    //=============================================================================
    // module BattleManager
    //=============================================================================

    (function($) {

        /**
         * On battle start, store the current game state.
         */
        var alias_startBattle = $.startBattle;
        $.startBattle = function() {
            _save();
            alias_startBattle.call(this);
        };

        /**
         * Redirect to our own gameover scene if:
         * - this is not a battle test.
         * - the whole party is dead (aka defeat).
         * - the battle would actually redirect to the gameover screen afterwards (isn't meant to be lost).
         * - the disable switch isn't set to ON.
         */
        var alias_updateBattleEnd = $.updateBattleEnd;
        $.updateBattleEnd = function() {
            if(!this.isBattleTest() && $gameParty.isAllDead() &&
               !this._canLose && !$gameSwitches.value(_param_disableSwitch)) {
                SceneManager.goto(IAVRA.BATTLERETRY.Scene_Gameover);
            } else { alias_updateBattleEnd.call(this); }
        };

    })(BattleManager);

})();