Merc_LockPartyLeader

//=============================================================================
// Mercury Lock Party Leader
// Merc_LockPartyLeader.js
//=============================================================================

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

var Mercury = Mercury || {};
Mercury.LockPartyLeader = Mercury.LockPartyLeader || {};
Mercury.LockPartyLeader.version = 1.00;

/*:
* @target MZ
* @plugindesc [Version 1.00] Lock Party Leader
* @author Mercury
*
* @param isLockEnabled
* @text Lock Enabled
* @desc Whether or not to lock the party leader by default.
* @type boolean
* @default true
*
* @command setLock
* @text Set Lock
* @desc Enable or disable the lock on the party leader.
*
* @arg enabled
* @text Enabled
* @desc Whether to enable the lock (true) or disable it (false).
* @type boolean
* @default true
*
* @command setLeader
* @text Set Leader
* @desc Change which party member is considered the leader.
*
* @arg actorId
* @text Actor ID
* @desc The ID of the actor to set as the leader.
* @type actor
* @default 1
*
* @command openFormation
* @text Open Formation Menu
* @desc Open the party formation menu.
*
* @help
*
* ------------------------------------------------------------------------
* Information
* ------------------------------------------------------------------------
* This plugin allows you to lock the party leader in the party formation menu.
*
* There is also a plugin command to enable or disable the lock, and a plugin command
* to change which actor is considered the leader. I have also included a plugin
* command that allows you to open the party formation menu directly from an event.
*
* ------------------------------------------------------------------------
* Terms of Use
* ------------------------------------------------------------------------
* - Free for commercial and non-commercial use.
* - You may do whatever you want with this plugin, aside from directly selling it.
*/

//=============================================================================
// Settings
//=============================================================================

Mercury.LockPartyLeader.parameters = PluginManager.parameters('Merc_LockPartyLeader');
Mercury.LockPartyLeader.isLockEnabled = Mercury.LockPartyLeader.parameters['isLockEnabled'] === 'true';
Mercury.LockPartyLeader.needFormationMenu = false;

//=============================================================================
// Plugin Commands
//=============================================================================

PluginManager.registerCommand('Merc_LockPartyLeader', 'setLock', function(args) {
    Mercury.LockPartyLeader.isLockEnabled = args.enabled === 'true';
});

PluginManager.registerCommand('Merc_LockPartyLeader', 'setLeader', function(args) {
    $gameParty.setLeader(Number(args.actorId));
});

PluginManager.registerCommand('Merc_LockPartyLeader', 'openFormation', function() {
    Mercury.LockPartyLeader.needFormationMenu = true;
    SceneManager.push(Scene_Menu);
});

//=============================================================================
// Game_Actor
//=============================================================================

Mercury.LockPartyLeader.Game_Actor_isFormationChangeOk = Game_Actor.prototype.isFormationChangeOk;
Game_Actor.prototype.isFormationChangeOk = function() {
    if (Mercury.LockPartyLeader.isLockEnabled && this.index() === 0) {
        return false;
    }
    return Mercury.LockPartyLeader.Game_Actor_isFormationChangeOk.call(this);
};

//=============================================================================
// Game_Party
//=============================================================================

Game_Party.prototype.setLeader = function(actorId) {
    const actorIndex = this._actors.indexOf(actorId);
    if (actorIndex > -1) {
        this.swapOrder(0, actorIndex);
    } else {
        console.warn(`Actor ID ${actorId} is not in the party.`);
    }
};

//=============================================================================
// Scene_Menu
//=============================================================================

Mercury.LockPartyLeader.Scene_Menu_start = Scene_Menu.prototype.start;
Scene_Menu.prototype.start = function() {
    Mercury.LockPartyLeader.Scene_Menu_start.call(this);
    if (Mercury.LockPartyLeader.needFormationMenu) {
        this._commandWindow.selectSymbol('formation');
        this._commandWindow.deactivate();
        this.commandFormation();
        Mercury.LockPartyLeader.needFormationMenu = false;
    }
};

//=============================================================================
// Window_MenuCommand
//=============================================================================

Mercury.LockPartyLeader.Window_MenuCommand_needsCommand = Window_MenuCommand.prototype.needsCommand;
Window_MenuCommand.prototype.needsCommand = function(name) {
    if (name === 'formation' && Mercury.LockPartyLeader.needFormationMenu) {
        return true;
    }
    return Mercury.LockPartyLeader.Window_MenuCommand_needsCommand.call(this, name);
};