From a84bad9647af84d04f163b1ed954733927c9d32a Mon Sep 17 00:00:00 2001
From: Avinash Kumar Deepak <avinash8655279@gmail.com>
Date: Wed, 8 Apr 2026 19:11:30 +0530
Subject: [PATCH] fix(sync): make server conflict resolution explicit

---
 src/GraphWorkspace.jsx                   |  1 +
 src/component/modals/ConfirmModal.jsx    | 26 ++++++-
 src/component/modals/confirmModal.css    |  1 +
 src/graph-builder/graph-core/6-server.js | 94 +++++++++++++++++++++++-
 4 files changed, 116 insertions(+), 6 deletions(-)

diff --git a/src/GraphWorkspace.jsx b/src/GraphWorkspace.jsx
index 53e3504..4045757 100644
--- a/src/GraphWorkspace.jsx
+++ b/src/GraphWorkspace.jsx
@@ -84,6 +84,7 @@ const GraphComp = (props) => {
                 isOpen={superState.confirmModal.open}
                 title="Confirm"
                 message={superState.confirmModal.message}
+                actions={superState.confirmModal.actions}
                 onConfirm={() => {
                     if (superState.confirmModal.onConfirm) superState.confirmModal.onConfirm();
                     dispatcher({ type: T.SET_CONFIRM_MODAL, payload: { open: false, message: '', onConfirm: null } });
diff --git a/src/component/modals/ConfirmModal.jsx b/src/component/modals/ConfirmModal.jsx
index 787ab33..e564dbf 100644
--- a/src/component/modals/ConfirmModal.jsx
+++ b/src/component/modals/ConfirmModal.jsx
@@ -3,14 +3,34 @@ import ParentModal from './ParentModal';
 import './confirmModal.css';
 
 const ConfirmModal = ({
-    isOpen, title, message, onConfirm, onCancel,
+    isOpen, title, message, onConfirm, onCancel, actions,
 }) => (
     <ParentModal ModelOpen={isOpen} closeModal={onCancel} title={title}>
         <div className="confirm-modal-content">
             <div className="confirm-modal-message">{message}</div>
             <div className="confirm-modal-actions">
-                <button type="button" className="confirm-btn" onClick={onConfirm}>Yes</button>
-                <button type="button" className="cancel-btn" onClick={onCancel}>No</button>
+                {
+                    actions && actions.length
+                        ? actions.map((action) => (
+                            <button
+                                key={action.label}
+                                type="button"
+                                className={action.className || 'cancel-btn'}
+                                onClick={() => {
+                                    if (action.onClick) action.onClick();
+                                    onCancel();
+                                }}
+                            >
+                                {action.label}
+                            </button>
+                        ))
+                        : (
+                            <>
+                                <button type="button" className="confirm-btn" onClick={onConfirm}>Yes</button>
+                                <button type="button" className="cancel-btn" onClick={onCancel}>No</button>
+                            </>
+                        )
+                }
             </div>
         </div>
     </ParentModal>
diff --git a/src/component/modals/confirmModal.css b/src/component/modals/confirmModal.css
index 5402b8b..e03e316 100644
--- a/src/component/modals/confirmModal.css
+++ b/src/component/modals/confirmModal.css
@@ -5,6 +5,7 @@
 .confirm-modal-message {
   margin-bottom: 20px;
   font-size: 1.1em;
+  white-space: pre-line;
 }
 .confirm-modal-actions {
   display: flex;
diff --git a/src/graph-builder/graph-core/6-server.js b/src/graph-builder/graph-core/6-server.js
index d396bbb..15bf43e 100644
--- a/src/graph-builder/graph-core/6-server.js
+++ b/src/graph-builder/graph-core/6-server.js
@@ -1,7 +1,7 @@
 import { toast } from 'react-toastify';
 import Axios from 'axios';
 import { actionType as T } from '../../reducer';
-import { EXECUTION_ENGINE_URL } from '../../serverCon/config';
+import serverConConfig, { EXECUTION_ENGINE_URL } from '../../serverCon/config';
 import GraphLoadSave from './5-load-save';
 // import {
 //     postGraph, updateGraph, forceUpdateGraph, getGraph, getGraphWithHashCheck,
@@ -11,6 +11,86 @@ import {
 } from '../../serverCon/crud_http';
 
 class GraphServer extends GraphLoadSave {
+    static isSyncConflictError(err) {
+        const msg = (err && err.message ? err.message : '').toLowerCase();
+        return msg.includes('different history')
+            || msg.includes('latest changes')
+            || msg.includes('can not update');
+    }
+
+    showSyncConflictModal(reason) {
+        const localHash = this.actionArr.length ? this.actionArr.at(-1).hash : 'None';
+        const setModal = (remoteHash) => {
+            const message = [
+                reason || 'Sync conflict detected.',
+                `Local hash: ${localHash}`,
+                `Remote hash: ${remoteHash || 'Remote history is newer/different'}`,
+                'Choose how to resolve this conflict.',
+            ].join('\n');
+            this.dispatcher({
+                type: T.SET_CONFIRM_MODAL,
+                payload: {
+                    open: true,
+                    message,
+                    actions: [
+                        {
+                            label: 'Pull remote',
+                            className: 'confirm-btn',
+                            onClick: () => this.forcePullFromServer(),
+                        },
+                        {
+                            label: 'Force push local',
+                            className: 'confirm-btn',
+                            onClick: () => {
+                                if (this.serverID) {
+                                    forceUpdateGraph(this.serverID, this.getGraphML()).catch((err) => {
+                                        toast.error(err.response?.data?.message || err.message);
+                                    });
+                                } else {
+                                    postGraph(this.getGraphML()).then((serverID) => {
+                                        this.set({ serverID });
+                                    }).catch((err) => {
+                                        toast.error(err.response?.data?.message || err.message);
+                                    });
+                                }
+                            },
+                        },
+                        {
+                            label: 'Open remote in new tab',
+                            className: 'cancel-btn',
+                            onClick: () => {
+                                if (!this.serverID) return;
+                                const remotePath = serverConConfig.getGraph(this.serverID);
+                                const remoteURL = `${serverConConfig.baseURL}${remotePath}`;
+                                window.open(remoteURL, '_blank', 'noopener,noreferrer');
+                            },
+                        },
+                        {
+                            label: 'Cancel',
+                            className: 'cancel-btn',
+                            onClick: null,
+                        },
+                    ],
+                },
+            });
+        };
+        if (!this.serverID) {
+            setModal('Unknown');
+            return;
+        }
+        getGraph(this.serverID).then((graphXML) => {
+            try {
+                const doc = new DOMParser().parseFromString(graphXML, 'application/xml');
+                const hashes = doc.getElementsByTagName('hash');
+                setModal(hashes.length ? (hashes[hashes.length - 1].textContent || '') : '');
+            } catch {
+                setModal('Unavailable');
+            }
+        }).catch(() => {
+            setModal('Unavailable');
+        });
+    }
+
     set(config) {
         const { serverID } = config;
         super.set(config);
@@ -73,6 +153,10 @@ class GraphServer extends GraphLoadSave {
             updateGraph(this.serverID, this.getGraphML()).then(() => {
 
             }).catch((err) => {
+                if (GraphServer.isSyncConflictError(err)) {
+                    this.showSyncConflictModal('Cannot push: local and remote histories diverged.');
+                    return;
+                }
                 toast.error(err.response?.data?.message || err.message);
             });
         } else {
@@ -127,8 +211,12 @@ class GraphServer extends GraphLoadSave {
         if (this.serverID) {
             getGraphWithHashCheck(this.serverID, this.actionArr.at(-1).hash).then((graphXML) => {
                 this.setGraphML(graphXML);
-            }).catch(() => {
-
+            }).catch((err) => {
+                if (GraphServer.isSyncConflictError(err)) {
+                    this.showSyncConflictModal('Cannot pull: local and remote histories diverged.');
+                    return;
+                }
+                toast.error(err.response?.data?.message || err.message);
             });
         } else {
             toast.success('Not on server');