From c35492605337f5021f36f3f81c5e374aadac3aae Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 5 Mar 2026 15:09:43 +0000
Subject: [PATCH 1/2] Initial plan


From d1f9e5fa127ddef43e0873cf565fa840792d80f1 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 5 Mar 2026 15:18:36 +0000
Subject: [PATCH 2/2] Add per-node first-seen timestamp via NodeBlock model

- Create node_blocks migration and model (node_id, block_id, first_seen_at)
- Add has_many :node_blocks to Node and Block models
- Populate NodeBlock in Block.create_or_update_with and create_headers_only
- Add block_first_seen_at to Node#as_json
- Add includes(node: :node_blocks) in Chaintip#nodes_for_identical_chaintips
- Remove global First seen from blockInfo.jsx
- Add per-node first-seen with colour coding in node.jsx

Assisted-by: GitHub Copilot
Assisted-by: OpenAI GPT-5-Codex

Co-authored-by: jonathanbier <42411042+jonathanbier@users.noreply.github.com>
---
 .../forkMonitorApp/components/blockInfo.jsx   |  2 --
 .../packs/forkMonitorApp/components/node.jsx  | 22 +++++++++++++++++++
 app/models/block.rb                           |  7 ++++++
 app/models/chaintip.rb                        |  4 +++-
 app/models/node.rb                            |  4 +++-
 app/models/node_block.rb                      |  6 +++++
 .../20260305151011_create_node_blocks.rb      | 15 +++++++++++++
 7 files changed, 56 insertions(+), 4 deletions(-)
 create mode 100644 app/models/node_block.rb
 create mode 100644 db/migrate/20260305151011_create_node_blocks.rb

diff --git a/app/javascript/packs/forkMonitorApp/components/blockInfo.jsx b/app/javascript/packs/forkMonitorApp/components/blockInfo.jsx
index 087e3c1a..18192a9f 100644
--- a/app/javascript/packs/forkMonitorApp/components/blockInfo.jsx
+++ b/app/javascript/packs/forkMonitorApp/components/blockInfo.jsx
@@ -18,8 +18,6 @@ class BlockInfo extends React.Component {
         <br/>
         Miner timestamp: <Moment format="YYYY-MM-DD HH:mm:ss" tz="UTC" parse="X">{this.props.block.timestamp}</Moment> UTC
         <br/>
-        First seen: <Moment format="HH:mm:ss" tz="UTC">{this.props.block.created_at}</Moment> UTC
-        <br/>
         { this.props.block.pool &&
           <span>
             Mined by: { this.props.block.pool }
diff --git a/app/javascript/packs/forkMonitorApp/components/node.jsx b/app/javascript/packs/forkMonitorApp/components/node.jsx
index 4e8b0ee3..f27b4434 100644
--- a/app/javascript/packs/forkMonitorApp/components/node.jsx
+++ b/app/javascript/packs/forkMonitorApp/components/node.jsx
@@ -3,6 +3,7 @@ import React from 'react';
 import PropTypes from 'prop-types';
 
 import Moment from 'react-moment';
+import 'moment-timezone';
 
 import {
     BreadcrumbItem,
@@ -33,6 +34,27 @@ class Node extends React.Component {
           <NodeBehind chaintip={ this.props.chaintip } node={ this.props.node } />
         </td>
         <td align="right">
+          { this.props.chaintip && this.props.chaintip.block && this.props.node.block_first_seen_at &&
+            (() => {
+              const times = this.props.chaintip.nodes
+                .map(n => n.block_first_seen_at)
+                .filter(Boolean)
+                .map(t => new Date(t).getTime());
+              const minTime = Math.min(...times);
+              const maxTime = Math.max(...times);
+              const myTime = new Date(this.props.node.block_first_seen_at).getTime();
+              let color = 'black';
+              if (times.length > 1) {
+                if (myTime === minTime) color = 'green';
+                else if (myTime === maxTime) color = 'red';
+              }
+              return (
+                <span style={{ color }}>
+                  First seen: <Moment format="HH:mm:ss" tz="UTC">{ this.props.node.block_first_seen_at }</Moment> UTC
+                </span>
+              );
+            })()
+          }
           { this.props.node.has_mirror_node &&
             <NodeInflation
               node={ this.props.node }
diff --git a/app/models/block.rb b/app/models/block.rb
index 7501e159..95f93c4b 100644
--- a/app/models/block.rb
+++ b/app/models/block.rb
@@ -29,6 +29,7 @@ class RollbackError < StandardError; end
   has_many :sweep_transactions, dependent: :destroy
   has_many :transactions, dependent: :destroy
   has_many :chaintips, dependent: :destroy
+  has_many :node_blocks, dependent: :destroy
 
   # Used to trigger and restore reorgs on the mirror node
   attr_accessor :invalidated_block_hashes
@@ -491,6 +492,9 @@ def create_or_update_with(block_info, _use_mirror, node, mark_valid)
         first_seen_by: node,
         headers_only: false
       )
+      NodeBlock.find_or_create_by(node: node, block: block) do |nb|
+        nb.first_seen_at = Time.current
+      end
       if mark_valid.present?
         if mark_valid == true
           block.update marked_valid_by: [node.id]
@@ -518,6 +522,9 @@ def create_headers_only(node, height, block_hash)
           first_seen_by: node,
           tx_count: nil
         )
+        NodeBlock.find_or_create_by(node: node, block: block) do |nb|
+          nb.first_seen_at = Time.current
+        end
         # Fetch headers
         block.fetch_header!(node)
         # TODO: connect longer branches to common ancestor (fetch more headers if needed)
diff --git a/app/models/chaintip.rb b/app/models/chaintip.rb
index abb9dfcd..ec297e78 100644
--- a/app/models/chaintip.rb
+++ b/app/models/chaintip.rb
@@ -13,7 +13,9 @@ class Chaintip < ApplicationRecord
   def nodes_for_identical_chaintips
     return nil if status != 'active'
 
-    chaintip_nodes = Chaintip.joins(:node).where('nodes.enabled = ? AND chaintips.status = ? AND chaintips.block_id = ?', true, status, block_id).order(
+    chaintip_nodes = Chaintip.joins(:node).where('nodes.enabled = ? AND chaintips.status = ? AND chaintips.block_id = ?', true, status, block_id)
+                             .includes(node: :node_blocks)
+                             .order(
       client_type: :asc, name: :asc, version: :desc
     )
     res = chaintip_nodes.collect(&:node)
diff --git a/app/models/node.rb b/app/models/node.rb
index f32f5ff7..fd3e18db 100644
--- a/app/models/node.rb
+++ b/app/models/node.rb
@@ -25,6 +25,7 @@ class NoTxIndexError < StandardError; end
   has_many :tx_outsets, dependent: :destroy
   belongs_to :mirror_block, optional: true, class_name: 'Block'
   has_one :active_chaintip, -> { where(status: 'active') }, class_name: 'Chaintip'
+  has_many :node_blocks, dependent: :destroy
   has_many :softforks, dependent: :destroy
 
   scope :bitcoin_core_by_version, lambda {
@@ -74,7 +75,8 @@ def as_json(options = nil)
                                                          last_tx_outset: tx_outsets.last,
                                                          has_mirror_node: mirror_rpchost.present?,
                                                          bip9_softforks: softforks.where(fork_type: :bip9), # rubocop:disable Naming/VariableNumber
-                                                         bip8_softforks: softforks.where(fork_type: :bip8) # rubocop:disable Naming/VariableNumber
+                                                         bip8_softforks: softforks.where(fork_type: :bip8), # rubocop:disable Naming/VariableNumber
+                                                         block_first_seen_at: active_chaintip&.block&.node_blocks&.find_by(node: self)&.first_seen_at
                                                        })
   end
 
diff --git a/app/models/node_block.rb b/app/models/node_block.rb
new file mode 100644
index 00000000..0060db6c
--- /dev/null
+++ b/app/models/node_block.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class NodeBlock < ApplicationRecord
+  belongs_to :node
+  belongs_to :block
+end
diff --git a/db/migrate/20260305151011_create_node_blocks.rb b/db/migrate/20260305151011_create_node_blocks.rb
new file mode 100644
index 00000000..b7afd504
--- /dev/null
+++ b/db/migrate/20260305151011_create_node_blocks.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class CreateNodeBlocks < ActiveRecord::Migration[6.1]
+  def change
+    create_table :node_blocks do |t|
+      t.references :node, null: false, foreign_key: true
+      t.references :block, null: false, foreign_key: true
+      t.datetime :first_seen_at, null: false
+
+      t.timestamps
+    end
+
+    add_index :node_blocks, %i[node_id block_id], unique: true
+  end
+end