From 0b0492a724b1e2d0434de9067d9197ae78fde559 Mon Sep 17 00:00:00 2001
From: Graham Forest <graham.forest@protonmail.com>
Date: Mon, 22 Dec 2025 11:01:14 -0800
Subject: [PATCH] Add a tool to show changes vs the published schema

`bin/diff-dat-schema` refreshes a local copy of the published schema
(efficiently), then sorts, filters, and version-filters for each game
version to show a summary of what changed.

Made this while verifying my own programmatic manipulation code, but it
seems generally useful.
---
 .gitignore          |  1 +
 bin/diff-dat-schema | 45 +++++++++++++++++++++++++++++++++++++++++++++
 package.json        |  3 ++-
 3 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100755 bin/diff-dat-schema

diff --git a/.gitignore b/.gitignore
index 7bf05ba..6d2e3ab 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 dist/
 schema.min.json
 schema.jsonl
+upstream.min.json
 
 # Logs
 logs
diff --git a/bin/diff-dat-schema b/bin/diff-dat-schema
new file mode 100755
index 0000000..1bd3044
--- /dev/null
+++ b/bin/diff-dat-schema
@@ -0,0 +1,45 @@
+#!/bin/bash -e
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+cd "$SCRIPT_DIR/.." || exit
+
+BOLD="$(tput bold)"
+NORM="$(tput sgr0)"
+
+TMPD=$(mktemp -d .dat-schema-XXX)
+trap 'rm -rf -- "$TMPD"' EXIT
+
+filter() {
+    jq '.tables | sort_by(.name)[] | select(.validFor == '"$1"' or .validFor == 3) | del(.validFor)' "$2" > "$3"
+}
+
+UPSTREAM="upstream.min.json"
+NEW="schema.min.json"
+
+# -c won't download unless upstream is newer
+wget -O "$UPSTREAM" -q -c https://github.com/poe-tool-dev/dat-schema/releases/download/latest/schema.min.json
+
+CHANGES=no
+
+for V in 1 2
+do
+    UPSTREAMV="$TMPD/upstream.$V.json"
+    NEWV="$TMPD/schema.$V.json"
+    TMPV="$TMPD/schema.$V.diff"
+    filter "$V" "$UPSTREAM" "$UPSTREAMV"
+    filter "$V" "$NEW" "$NEWV"
+    if ! diff -u "$UPSTREAMV" "$NEWV" > "$TMPV"
+    then
+        CHANGES=yes
+        echo "${BOLD}Changes for Version $V:${NORM}"
+        tail -n +3 < "$TMPV"
+        echo
+    fi
+done
+
+if [ "$CHANGES" == "yes" ]
+then
+    echo "Note: The above diff is against the published schema which may be behind the main branch"
+else
+    echo "No changes detected"
+fi
diff --git a/package.json b/package.json
index 486a8d7..5fc4356 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,8 @@
   "exports": "./dist/index.js",
   "scripts": {
     "generate": "tsc --noCheck && node dist/cli.js",
-    "generate:watch": "tsc --noCheck && node dist/cli.js --watch"
+    "generate:watch": "tsc --noCheck && node dist/cli.js --watch",
+    "diff": "./bin/diff-dat-schema"
   },
   "files": [
     "dist/index.*",