From 620cb8bb1d620cc6e28e93e4c2d3c5de8e0f5653 Mon Sep 17 00:00:00 2001
From: C-3PO <c-3po@jedipedia.net>
Date: Fri, 22 Jun 2018 18:16:59 +0200
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20Add=20release=20path=20module?=
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---
 src/ssn/releasePaths.ts | 94 +++++++++++++++++++++++++----------------
 1 file changed, 58 insertions(+), 36 deletions(-)

diff --git a/src/ssn/releasePaths.ts b/src/ssn/releasePaths.ts
index 587d0e2..530a578 100644
--- a/src/ssn/releasePaths.ts
+++ b/src/ssn/releasePaths.ts
@@ -2,51 +2,73 @@
 function getFroms({ product, to: releaseTo}: {product: string, to: number}) {
   //The launcher (patcher, patcher2014, patcher2017) is always installing from -1, never from a previous version
   if (product.startsWith('patcher')) {
-      return [-1];
+    return [-1];
   } else {
-      const froms: number[] = [];
+    const froms: number[] = [];
 
-      //Always X-1toX
-      froms.push(releaseTo - 1);
+    //Always X-1toX
+    froms.push(releaseTo - 1);
 
-      //Also 0toX, unless X is 0. And no need to add 0to1 a second time.
-      if (releaseTo >= 2) { froms.push(0); }
+    //Also 0toX, unless X is 0. And no need to add 0to1 a second time.
+    if (releaseTo >= 2) { froms.push(0); }
 
-      if ((releaseTo % 5) === 0) {
-          //Also X-5toX if X % 5
-          if (releaseTo >= 10) { froms.push(releaseTo - 5); }
-          //Also X-20toX if X % 5
-          if (releaseTo >= 25) { froms.push(releaseTo - 20); }
-          //Also downgrade from the following four releases
-          froms.push(releaseTo + 1);
-          froms.push(releaseTo + 2);
-          froms.push(releaseTo + 3);
-          froms.push(releaseTo + 4);
-      } else { //For some of the older releases, an update from _5 or _0 is possible
-          /*
-          e.g. in asset_swtor_main:
-          5to7, 5to8, 5to9,
-          10to12, 10to13, 10to14,
-          15to17, 15to18, 15to19,
-          20to22, 20to23, 20to24,
-          25to27, 25to28, 25to29,
-          30to32, 30to33, 30to34,
-          35to37, etc.  , 85to87
-          */
-          if (releaseTo >= 7 && (releaseTo % 5) > 1) { froms.push(releaseTo - (releaseTo % 5)); }
-      }
+    if ((releaseTo % 5) === 0) {
+      //Also X-5toX if X % 5
+      if (releaseTo >= 10) { froms.push(releaseTo - 5); }
+      //Also X-20toX if X % 5
+      if (releaseTo >= 25) { froms.push(releaseTo - 20); }
+      //Also downgrade from the following four releases
+      froms.push(releaseTo + 1);
+      froms.push(releaseTo + 2);
+      froms.push(releaseTo + 3);
+      froms.push(releaseTo + 4);
+    } else { //For some of the older releases, an update from _5 or _0 is possible
+      /*
+      e.g. in asset_swtor_main:
+      5to7, 5to8, 5to9,
+      10to12, 10to13, 10to14,
+      15to17, 15to18, 15to19,
+      20to22, 20to23, 20to24,
+      25to27, 25to28, 25to29,
+      30to32, 30to33, 30to34,
+      35to37, etc.  , 85to87
+      */
+      if (releaseTo >= 7 && (releaseTo % 5) > 1) { froms.push(releaseTo - (releaseTo % 5)); }
+    }
 
-      return froms;
+    return froms;
   }
 }
 
-/** Checks whether there is a valid path between our current release and the release we want to update to, and returns true or false.
+/**
+ * Checks whether there is a valid path between our current release and the release we want to update to, and returns an array with
+ * the release path, or an empty array if no path exists.
+ * E.g. for `{ from: 21, to: 24 }`, it returns [[21, 22], [22, 23], [23, 24]].
  * Does not actually look at the manifest.xml file but theorizes on possible patches based on the usually created patches, allowing
  * us to find release pathes for products that have not been released yet.
  */
-export default function findReleasePath({ product, from, to}: {product: string, from: number, to: number}) {
-    //TODO: need to recursively get froms until path is found
-    //TODO: need to ignore patches that we know are bugged (i.e. missing from CDN)
-    return getFroms({ product, to }).includes(from);
-    //TODO: we also need to return the release path, e.g. [[3, 4], [4, 5], [5, 6]]
+export default function findReleasePath({ product, from, to}: {product: string, from: number, to: number}): Array<[number, number]> {
+  //We assume that "from < to" is true for all patches
+
+  const froms = getFroms({ product, to });
+
+  //If we can patch, return immediately
+  if (froms.includes(from)) {
+    return [[from, to]];
+  }
+
+  //Otherwise, check all froms recursively, by checking interim releases
+  const smallerFroms = froms.filter((num) => num > from);
+  //Always prefer shortest release paths (e.g. 1->3 vs. 1->2->3) by ensuring we check smallest froms first
+  smallerFroms.sort();
+
+  for (let i = 0, il = smallerFroms.length; i < il; i += 1) {
+    const interim = smallerFroms[i];
+    const releasePath = findReleasePath({ product, from, to: interim} );
+    if (releasePath.length > 0) {
+      return [...releasePath, [interim, to]];
+    }
+  }
+
+  return [];
 }