feat: enable reordering of cards and lists

src/server/api/root.ts

@@ -1,5 +1,6 @@
 import { boardRouter } from "~/server/api/routers/board";
 import { cardRouter } from "~/server/api/routers/card";
+import { listRouter } from "~/server/api/routers/list";
 import { createTRPCRouter } from "~/server/api/trpc";
 
 /**
@@ -9,7 +10,8 @@ import { createTRPCRouter } from "~/server/api/trpc";
  */
 export const appRouter = createTRPCRouter({
   board: boardRouter,
-  card: cardRouter
+  card: cardRouter,
+  list: listRouter,
 });
 
 // export type definition of API

src/server/api/routers/card.ts

@@ -1,5 +1,5 @@
 import { z } from "zod";
-import { and, eq, gte, or} from "drizzle-orm";
+import { eq, sql } from "drizzle-orm";
 
 import { cards, lists } from "~/server/db/schema";
 
@@ -24,20 +24,33 @@ export const cardRouter = createTRPCRouter({
     if (!userId) return;
 
     return ctx.db.transaction(async (tx) => {
-      const [currentList, newList] = await tx.select({ id: lists.id }).from(lists).where(or(eq(lists.publicId, input.currentListId), eq(lists.publicId, input.newListId)))
-
+      const [currentList] = await tx.select({ id: lists.id }).from(lists).where(eq(lists.publicId, input.currentListId))
+      const [newList] = await tx.select({ id: lists.id }).from(lists).where(eq(lists.publicId, input.newListId))
 
       if (!currentList?.id || !newList?.id) return;
-      
-      await tx
-        .update(cards)
-        .set({ index: input.newIndex + 1 })
-        .where(and(eq(cards.listId, newList.id), gte(cards.index, input.newIndex)))
 
-      await tx
-        .update(cards)
-        .set({ listId: newList.id, index: input.newIndex })
-        .where(eq(cards.publicId, input.cardId))
+      if (currentList.id === newList.id) {
+        await tx.execute(sql`
+          UPDATE ${cards}
+          SET ${cards.index} =
+            CASE
+              WHEN ${cards.index} = ${input.currentIndex} THEN ${input.newIndex}
+              WHEN ${input.currentIndex} < ${input.newIndex} AND ${cards.index} > ${input.currentIndex} AND ${cards.index} <= ${input.newIndex} THEN ${cards.index} - 1
+              WHEN ${input.currentIndex} > ${input.newIndex} AND ${cards.index} >= ${input.newIndex} AND ${cards.index} < ${input.currentIndex} THEN ${cards.index} + 1
+              ELSE ${cards.index}
+            END
+          WHERE ${cards.listId} = ${currentList.id};
+        `);
+      } else {
+        await tx.execute(sql`UPDATE ${cards} SET ${cards.index} = ${cards.index} + 1 WHERE ${cards.listId} = ${newList.id} AND ${cards.index} >= ${input.newIndex};`)
+
+        await tx.execute(sql`UPDATE ${cards} SET ${cards.index} = ${cards.index} - 1 WHERE ${cards.listId} = ${currentList.id} AND ${cards.index} >= ${input.currentIndex};`)
+
+        await tx
+          .update(cards)
+          .set({ listId: newList.id, index: input.newIndex })
+          .where(eq(cards.publicId, input.cardId));
+      }
     })
-  }),
+  })
 });

src/server/api/routers/list.ts

@@ -0,0 +1,45 @@
+import { z } from "zod";
+import { eq, sql } from "drizzle-orm";
+
+import { lists } from "~/server/db/schema";
+
+import {
+  createTRPCRouter,
+  publicProcedure,
+} from "~/server/api/trpc";
+
+export const listRouter = createTRPCRouter({
+  update: publicProcedure
+    .input(
+      z.object({ 
+        boardId: z.string().min(12),
+        listId: z.string().min(12),
+        currentIndex: z.number(),
+        newIndex: z.number(),
+      }))
+    .mutation(({ ctx, input }) => {
+      const userId = ctx.session?.user.id;
+
+      if (!userId) return;
+
+      return ctx.db.transaction(async (tx) => {
+        const [list] = await tx.select({ id: lists.id, boardId: lists.boardId }).from(lists).where(eq(lists.publicId, input.listId))
+
+        if (!list) return;
+
+        await tx.execute(sql`
+          UPDATE ${lists}
+          SET ${lists.index} =
+            CASE
+              WHEN ${lists.index} = ${input.currentIndex} AND ${lists.id} = ${list.id} THEN ${input.newIndex}
+              WHEN ${input.currentIndex} < ${input.newIndex} AND ${lists.index} > ${input.currentIndex} AND ${lists.index} <= ${input.newIndex} THEN ${lists.index} - 1
+              WHEN ${input.currentIndex} > ${input.newIndex} AND ${lists.index} >= ${input.newIndex} AND ${lists.index} < ${input.currentIndex} THEN ${lists.index} + 1
+              ELSE ${lists.index}
+            END
+          WHERE ${lists.boardId} = ${list.boardId};
+        `);
+      })
+
+      
+    })
+});