feat(assignments): partial return schema, concurrency guard, domain error

src/schemas/assignment.schema.ts

@@ -79,9 +79,24 @@ export const updateAssignmentSchema = buildUpdateAssignmentSchema(
 export type UpdateAssignmentFormType = z.input<typeof updateAssignmentSchema>
 export type UpdateAssignmentData = z.output<typeof updateAssignmentSchema>
 
-export const returnAssignmentSchema = z.object({
+export function buildReturnAssignmentSchema(copy: AssignmentSchemaCopy) {
+  return z.object({
     id: z.string().min(1, {
-    error: defaultAssignmentSchemaCopy.idRequired,
+      error: copy.idRequired,
     }),
+    returns: z
+      .array(
+        z.object({
+          assignmentLineId: z.string().min(1),
+          quantity: z.number().int().positive(),
+          notes: z.string().optional(),
+        }),
+      )
+      .optional(),
   })
+}
+
+export const returnAssignmentSchema = buildReturnAssignmentSchema(
+  defaultAssignmentSchemaCopy,
+)
 export type ReturnAssignmentFormType = z.infer<typeof returnAssignmentSchema>

src/services/assignment.service.ts

@@ -23,6 +23,12 @@ type ReturnStockAssignmentResult = {
   returnedLines: { itemId: string; quantity: number }[]
 }
 
+export class ConcurrentReturnError extends Error {
+  constructor(public readonly assignmentLineId: string) {
+    super(`Concurrent return detected on line ${assignmentLineId}`)
+  }
+}
+
 type AssignmentWithLines = Prisma.AssignmentGetPayload<{
   include: {
     person: true
@@ -69,6 +75,9 @@ function toLegacyAssignment(
   const asset = assetLine?.asset ?? null
   const quantity = stockLine?.quantity ?? (assetLine ? 1 : null)
   const returnDate = assignment.closedAt ?? assetLine?.returnedAt ?? null
+  const remainingQuantity = stockLine
+    ? stockLine.quantity - stockLine.returnedQuantity
+    : undefined
 
   return {
     ...assignment,
@@ -80,6 +89,8 @@ function toLegacyAssignment(
     itemId: item?.id ?? null,
     assetId: asset?.id ?? null,
     quantity,
+    assignmentLineId: stockLine?.id,
+    remainingQuantity,
   }
 }
 
@@ -209,10 +220,29 @@ export const AssignmentService = {
     const stockLinesById = new Map(
       assignment.stockLines.map((line) => [line.id, line]),
     )
+    const observedReturnedQuantities = new Map(
+      assignment.stockLines.map((line) => [line.id, line.returnedQuantity]),
+    )
     const returnTimestamp = new Date()
     let returnedQuantity = 0
     const returnedLines: { itemId: string; quantity: number }[] = []
 
+    if (returns !== undefined) {
+      const lineIds = remainingReturns.map((entry) => entry.assignmentLineId)
+      const reloadedLines = await db.assignmentStockLine.findMany({
+        where: { id: { in: lineIds } },
+      })
+
+      for (const reloaded of reloadedLines) {
+        if (
+          reloaded.returnedQuantity !==
+          observedReturnedQuantities.get(reloaded.id)
+        ) {
+          throw new ConcurrentReturnError(reloaded.id)
+        }
+      }
+    }
+
     for (const returnLine of remainingReturns) {
       const stockLine = stockLinesById.get(returnLine.assignmentLineId)
 
@@ -224,7 +254,9 @@ export const AssignmentService = {
         return null
       }
 
-      const remainingQuantity = stockLine.quantity - stockLine.returnedQuantity
+      const observedReturnedQuantity =
+        observedReturnedQuantities.get(stockLine.id) ?? 0
+      const remainingQuantity = stockLine.quantity - observedReturnedQuantity
 
       if (returnLine.quantity > remainingQuantity) {
         return null
@@ -240,6 +272,21 @@ export const AssignmentService = {
         },
       })
 
+      if (returns !== undefined) {
+        const updated = await db.assignmentStockLine.updateMany({
+          where: {
+            id: stockLine.id,
+            returnedQuantity: observedReturnedQuantity,
+          },
+          data: {
+            returnedQuantity: observedReturnedQuantity + returnLine.quantity,
+          },
+        })
+
+        if (updated.count === 0) {
+          throw new ConcurrentReturnError(stockLine.id)
+        }
+      } else {
         await db.assignmentStockLine.update({
           where: { id: stockLine.id },
           data: {
@@ -248,6 +295,7 @@ export const AssignmentService = {
             },
           },
         })
+      }
 
       returnedQuantity += returnLine.quantity
       returnedLines.push({

src/types/assignment.ts

@@ -35,4 +35,6 @@ export type AssignmentWithPersonItemAsset = Assignment & {
   itemId: string | null
   assetId: string | null
   quantity: number | null
+  assignmentLineId?: string
+  remainingQuantity?: number
 }

src/use-cases/assignment.use-cases.ts

@@ -1,11 +1,14 @@
-import { type Prisma } from "@/generated/prisma/client"
+import type { Prisma } from "@/generated/prisma/client"
 import prisma from "@/lib/prisma"
 import type {
   CreateAssignmentData,
   UpdateAssignmentData,
 } from "@/schemas/assignment.schema"
 import { AssetService } from "@/services/asset.service"
-import { AssignmentService } from "@/services/assignment.service"
+import {
+  AssignmentService,
+  ConcurrentReturnError,
+} from "@/services/assignment.service"
 import { ItemService } from "@/services/item.service"
 import { MovementService } from "@/services/movement.service"
 import type {
@@ -160,11 +163,7 @@ export async function reassignAssignment(
   if (oldAssignment.itemId) {
     const oldItem = await ItemService.findById(oldAssignment.itemId, tx)
     if (oldItem && oldItem.trackingType === "QUANTITY") {
-      await ItemService.updateStock(
-        oldAssignment.itemId,
-        returnedQuantity,
-        tx,
-      )
+      await ItemService.updateStock(oldAssignment.itemId, returnedQuantity, tx)
     }
   }
   await MovementService.create(
@@ -338,10 +337,7 @@ export async function updateAssignmentUseCase(
       return updateAssignmentError({ id: ["Assignment not found"] })
     }
 
-    if (
-      assignment.status === "RETURNED" ||
-      assignment.status === "CANCELLED"
-    ) {
+    if (assignment.status === "RETURNED" || assignment.status === "CANCELLED") {
       return updateAssignmentError({ id: ["Assignment is closed"] })
     }
 
@@ -427,7 +423,8 @@ export async function returnAssignmentUseCase(
     return returnAssignmentError({ id: ["Assignment ID is required"] })
   }
 
-  return prisma.$transaction(async (tx) => {
+  try {
+    return await prisma.$transaction(async (tx) => {
       const assignment = await AssignmentService.findById(id, tx)
 
       if (!assignment) {
@@ -483,4 +480,11 @@ export async function returnAssignmentUseCase(
         success: true,
       }
     })
+  } catch (error) {
+    if (error instanceof ConcurrentReturnError) {
+      return returnAssignmentError({ error: ["errorConcurrent"] })
+    }
+
+    throw error
+  }
 }

tests/integration/use-cases/assignment.use-cases.test.ts

@@ -287,7 +287,7 @@ describe("assignment use-cases", () => {
     })
   })
 
-  it("records partial quantity returns before fully closing the assignment", async () => {
+  it("records sequential partial returns of 2, 1, then 2 before fully closing the assignment", async () => {
     const actor = await createTestUser(prisma)
     const person = await createTestPerson(prisma)
     const item = await createTestItem(prisma, { stock: 5 })
@@ -349,13 +349,26 @@ describe("assignment use-cases", () => {
       returns: [
         {
           assignmentLineId: assignment.stockLines[0].id,
-          quantity: 3,
+          quantity: 1,
         },
       ],
     })
 
     expect(secondReturn).toEqual({ success: true })
 
+    const thirdReturn = await returnAssignmentUseCase({
+      id: created.assignmentId,
+      actorId: actor.id,
+      returns: [
+        {
+          assignmentLineId: assignment.stockLines[0].id,
+          quantity: 2,
+        },
+      ],
+    })
+
+    expect(thirdReturn).toEqual({ success: true })
+
     const fullyReturned = await prisma.assignment.findUniqueOrThrow({
       where: { id: created.assignmentId },
       include: { stockLines: { include: { returns: true } } },
@@ -370,13 +383,102 @@ describe("assignment use-cases", () => {
       quantity: 5,
       returnedQuantity: 5,
     })
-    expect(fullyReturned.stockLines[0].returns).toHaveLength(2)
+    expect(fullyReturned.stockLines[0].returns).toHaveLength(3)
 
     expect(
       await prisma.item.findUniqueOrThrow({ where: { id: item.id } }),
     ).toMatchObject({
       stock: 5,
     })
+
+    const returnMovements = await prisma.inventoryMovement.findMany({
+      where: { type: "RETURN" },
+      include: { stockLines: true },
+      orderBy: [{ createdAt: "asc" }, { id: "asc" }],
+    })
+
+    expect(returnMovements).toHaveLength(3)
+    expect(returnMovements[0].stockLines[0]).toMatchObject({
+      stockDelta: 2,
+      previousStock: 0,
+      newStock: 2,
+    })
+    expect(returnMovements[1].stockLines[0]).toMatchObject({
+      stockDelta: 1,
+      previousStock: 2,
+      newStock: 3,
+    })
+    expect(returnMovements[2].stockLines[0]).toMatchObject({
+      stockDelta: 2,
+      previousStock: 3,
+      newStock: 5,
+    })
+  })
+
+  it("rejects a concurrent partial return with a domain error", async () => {
+    const actor = await createTestUser(prisma)
+    const person = await createTestPerson(prisma)
+    const item = await createTestItem(prisma, { stock: 5 })
+
+    const created = await createAssignmentUseCase({
+      actorId: actor.id,
+      itemId: item.id,
+      personId: person.id,
+      quantity: 5,
+    })
+
+    expect(created.success).toBe(true)
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
+
+    const assignment = await prisma.assignment.findUniqueOrThrow({
+      where: { id: created.assignmentId },
+      include: { stockLines: true },
+    })
+
+    const [resultA, resultB] = await Promise.all([
+      returnAssignmentUseCase({
+        id: created.assignmentId,
+        actorId: actor.id,
+        returns: [
+          {
+            assignmentLineId: assignment.stockLines[0].id,
+            quantity: 2,
+          },
+        ],
+      }),
+      returnAssignmentUseCase({
+        id: created.assignmentId,
+        actorId: actor.id,
+        returns: [
+          {
+            assignmentLineId: assignment.stockLines[0].id,
+            quantity: 1,
+          },
+        ],
+      }),
+    ])
+
+    const successes = [resultA, resultB].filter((result) => result.success)
+    const failures = [resultA, resultB].filter((result) => !result.success)
+
+    expect(successes).toHaveLength(1)
+    expect(failures).toHaveLength(1)
+    expect(failures[0]).toEqual({
+      success: false,
+      errors: { error: ["errorConcurrent"] },
+    })
+
+    const finalAssignment = await prisma.assignment.findUniqueOrThrow({
+      where: { id: created.assignmentId },
+      include: { stockLines: { include: { returns: true } } },
+    })
+
+    expect(finalAssignment.status).toBe("PARTIALLY_RETURNED")
+    expect(finalAssignment.stockLines[0].returns).toHaveLength(1)
+    expect(finalAssignment.stockLines[0].returnedQuantity).toBe(
+      finalAssignment.stockLines[0].returns[0].quantity,
+    )
   })
 
   it("rejects returning the same assignment twice", async () => {
@@ -420,7 +522,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 2 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const updated = await updateAssignmentUseCase({
       actorId: actor.id,
@@ -440,7 +543,9 @@ describe("assignment use-cases", () => {
     ])
 
     expect(updatedItem.stock).toBe(4)
-    const adjustment = movements.find((movement) => movement.type === "ADJUSTMENT")
+    const adjustment = movements.find(
+      (movement) => movement.type === "ADJUSTMENT",
+    )
     expect(adjustment).toBeDefined()
     expect(adjustment).toMatchObject({
       type: "ADJUSTMENT",
@@ -465,7 +570,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 3 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const createdAssignment = await prisma.assignment.findUniqueOrThrow({
       where: { id: created.assignmentId },
@@ -502,7 +608,9 @@ describe("assignment use-cases", () => {
     ])
 
     expect(updatedItem.stock).toBe(5)
-    const adjustment = movements.find((movement) => movement.type === "ADJUSTMENT")
+    const adjustment = movements.find(
+      (movement) => movement.type === "ADJUSTMENT",
+    )
     expect(adjustment).toBeDefined()
     expect(adjustment).toMatchObject({
       type: "ADJUSTMENT",
@@ -527,7 +635,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 2 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const updated = await updateAssignmentUseCase({
       actorId: actor.id,
@@ -547,7 +656,9 @@ describe("assignment use-cases", () => {
     ])
 
     expect(updatedItem.stock).toBe(2)
-    const adjustment = movements.find((movement) => movement.type === "ADJUSTMENT")
+    const adjustment = movements.find(
+      (movement) => movement.type === "ADJUSTMENT",
+    )
     expect(adjustment).toBeDefined()
     expect(adjustment).toMatchObject({
       type: "ADJUSTMENT",
@@ -572,7 +683,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 2 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const returned = await returnAssignmentUseCase({
       id: created.assignmentId,
@@ -606,7 +718,9 @@ describe("assignment use-cases", () => {
 
     expect(assignment.stockLines[0].quantity).toBe(2)
     expect(movements).toHaveLength(movementsBefore)
-    expect(movements.some((movement) => movement.type === "ADJUSTMENT")).toBe(false)
+    expect(movements.some((movement) => movement.type === "ADJUSTMENT")).toBe(
+      false,
+    )
   })
 
   it("writes no movement when quantity is unchanged on an OPEN assignment", async () => {
@@ -620,7 +734,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 2 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const movementsBefore = await prisma.inventoryMovement.count()
 
@@ -642,7 +757,9 @@ describe("assignment use-cases", () => {
 
     expect(updatedItem.stock).toBe(3)
     expect(movements).toHaveLength(movementsBefore)
-    expect(movements.some((movement) => movement.type === "ADJUSTMENT")).toBe(false)
+    expect(movements.some((movement) => movement.type === "ADJUSTMENT")).toBe(
+      false,
+    )
   })
 
   it("closes the old assignment and creates a new one with RETURN+ASSIGNMENT pair on person swap for QUANTITY", async () => {
@@ -657,7 +774,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 2 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const updated = await updateAssignmentUseCase({
       actorId: actor.id,
@@ -774,7 +892,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 1 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const updated = await updateAssignmentUseCase({
       actorId: actor.id,
@@ -863,7 +982,8 @@ describe("assignment use-cases", () => {
       lines: [{ itemId: item.id, quantity: 2 }],
     })
     expect(created.success).toBe(true)
-    if (!created.success) throw new Error("Expected assignment creation success")
+    if (!created.success)
+      throw new Error("Expected assignment creation success")
 
     const updated = await updateAssignmentUseCase({
       actorId: actor.id,

tests/unit/schemas/assignment.schema.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from "vitest"
 
 import {
   buildCreateAssignmentSchema,
+  buildReturnAssignmentSchema,
   buildUpdateAssignmentSchema,
 } from "@/schemas/assignment.schema"
 
@@ -96,3 +97,90 @@ describe("assignment schema localization", () => {
     }
   })
 })
+
+describe("return assignment schema", () => {
+  it("accepts a partial return payload with optional notes", () => {
+    const result = buildReturnAssignmentSchema(schemaCopy).safeParse({
+      id: "assignment-1",
+      returns: [
+        {
+          assignmentLineId: "line-1",
+          quantity: 2,
+          notes: "Slightly damaged",
+        },
+      ],
+    })
+
+    expect(result.success).toBe(true)
+    if (result.success) {
+      expect(result.data.id).toBe("assignment-1")
+      expect(result.data.returns).toHaveLength(1)
+      expect(result.data.returns?.[0]).toMatchObject({
+        assignmentLineId: "line-1",
+        quantity: 2,
+        notes: "Slightly damaged",
+      })
+    }
+  })
+
+  it("rejects a non-integer quantity", () => {
+    const result = buildReturnAssignmentSchema(schemaCopy).safeParse({
+      id: "assignment-1",
+      returns: [
+        {
+          assignmentLineId: "line-1",
+          quantity: 1.5,
+        },
+      ],
+    })
+
+    expect(result.success).toBe(false)
+    if (!result.success) {
+      expect(
+        result.error.issues.some((issue) => issue.path.includes("quantity")),
+      ).toBe(true)
+    }
+  })
+
+  it("rejects a quantity less than or equal to zero", () => {
+    const zeroResult = buildReturnAssignmentSchema(schemaCopy).safeParse({
+      id: "assignment-1",
+      returns: [{ assignmentLineId: "line-1", quantity: 0 }],
+    })
+
+    expect(zeroResult.success).toBe(false)
+    if (!zeroResult.success) {
+      expect(
+        zeroResult.error.issues.some((issue) =>
+          issue.path.includes("quantity"),
+        ),
+      ).toBe(true)
+    }
+
+    const negativeResult = buildReturnAssignmentSchema(schemaCopy).safeParse({
+      id: "assignment-1",
+      returns: [{ assignmentLineId: "line-1", quantity: -1 }],
+    })
+
+    expect(negativeResult.success).toBe(false)
+    if (!negativeResult.success) {
+      expect(
+        negativeResult.error.issues.some((issue) =>
+          issue.path.includes("quantity"),
+        ),
+      ).toBe(true)
+    }
+  })
+
+  it("keeps the legacy full-return shape valid", () => {
+    const result = buildReturnAssignmentSchema(schemaCopy).safeParse({
+      id: "assignment-1",
+    })
+
+    expect(result.success).toBe(true)
+    if (result.success) {
+      expect(result.data.id).toBe("assignment-1")
+      expect(result.data.returns).toBeUndefined()
+    }
+  })
+})