import { createContext, DomainError } from "@tailor-platform/erp-kit/app";
import { createResolver, t } from "@tailor-platform/sdk";
import { getDB } from "@/generated/kysely-tailordb";
import { purchaseModules } from "@/modules";

/**
 * Update a draft PurchaseOrder.
 *
 * erp-kit 0.39 made line edits incremental: the command takes headerPatch +
 * addLines / updateLines (by lineId) / removeLineIds and leaves any line it
 * isn't told about untouched. We expose that shape on the GraphQL input so the
 * edit form sends explicit add / update / remove ops — a header-only save sends
 * no line ops, and removeLineIds is driven solely by explicit caller intent
 * (the lines the user removed), never derived from "existing lines minus what
 * was sent". That is the structural guard against the #350-class silent
 * deletion: once the edit form paginates lines (loads a page at a time instead
 * of the current first: 1000), the lines it never loaded are simply absent from
 * every op collection and stay put.
 */
export default createResolver({
  name: "updatePurchaseOrder",
  operation: "mutation",
  input: {
    id: t.string().description("Purchase order ID"),
    orderDate: t.string({ optional: true }).description("Order date (ISO 8601)"),
    receivingSiteId: t
      .string({ optional: true })
      .description("Default receiving site for all lines"),
    externalSupplierOrderReference: t
      .string({ optional: true })
      .description("External supplier order reference"),
    // erp-kit 0.39: line edits are incremental, not a whole-array replace. A
    // header-only save sends no line ops, so lines the form never loaded (beyond
    // its page once paginated) are left untouched. Removals are driven only by
    // explicit removeLineIds, never derived from "existing minus what was sent".
    addLines: t
      .object(
        {
          itemId: t.string().description("Item ID"),
          quantity: t.string().description("Quantity"),
          unitPrice: t.string().description("Unit price"),
          unitId: t.string().description("Unit ID"),
        },
        { array: true, optional: true },
      )
      .description("New order lines to add"),
    updateLines: t
      .object(
        {
          lineId: t.string().description("Existing line ID to patch"),
          itemId: t.string({ optional: true }).description("Item ID"),
          quantity: t.string({ optional: true }).description("Quantity"),
          unitPrice: t.string({ optional: true }).description("Unit price"),
          unitId: t.string({ optional: true }).description("Unit ID"),
        },
        { array: true, optional: true },
      )
      .description("Existing order lines to patch, keyed by lineId"),
    removeLineIds: t
      .string({ array: true, optional: true })
      .description("Existing order line IDs to remove"),
  },
  body: async (context) => {
    const ctx = createContext(context);
    const db = getDB("main-db");
    return db
      .transaction()
      .execute(async (trx) => {
        const addLines = context.input.addLines ?? [];
        const updateLines = context.input.updateLines ?? [];
        const removeLineIds = context.input.removeLineIds ?? [];

        // Added lines carry their full value set.
        const builtAddLines = addLines.map((line) => ({
          itemId: line.itemId,
          quantity: line.quantity,
          unitPrice: line.unitPrice,
          unitId: line.unitId,
        }));

        // Each patch carries only the fields the caller changed. A changed itemId
        // re-snapshots name/sku in the command.
        const builtUpdateLines = updateLines.map((edit) => {
          const linePatch: {
            itemId?: string;
            quantity?: string;
            unitPrice?: string;
            unitId?: string;
          } = {};
          if (edit.itemId != null) linePatch.itemId = edit.itemId;
          if (edit.quantity != null) linePatch.quantity = edit.quantity;
          if (edit.unitPrice != null) linePatch.unitPrice = edit.unitPrice;
          if (edit.unitId != null) linePatch.unitId = edit.unitId;
          return { lineId: edit.lineId, linePatch };
        });

        const result = await purchaseModules.commands.updatePurchaseOrder(
          trx,
          {
            id: context.input.id,
            headerPatch: {
              orderDate: context.input.orderDate ? new Date(context.input.orderDate) : undefined,
              receivingSiteId: context.input.receivingSiteId ?? undefined,
              externalSupplierOrderReference:
                context.input.externalSupplierOrderReference ?? undefined,
            },
            addLines: builtAddLines.length ? builtAddLines : undefined,
            updateLines: builtUpdateLines.length ? builtUpdateLines : undefined,
            removeLineIds: removeLineIds.length ? removeLineIds : undefined,
          },
          ctx,
        );

        if (!result.ok) {
          switch (result.error.code) {
            case "PURCHASE_PURCHASE_ORDER_NOT_FOUND":
              throw new DomainError(`Purchase order not found: ${context.input.id}`);
            case "PURCHASE_PURCHASE_ORDER_NOT_DRAFT":
              throw new DomainError(`Purchase order is not in DRAFT status: ${context.input.id}`);
            case "PURCHASE_LINE_NOT_FOUND":
              throw new DomainError(`Order line not found: ${result.error.message}`);
            case "PURCHASE_ITEM_NOT_FOUND":
              throw new DomainError(`Item not found: ${result.error.message}`);
            case "PURCHASE_ITEM_NOT_ACTIVE":
              throw new DomainError(`Item is not active: ${result.error.message}`);
            case "PURCHASE_ITEM_NOT_PURCHASABLE":
              throw new DomainError(`Item has no purchasing record: ${result.error.message}`);
            case "PURCHASE_INVALID_QUANTITY":
              throw new DomainError(`Invalid quantity: ${result.error.message}`);
            case "PURCHASE_INVALID_UNIT_PRICE":
              throw new DomainError(`Invalid unit price: ${result.error.message}`);
            case "PURCHASE_RECEIVING_SITE_NOT_FOUND":
              throw new DomainError(`Receiving site not found: ${result.error.message}`);
            case "PURCHASE_RECEIVING_SITE_REQUIRED":
              throw new DomainError(`Receiving site is required for line: ${result.error.message}`);
            case "PURCHASE_EMPTY_PURCHASE_ORDER_LINES":
              throw new DomainError("The purchase order must have at least one line");
            case "UNAUTHENTICATED":
              throw new DomainError("Authentication is required");
            case "INSUFFICIENT_PERMISSION":
              throw new DomainError("You do not have permission to perform this action");
            default:
              throw result.error satisfies never;
          }
        }

        return { id: result.value.purchaseOrderId };
      })
      .catch((err: unknown) => {
        if (err instanceof DomainError) throw err;
        throw new Error("Failed to update the purchase order", { cause: err });
      });
  },
  output: t
    .object({
      id: t.string().description("Updated purchase order ID"),
    })
    .description("UpdatePurchaseOrder response"),
});