"use server";

import { auth } from "@/auth";
import { db } from "@/lib/db";
import { requirePermission } from "@/lib/permissions";
import { createPoSchema } from "@/lib/validations/po";
import { generatePoNumber } from "@/lib/utils";
import { notify } from "@/lib/notifier";
import { revalidatePath } from "next/cache";

export async function createPo(
  formData: FormData
): Promise<{ id: string } | { error: string }> {
  const session = await auth();
  if (!session?.user) return { error: "Unauthorized" };

  try {
    requirePermission(session.user.role, "create_po");
  } catch {
    return { error: "You do not have permission to create purchase orders." };
  }

  const intent = formData.get("intent") as "draft" | "submit";

  const lineItems: Array<{
    name: string;
    description?: string;
    quantity: number;
    unit: string;
    size?: string;
    unitPrice: number;
    gstRate: number;
    productId?: string;
    accountId?: string;
  }> = [];
  let i = 0;
  while (formData.has(`lineItems[${i}].name`)) {
    lineItems.push({
      name: formData.get(`lineItems[${i}].name`) as string,
      description: (formData.get(`lineItems[${i}].description`) as string) || undefined,
      quantity: Number(formData.get(`lineItems[${i}].quantity`)),
      unit: formData.get(`lineItems[${i}].unit`) as string,
      size: (formData.get(`lineItems[${i}].size`) as string) || undefined,
      unitPrice: Number(formData.get(`lineItems[${i}].unitPrice`)),
      gstRate: Number(formData.get(`lineItems[${i}].gstRate`) ?? 0.18),
      productId: (formData.get(`lineItems[${i}].productId`) as string) || undefined,
      accountId: (formData.get(`lineItems[${i}].accountId`) as string) || undefined,
    });
    i++;
  }

  const parsed = createPoSchema.safeParse({
    title: formData.get("title"),
    vesselId: formData.get("vesselId"),
    accountId: formData.get("accountId"),
    projectCode: formData.get("projectCode") || undefined,
    dateRequired: formData.get("dateRequired") || undefined,
    vendorId: formData.get("vendorId") || undefined,
    piQuotationNo: formData.get("piQuotationNo") || undefined,
    piQuotationDate: formData.get("piQuotationDate") || undefined,
    requisitionNo: formData.get("requisitionNo") || undefined,
    requisitionDate: formData.get("requisitionDate") || undefined,
    placeOfDelivery: formData.get("placeOfDelivery") || undefined,
    tcDelivery: formData.get("tcDelivery") || undefined,
    tcDispatch: formData.get("tcDispatch") || undefined,
    tcInspection: formData.get("tcInspection") || undefined,
    tcTransitInsurance: formData.get("tcTransitInsurance") || undefined,
    tcPaymentTerms: formData.get("tcPaymentTerms") || undefined,
    tcOthers: formData.get("tcOthers") || undefined,
    lineItems,
  });

  if (!parsed.success) {
    return { error: parsed.error.errors[0]?.message ?? "Validation failed" };
  }

  const data = parsed.data;
  // totalAmount = grand total including GST
  const total = data.lineItems.reduce(
    (sum, item) => sum + item.quantity * item.unitPrice * (1 + item.gstRate),
    0
  );

  const po = await db.purchaseOrder.create({
    data: {
      poNumber: generatePoNumber(),
      title: data.title,
      status: intent === "submit" ? "SUBMITTED" : "DRAFT",
      totalAmount: total,
      currency: data.currency,
      vesselId: data.vesselId,
      accountId: data.accountId,
      vendorId: data.vendorId ?? null,
      projectCode: data.projectCode ?? null,
      dateRequired: data.dateRequired ? new Date(data.dateRequired) : null,
      piQuotationNo: data.piQuotationNo ?? null,
      piQuotationDate: data.piQuotationDate ? new Date(data.piQuotationDate) : null,
      requisitionNo: data.requisitionNo ?? null,
      requisitionDate: data.requisitionDate ? new Date(data.requisitionDate) : null,
      placeOfDelivery: data.placeOfDelivery ?? null,
      tcDelivery: data.tcDelivery ?? null,
      tcDispatch: data.tcDispatch ?? null,
      tcInspection: data.tcInspection ?? null,
      tcTransitInsurance: data.tcTransitInsurance ?? null,
      tcPaymentTerms: data.tcPaymentTerms ?? null,
      tcOthers: data.tcOthers ?? null,
      submitterId: session.user.id,
      submittedAt: intent === "submit" ? new Date() : null,
      lineItems: {
        create: data.lineItems.map((item, idx) => ({
          name: item.name,
          description: item.description ?? null,
          quantity: item.quantity,
          unit: item.unit,
          size: item.size ?? null,
          unitPrice: item.unitPrice,
          totalPrice: item.quantity * item.unitPrice,
          gstRate: item.gstRate,
          sortOrder: idx,
          productId: item.productId ?? null,
          accountId: item.accountId ?? null,
        })),
      },
      actions: {
        create: {
          actionType: "CREATED",
          actorId: session.user.id,
        },
      },
    },
  });

  if (intent === "submit") {
    await db.purchaseOrder.update({
      where: { id: po.id },
      data: {
        status: "MGR_REVIEW",
        actions: {
          create: { actionType: "SUBMITTED", actorId: session.user.id },
        },
      },
    });

    const [fullPo, managers] = await Promise.all([
      db.purchaseOrder.findUnique({ where: { id: po.id }, include: { submitter: true } }),
      db.user.findMany({ where: { role: "MANAGER", isActive: true } }),
    ]);
    if (fullPo) {
      await notify({ event: "PO_SUBMITTED", po: fullPo, recipients: managers });
    }
  }

  revalidatePath("/dashboard");
  revalidatePath("/approvals");
  return { id: po.id };
}