import { prisma } from "@/lib/prisma";
import { errorResponse, getJsonBody, jsonResponse } from "@/lib/api-helpers";

async function recalcOrderTotal(orderId: number) {
  const tasks = await prisma.task.findMany({
    where: { orderId },
    include: { parts: true },
  });

  const total = tasks.reduce((sum, task) => {
    const partsCost = task.parts.reduce(
      (p, tp) => p + (tp.price || 0) * tp.qty,
      0,
    );
    const laborCost = task.laborHours * task.hourlyRate;
    const price = task.price > 0 ? task.price : partsCost + laborCost;
    return sum + price;
  }, 0);

  await prisma.order.update({ where: { id: orderId }, data: { total } });
}

export async function POST(req: Request) {
  const body = await getJsonBody(req);
  if (!body) return errorResponse("Invalid JSON");
  const {
    orderId,
    title,
    notes,
    laborHours,
    hourlyRate,
    price,
    partIds = [],
    templateParts = [],
  } = body;
  if (!orderId || !title)
    return errorResponse("orderId and title are required");

  const order = await prisma.order.findUnique({
    where: { id: Number(orderId) },
    include: { car: true },
  });
  if (!order) return errorResponse("Order not found", 404);

  const last = await prisma.task.findFirst({
    where: { orderId: Number(orderId) },
    orderBy: { orderIndex: "desc" },
  });

  // If the title matches a quick task template, pull its defaults.
  const quickTask = await prisma.quickTask.findFirst({
    where: { title },
    include: { parts: true },
  });

  if (quickTask) {
    await prisma.quickTask.update({
      where: { id: quickTask.id },
      data: { useCount: { increment: 1 } },
    });
  }

  const hasExplicitLabor =
    laborHours !== undefined && String(laborHours).trim() !== "";
  const hasExplicitRate =
    hourlyRate !== undefined && String(hourlyRate).trim() !== "";
  const hasExplicitPrice = price !== undefined && String(price).trim() !== "";
  const taskLaborHours =
    quickTask && !hasExplicitLabor
      ? quickTask.laborHours
      : Number(laborHours) || 0;
  const taskHourlyRate =
    quickTask && !hasExplicitRate
      ? quickTask.hourlyRate
      : Number(hourlyRate) || 50;
  const taskPrice =
    quickTask && !hasExplicitPrice
      ? quickTask.price
      : hasExplicitPrice
        ? Number(price) || 0
        : null;
  const effectiveTemplateParts =
    templateParts && templateParts.length > 0
      ? templateParts
      : quickTask?.parts || [];

  const task = await prisma.task.create({
    data: {
      orderId: Number(orderId),
      title,
      notes: notes || "",
      laborHours: Number(taskLaborHours) || 0,
      hourlyRate: Number(taskHourlyRate) || 50,
      price: taskPrice ?? undefined,
      orderIndex: (last?.orderIndex ?? -1) + 1,
    },
    include: { parts: { include: { part: true } } },
  });

  // Attach selected existing parts — only link to the same car or global parts.
  for (const item of partIds) {
    const { partId, qty = 1, price: partPrice } = item;
    const part = await prisma.part.findFirst({
      where: {
        id: Number(partId),
        OR: [{ carId: order.carId }, { isGlobal: true }],
      },
    });
    if (part) {
      await prisma.taskPart.create({
        data: {
          taskId: task.id,
          partId: part.id,
          qty: Number(qty) || 1,
          price: partPrice != null ? Number(partPrice) : part.purchasePrice,
        },
      });
    }
  }

  // Convert template parts into private car parts (or link globals) and attach them.
  for (const tp of effectiveTemplateParts) {
    const isGlobal = tp.isGlobal || false;
    let partId: number | undefined;
    if (isGlobal) {
      // Try to find an existing global part with the same name.
      const existing = await prisma.part.findFirst({
        where: { name: tp.name, isGlobal: true },
      });
      if (existing) {
        partId = existing.id;
      } else {
        const created = await prisma.part.create({
          data: {
            name: tp.name,
            purchasePrice: Number(tp.price) || 0,
            notes: "",
            isGlobal: true,
          },
        });
        partId = created.id;
      }
    } else {
      const existing = await prisma.part.findFirst({
        where: { name: tp.name, carId: order.carId, isGlobal: false },
      });
      if (existing) {
        partId = existing.id;
      } else {
        const created = await prisma.part.create({
          data: {
            name: tp.name,
            purchasePrice: Number(tp.price) || 0,
            notes: "",
            carId: order.carId,
            isGlobal: false,
          },
        });
        partId = created.id;
      }
    }
    if (partId) {
      await prisma.taskPart.create({
        data: {
          taskId: task.id,
          partId,
          qty: Number(tp.qty) || 1,
          price: Number(tp.price) || 0,
        },
      });
    }
  }

  await recalcOrderTotal(Number(orderId));
  if (quickTask) {
    await prisma.quickTask.update({
      where: { id: quickTask.id },
      data: { useCount: { increment: 1 } },
    });
  } else {
    await prisma.quickTask.upsert({
      where: { title },
      update: { useCount: { increment: 1 } },
      create: { title, useCount: 1 },
    });
  }

  const full = await prisma.task.findUnique({
    where: { id: task.id },
    include: { parts: { include: { part: true } } },
  });

  return jsonResponse(full, 201);
}