import { NextRequest, NextResponse } from "next/server";
import { getDb } from "@/lib/db";

export async function GET(
  _request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const sql = getDb();
    const { id } = await params;

    const orderRows = await sql(
      `SELECT po.*, c.name AS customer_name, c.code AS customer_code,
        c.email AS customer_email, c.phone AS customer_phone,
        c.address AS customer_address, c.contact_person AS customer_contact
       FROM purchase_orders po
       JOIN customers c ON c.id = po.customer_id
       WHERE po.id = $1`,
      [Number(id)]
    );

    if (orderRows.length === 0) {
      return NextResponse.json({ error: "Order not found" }, { status: 404 });
    }

    const items = await sql(
      `SELECT poi.*, p.name AS product_name, p.sku AS product_sku,
        (poi.quantity * poi.unit_price) AS line_total,
        COALESCE(poi.shipped_quantity, 0) AS shipped_quantity,
        (poi.quantity - COALESCE(poi.shipped_quantity, 0)) AS remaining_quantity
       FROM purchase_order_items poi
       JOIN products p ON p.id = poi.product_id
       WHERE poi.purchase_order_id = $1
       ORDER BY poi.created_at ASC`,
      [Number(id)]
    );

    return NextResponse.json({ ...orderRows[0], items });
  } catch (error) {
    console.error("[v0] Order GET error:", error);
    return NextResponse.json(
      { error: error instanceof Error ? error.message : "Failed to fetch order" },
      { status: 500 }
    );
  }
}

export async function PUT(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const sql = getDb();
    const { id } = await params;
    const body = await request.json();
    const { customer_id, po_number, customer_ref, status, order_date, due_date, notes, items } = body;

    const orderRows = await sql(
      `UPDATE purchase_orders SET
        customer_id = $1, po_number = $2, customer_ref = $3, status = $4,
        order_date = $5, due_date = $6, notes = $7, updated_at = NOW()
       WHERE id = $8
       RETURNING *`,
      [customer_id, po_number, customer_ref || null, status, order_date, due_date || null, notes || null, Number(id)]
    );

    if (orderRows.length === 0) {
      return NextResponse.json({ error: "Order not found" }, { status: 404 });
    }

    // Replace items
    if (items && Array.isArray(items)) {
      await sql(`DELETE FROM purchase_order_items WHERE purchase_order_id = $1`, [Number(id)]);
      for (const item of items) {
        await sql(
          `INSERT INTO purchase_order_items (purchase_order_id, product_id, quantity, unit_price, notes)
           VALUES ($1, $2, $3, $4, $5)`,
          [Number(id), item.product_id, item.quantity, item.unit_price || 0, item.notes || null]
        );
      }
    }

    return NextResponse.json(orderRows[0]);
  } catch (error) {
    console.error("[v0] Order PUT error:", error);
    return NextResponse.json(
      { error: error instanceof Error ? error.message : "Failed to update order" },
      { status: 500 }
    );
  }
}

export async function DELETE(
  _request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const sql = getDb();
    const { id } = await params;

    await sql(`DELETE FROM purchase_order_items WHERE purchase_order_id = $1`, [Number(id)]);
    await sql(`DELETE FROM purchase_orders WHERE id = $1`, [Number(id)]);

    return NextResponse.json({ success: true });
  } catch (error) {
    console.error("[v0] Order DELETE error:", error);
    return NextResponse.json(
      { error: error instanceof Error ? error.message : "Failed to delete order" },
      { status: 500 }
    );
  }
}