import { NextResponse } from "next/server";
import bcrypt from "bcryptjs";
import { requireCurrentUser, UnauthorizedError } from "@/lib/auth";
import { prisma } from "@/lib/prisma";
import {
  normalizeDisplayName,
  normalizeEmail,
  normalizePassword,
  normalizeUserRole
} from "@/lib/validation";

export async function GET() {
  try {
    const currentUser = await requireCurrentUser();

    if (currentUser.role !== "ADMIN") {
      return NextResponse.json({ error: "Keine Berechtigung." }, { status: 403 });
    }

    const users = await prisma.user.findMany({
      orderBy: {
        createdAt: "asc"
      },
      select: {
        id: true,
        email: true,
        displayName: true,
        role: true,
        createdAt: true
      }
    });

    return NextResponse.json({
      users
    });
  } catch (error) {
    if (error instanceof UnauthorizedError) {
      return NextResponse.json({ error: "Nicht angemeldet." }, { status: 401 });
    }

    return NextResponse.json({ error: "Nutzer konnten nicht geladen werden." }, { status: 500 });
  }
}

export async function POST(request: Request) {
  try {
    const currentUser = await requireCurrentUser();

    if (currentUser.role !== "ADMIN") {
      return NextResponse.json({ error: "Keine Berechtigung." }, { status: 403 });
    }

    const body = (await request.json().catch(() => null)) as {
      email?: unknown;
      password?: unknown;
      displayName?: unknown;
      role?: unknown;
    } | null;

    const email = normalizeEmail(body?.email);
    const password = normalizePassword(body?.password);
    const displayName = normalizeDisplayName(body?.displayName);
    const role = normalizeUserRole(body?.role) ?? "USER";

    if (!email || !password) {
      return NextResponse.json(
        {
          error: "E-Mail oder Passwort ungültig. Das Passwort muss 10 bis 128 Zeichen lang sein."
        },
        { status: 400 }
      );
    }

    const existingUser = await prisma.user.findUnique({
      where: {
        email
      },
      select: {
        id: true
      }
    });

    if (existingUser) {
      return NextResponse.json(
        {
          error: "Ein Nutzer mit dieser E-Mail existiert bereits."
        },
        { status: 409 }
      );
    }

    const passwordHash = await bcrypt.hash(password, 12);

    const user = await prisma.user.create({
      data: {
        email,
        passwordHash,
        displayName,
        role,
        settings: {
          create: {
            darkMode: false,
            calendarMaxEvents: 8,
            calendarLookaheadDays: 60,
            dashboardTitle: "Personal Dashboard",
            logoUrl: "/logo.svg",
            primaryColor: "#2563eb",
            secondaryColor: "#dbeafe"
          }
        },
        widgets: {
          create: [
            {
              type: "favorites",
              title: "Links/Favoriten",
              position: 0,
              x: 0,
              y: 0,
              w: 3,
              h: 6
            },
            {
              type: "note",
              title: "Notiz",
              position: 1,
              x: 3,
              y: 0,
              w: 3,
              h: 4
            },
            {
              type: "search",
              title: "Suche",
              position: 3,
              x: 9,
              y: 0,
              w: 3,
              h: 2
            },
            {
              type: "calendar",
              title: "Kalender",
              position: 4,
              x: 9,
              y: 2,
              w: 3,
              h: 7
            }
          ]
        }
      },
      select: {
        id: true,
        email: true,
        displayName: true,
        role: true,
        createdAt: true
      }
    });

    const createdWidgets = await prisma.widget.findMany({
      where: {
        userId: user.id,
        type: {
          in: ["note"]
        }
      }
    });

    await Promise.all(
      createdWidgets.map((widget) =>
        prisma.noteBoardItem.create({
          data: {
            id: widget.id,
            userId: user.id,
            type: widget.type,
            title: widget.title,
            content: ""
          }
        })
      )
    );

    return NextResponse.json(
      {
        user
      },
      { status: 201 }
    );
  } catch (error) {
    if (error instanceof UnauthorizedError) {
      return NextResponse.json({ error: "Nicht angemeldet." }, { status: 401 });
    }

    return NextResponse.json({ error: "Nutzer konnte nicht erstellt werden." }, { status: 500 });
  }
}