import { NextRequest, NextResponse } from "next/server";
import { getServerSession } from "next-auth/next";
import { authOptions } from "@/app/api/auth/[...nextauth]/route";
import { prisma } from "@/lib/prisma";

/**
 * Handles the GET request to retrieve events for a specific calendar.
 *
 * @param req - The incoming request object.
 * @param params - An object containing the route parameters.
 * @param params.id - The ID of the calendar.
 * @returns A JSON response containing the events or an error message.
 *
 * The function performs the following steps:
 * 1. Retrieves the server session to check if the user is authenticated.
 * 2. Verifies that the calendar exists and belongs to the authenticated user.
 * 3. Retrieves and filters events based on optional date parameters (`start` and `end`).
 * 4. Returns the filtered events in ascending order of their start date.
 *
 * Possible response statuses:
 * - 200: Successfully retrieved events.
 * - 401: User is not authenticated.
 * - 403: User is not authorized to access the calendar.
 * - 404: Calendar not found.
 * - 500: Server error occurred while retrieving events.
 */
export async function GET(
  req: NextRequest,
  { params }: { params: { id: string } }
) {
  const session = await getServerSession(authOptions);

  if (!session?.user?.username) {
    return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
  }

  try {
    // Vérifier que le calendrier appartient à l'utilisateur
    const calendar = await prisma.calendar.findUnique({
      where: {
        id: params.id,
      },
    });

    if (!calendar) {
      return NextResponse.json(
        { error: "Calendrier non trouvé" },
        { status: 404 }
      );
    }

    if (calendar.userId !== session.user.username) {
      return NextResponse.json({ error: "Non autorisé" }, { status: 403 });
    }

    // Récupérer les paramètres de filtrage de date s'ils existent
    const { searchParams } = new URL(req.url);
    const startParam = searchParams.get("start");
    const endParam = searchParams.get("end");

    let whereClause: any = {
      calendarId: params.id,
    };

    if (startParam && endParam) {
      whereClause.AND = [
        {
          start: {
            lte: new Date(endParam),
          },
        },
        {
          end: {
            gte: new Date(startParam),
          },
        },
      ];
    }

    const events = await prisma.event.findMany({
      where: whereClause,
      orderBy: {
        start: "asc",
      },
    });

    return NextResponse.json(events);
  } catch (error) {
    console.error("Erreur lors de la récupération des événements:", error);
    return NextResponse.json({ error: "Erreur serveur" }, { status: 500 });
  }
}

/**
 * Handles the creation of a new event for a specific calendar.
 *
 * @param req - The incoming request object.
 * @param params - An object containing the route parameters.
 * @param params.id - The ID of the calendar to which the event will be added.
 * @returns A JSON response with the created event data or an error message.
 *
 * @throws {401} If the user is not authenticated.
 * @throws {404} If the specified calendar is not found.
 * @throws {403} If the user is not authorized to add events to the specified calendar.
 * @throws {400} If the required fields (title, start, end) are missing.
 * @throws {500} If there is a server error during event creation.
 */
export async function POST(
  req: NextRequest,
  { params }: { params: { id: string } }
) {
  const session = await getServerSession(authOptions);

  if (!session?.user?.username) {
    return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
  }

  try {
    const calendar = await prisma.calendar.findUnique({
      where: {
        id: params.id,
      },
    });

    if (!calendar) {
      return NextResponse.json(
        { error: "Calendrier non trouvé" },
        { status: 404 }
      );
    }

    if (calendar.userId !== session.user.username) {
      return NextResponse.json({ error: "Non autorisé" }, { status: 403 });
    }

    const { title, description, start, end, location, isAllDay } =
      await req.json();

    // Validation
    if (!title) {
      return NextResponse.json(
        { error: "Le titre est requis" },
        { status: 400 }
      );
    }

    if (!start || !end) {
      return NextResponse.json(
        { error: "Les dates de début et de fin sont requises" },
        { status: 400 }
      );
    }

    const event = await prisma.event.create({
      data: {
        title,
        description,
        start: new Date(start),
        end: new Date(end),
        location,
        isAllDay: isAllDay || false,
        calendarId: params.id,
      },
    });

    return NextResponse.json(event, { status: 201 });
  } catch (error) {
    console.error("Erreur lors de la création de l'événement:", error);
    return NextResponse.json({ error: "Erreur serveur" }, { status: 500 });
  }
}