import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { db } from '@/lib/db';
import { z } from 'zod';
import { Decimal } from '@prisma/client/runtime/library';

// Validation schema for creating a tournament
const createTournamentSchema = z.object({
  siteId: z.string().cuid('Invalid site ID'),
  name: z.string().min(1, 'Name is required').max(100),
  description: z.string().max(500).optional(),
  date: z.string().datetime({ message: 'Invalid date format' }),
  endDate: z.string().datetime({ message: 'Invalid end date format' }).optional(),
  type: z.enum(['SINGLE_ELIMINATION', 'DOUBLE_ELIMINATION', 'ROUND_ROBIN', 'LEAGUE']),
  category: z.string().max(50).optional(),
  maxTeams: z.number().int().min(2, 'Minimum 2 teams required'),
  price: z.number().nonnegative('Price must be non-negative'),
});

// Map API types to database types
function mapTournamentType(type: string): 'AMERICANO' | 'MEXICANO' | 'BRACKET' | 'ROUND_ROBIN' | 'LEAGUE' {
  const mapping: Record<string, 'AMERICANO' | 'MEXICANO' | 'BRACKET' | 'ROUND_ROBIN' | 'LEAGUE'> = {
    'SINGLE_ELIMINATION': 'BRACKET',
    'DOUBLE_ELIMINATION': 'BRACKET',
    'ROUND_ROBIN': 'ROUND_ROBIN',
    'LEAGUE': 'LEAGUE',
  };
  return mapping[type] || 'BRACKET';
}

// GET /api/tournaments - List tournaments with filters
export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);

    if (!session?.user) {
      return NextResponse.json(
        { error: 'Unauthorized' },
        { status: 401 }
      );
    }

    const { searchParams } = new URL(request.url);
    const siteId = searchParams.get('siteId');
    const status = searchParams.get('status');
    const startDate = searchParams.get('startDate');
    const endDate = searchParams.get('endDate');

    // Build the where clause
    interface TournamentWhereClause {
      organizationId: string;
      siteId?: string;
      status?: 'DRAFT' | 'REGISTRATION_OPEN' | 'REGISTRATION_CLOSED' | 'IN_PROGRESS' | 'COMPLETED' | 'CANCELLED';
      startDate?: {
        gte?: Date;
        lte?: Date;
      };
    }

    const whereClause: TournamentWhereClause = {
      organizationId: session.user.organizationId,
    };

    // Filter by site
    if (siteId) {
      whereClause.siteId = siteId;
    } else if (session.user.siteId) {
      whereClause.siteId = session.user.siteId;
    }

    // Filter by status
    if (status) {
      const validStatuses = ['DRAFT', 'REGISTRATION_OPEN', 'REGISTRATION_CLOSED', 'IN_PROGRESS', 'COMPLETED', 'CANCELLED'] as const;
      const upperStatus = status.toUpperCase();
      if (validStatuses.includes(upperStatus as typeof validStatuses[number])) {
        whereClause.status = upperStatus as typeof validStatuses[number];
      }
    }

    // Filter by date range
    if (startDate || endDate) {
      whereClause.startDate = {};

      if (startDate) {
        const start = new Date(startDate);
        start.setHours(0, 0, 0, 0);
        whereClause.startDate.gte = start;
      }

      if (endDate) {
        const end = new Date(endDate);
        end.setHours(23, 59, 59, 999);
        whereClause.startDate.lte = end;
      }
    }

    const tournaments = await db.tournament.findMany({
      where: whereClause,
      include: {
        site: {
          select: {
            id: true,
            name: true,
            slug: true,
          },
        },
        _count: {
          select: {
            inscriptions: true,
            matches: true,
          },
        },
      },
      orderBy: {
        startDate: 'desc',
      },
    });

    return NextResponse.json(tournaments);
  } catch (error) {
    console.error('Error fetching tournaments:', error);
    return NextResponse.json(
      { error: 'Failed to fetch tournaments' },
      { status: 500 }
    );
  }
}

// POST /api/tournaments - Create a new tournament
export async function POST(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);

    if (!session?.user) {
      return NextResponse.json(
        { error: 'Unauthorized' },
        { status: 401 }
      );
    }

    // Check if user has admin role
    const allowedRoles = ['SUPER_ADMIN', 'ORG_ADMIN', 'SITE_ADMIN'];
    if (!allowedRoles.includes(session.user.role)) {
      return NextResponse.json(
        { error: 'Forbidden: Insufficient permissions' },
        { status: 403 }
      );
    }

    const body = await request.json();

    // Validate input with Zod schema
    const validationResult = createTournamentSchema.safeParse(body);
    if (!validationResult.success) {
      return NextResponse.json(
        {
          error: 'Invalid tournament data',
          details: validationResult.error.flatten().fieldErrors,
        },
        { status: 400 }
      );
    }

    const { siteId, name, description, date, endDate, type, category, maxTeams, price } = validationResult.data;

    // Verify site belongs to user's organization
    const site = await db.site.findFirst({
      where: {
        id: siteId,
        organizationId: session.user.organizationId,
      },
    });

    if (!site) {
      return NextResponse.json(
        { error: 'Site not found or does not belong to your organization' },
        { status: 404 }
      );
    }

    // If user is SITE_ADMIN, verify they have access to this site
    if (session.user.role === 'SITE_ADMIN' && session.user.siteId !== siteId) {
      return NextResponse.json(
        { error: 'Forbidden: You do not have access to this site' },
        { status: 403 }
      );
    }

    // Create tournament
    const tournament = await db.tournament.create({
      data: {
        organizationId: session.user.organizationId,
        siteId,
        name,
        description: description || null,
        type: mapTournamentType(type),
        status: 'DRAFT',
        startDate: new Date(date),
        endDate: endDate ? new Date(endDate) : null,
        maxPlayers: maxTeams,
        entryFee: new Decimal(price),
        settings: {
          tournamentFormat: type,
          category: category || null,
        },
      },
      include: {
        site: {
          select: {
            id: true,
            name: true,
            slug: true,
          },
        },
        _count: {
          select: {
            inscriptions: true,
            matches: true,
          },
        },
      },
    });

    return NextResponse.json(tournament, { status: 201 });
  } catch (error) {
    console.error('Error creating tournament:', error);
    return NextResponse.json(
      { error: 'Failed to create tournament' },
      { status: 500 }
    );
  }
}