import { NextRequest, NextResponse } from 'next/server';
import { prisma } from '@/lib/prisma';
import { apiCache } from '@/lib/cache';
import { checkRateLimit, getRateLimitHeaders, requireSessionAuth } from '@/lib/auth';
import { PrismaClientKnownRequestError } from '@prisma/client/runtime/library';

export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const { id: idParam } = await params;
    const id = parseInt(idParam);
    if (!Number.isFinite(id)) {
      return NextResponse.json({ error: 'Invalid project id' }, { status: 400 });
    }
    
    const project = await prisma.project.findUnique({
      where: { id }
    });

    if (!project) {
      return NextResponse.json(
        { error: 'Project not found' },
        { status: 404 }
      );
    }

    return NextResponse.json(project);
  } catch (error) {
    // Handle missing database table gracefully
    if (error instanceof PrismaClientKnownRequestError && error.code === 'P2021') {
      if (process.env.NODE_ENV === 'development') {
        console.warn('Project table does not exist. Returning 404.');
      }
      return NextResponse.json(
        { error: 'Project not found' },
        { status: 404 }
      );
    }
    
    if (process.env.NODE_ENV === 'development') {
      console.error('Error fetching project:', error);
    }
    return NextResponse.json(
      { error: 'Failed to fetch project' },
      { status: 500 }
    );
  }
}

export async function PUT(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    // Rate limiting for PUT requests
    const ip = request.headers.get('x-forwarded-for') || request.headers.get('x-real-ip') || 'unknown';
    if (!checkRateLimit(ip, 5, 60000)) { // 5 requests per minute for PUT
      return new NextResponse(
        JSON.stringify({ error: 'Rate limit exceeded' }), 
        { 
          status: 429, 
          headers: { 
            'Content-Type': 'application/json',
            ...getRateLimitHeaders(ip, 5, 60000)
          } 
        }
      );
    }

    // Check if this is an admin request
    const isAdminRequest = request.headers.get('x-admin-request') === 'true';
    if (!isAdminRequest) {
      return NextResponse.json(
        { error: 'Admin access required' },
        { status: 403 }
      );
    }
    const authError = requireSessionAuth(request);
    if (authError) return authError;

    const { id: idParam } = await params;
    const id = parseInt(idParam);
    if (!Number.isFinite(id)) {
      return NextResponse.json({ error: 'Invalid project id' }, { status: 400 });
    }
    const data = await request.json();
    
    // Remove difficulty field if it exists (since we're removing it)
    const { difficulty, ...projectData } = data;
    
    const project = await prisma.project.update({
      where: { id },
      data: { 
        ...projectData, 
        updatedAt: new Date(),
        // Keep existing difficulty if not provided
        ...(difficulty ? { difficulty } : {})
      }
    });

    // Invalidate cache after successful update
    await apiCache.invalidateProject(id);
    await apiCache.invalidateAll();

    return NextResponse.json(project);
  } catch (error) {
    // Handle missing database table gracefully
    if (error instanceof PrismaClientKnownRequestError && error.code === 'P2021') {
      if (process.env.NODE_ENV === 'development') {
        console.warn('Project table does not exist.');
      }
      return NextResponse.json(
        { error: 'Database table not found. Please run migrations.' },
        { status: 503 }
      );
    }
    
    if (process.env.NODE_ENV === 'development') {
      console.error('Error updating project:', error);
    }
    return NextResponse.json(
      { error: 'Failed to update project', details: error instanceof Error ? error.message : 'Unknown error' },
      { status: 500 }
    );
  }
}

export async function DELETE(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    // Rate limiting for DELETE requests
    const ip = request.headers.get('x-forwarded-for') || request.headers.get('x-real-ip') || 'unknown';
    if (!checkRateLimit(ip, 3, 60000)) { // 3 requests per minute for DELETE (more restrictive)
      return new NextResponse(
        JSON.stringify({ error: 'Rate limit exceeded' }), 
        { 
          status: 429, 
          headers: { 
            'Content-Type': 'application/json',
            ...getRateLimitHeaders(ip, 3, 60000)
          } 
        }
      );
    }

    // Check if this is an admin request
    const isAdminRequest = request.headers.get('x-admin-request') === 'true';
    if (!isAdminRequest) {
      return NextResponse.json(
        { error: 'Admin access required' },
        { status: 403 }
      );
    }
    const authError = requireSessionAuth(request);
    if (authError) return authError;

    const { id: idParam } = await params;
    const id = parseInt(idParam);
    if (!Number.isFinite(id)) {
      return NextResponse.json({ error: 'Invalid project id' }, { status: 400 });
    }
    
    await prisma.project.delete({
      where: { id }
    });

    // Invalidate cache after successful deletion
    await apiCache.invalidateProject(id);
    await apiCache.invalidateAll();

    return NextResponse.json({ success: true });
  } catch (error) {
    // Handle missing database table gracefully
    if (error instanceof PrismaClientKnownRequestError && error.code === 'P2021') {
      if (process.env.NODE_ENV === 'development') {
        console.warn('Project table does not exist.');
      }
      return NextResponse.json(
        { error: 'Database table not found. Please run migrations.' },
        { status: 503 }
      );
    }
    
    if (process.env.NODE_ENV === 'development') {
      console.error('Error deleting project:', error);
    }
    return NextResponse.json(
      { error: 'Failed to delete project' },
      { status: 500 }
    );
  }
}