import { NextRequest, NextResponse } from 'next/server'
import { validateSession, hasPermission } from '@/lib/auth'
import connectToDatabase from '@/lib/mongodb'
import { Server } from '@/lib/models'
import { isValidObjectId } from '@/lib/input-validation'
import { createAuditLog, getClientIP } from '@/lib/audit'
import { getServerPath } from '@/lib/docker'
import { readdir, stat, writeFile } from 'fs/promises'
import path from 'path'

// GET /api/servers/[id]/mods — List mods
export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const session = await validateSession(request)
    if (!session) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    if (!hasPermission(session, 'mods:view')) {
      return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
    }

    const { id } = await params
    if (!isValidObjectId(id)) {
      return NextResponse.json({ error: 'Invalid server ID' }, { status: 400 })
    }

    await connectToDatabase()
    const server = await Server.findById(id)
    if (!server) {
      return NextResponse.json({ error: 'Server not found' }, { status: 404 })
    }

    if (server.type !== 'forge' && server.type !== 'fabric') {
      return NextResponse.json({ error: 'Mods are only available for Forge/Fabric servers' }, { status: 400 })
    }

    const modsDir = path.join(getServerPath(server._id.toString()), 'mods')
    const mods = []

    try {
      const files = await readdir(modsDir)
      for (const file of files) {
        if (file.endsWith('.jar') || file.endsWith('.jar.disabled')) {
          const filePath = path.join(modsDir, file)
          const stats = await stat(filePath)
          const enabled = file.endsWith('.jar') && !file.endsWith('.jar.disabled')
          const name = file.replace(/\.jar(\.disabled)?$/, '')
          mods.push({
            name,
            filename: file,
            size: stats.size,
            enabled,
          })
        }
      }
    } catch {
      // Directory doesn't exist yet
    }

    return NextResponse.json({ success: true, data: mods })
  } catch (error) {
    console.error('Fetch mods error:', error)
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 })
  }
}

// POST /api/servers/[id]/mods — Upload a mod
export async function POST(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  const clientIP = getClientIP(request)

  try {
    const session = await validateSession(request)
    if (!session) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    if (!hasPermission(session, 'mods:install')) {
      return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
    }

    const { id } = await params
    if (!isValidObjectId(id)) {
      return NextResponse.json({ error: 'Invalid server ID' }, { status: 400 })
    }

    await connectToDatabase()
    const server = await Server.findById(id)
    if (!server) {
      return NextResponse.json({ error: 'Server not found' }, { status: 404 })
    }

    if (server.type !== 'forge' && server.type !== 'fabric') {
      return NextResponse.json({ error: 'Mods are only available for Forge/Fabric servers' }, { status: 400 })
    }

    const formData = await request.formData()
    const file = formData.get('file') as File | null
    if (!file || !file.name.endsWith('.jar')) {
      return NextResponse.json({ error: 'A .jar file is required' }, { status: 400 })
    }

    const modsDir = path.join(getServerPath(server._id.toString()), 'mods')
    const { execSync } = await import('child_process')
    execSync(`mkdir -p "${modsDir}"`)

    const buffer = Buffer.from(await file.arrayBuffer())
    await writeFile(path.join(modsDir, file.name), buffer)

    await createAuditLog({
      action: 'mod_installed',
      entityType: 'mod',
      entityName: file.name,
      userId: session._id,
      userName: session.username,
      userEmail: session.email,
      newValues: { serverId: server._id.toString(), filename: file.name },
      clientIP,
      status: 'success',
      statusCode: 201,
    })

    return NextResponse.json({ success: true, message: 'Mod uploaded. Restart the server to load it.' }, { status: 201 })
  } catch (error) {
    console.error('Upload mod error:', error)
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 })
  }
}