import { NextRequest, NextResponse } from 'next/server'
import { auth } from '@/auth'
import { prisma } from '@/lib/prisma'
import { createHash } from 'crypto'

/**
 * POST /api/user/ai-consent
 * Explicit AI Processing Consent — Logs explicit user consent for compliance.
 * Optionally syncs consent state to UserAISettings if remember=true.
 *
 * Body: { consent: boolean, remember: boolean }
 */
export async function POST(req: NextRequest) {
  try {
    const session = await auth()
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const userId = session.user.id

    let body: { consent?: boolean; remember?: boolean } = {}
    try {
      body = await req.json()
    } catch {
      return NextResponse.json({ error: 'Invalid request body' }, { status: 400 })
    }

    const consent = body.consent ?? false
    const remember = body.remember ?? false

    // Get IP address and User-Agent
    const ip = req.headers.get('x-forwarded-for') || '127.0.0.1'
    const userAgent = req.headers.get('user-agent') || 'unknown'

    // Hash/Anonymize IP address for strict GDPR compliance
    const anonymizedIp = ip ? createHash('sha256').update(ip).digest('hex') : null

    let auditOk = true
    try {
      await prisma.aiConsentLog.create({
        data: {
          userId,
          consent,
          ipAddress: anonymizedIp,
          userAgent,
        },
      })
    } catch (auditError) {
      auditOk = false
      console.error('[POST /api/user/ai-consent] audit log failed:', auditError)
    }

    if (remember) {
      try {
        await prisma.userAISettings.upsert({
          where: { userId },
          create: {
            userId,
            aiProcessingConsent: consent,
          },
          update: {
            aiProcessingConsent: consent,
          },
        })
      } catch (settingsError) {
        console.error('[POST /api/user/ai-consent] settings upsert failed:', settingsError)
        return NextResponse.json({ error: 'settings_update_failed' }, { status: 500 })
      }
    }

    if (!auditOk) {
      return NextResponse.json({
        success: true,
        auditLogged: false,
        warning: 'audit_log_failed',
      })
    }

    return NextResponse.json({ success: true, auditLogged: true })
  } catch (error) {
    console.error('[POST /api/user/ai-consent] failed:', error)
    return NextResponse.json({ error: 'Internal Server Error' }, { status: 500 })
  }
}