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

function resolveAccessRole(
  brainstormSession: any,
  userId: string | null
): 'owner' | 'editor' | 'viewer' | 'guest' | 'none' {
  if (!userId) {
    return brainstormSession.isPublic ? 'guest' : 'none'
  }
  if (brainstormSession.userId === userId) return 'owner'
  const participant = brainstormSession.participants?.find(
    (p: any) => p.userId === userId
  )
  if (participant) return participant.role
  const acceptedShare = brainstormSession.shares?.find(
    (s: any) => s.userId === userId && s.status === 'accepted'
  )
  if (acceptedShare) return acceptedShare.permission
  return brainstormSession.isPublic ? 'guest' : 'none'
}

function filterNoteRefsByRole(ideas: any[], role: string): any[] {
  const allowedVis = role === 'owner'
    ? ['public', 'participants', 'owner_only']
    : role === 'editor'
      ? ['public', 'participants', 'owner_only']
      : role === 'viewer'
        ? ['public', 'participants']
        : ['public']

  return ideas.map((idea: any) => ({
    ...idea,
    noteRefs: (idea.noteRefs || []).filter(
      (ref: any) => allowedVis.includes(ref.visibility || 'participants')
    ),
  }))
}

function sanitizeForGuest(session: any): any {
  const { participants, shares, ...rest } = session
  const filteredIdeas = filterNoteRefsByRole(rest.ideas || [], 'guest')
  return {
    ...rest,
    ideas: filteredIdeas,
    sourceNote: null,
    exportedNote: null,
  }
}

export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ sessionId: string }> }
) {
  const authSession = await auth()
  const userId = authSession?.user?.id || null

  try {
    const { sessionId } = await params
    const brainstormSession = await prisma.brainstormSession.findFirst({
      where: { id: sessionId },
      include: {
        ideas: {
          orderBy: [{ waveNumber: 'asc' }, { createdAt: 'asc' }],
          include: {
            noteRefs: {
              include: {
                note: { select: { id: true, title: true } },
              },
            },
          },
        },
        sourceNote: {
          select: { id: true, title: true },
        },
        exportedNote: {
          select: { id: true, title: true },
        },
        participants: {
          where: userId ? { userId } : undefined,
          select: { userId: true, role: true },
        },
        shares: userId
          ? {
              where: { userId, status: 'accepted' },
              select: { userId: true, permission: true },
            }
          : false,
      },
    })

    if (!brainstormSession) {
      return NextResponse.json({ error: 'Not found' }, { status: 404 })
    }

    const creatorIds = [...new Set(brainstormSession.ideas.map((i: any) => i.createdBy).filter(Boolean))]
    const creators = creatorIds.length > 0
      ? await prisma.user.findMany({ where: { id: { in: creatorIds } }, select: { id: true, name: true, image: true } })
      : []
    const creatorMap = new Map(creators.map((c: any) => [c.id, c]))
    for (const idea of brainstormSession.ideas) {
      (idea as any).creator = (idea as any).createdBy ? creatorMap.get((idea as any).createdBy) || null : null
    }

    const role = resolveAccessRole(brainstormSession, userId)

    if (role === 'none') {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    let responseData: any = brainstormSession

    if (role === 'guest') {
      responseData = sanitizeForGuest(brainstormSession)
    } else if (role === 'viewer') {
      const { participants: _p, shares: _s, ...rest } = brainstormSession as any
      responseData = {
        ...rest,
        ideas: filterNoteRefsByRole(rest.ideas || [], 'viewer'),
      }
    } else {
      const { participants: _p, shares: _s, ...rest } = brainstormSession as any
      responseData = rest
    }

    return NextResponse.json({
      success: true,
      data: responseData,
      _meta: { role, canEdit: ['owner', 'editor'].includes(role) || (role === 'guest' && brainstormSession.guestCanEdit) },
    })
  } catch (error) {
    console.error('Error fetching brainstorm session:', error)
    return NextResponse.json(
      { error: 'Failed to fetch session' },
      { status: 500 }
    )
  }
}

export async function PATCH(
  request: NextRequest,
  { params }: { params: Promise<{ sessionId: string }> }
) {
  const session = await auth()
  if (!session?.user?.id) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  }

  try {
    const { sessionId } = await params
    const body = await request.json()
    const brainstormSession = await prisma.brainstormSession.findFirst({
      where: { id: sessionId, userId: session.user.id },
    })

    if (!brainstormSession) {
      return NextResponse.json({ error: 'Not found' }, { status: 404 })
    }

    const updates: Record<string, any> = {}
    if (typeof body.isPublic === 'boolean') updates.isPublic = body.isPublic
    if (typeof body.guestCanEdit === 'boolean') updates.guestCanEdit = body.guestCanEdit
    if (typeof body.seedIdea === 'string' && body.seedIdea.trim()) updates.seedIdea = body.seedIdea.trim()

    if (Object.keys(updates).length === 0) {
      return NextResponse.json({ error: 'No valid fields to update' }, { status: 400 })
    }

    const updated = await prisma.brainstormSession.update({
      where: { id: sessionId },
      data: updates,
    })

    return NextResponse.json({ success: true, data: updated })
  } catch (error) {
    console.error('Error updating brainstorm session:', error)
    return NextResponse.json(
      { error: 'Failed to update session' },
      { status: 500 }
    )
  }
}

export async function DELETE(
  request: NextRequest,
  { params }: { params: Promise<{ sessionId: string }> }
) {
  const session = await auth()
  if (!session?.user?.id) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  }

  try {
    const { sessionId } = await params
    const brainstormSession = await prisma.brainstormSession.findFirst({
      where: { id: sessionId, userId: session.user.id },
    })

    if (!brainstormSession) {
      return NextResponse.json({ error: 'Not found' }, { status: 404 })
    }

    await prisma.brainstormSession.delete({
      where: { id: sessionId },
    })

    return NextResponse.json({ success: true })
  } catch (error) {
    console.error('Error deleting brainstorm session:', error)
    return NextResponse.json(
      { error: 'Failed to delete session' },
      { status: 500 }
    )
  }
}