import { NextResponse } from 'next/server'
import prisma from '@/lib/prisma'
import { getAuthUser } from '@/lib/auth'
import { updateProfileSchema, syncProfileSchema, parseBody } from '@/lib/validations'

export const dynamic = 'force-dynamic'

// GET - Fetch user profile
// Only the profile owner can see private fields (email, notification prefs)
export async function GET(req: Request) {
    try {
        const { searchParams } = new URL(req.url)
        const userId = searchParams.get('userId')
        const username = searchParams.get('username')

        if (!userId && !username) {
            return NextResponse.json(
                { error: 'userId or username required' },
                { status: 400 }
            )
        }

        // Check if the viewer is the profile owner
        const authUser = await getAuthUser()
        const isOwner = authUser && (
            (userId && authUser.id === userId) ||
            false // username check happens after fetch
        )

        const user = await prisma.user.findFirst({
            where: userId ? { id: userId } : { username },
            select: {
                id: true,
                name: true,
                username: true,
                image: true,
                bio: true,
                rank: true,
                totalRuns: true,
                totalStars: true,
                totalRemixes: true,
                socialLinks: true,
                createdAt: true,
                // Sensitive fields — only for owner
                email: true,
                notifyEmail: true,
                notifyStars: true,
                notifyRemixes: true,
                _count: {
                    select: {
                        prompts: true,
                        collections: true,
                    },
                },
            },
        })

        if (!user) {
            return NextResponse.json(
                { error: 'User not found' },
                { status: 404 }
            )
        }

        // Strip sensitive fields if not the owner
        const isRealOwner = isOwner || (authUser && authUser.id === user.id)
        if (!isRealOwner) {
            return NextResponse.json({
                id: user.id,
                name: user.name,
                username: user.username,
                image: user.image,
                bio: user.bio,
                rank: user.rank,
                totalRuns: user.totalRuns,
                totalStars: user.totalStars,
                totalRemixes: user.totalRemixes,
                socialLinks: user.socialLinks,
                createdAt: user.createdAt,
                _count: user._count,
            })
        }

        return NextResponse.json(user)
    } catch (error) {
        console.error('Get profile error:', error)
        return NextResponse.json(
            { error: 'Failed to fetch profile' },
            { status: 500 }
        )
    }
}

// PUT - Update user profile — requires authentication (uses server-side auth, not client userId)
export async function PUT(req: Request) {
    try {
        const authUser = await getAuthUser()
        if (!authUser) {
            return NextResponse.json({ error: 'Authentication required' }, { status: 401 })
        }

        const body = await req.json()
        const parsed = parseBody(updateProfileSchema, body)
        if (!parsed.success) return parsed.response

        const {
            name,
            username,
            bio,
            socialLinks,
            image,
            notifyEmail,
            notifyStars,
            notifyRemixes
        } = parsed.data

        // Check if username is taken (if changing username)
        if (username) {
            const existingUser = await prisma.user.findFirst({
                where: {
                    username,
                    NOT: { id: authUser.id },
                },
            })

            if (existingUser) {
                return NextResponse.json(
                    { error: 'Username is already taken' },
                    { status: 409 }
                )
            }
        }

        // Upsert — uses authUser.id from server session, NOT from client body
        const updatedUser = await prisma.user.upsert({
            where: { id: authUser.id },
            create: {
                id: authUser.id,
                email: authUser.email || `${authUser.id}@stackauth.local`,
                name: name || null,
                username: username || null,
                bio: bio || null,
                image: image || null,
                notifyEmail: notifyEmail ?? true,
                notifyStars: notifyStars ?? true,
                notifyRemixes: notifyRemixes ?? true,
            },
            update: {
                ...(name !== undefined && { name }),
                ...(username !== undefined && { username }),
                ...(bio !== undefined && { bio }),
                ...(socialLinks !== undefined && { socialLinks }),
                ...(image !== undefined && { image }),
                ...(notifyEmail !== undefined && { notifyEmail }),
                ...(notifyStars !== undefined && { notifyStars }),
                ...(notifyRemixes !== undefined && { notifyRemixes }),
            },
            select: {
                id: true,
                name: true,
                username: true,
                image: true,
                bio: true,
                socialLinks: true,
                notifyEmail: true,
                notifyStars: true,
                notifyRemixes: true,
            },
        })

        return NextResponse.json(updatedUser)
    } catch (error) {
        console.error('Update profile error:', error)
        return NextResponse.json(
            { error: 'Failed to update profile' },
            { status: 500 }
        )
    }
}

// POST - Create or sync user from Stack Auth
export async function POST(req: Request) {
    try {
        const body = await req.json()
        const parsed = parseBody(syncProfileSchema, body)
        if (!parsed.success) return parsed.response

        const { id, email, name, image } = parsed.data

        // Upsert user - create if doesn't exist, update if does
        const user = await prisma.user.upsert({
            where: { id },
            create: {
                id,
                email,
                name: name || null,
                image: image || null,
                username: email.split('@')[0], // Default username from email
            },
            update: {
                email,
                name: name || null,
                image: image || null,
            },
        })

        return NextResponse.json(user)
    } catch (error) {
        console.error('Sync user error:', error)
        return NextResponse.json(
            { error: 'Failed to sync user' },
            { status: 500 }
        )
    }
}