import { NextResponse } from 'next/server'
import prisma from '@/lib/prisma'
import { getAuthUser } from '@/lib/auth'
import { createCollectionSchema, updateCollectionSchema, parseBody } from '@/lib/validations'
import { checkRateLimit, getClientIdentifier, getRateLimitHeaders } from '@/lib/rate-limit'
import type { Prisma } from '@prisma/client'

export const dynamic = 'force-dynamic'

// Get user's collections — with pagination
export async function GET(req: Request) {
    try {
        const { searchParams } = new URL(req.url)
        const userId = searchParams.get('userId')
        const isPublic = searchParams.get('public') === 'true'
        const limit = Math.min(parseInt(searchParams.get('limit') || '20'), 100)
        const offset = Math.max(parseInt(searchParams.get('offset') || '0'), 0)

        if (!userId) {
            return NextResponse.json([], { status: 200 })
        }

        const where: Prisma.CollectionWhereInput = { userId }
        if (isPublic) {
            where.isPublic = true
        }

        const [collections, total] = await Promise.all([
            prisma.collection.findMany({
                where,
                include: {
                    prompts: {
                        include: {
                            prompt: {
                                select: {
                                    id: true,
                                    slug: true,
                                    title: true,
                                    description: true,
                                    category: true,
                                },
                            },
                        },
                    },
                    user: {
                        select: {
                            name: true,
                            username: true,
                            image: true,
                        },
                    },
                },
                orderBy: { updatedAt: 'desc' },
                take: limit,
                skip: offset,
            }),
            prisma.collection.count({ where }),
        ])

        return NextResponse.json({ collections, total, hasMore: offset + collections.length < total })

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

// Create new collection — requires auth
export async function POST(req: Request) {
    try {
        const authUser = await getAuthUser()
        if (!authUser) {
            return NextResponse.json({ error: 'Authentication required' }, { status: 401 })
        }

        // Rate limit
        const identifier = getClientIdentifier(req, authUser.id)
        const rateLimit = await checkRateLimit(`collections:${identifier}`, true)
        if (!rateLimit.success) {
            return NextResponse.json({ error: rateLimit.error }, { status: 429 })
        }

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

        const { name, description, isPublic } = parsed.data

        const collection = await prisma.collection.create({
            data: {
                name,
                description: description || null,
                userId: authUser.id,
                isPublic: isPublic || false,
            },
        })

        return NextResponse.json(collection)

    } catch (error) {
        console.error('Create collection error:', error)
        return NextResponse.json(
            { error: 'Failed to create collection' },
            { status: 500 }
        )
    }
}

// Update collection — requires auth + ownership
export async function PATCH(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(updateCollectionSchema, body)
        if (!parsed.success) return parsed.response

        const { id, name, description, isPublic } = parsed.data

        // Verify ownership
        const existing = await prisma.collection.findUnique({
            where: { id },
            select: { userId: true },
        })
        if (!existing || existing.userId !== authUser.id) {
            return NextResponse.json({ error: 'Not found or not authorized' }, { status: 403 })
        }

        const collection = await prisma.collection.update({
            where: { id },
            data: {
                ...(name && { name }),
                ...(description !== undefined && { description }),
                ...(isPublic !== undefined && { isPublic }),
            },
        })

        return NextResponse.json(collection)

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

// Delete collection — requires auth + ownership
export async function DELETE(req: Request) {
    try {
        const authUser = await getAuthUser()
        if (!authUser) {
            return NextResponse.json({ error: 'Authentication required' }, { status: 401 })
        }

        const { searchParams } = new URL(req.url)
        const id = searchParams.get('id')

        if (!id) {
            return NextResponse.json(
                { error: 'Collection ID is required' },
                { status: 400 }
            )
        }

        // Verify ownership
        const existing = await prisma.collection.findUnique({
            where: { id },
            select: { userId: true },
        })
        if (!existing || existing.userId !== authUser.id) {
            return NextResponse.json({ error: 'Not found or not authorized' }, { status: 403 })
        }

        await prisma.collection.delete({ where: { id } })

        return NextResponse.json({ success: true })

    } catch (error) {
        console.error('Delete collection error:', error)
        return NextResponse.json(
            { error: 'Failed to delete collection' },
            { status: 500 }
        )
    }
}