import { NextRequest, NextResponse } from 'next/server'

export async function GET(request: NextRequest) {
    const { searchParams } = new URL(request.url)
    const targetUrl = searchParams.get('url')

    if (!targetUrl) {
        return NextResponse.json({ error: 'URL parameter required' }, { status: 400 })
    }

    try {
        // Validate URL
        const url = new URL(targetUrl)

        // Only allow http/https
        if (!['http:', 'https:'].includes(url.protocol)) {
            return NextResponse.json({ error: 'Invalid URL protocol' }, { status: 400 })
        }

        // Fetch the page
        const response = await fetch(targetUrl, {
            headers: {
                'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
                'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
                'Accept-Language': 'en-US,en;q=0.5',
            },
        })

        if (!response.ok) {
            return NextResponse.json(
                { error: `Failed to fetch: ${response.status}` },
                { status: response.status }
            )
        }

        let html = await response.text()

        // Inject base tag to fix relative URLs
        const baseTag = `<base href="${url.origin}${url.pathname.substring(0, url.pathname.lastIndexOf('/') + 1)}">`
        html = html.replace(/<head([^>]*)>/i, `<head$1>${baseTag}`)

        // Disable all scripts for security
        html = html.replace(/<script\b[^<]*(?:(?!<\/script>)<[^<]*)*<\/script>/gi, '')

        // Remove event handlers
        html = html.replace(/\son\w+="[^"]*"/gi, '')
        html = html.replace(/\son\w+='[^']*'/gi, '')

        // Add visual selector helper styles
        const helperStyles = `
            <style>
                * { cursor: crosshair !important; }
                a { pointer-events: none; }
            </style>
        `
        html = html.replace('</head>', `${helperStyles}</head>`)

        return new NextResponse(html, {
            headers: {
                'Content-Type': 'text/html; charset=utf-8',
                'X-Frame-Options': 'SAMEORIGIN',
            },
        })
    } catch (error) {
        console.error('[Proxy] Error fetching URL:', error)
        return NextResponse.json(
            { error: error instanceof Error ? error.message : 'Failed to fetch URL' },
            { status: 500 }
        )
    }
}