/**
 * Stripe Checkout Session API
 * Deploy as a Cloudflare Worker, Vercel function, or standalone server.
 *
 * Environment variables needed:
 * - STRIPE_SECRET_KEY: sk_live_... or sk_test_...
 * - FRONTEND_URL: https://git.fdsa.agency (or your domain)
 *
 * Usage:
 *   POST /api/checkout
 *   Body: { "price_id": "price_abc123", "mode": "payment", "customer_email": "..." }
 */

const stripeEndpoint = 'https://api.stripe.com/v1/checkout/sessions'

async function handleRequest(request) {
  // CORS for frontend
  if (request.method === 'OPTIONS') {
    return new Response(null, {
      headers: {
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'POST, OPTIONS',
        'Access-Control-Allow-Headers': 'Content-Type',
      },
    })
  }

  if (request.method !== 'POST') {
    return new Response(JSON.stringify({ error: 'Method not allowed' }), { status: 405 })
  }

  const stripeKey = globalThis.STRIPE_SECRET_KEY || process?.env?.STRIPE_SECRET_KEY
  const frontendUrl = globalThis.FRONTEND_URL || process?.env?.FRONTEND_URL || 'https://git.fdsa.agency'

  if (!stripeKey) {
    return new Response(JSON.stringify({ error: 'Stripe not configured' }), {
      status: 500,
      headers: { 'Access-Control-Allow-Origin': '*' },
    })
  }

  try {
    const { price_id, mode, customer_email } = await request.json()

    const body = new URLSearchParams({
      'mode': mode || 'payment',
      'success_url': `${frontendUrl}/checkout/success?session_id={CHECKOUT_SESSION_ID}`,
      'cancel_url': `${frontendUrl}/checkout/cancel`,
      'allow_promotion_codes': 'true',
      'line_items[0][price]': price_id,
      'line_items[0][quantity]': '1',
    })

    if (customer_email) {
      body.set('customer_email', customer_email)
    }

    const stripeResp = await fetch(stripeEndpoint, {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${stripeKey}`,
        'Content-Type': 'application/x-www-form-urlencoded',
      },
      body: body.toString(),
    })

    const data = await stripeJson(stripeResp)

    if (!stripeResp.ok) {
      throw new Error(data.error?.message || 'Stripe error')
    }

    return new Response(JSON.stringify({ url: data.url, session_id: data.id }), {
      status: 200,
      headers: {
        'Content-Type': 'application/json',
        'Access-Control-Allow-Origin': '*',
      },
    })
  } catch (e) {
    return new Response(JSON.stringify({ error: e.message }), {
      status: 500,
      headers: {
        'Content-Type': 'application/json',
        'Access-Control-Allow-Origin': '*',
      },
    })
  }
}

async function stripeJson(response) {
  const text = await response.text()
  try {
    return JSON.parse(text)
  } catch {
    // Stripe sometimes returns unexpected formats — parse query string
    const params = new URLSearchParams(text)
    const obj = {}
    for (const [k, v] of params) {
      // Handle nested keys like 'error.message'
      const parts = k.split('.')
      if (parts.length > 1) {
        let cursor = obj
        for (let i = 0; i < parts.length - 1; i++) {
          cursor[parts[i]] = cursor[parts[i]] || {}
          cursor = cursor[parts[i]]
        }
        cursor[parts[parts.length - 1]] = v
      } else {
        obj[k] = v
      }
    }
    return obj
  }
}

// Cloudflare Worker entry
export default { fetch: handleRequest }

// Node.js entry
if (typeof module !== 'undefined' && require?.main === module) {
  const http = require('http')
  const server = http.createServer((req, res) => {
    // Minimal Node.js adapter — assumes body is JSON
    let body = ''
    req.on('data', chunk => body += chunk)
    req.on('end', async () => {
      globalThis.process = process
      globalThis.request = new Request(`http://localhost${req.url}`, {
        method: req.method,
        headers: req.headers,
        body: body || undefined,
      })
      const response = await handleRequest(globalThis.request)
      res.writeHead(response.status, Object.fromEntries(response.headers))
      res.end(await response.text())
    })
  })
  const port = process.env.PORT || 8787
  server.listen(port, () => console.log(`Checkout API on :${port}`))
}