const config = require('@config/index')
const rawBody = require('raw-body')
const crypto = require('crypto')

const verifyLine = async (c, n) => {
  if (!('request' in c) || !('raw' in c.request)) return c.throw(400, 'body not found')
  let xSignature = c.get('x-line-signature') || ''
  if (typeof xSignature !== 'string' || xSignature.length === 0) return c.throw(400, 'signature not found')
  let signature = crypto.createHmac('SHA256', config.line.secret).update(c.request.raw).digest('base64')
  if (signature !== xSignature) return c.throw(403, 'signature not match')
  return n()
}

const getRaw = async (c, n) => {
  let raw = await rawBody(c.req, {
    length: c.request.length,
    limit: '5mb',
    encoding: c.request.charset
  })
  c.request.raw = raw
  let txt = raw instanceof Buffer ? raw.toString() : raw
  if (c.request.type === 'application/json') {
    try {
      c.request.body = JSON.parse(txt)
    } catch (err) {
      c.request.body = txt
    }
  }
  return n()
}

module.exports = {
  verifyLine,
  getRaw
}