const casbin = require('casbin')
const Koa = require('koa')
const app = new Koa()
const authz = require('koa-authz')
// response
app.use(async (ctx, next) => {
  const start = new Date()
  await next()
  console.log(new Date() - start)
})
// use authz middleware
app.use(authz({
  newEnforcer: async() => {
    // load the casbin model and policy from files, database is also supported.
    const enforcer = await casbin.newEnforcer('authz_model.conf', 'authz_policy.csv')
    return enforcer
  }
}))
// reload routes
const router = require('koa-router')({prefix: '/user'})
router.get('/', (ctx) => {
  ctx.body = {name: 'Chalin', age: 26}
})
router.put('/', (ctx) => {
  ctx.body = {status: 'success'}
})
app.use(router.routes(), router.allowedMethods())
app.listen(3000)

class MyAuthorizer extends BasicAuthorizer {
  // override function
  getUserName () {
    const { username } = this.ctx.state.user
    return username
  }
}
app.use(authz({
  newEnforcer: async () => {
    // load the casbin model and policy from files, database is also supported.
    const enforcer = await casbin.newEnforcer('examples/authz_model.conf', 'examples/authz_policy.csv')
    return enforcer
  },
  authorizer: (ctx, option) => new MyAuthorizer(ctx, option)
}))