<template>
  <v-button v-if="githubAuth" color="gray" type="button" @click="login">
    <div class="flex justify-center">
      Login with
      <svg class="w-6 h-6 text-white ml-2" xmlns="http://www.w3.org/2000/svg"
           viewBox="0 0 24 24"
      >
        <path
          d="M12 0c-6.626 0-12 5.373-12 12 0 5.302 3.438 9.8 8.207 11.387.599.111.793-.261.793-.577v-2.234c-3.338.726-4.033-1.416-4.033-1.416-.546-1.387-1.333-1.756-1.333-1.756-1.089-.745.083-.729.083-.729 1.205.084 1.839 1.237 1.839 1.237 1.07 1.834 2.807 1.304 3.492.997.107-.775.418-1.305.762-1.604-2.665-.305-5.467-1.334-5.467-5.931 0-1.311.469-2.381 1.236-3.221-.124-.303-.535-1.524.117-3.176 0 0 1.008-.322 3.301 1.23.957-.266 1.983-.399 3.003-.404 1.02.005 2.047.138 3.006.404 2.291-1.552 3.297-1.23 3.297-1.23.653 1.653.242 2.874.118 3.176.77.84 1.235 1.911 1.235 3.221 0 4.609-2.807 5.624-5.479 5.921.43.372.823 1.102.823 2.222v3.293c0 .319.192.694.801.576 4.765-1.589 8.199-6.086 8.199-11.386 0-6.627-5.373-12-12-12z"
        />
      </svg>
    </div>
  </v-button>
</template>

<script>
export default {
  name: 'LoginWithGithub',

  computed: {
    githubAuth: () => window.config.githubAuth,
    url: () => '/api/oauth/github'
  },

  mounted () {
    window.addEventListener('message', this.onMessage, false)
  },

  beforeUnmount () {
    window.removeEventListener('message', this.onMessage)
  },

  methods: {
    async login () {
      const newWindow = openWindow('', 'Login')

      const url = await this.$store.dispatch('auth/fetchOauthUrl', {
        provider: 'github'
      })

      newWindow.location.href = url
    },

    /**
     * @param {MessageEvent} e
     */
    onMessage (e) {
      if (e.origin !== window.origin || !e.data.token) {
        return
      }

      this.$store.dispatch('auth/saveToken', {
        token: e.data.token
      })

      this.$router.push({ name: 'home' })
    }
  }
}

/**
 * @param  {Object} options
 * @return {Window}
 */
function openWindow (url, title, options = {}) {
  if (typeof url === 'object') {
    options = url
    url = ''
  }

  options = { url, title, width: 600, height: 720, ...options }

  const dualScreenLeft = window.screenLeft !== undefined ? window.screenLeft : window.screen.left
  const dualScreenTop = window.screenTop !== undefined ? window.screenTop : window.screen.top
  const width = window.innerWidth || document.documentElement.clientWidth || window.screen.width
  const height = window.innerHeight || document.documentElement.clientHeight || window.screen.height

  options.left = ((width / 2) - (options.width / 2)) + dualScreenLeft
  options.top = ((height / 2) - (options.height / 2)) + dualScreenTop

  const optionsStr = Object.keys(options).reduce((acc, key) => {
    acc.push(`${key}=${options[key]}`)
    return acc
  }, []).join(',')

  const newWindow = window.open(url, title, optionsStr)

  if (window.focus) {
    newWindow.focus()
  }

  return newWindow
}
</script>
