<template>
  <form
    id="basic-signup-form"
    @submit.prevent="submitHandler"
  >
    <h2>Sign up for FormulateConf 2020 in Charlottesville, VA</h2>
    <div class="form-input">
      <label for="username">
        Username
      </label>
      <input
        id="username"
        ref="username"
        @keyup="checkUsername" 
        type="text"
        name="username" 
        pattern="[a-z]{4,8}"
        required
      />
      <p class="help-text">
        Usernames must be lowercase and between 4-8 characters in length.
      </p>
      <p 
        v-if="usernameTaken"
        class="error"
      >
        Sorry, that username is already taken.
      </p>
    </div>
    
    <div class="form-input">
      <label for="email">
        Email
      </label>
      <input 
        id="email"
        type="email"
        name="email"
        required
      />
    </div>
    
    <div class="form-input">
      <label for="bio">
        Bio
      </label>
      <textarea
        id="bio"
        name="bio"
        required
      />
      <p class="help-text">
        Help others get to know you a bit.
      </p>
    </div>
    
    <div class="form-input">
      <label for="password">
        Password
      </label>
      <input
        id="password"
        ref="password"
        @keyup="passwordsMatch = true"
        @blur="comparePasswords"
        type="text"
        name="password"
        minlength="6"
        autocomplete="off"
        required
      />
      <p class="help-text">
        Your password must be at least 6 characters long.
      </p>
    </div>
    
    <div class="form-input">
      <label for="password-confirm">
        Confirm Password
      </label>
      <input
        id="password-confirm"
        ref="passwordConfirm"
        @keyup="passwordsMatch = true"
        @blur="comparePasswords"
        type="text"
        name="password-confirm"
        minlength="6"
        autocomplete="off"
        required
      />
      <p 
        v-if="!passwordsMatch"
        class="error"
      >
        Oops! Your passwords do not match.
      </p>
    </div>
    
    <input type="submit" value="Register!" />
  </form>
</template>

<script>
export default {
  data () {
    return {
      takenNamePartials: [
        'dawg',
        'js',
        'boss',
        'oy'
      ],
      usernameTaken: false,
      passwordsMatch: true
    }
  },
  computed: {
    hasErrors () {
      return this.usernameTaken || !this.passwordsMatch
    }
  },
  methods: {
    submitHandler () {
      if (!this.hasErrors) {
        alert('Thank you for signing up!')
      } else {
        alert('There are errors with your form submission.')
      }
    },
    async checkUsername () {
      // reset the usernameTaken variable to false
      // when the user starts typing
      this.usernameTaken = false
      // check to see if the username contains any of 
      // our partial matches to simulate taken usernames.
      // wrap it in a promise and timeout to simulate an xhr request.
      let match = false
      await new Promise((resolve) => {
        setTimeout(() => {
          // use .find() to check for matches and bail on first success
          match = this.takenNamePartials.find(partial => this.$refs.username.value.includes(partial))
          resolve()
        }, 2500)
      })
      // set usernameTaken to the cooerced Boolean value of match
      this.usernameTaken = !!match
    },
    comparePasswords () {
      // if both inputs have been filled out then compare their values and store
      // the comparison result in this.passwordsMatch
      if (this.$refs.password.value && this.$refs.passwordConfirm.value) {
        this.passwordsMatch = this.$refs.password.value === this.$refs.passwordConfirm.value
      }
    }
  }
}
</script>

<style lang="scss">
body {
  min-height: 100vh;
  padding: 2em;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(to bottom right, cyan, magenta);
}
  
form {
  display: flex;
  flex-direction: column;
  background-color: #fff;
  border: 1px solid #999;
  width: 90%;
  max-width: 320px;
  padding: 3em 2em;
  border-radius: 0.3em;
  box-shadow: 0.25em 0.15em 12em 0 rgba(#000, 0.25);
  
  * {
    box-sizing: border-box;
  }
  
  h2 {
    margin-top: 0;
    color: #555;
  }
}
  
.form-input {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  margin-bottom: 1em;
  
  input, textarea {
    width: 100%;
    margin-bottom: 0;
    border: 1px solid #cacaca;
    padding: 0.5em;
    border-radius: 0.25em;
  }
  
  label {
    font-weight: bold;
    font-size: 0.85em;
    margin-bottom: 0.5em;
  }
  
  .help-text {
    margin-top: 0.5em;
    margin-bottom: 0;
    color: #999;
    font-size: 0.75em;
    
  }
  .error {
    color: red;
    font-size: 0.8em;
  }
}
  
input[type="submit"] {
  appearance: none;
  border: 1px solid deeppink;
  background-color: magenta;
  padding: 1em 1.5em;
  font-weight: bold;
  color: #fff;
  text-transform: uppercase;
  border-radius: 0.5em;
  margin: 1em auto 0 auto;
}
</style>