<template>
  <div class="virtual-keyboard">
    <!-- Allow focus on the keyboard to automatically restore focus on the input -->
    <section tabindex="0">
      <div class="header">
        <a v-if="manager" v-on:click.prevent="optionsModal = true" href="#">
          Manage Keyboards
        </a>
      </div>

      <div class="content" v-if="keyboard">
        <KeyboardDisplay
          :keyboard-index="selectedKeyboard"
          v-on:input="addChar"
        />
      </div>
      <div v-else>No keyboard to display, please add one.</div>

      <Modal v-if="optionsModal" v-model="optionsModal">
        <KeyboardManager />
      </Modal>
    </section>
  </div>
</template>

<script>
import { mapState } from "vuex";
import KeyboardDisplay from "./KeyboardDisplay.vue";
import KeyboardManager from "./KeyboardManager.vue";
import Modal from "./Modal.vue";

export default {
  components: {
    KeyboardDisplay,
    KeyboardManager,
    Modal,
  },
  props: {
    inputField: {
      type: [HTMLInputElement, HTMLTextAreaElement],
      required: true,
    },
    manager: {
      type: Boolean,
      default: false,
    },
  },
  data: () => ({
    optionsModal: false,
    // Select the keyboard at index 0 in the keyboard list by default
    selectedKeyboard: 0,
  }),
  created() {
    this.inputField.addEventListener("blur", this.looseFocus);
    this.inputField.addEventListener("keydown", this.keyInput);
  },
  beforeDestroy() {
    this.inputField.removeEventListener("blur", this.looseFocus);
    this.inputField.removeEventListener("keydown", this.keyInput);
  },
  computed: {
    ...mapState(["keyboards"]),
    keyboard() {
      return this.keyboards[this.selectedKeyboard];
    },
  },
  methods: {
    addChar(key) {
      if (!key.character) return;
      // Add a character to the input depending on the cursor selection
      const start = this.inputField.selectionStart;
      const value = this.inputField.value;
      this.inputField.value =
        value.slice(0, start) +
        key.character +
        value.slice(this.inputField.selectionEnd);
      // Reset the input caret after modifying the input value
      this.inputField.selectionStart = this.inputField.selectionEnd =
        start + key.character.length;
    },
    keyInput(e) {
      if (!this.keyboard) return;
      const key = this.keyboard.characters.find(
        (c) => c.keyboard_code == e.key.charCodeAt()
      );
      if (!key) return;
      this.addChar({ character: key.character });
      e.preventDefault();
    },
    looseFocus() {
      if (this.optionsModal) return;
      // We need a short delay before checking where the user moved the focus
      setTimeout(() => {
        // In case the user typed on the keyboard, restore focus on the input
        if (this.$el.contains(document.activeElement))
          return this.inputField.focus();
        // Otherwise emit a custom event on the input for the keyboard to be removed
        this.inputField.dispatchEvent(
          new CustomEvent("vk_rmkeyboard", { detail: this })
        );
      }, 1);
    },
  },
  watch: {
    optionsModal(value) {
      // Focus the input when closing the modal
      if (!value) this.inputField.focus();
    },
  },
};
</script>

<style scoped>
.virtual-keyboard {
  /* Avoid properties inheritance */
  all: initial;
  /* Override required attributes */
  position: absolute;
  display: flex;
  /* Arbitrary z-index */
  z-index: 99999;
  min-width: 20rem;
}
.virtual-keyboard > section {
  /* reset style in order to use Pure CSS framework only */
  all: unset;
  width: 100%;
  background-color: white;
  border: solid #bfbfbf 1px;
  border-radius: 0.25rem;
}
.virtual-keyboard .header {
  border-bottom: solid #bfbfbf 1px;
  height: 2rem;
}
.virtual-keyboard .content {
  padding: 0.25rem;
}
</style>