<script lang="ts">
import type { LIGHT_DARK_MODE } from "@/types/config.ts";
import { AUTO_MODE, DARK_MODE, LIGHT_MODE } from "@constants/constants.ts";
import I18nKey from "@i18n/i18nKey";
import { i18n } from "@i18n/translation";
import Icon from "@iconify/svelte";
import {
  applyThemeToDocument,
  getStoredTheme,
  setTheme,
} from "@utils/setting-utils.ts";
import { onMount } from "svelte";

const seq: LIGHT_DARK_MODE[] = [LIGHT_MODE, DARK_MODE, AUTO_MODE];
let mode: LIGHT_DARK_MODE = AUTO_MODE;

onMount(() => {
  mode = getStoredTheme();
  const darkModePreference = window.matchMedia("(prefers-color-scheme: dark)");
  const changeThemeWhenSchemeChanged: Parameters<
    typeof darkModePreference.addEventListener<"change">
  >[1] = e => {
    applyThemeToDocument(mode);
  };
  darkModePreference.addEventListener("change", changeThemeWhenSchemeChanged);
  return () => {
    darkModePreference.removeEventListener(
      "change",
      changeThemeWhenSchemeChanged,
    );
  };
});

function switchScheme(newMode: LIGHT_DARK_MODE) {
  mode = newMode;
  setTheme(newMode);
}

function toggleScheme() {
  let i = 0;
  for (; i < seq.length; i++) {
    if (seq[i] === mode) {
      break;
    }
  }
  switchScheme(seq[(i + 1) % seq.length]);
}

function showPanel() {
  const panel = document.querySelector("#light-dark-panel");
  panel?.classList.remove("float-panel-closed");
}

function hidePanel() {
  const panel = document.querySelector("#light-dark-panel");
  panel?.classList.add("float-panel-closed");
}
</script>

<!-- z-50 make the panel higher than other float panels -->
<div class="relative z-50" role="menu" tabindex="-1" on:mouseleave={hidePanel}>
    <button aria-label="Light/Dark Mode" role="menuitem" class="relative btn-plain scale-animation rounded-lg h-11 w-11 active:scale-90" id="scheme-switch" on:click={toggleScheme} on:mouseenter={showPanel}>
        <div class="absolute" class:opacity-0={mode !== LIGHT_MODE}>
            <Icon icon="material-symbols:wb-sunny-outline-rounded" class="text-[1.25rem]"></Icon>
        </div>
        <div class="absolute" class:opacity-0={mode !== DARK_MODE}>
            <Icon icon="material-symbols:dark-mode-outline-rounded" class="text-[1.25rem]"></Icon>
        </div>
        <div class="absolute" class:opacity-0={mode !== AUTO_MODE}>
            <Icon icon="material-symbols:radio-button-partial-outline" class="text-[1.25rem]"></Icon>
        </div>
    </button>

    <div id="light-dark-panel" class="hidden lg:block absolute transition float-panel-closed top-11 -right-2 pt-5" >
        <div class="card-base float-panel p-2">
            <button class="flex transition whitespace-nowrap items-center justify-start w-full btn-plain scale-animation rounded-lg h-9 px-3 font-medium active:scale-95 mb-0.5"
                    class:current-theme-btn={mode === LIGHT_MODE}
                    on:click={() => switchScheme(LIGHT_MODE)}
            >
                <Icon icon="material-symbols:wb-sunny-outline-rounded" class="text-[1.25rem] mr-3"></Icon>
                {i18n(I18nKey.lightMode)}
            </button>
            <button class="flex transition whitespace-nowrap items-center justify-start w-full btn-plain scale-animation rounded-lg h-9 px-3 font-medium active:scale-95 mb-0.5"
                    class:current-theme-btn={mode === DARK_MODE}
                    on:click={() => switchScheme(DARK_MODE)}
            >
                <Icon icon="material-symbols:dark-mode-outline-rounded" class="text-[1.25rem] mr-3"></Icon>
                {i18n(I18nKey.darkMode)}
            </button>
            <button class="flex transition whitespace-nowrap items-center justify-start w-full btn-plain scale-animation rounded-lg h-9 px-3 font-medium active:scale-95"
                    class:current-theme-btn={mode === AUTO_MODE}
                    on:click={() => switchScheme(AUTO_MODE)}
            >
                <Icon icon="material-symbols:radio-button-partial-outline" class="text-[1.25rem] mr-3"></Icon>
                {i18n(I18nKey.systemMode)}
            </button>
        </div>
    </div>
</div>

<style lang="css">
.current-setting {
    background: var(--btn-plain-bg-hover);
    color: var(--primary);
}
</style>