<template>
  <h2 ref="containerRef" :class="`overflow-hidden ${containerClassName}`">
    <span :class="`inline-block text-center leading-relaxed font-black ${textClassName}`" style="font-size: clamp(1.6rem, 8vw, 10rem);">
      <span
        v-for="(char, index) in splitText"
        :key="index"
        class="inline-block char"
      >
        {{ char === " " ? "\u00A0" : char }}
      </span>
    </span>
  </h2>
</template>

<script setup lang="ts">
import { ref, computed, onMounted, onUnmounted, watch } from 'vue';
import { gsap } from 'gsap';
import { ScrollTrigger } from 'gsap/ScrollTrigger';

gsap.registerPlugin(ScrollTrigger);

interface Props {
  children: string;
  scrollContainerRef?: { current: HTMLElement | null };
  containerClassName?: string;
  textClassName?: string;
  animationDuration?: number;
  ease?: string;
  scrollStart?: string;
  scrollEnd?: string;
  stagger?: number;
}

const props = withDefaults(defineProps<Props>(), {
  containerClassName: '',
  textClassName: '',
  animationDuration: 1,
  ease: 'back.inOut(2)',
  scrollStart: 'center bottom+=50%',
  scrollEnd: 'bottom bottom-=40%',
  stagger: 0.03
});

const containerRef = ref<HTMLElement | null>(null);
let scrollTriggerInstance: ScrollTrigger | null = null;

const splitText = computed(() => {
  const text = typeof props.children === 'string' ? props.children : '';
  return text.split("");
});

const initializeAnimation = () => {
  const el = containerRef.value;
  if (!el) return;

  const scroller =
    props.scrollContainerRef && props.scrollContainerRef.current
      ? props.scrollContainerRef.current
      : window;

  const charElements = el.querySelectorAll('.char');

  if (scrollTriggerInstance) {
    scrollTriggerInstance.kill();
  }

  const tl = gsap.fromTo(
    charElements,
    {
      willChange: 'opacity, transform',
      opacity: 0,
      yPercent: 120,
      scaleY: 2.3,
      scaleX: 0.7,
      transformOrigin: '50% 0%'
    },
    {
      duration: props.animationDuration,
      ease: props.ease,
      opacity: 1,
      yPercent: 0,
      scaleY: 1,
      scaleX: 1,
      stagger: props.stagger,
      scrollTrigger: {
        trigger: el,
        scroller,
        start: props.scrollStart,
        end: props.scrollEnd,
        scrub: true
      }
    }
  );

  scrollTriggerInstance = tl.scrollTrigger || null;
};

onMounted(() => {
  initializeAnimation();
});

onUnmounted(() => {
  if (scrollTriggerInstance) {
    scrollTriggerInstance.kill();
  }
});

watch(
  [
    () => props.children,
    () => props.scrollContainerRef,
    () => props.animationDuration,
    () => props.ease,
    () => props.scrollStart,
    () => props.scrollEnd,
    () => props.stagger
  ],
  () => {
    initializeAnimation();
  },
  { deep: true }
);
</script>