<template>
<transition :name="$store.state.animation ? 'popup-menu' : ''" appear @after-leave="onClosed" @enter="$emit('opening')" @after-enter="childRendered">
	<div v-show="manualShowing != null ? manualShowing : showing" class="ccczpooj" :class="{ front, fixed, top: position === 'top' }" ref="content" :style="{ pointerEvents: (manualShowing != null ? manualShowing : showing) ? 'auto' : 'none', '--transformOrigin': transformOrigin }">
		<slot></slot>
	</div>
</transition>
</template>

<script lang="ts">
import { defineComponent, PropType } from 'vue';

function getFixedContainer(el: Element | null): Element | null {
	if (el == null || el.tagName === 'BODY') return null;
	const position = window.getComputedStyle(el).getPropertyValue('position');
	if (position === 'fixed') {
		return el;
	} else {
		return getFixedContainer(el.parentElement);
	}
}

export default defineComponent({
	props: {
		manualShowing: {
			type: Boolean,
			required: false,
			default: null,
		},
		srcCenter: {
			type: Boolean,
			required: false
		},
		src: {
			type: Object as PropType<HTMLElement>,
			required: false,
		},
		position: {
			required: false
		},
		front: {
			type: Boolean,
			required: false,
			default: false,
		}
	},

	emits: ['opening', 'click', 'esc', 'close', 'closed'],

	data() {
		return {
			showing: true,
			fixed: false,
			transformOrigin: 'center',
			contentClicking: false,
		};
	},

	mounted() {
		this.$watch('src', () => {
			if (this.src) {
				// eslint-disable-next-line vue/no-mutating-props
				this.src.style.pointerEvents = 'none';
			}
			this.fixed = getFixedContainer(this.src) != null;
			this.$nextTick(() => {
				this.align();
			});
		}, { immediate: true });

		this.$nextTick(() => {
			const popover = this.$refs.content as any;
			new ResizeObserver((entries, observer) => {
				this.align();
			}).observe(popover);
		});

		document.addEventListener('mousedown', this.onDocumentClick, { passive: true });
	},

	beforeUnmount() {
		document.removeEventListener('mousedown', this.onDocumentClick);
	},

	methods: {
		align() {
			if (this.src == null) return;

			const popover = this.$refs.content as any;

			if (popover == null) return;

			const rect = this.src.getBoundingClientRect();
			
			const width = popover.offsetWidth;
			const height = popover.offsetHeight;

			let left;
			let top;

			if (this.srcCenter) {
				const x = rect.left + (this.fixed ? 0 : window.pageXOffset) + (this.src.offsetWidth / 2);
				const y = rect.top + (this.fixed ? 0 : window.pageYOffset) + (this.src.offsetHeight / 2);
				left = (x - (width / 2));
				top = (y - (height / 2));
			} else {
				const x = rect.left + (this.fixed ? 0 : window.pageXOffset) + (this.src.offsetWidth / 2);
				const y = rect.top + (this.fixed ? 0 : window.pageYOffset) + this.src.offsetHeight;
				left = (x - (width / 2));
				top = y;
			}

			if (this.fixed) {
				if (left + width > window.innerWidth) {
					left = window.innerWidth - width;
				}

				if (top + height > window.innerHeight) {
					top = window.innerHeight - height;
				}
			} else {
				if (left + width - window.pageXOffset > window.innerWidth) {
					left = window.innerWidth - width + window.pageXOffset - 1;
				}

				if (top + height - window.pageYOffset > window.innerHeight) {
					top = window.innerHeight - height + window.pageYOffset - 1;
				}
			}

			if (top < 0) {
				top = 0;
			}

			if (left < 0) {
				left = 0;
			}

			if (top > rect.top + (this.fixed ? 0 : window.pageYOffset)) {
				this.transformOrigin = 'center top';
			} else {
				this.transformOrigin = 'center';
			}

			popover.style.left = left + 'px';
			popover.style.top = top + 'px';
		},

		childRendered() {
			// モーダルコンテンツにマウスボタンが押され、コンテンツ外でマウスボタンが離されたときにモーダルバックグラウンドクリックと判定させないためにマウスイベントを監視しフラグ管理する
			const content = this.$refs.content.children[0];
			content.addEventListener('mousedown', e => {
				this.contentClicking = true;
				window.addEventListener('mouseup', e => {
					// click イベントより先に mouseup イベントが発生するかもしれないのでちょっと待つ
					setTimeout(() => {
						this.contentClicking = false;
					}, 100);
				}, { passive: true, once: true });
			}, { passive: true });
		},

		close() {
			// eslint-disable-next-line vue/no-mutating-props
			if (this.src) this.src.style.pointerEvents = 'auto';
			this.showing = false;
			this.$emit('close');
		},

		onClosed() {
			this.$emit('closed');
		},

		onDocumentClick(ev) {
			const flyoutElement = this.$refs.content;
			let targetElement = ev.target;
			do {
				if (targetElement === flyoutElement) {
					return;
				}
				targetElement = targetElement.parentNode;
			} while (targetElement);
			this.close();
		}
	}
});
</script>

<style lang="scss" scoped>
.popup-menu-enter-active {
	transform-origin: var(--transformOrigin);
	transition: opacity 0.2s cubic-bezier(0, 0, 0.2, 1), transform 0.2s cubic-bezier(0, 0, 0.2, 1) !important;
}
.popup-menu-leave-active {
	transform-origin: var(--transformOrigin);
	transition: opacity 0.2s cubic-bezier(0.4, 0, 1, 1), transform 0.2s cubic-bezier(0.4, 0, 1, 1) !important;
}
.popup-menu-enter-from, .popup-menu-leave-to {
	pointer-events: none;
	opacity: 0;
	transform: scale(0.9);
}

.ccczpooj {
	position: absolute;
	z-index: 10000;

	&.fixed {
		position: fixed;
	}

	&.front {
		z-index: 20000;
	}
}
</style>
