<template>
	<div class="timctyfi" :class="{ disabled, easing }">
		<div class="label"><slot name="label"></slot></div>
		<div v-adaptive-border class="body">
			<div ref="containerEl" class="container">
				<div class="track">
					<div
						class="highlight"
						:style="{ width: steppedRawValue * 100 + '%' }"
					></div>
				</div>
				<div v-if="steps && showTicks" class="ticks">
					<div
						v-for="i in steps + 1"
						class="tick"
						:style="{ left: ((i - 1) / steps) * 100 + '%' }"
					></div>
				</div>
				<div
					ref="thumbEl"
					v-tooltip="textConverter(finalValue)"
					class="thumb"
					:style="{ left: thumbPosition + 'px' }"
					@mousedown="onMousedown"
					@touchstart="onMousedown"
				></div>
			</div>
		</div>
		<div class="caption"><slot name="caption"></slot></div>
	</div>
</template>

<script lang="ts" setup>
import {
	computed,
	defineAsyncComponent,
	onMounted,
	onUnmounted,
	ref,
	watch,
} from "vue";
import * as os from "@/os";

const props = withDefaults(
	defineProps<{
		modelValue: number;
		disabled?: boolean;
		min: number;
		max: number;
		step?: number;
		textConverter?: (value: number) => string;
		showTicks?: boolean;
		easing?: boolean;
	}>(),
	{
		step: 1,
		textConverter: (v) => v.toString(),
		easing: false,
	}
);

const emit = defineEmits<{
	(ev: "update:modelValue", value: number): void;
}>();

const containerEl = ref<HTMLElement>();
const thumbEl = ref<HTMLElement>();

const rawValue = ref((props.modelValue - props.min) / (props.max - props.min));
const steppedRawValue = computed(() => {
	if (props.step) {
		const step = props.step / (props.max - props.min);
		return step * Math.round(rawValue.value / step);
	} else {
		return rawValue.value;
	}
});
const finalValue = computed(() => {
	if (Number.isInteger(props.step)) {
		return Math.round(
			steppedRawValue.value * (props.max - props.min) + props.min
		);
	} else {
		return steppedRawValue.value * (props.max - props.min) + props.min;
	}
});

const thumbWidth = computed(() => {
	if (thumbEl.value == null) return 0;
	return thumbEl.value!.offsetWidth;
});
const thumbPosition = ref(0);
const calcThumbPosition = () => {
	if (containerEl.value == null) {
		thumbPosition.value = 0;
	} else {
		thumbPosition.value =
			(containerEl.value.offsetWidth - thumbWidth.value) *
			steppedRawValue.value;
	}
};
watch([steppedRawValue, containerEl], calcThumbPosition);

let ro: ResizeObserver | undefined;

onMounted(() => {
	ro = new ResizeObserver((entries, observer) => {
		calcThumbPosition();
	});
	ro.observe(containerEl.value);
});

onUnmounted(() => {
	if (ro) ro.disconnect();
});

const steps = computed(() => {
	if (props.step) {
		return (props.max - props.min) / props.step;
	} else {
		return 0;
	}
});

const onMousedown = (ev: MouseEvent | TouchEvent) => {
	ev.preventDefault();

	const tooltipShowing = ref(true);
	os.popup(
		defineAsyncComponent(() => import("@/components/MkTooltip.vue")),
		{
			showing: tooltipShowing,
			text: computed(() => {
				return props.textConverter(finalValue.value);
			}),
			targetElement: thumbEl,
		},
		{},
		"closed"
	);

	const style = document.createElement("style");
	style.appendChild(
		document.createTextNode(
			"* { cursor: grabbing !important; } body * { pointer-events: none !important; }"
		)
	);
	document.head.appendChild(style);

	const onDrag = (ev: MouseEvent | TouchEvent) => {
		ev.preventDefault();
		const containerRect = containerEl.value!.getBoundingClientRect();
		const pointerX =
			ev.touches && ev.touches.length > 0
				? ev.touches[0].clientX
				: ev.clientX;
		const pointerPositionOnContainer =
			pointerX - (containerRect.left + thumbWidth.value / 2);
		rawValue.value = Math.min(
			1,
			Math.max(
				0,
				pointerPositionOnContainer /
					(containerEl.value!.offsetWidth - thumbWidth.value)
			)
		);
	};

	let beforeValue = finalValue.value;

	const onMouseup = () => {
		document.head.removeChild(style);
		tooltipShowing.value = false;
		window.removeEventListener("mousemove", onDrag);
		window.removeEventListener("touchmove", onDrag);
		window.removeEventListener("mouseup", onMouseup);
		window.removeEventListener("touchend", onMouseup);

		// 値が変わってたら通知
		if (beforeValue !== finalValue.value) {
			emit("update:modelValue", finalValue.value);
		}
	};

	window.addEventListener("mousemove", onDrag);
	window.addEventListener("touchmove", onDrag);
	window.addEventListener("mouseup", onMouseup, { once: true });
	window.addEventListener("touchend", onMouseup, { once: true });
};
</script>

<style lang="scss" scoped>
@use "sass:math";

.timctyfi {
	position: relative;

	> .label {
		font-size: 0.85em;
		padding: 0 0 8px 0;
		user-select: none;

		&:empty {
			display: none;
		}
	}

	> .caption {
		font-size: 0.85em;
		padding: 8px 0 0 0;
		color: var(--fgTransparentWeak);

		&:empty {
			display: none;
		}
	}

	$thumbHeight: 20px;
	$thumbWidth: 20px;

	> .body {
		padding: 10px 12px;
		background: var(--panel);
		border: solid 1px var(--panel);
		border-radius: 6px;

		> .container {
			position: relative;
			height: $thumbHeight;

			> .track {
				position: absolute;
				top: 0;
				bottom: 0;
				left: 0;
				right: 0;
				margin: auto;
				width: calc(100% - #{$thumbWidth});
				height: 3px;
				background: rgba(0, 0, 0, 0.1);
				border-radius: 999px;
				overflow: clip;

				> .highlight {
					position: absolute;
					top: 0;
					left: 0;
					height: 100%;
					background: var(--accent);
					opacity: 0.5;
				}
			}

			> .ticks {
				$tickWidth: 3px;

				position: absolute;
				top: 0;
				bottom: 0;
				left: 0;
				right: 0;
				margin: auto;
				width: calc(100% - #{$thumbWidth});

				> .tick {
					position: absolute;
					bottom: 0;
					width: $tickWidth;
					height: 3px;
					margin-left: math.div($tickWidth, 2);
					background: var(--divider);
					border-radius: 999px;
				}
			}

			> .thumb {
				position: absolute;
				width: $thumbWidth;
				height: $thumbHeight;
				cursor: grab;
				background: var(--accent);
				border-radius: 999px;

				&:hover {
					background: var(--accentLighten);
				}
			}
		}
	}

	&.easing {
		> .body {
			> .container {
				> .track {
					> .highlight {
						transition: width 0.2s cubic-bezier(0, 0, 0, 1);
					}
				}

				> .thumb {
					transition: left 0.2s cubic-bezier(0, 0, 0, 1);
				}
			}
		}
	}
}
</style>