import { ref, onMounted, onUnmounted } from 'vue'
import { onResize } from '@dcloudio/uni-app'

export type PageLayout = {
	pageStyle: () => string,
	contentStyle: (offset: number, minimum: boolean) => string,
	statusStyle: (offset: number) => string,
	navigationStyle: () => string,
	navigationTitleStyle: () => string,
	navigationActionStyle: (headerHeight: number) => string,
	navigationBrandStyle: (headerHeight: number) => string,
	bottomStyle: (padding: number) => string
}

// 原生渲染不支持 vh/calc，统一以窗口尺寸计算，并随旋转更新。
export function usePageLayout(): PageLayout {
	const windowInfo = ref(uni.getWindowInfo())
	const capsuleLeft = ref(-1)
	const capsuleTop = ref(0)
	const capsuleHeight = ref(0)
	const readCapsule = () => {
		// #ifdef MP-WEIXIN
		try {
			const capsule = uni.getMenuButtonBoundingClientRect()
			const valid = capsule.width > 0 && capsule.height > 0 && capsule.left > 0 && capsule.left < windowInfo.value.windowWidth
			capsuleLeft.value = valid ? capsule.left : -1
			capsuleTop.value = valid ? capsule.top : 0
			capsuleHeight.value = valid ? capsule.height : 0
		} catch (_error) { capsuleLeft.value = -1; capsuleTop.value = 0; capsuleHeight.value = 0 }
		// #endif
	}
	readCapsule()
	const refresh = () => { windowInfo.value = uni.getWindowInfo(); readCapsule() }
	onMounted(() => refresh())
	// #ifdef APP
	onResize((_options) => { refresh() })
	// #endif
	// #ifndef APP
	const handleResize = (_options: OnWindowResizeCallbackResult) => { refresh() }
	uni.onWindowResize(handleResize)
	onUnmounted(() => { uni.offWindowResize(handleResize) })
	// #endif
	const rpx = (value: number): number => value * windowInfo.value.windowWidth / 750
	const status = (): number => Math.max(windowInfo.value.statusBarHeight ?? 0, windowInfo.value.safeAreaInsets?.top ?? 0)
	const navigationStyle = (): string => {
		// 只在微信端横向避让胶囊，保持业务导航原有高度。
		// #ifdef MP-WEIXIN
		const reserved = capsuleLeft.value > 0 ? windowInfo.value.windowWidth - capsuleLeft.value + 8 : 104
		return 'padding-right:' + reserved + 'px;'
		// #endif
		// #ifndef MP-WEIXIN
		return ''
		// #endif
	}
	const navigationTitleStyle = (): string => {
		// 标题左右使用相同留白，以屏幕中心对齐，同时避开微信胶囊。
		// #ifdef MP-WEIXIN
		const reserved = capsuleLeft.value > 0 ? windowInfo.value.windowWidth - capsuleLeft.value + 8 : 104
		const inset = Math.max(rpx(112), reserved)
		return 'left:' + inset + 'px;right:' + inset + 'px;'
		// #endif
		// #ifndef MP-WEIXIN
		return ''
		// #endif
	}
	const navigationActionStyle = (headerHeight: number): string => {
		// 微信通知按钮与系统胶囊等高、顶部对齐；App 保持导航行内居中。
		// #ifdef MP-WEIXIN
		const size = capsuleHeight.value > 0 ? capsuleHeight.value : 32
		const top = capsuleHeight.value > 0 ? Math.max(0, capsuleTop.value - status()) : Math.max(0, (rpx(headerHeight) - size) / 2)
		const right = capsuleLeft.value > 0 ? windowInfo.value.windowWidth - capsuleLeft.value + 8 : 104
		return 'position:absolute;top:' + top + 'px;right:' + right + 'px;width:' + size + 'px;height:' + size + 'px;'
		// #endif
		// #ifndef MP-WEIXIN
		return ''
		// #endif
	}
	const navigationBrandStyle = (headerHeight: number): string => {
		// Logo 保留自身比例，与胶囊共享垂直中心，不改变登录页和启动页的 Logo。
		// #ifdef MP-WEIXIN
		const height = rpx(68)
		const center = capsuleHeight.value > 0 ? capsuleTop.value - status() + capsuleHeight.value / 2 : rpx(headerHeight) / 2
		return 'align-self:flex-start;margin-top:' + Math.max(0, center - height / 2) + 'px;height:' + height + 'px;'
		// #endif
		// #ifndef MP-WEIXIN
		return ''
		// #endif
	}
	const pageStyle = (): string => 'min-height:' + windowInfo.value.windowHeight + 'px;'
	const contentStyle = (offset: number, minimum: boolean): string => {
		// #ifdef WEB
		return (minimum ? 'min-height:' : 'height:') + 'calc(100vh - ' + status() + 'px - ' + offset + 'rpx);'
		// #endif
		// #ifndef WEB
		const height = Math.max(0, windowInfo.value.windowHeight - status() - rpx(offset))
		return (minimum ? 'min-height:' : 'height:') + height + 'px;'
		// #endif
	}
	const statusStyle = (offset: number): string => 'height:' + (status() + rpx(offset)) + 'px;'
	const bottomStyle = (padding: number): string => 'padding-bottom:' + (rpx(padding) + (windowInfo.value.safeAreaInsets?.bottom ?? 0)) + 'px;'
	return { pageStyle, contentStyle, statusStyle, navigationStyle, navigationTitleStyle, navigationActionStyle, navigationBrandStyle, bottomStyle }
}