'use strict'

function call(method, params) {
	// TODO: Make it apparent when results result in errors:
	//  - With responseType == "json", m.request() always expects JSON,
	//    and error.message is null if it fails, but we can handle it manually.
	//  - Go can wrap all errors into trivial strings before writing.
	return m.request({
		method: "POST",
		url: `/api/${method}`,
		body: params,
	})
}

const loading = (window.location.hostname !== 'localhost') ? 'lazy' : undefined

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

let BrowseModel = {
	path: undefined,
	subdirectories: [],
	entries: [],
	collator: new Intl.Collator(undefined, {numeric: true}),

	async reload(path) {
		if (this.path !== path) {
			this.path = path
			this.subdirectories = []
			this.entries = []
		}

		let resp = await call('browse', {path: path})
		this.subdirectories = resp.subdirectories
		this.entries = resp.entries.sort((a, b) =>
			this.collator.compare(a.name, b.name))
	},

	joinPath(parent, child) {
		if (!parent)
			return child
		if (!child)
			return parent
		return `${parent}/${child}`
	},

	getBrowseLinks() {
		if (this.path === undefined)
			return []

		let links = [{name: "Root", path: "", level: -1}], path
		for (const crumb of this.path.split('/').filter(s => !!s)) {
			path = this.joinPath(path, crumb)
			links.push({name: crumb, path: path, level: -1})
		}

		links[links.length - 1].level = 0

		for (const sub of this.subdirectories) {
			links.push(
				{name: sub, path: this.joinPath(this.path, sub), level: +1})
		}
		return links
	},
}

let BrowseBarLink = {
	view(vnode) {
		const link = vnode.attrs.link

		let c = 'selected'
		if (link.level < 0)
			c = 'parent'
		if (link.level > 0)
			c = 'child'

		return m('li', {
			class: c,
		}, m(m.route.Link, {
			href: `/browse/:key`,
			params: {key: link.path},
		}, link.name))
	},
}

let BrowseView = {
	// So that Page Up/Down, etc., work after changing directories.
	// Programmatically focusing a scrollable element requires setting tabindex,
	// and causes :focus-visible on page load, which we suppress in CSS.
	// I wish there was another way, but the workaround isn't particularly bad.
	// focus({focusVisible: true}) is FF 104+ only and experimental.
	oncreate(vnode) { vnode.dom.focus() },

	view(vnode) {
		return m('.browser[tabindex=0]', {
			// Trying to force the oncreate on path changes.
			key: BrowseModel.path,
		}, BrowseModel.entries.map(e => {
			return m(m.route.Link, {href: `/view/${e.sha1}`},
				m('img.thumbnail', {src: `/thumb/${e.sha1}`,
					width: e.thumbW, height: e.thumbH, title: e.name, loading}))
		}))
	},
}

let Browse = {
	// Reload the model immediately, to improve responsivity.
	// But we don't need to: https://mithril.js.org/route.html#preloading-data
	// Also see: https://mithril.js.org/route.html#route-cancellation--blocking
	oninit(vnode) {
		let path = vnode.attrs.key || ""
		BrowseModel.reload(path)
	},

	view(vnode) {
		return m('.container', {}, [
			m('.header', {}, "Browser"),
			m('.body', {}, [
				m('ul.sidebar', BrowseModel.getBrowseLinks().map(link =>
					m(BrowseBarLink, {link}))),
				m(BrowseView),
			]),
		])
	},
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

let ViewModel = {
	sha1: undefined,
	width: 0,
	height: 0,
	paths: [],
	tags: {},

	async reload(sha1) {
		if (this.sha1 !== sha1) {
			this.sha1 = sha1
			this.width = this.height = 0
			this.paths = []
			this.tags = {}
		}

		let resp = await call('info', {sha1: sha1})
		this.width = resp.width
		this.height = resp.height
		this.paths = resp.paths
		this.tags = resp.tags
	},
}

let ViewBarBrowseLink = {
	view(vnode) {
		return m(m.route.Link, {
			href: `/browse/:key`,
			params: {key: vnode.attrs.path},
		}, vnode.attrs.name)
	},
}

let ViewBarPath = {
	view(vnode) {
		const parents = vnode.attrs.path.split('/')
		const basename = parents.pop()

		let result = [], path
		if (!parents.length)
			result.push(m(ViewBarBrowseLink, {path: "", name: "Root"}), "/")
		for (const crumb of parents) {
			path = BrowseModel.joinPath(path, crumb)
			result.push(m(ViewBarBrowseLink, {path, name: crumb}), "/")
		}
		result.push(basename)
		return result
	},
}

let ViewBar = {
	view(vnode) {
		return m('.viewbar', [
			m('h2', "Locations"),
			m('ul', ViewModel.paths.map(path =>
				m('li', m(ViewBarPath, {path})))),
			m('h2', "Tags"),
			Object.entries(ViewModel.tags).map(([group, tags]) => [
				m("h3", group),
				m("ul.tags", Object.entries(tags)
					.sort(([t1, w1], [t2, w2]) => (w2 - w1))
					.map(([tag, weight]) => m("li", [
						m("meter[max=1.0]",
							{value: weight, title: weight}, weight),
						` ${tag}`,
					]))),
			]),
		])
	},
}

let View = {
	oninit(vnode) {
		let sha1 = vnode.attrs.key || ""
		ViewModel.reload(sha1)
	},

	view(vnode) {
		const view = m('.view', [
			ViewModel.sha1 !== undefined
				? m('img', {src: `/image/${ViewModel.sha1}`,
					width: ViewModel.width, height: ViewModel.height})
				: "No image.",
		])
		return m('.container', {}, [
			m('.header', {}, [
				"View",
				m(m.route.Link, {
					href: `/similar/:key`,
					params: {key: ViewModel.sha1},
				}, "Similar"),
			]),
			m('.body', {}, [view, m(ViewBar)]),
		])
	},
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

let SimilarModel = {
	sha1: undefined,
	info: {paths: []},
	groups: {},

	async reload(sha1) {
		if (this.sha1 !== sha1) {
			this.sha1 = sha1
			this.info = {paths: []}
			this.groups = {}
		}

		let resp = await call('similar', {sha1: sha1})
		this.info = resp.info
		this.groups = resp.groups
	},
}

let SimilarThumbnail = {
	view(vnode) {
		const info = vnode.attrs.info
		return m(m.route.Link, {href: `/view/${info.sha1}`},
			m('img.thumbnail', {src: `/thumb/${info.sha1}`,
				width: info.thumbW, height: info.thumbH, loading}))
	},
}

let SimilarGroup = {
	view(vnode) {
		const images = vnode.attrs.images
		let result = [
			m('h2', vnode.attrs.name),
			images.map(info => m('.row', [
				m(SimilarThumbnail, {info}),
				m('ul', [
					m('li', Math.round(info.pixelsRatio * 100) +
						"% pixels of input image"),
					info.paths.map(path =>
						m('li', m(ViewBarPath, {path}))),
				]),
			]))
		]
		if (!images.length)
			result.push("No matches.")
		return result
	},
}

let SimilarList = {
	view(vnode) {
		if (SimilarModel.sha1 === undefined ||
			SimilarModel.info.paths.length == 0)
			return "No image"

		const info = SimilarModel.info
		return m('.similar', {}, [
			m('.row', [
				m(SimilarThumbnail, {info}),
				m('ul', info.paths.map(path =>
					m('li', m(ViewBarPath, {path})))),
			]),
			Object.entries(SimilarModel.groups).map(([name, images]) =>
				m(SimilarGroup, {name, images})),
		])
	},
}

let Similar = {
	oninit(vnode) {
		let sha1 = vnode.attrs.key || ""
		SimilarModel.reload(sha1)
	},

	view(vnode) {
		return m('.container', {}, [
			m('.header', {}, [
				"Similarity search",
				m(m.route.Link, {
					href: `/view/:key`,
					params: {key: SimilarModel.sha1},
				}, "View"),
			]),
			m('.body', {}, m(SimilarList)),
		])
	},
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

let DuplicatesModel = {
	entries: [],

	async reload() {
		this.entries = await call('duplicates', {})
	},
}

let DuplicatesThumbnail = {
	view(vnode) {
		const info = vnode.attrs.info
		return [
			m(m.route.Link, {href: `/similar/${info.sha1}`},
				m('img.thumbnail', {src: `/thumb/${info.sha1}`,
					width: info.thumbW, height: info.thumbH, loading})),
			(info.occurences != 1) ? ` ×${info.occurences}` : [],
		]
	},
}

let DuplicatesList = {
	// See BrowseView.
	oncreate(vnode) { vnode.dom.focus() },

	view(vnode) {
		let children = (DuplicatesModel.entries.length == 0)
			? "No duplicates"
			: DuplicatesModel.entries.map(group =>
				m('.row', group.map(entry =>
					m(DuplicatesThumbnail, {info: entry}))))
		return m('.duplicates[tabindex=0]', {}, children)
	},
}

let Duplicates = {
	oninit(vnode) {
		DuplicatesModel.reload()
	},

	view(vnode) {
		return m('.container', {}, [
			m('.header', {}, [
				"Duplicates",
			]),
			m('.body', {}, m(DuplicatesList)),
		])
	},
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

window.addEventListener('load', () => {
	m.route(document.body, "/browse/", {
		// The path doesn't need to be escaped, perhaps change that (":key...").
		"/browse/": Browse,
		"/browse/:key": Browse,
		"/view/:key": View,
		"/similar/:key": Similar,
		"/duplicates": Duplicates,

		"/tags": undefined,
		"/tags/:space": undefined,
		"/tags/:space/:tag": undefined,
	})
})