import { h, Component, createRef } from 'preact'
import { signal } from 'preact/signals'
import htm from 'htm'
import { Node, NodeUI } from 'node'
import { ROOT_NODE } from 'node_store'
const html = htm.bind(h)

export class Notes2 extends Component {
	state = {
		startNode: null,
	}
	constructor() {//{{{
		super()
		this.tree = createRef()
		this.nodeUI = createRef()

		this.getStartNode()
	}//}}}
	render({}, { startNode }) {//{{{
		if (startNode === null)
			return

		return html`
			<${Tree} ref=${this.tree} app=${this} startNode=${startNode} />

			<div id="nodeui">
				<${NodeUI} app=${this} ref=${this.nodeUI} startNode=${startNode} />
			</div>
		`
	}//}}}
	getStartNode() {//{{{
		let nodeUUID = ROOT_NODE

		// Is a UUID provided on the URI as an anchor?
		const parts = document.URL.split('#')
		if (parts[1]?.match(/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i))
			nodeUUID = parts[1]

		nodeStore.get(nodeUUID).then(node => {
			this.setState({ startNode: node })
		})
	}//}}}
	goToNode(nodeUUID, dontPush) {//{{{
		// Don't switch notes until saved.
		if (this.nodeUI.current.nodeModified.value) {
			if (!confirm("Changes not saved. Do you want to discard changes?"))
				return
		}

		if (!dontPush)
			history.pushState({ nodeUUID }, '', `/notes2#${nodeUUID}`)

		// New node is fetched in order to retrieve content and files.
		// Such data is unnecessary to transfer for tree/navigational purposes.
		nodeStore.get(nodeUUID).then(node => {
			this.nodeUI.current.setNode(node)
			//this.showPage('node')
		})
	}//}}}
	logout() {//{{{
		localStorage.removeItem('session.UUID')
		location.href = '/'
	}//}}}
}

class Tree extends Component {
	constructor(props) {//{{{
		super(props)
		this.treeNodes = {}
		this.treeNodeComponents = {}
		this.treeTrunk = []
		this.selectedTreeNode = null
		this.props.app.tree = this

		this.populateFirstLevel()
	}//}}}
	render({ app }) {//{{{
		const renderedTreeTrunk = this.treeTrunk.map(node => {
			this.treeNodeComponents[node.UUID] = createRef()
			return html`<${TreeNode} key=${`treenode_${node.UUID}`} tree=${this} node=${node} ref=${this.treeNodeComponents[node.UUID]} selected=${node.UUID === app.startNode?.UUID} />`
		})
		return html`
			<div id="tree">
				<div id="logo"><img src="/images/${_VERSION}/logo.svg" /></div>
				${renderedTreeTrunk}
			</div>`
	}//}}}

	populateFirstLevel(callback = null) {//{{{
		nodeStore.getTreeNodes('', 0)
			.then(async res => {
				res.sort(Node.sort)

				this.treeNodes = {}
				this.treeNodeComponents = {}
				this.treeTrunk = []
				this.selectedTreeNode = null

				//  A tree of nodes is built. This requires the list of nodes
				//  returned from the server to be sorted in such a way that
				//  a parent node always appears before a child node.
				//  The server uses a recursive SQL query delivering this.
				for (const node of res) {
					this.treeNodes[node.UUID] = node

					if (node.ParentUUID === '')
						this.treeTrunk.push(node)
					else if (this.treeNodes[node.ParentUUD] !== undefined)
						this.treeNodes[node.ParentUUID].Children.push(node)
				}
				// When starting with an explicit node value, expanding all nodes
				// on its path gives the user a sense of location. Not necessarily working
				// as the start node isn't guaranteed to have returned data yet.
				// XXX this.crumbsUpdateNodes()
				this.forceUpdate()

				if (callback)
					callback()

			})
			.catch(e => { console.log(e); console.log(e.type, e.error); alert(e.error) })
	}//}}}
	setSelected(node) {//{{{
		return // TODO
		if (this.selectedTreeNode)
			this.selectedTreeNode.selected.value = false

		this.selectedTreeNode = this.treeNodeComponents[node.ID].current
		this.selectedTreeNode.selected.value = true
		this.selectedTreeNode.expanded.value = true
		this.expandToTrunk(node.ID)
	}//}}}
	crumbsUpdateNodes(node) {//{{{
		console.log('crumbs', this.props.app.startNode.Crumbs)
		for (const crumb in this.props.app.startNode.Crumbs) {
			// Start node is loaded before the tree.
			const node = this.treeNodes[crumb.ID]
			if (node)
				node._expanded = true

			// Tree is done before the start node.
			const component = this.treeNodeComponents[crumb.ID]
			if (component?.component.current)
				component.current.expanded.value = true
		}

		// Will be undefined when called from tree initialization
		// (as tree nodes aren't rendered yet)
		if (node !== undefined)
			this.setSelected(node)
	}//}}}
	expandToTrunk(nodeUUID) {//{{{
		let node = this.treeNodes[nodeUUID]
		if (node === undefined)
			return

		node = this.treeNodes[node.ParentUUID]
		while (node !== undefined) {
			this.treeNodeComponents[node.UUID].current.expanded.value = true
			node = this.treeNodes[node.ParentUUID]
		}
	}//}}}
}

class TreeNode extends Component {
	constructor(props) {//{{{
		super(props)
		this.selected = signal(props.selected)
		this.expanded = signal(this.props.node._expanded)

		this.children_populated = signal(false)
		if (this.props.node.Level === 0)
			this.fetchChildren()
	}//}}}
	render({ tree, node, parent }) {//{{{
		// Fetch the next level of children if the parent tree node is expanded and our children thus will be visible.
		if (!this.children_populated.value && parent?.expanded.value)
			this.fetchChildren()

		const children = node.Children.map(node => {
			tree.treeNodeComponents[node.UUID] = createRef()
			return html`<${TreeNode} key=${`treenode_${node.UUID}`} tree=${tree} node=${node} parent=${this} ref=${tree.treeNodeComponents[node.UUID]} selected=${node.UUID === tree.props.app.startNode?.UUID} />`
		})

		let expandImg = ''
		if (node.Children.length === 0)
			expandImg = html`<img src="/images/${window._VERSION}/leaf.svg" />`
		else {
			if (this.expanded.value)
				expandImg = html`<img src="/images/${window._VERSION}/expanded.svg" />`
			else
				expandImg = html`<img src="/images/${window._VERSION}/collapsed.svg" />`
		}

		const selected = (this.selected.value ? 'selected' : '')

		return html`
			<div class="node">
				<div class="expand-toggle" onclick=${() => { this.expanded.value ^= true }}>${expandImg}</div>
				<div class="name ${selected}" onclick=${() => window._notes2.current.goToNode(node.UUID)}>${node.Name}</div>
				<div class="children ${node.Children.length > 0 && this.expanded.value ? 'expanded' : 'collapsed'}">${children}</div>
			</div>`
	}//}}}
	fetchChildren() {//{{{
		this.props.node.fetchChildren().then(() => {
			this.children_populated.value = true
		})
	}//}}}
}

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