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

class App extends Component {
	constructor() {//{{{
		super()
		this.websocket_uri = `ws://localhost:1371/ws`
		this.websocket = null
		this.websocket_int_ping = null
		this.websocket_int_reconnect = null
		this.wsConnect()
		this.wsLoop()

		this.session = new Session(this)
		this.session.initialize()
		this.login = createRef()
		this.tree = null
		this.nodeUI = createRef()
		this.nodeModified = signal(false)

		this.startNode = null

		this.setStartNode()
	}//}}}
	render() {//{{{
		if(!this.session.initialized) {
			return html`<div>Validating session</div>`
		}
 
		if(!this.session.authenticated()) {
			return html`<${Login} ref=${this.login} />`
		}

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

	wsLoop() {//{{{
		setInterval(()=>{
			if(this.websocket === null) {
				console.log("wsLoop connect")
				this.wsConnect()
			}
		}, 1000)
	}//}}}
	wsConnect() {//{{{
		this.websocket = new WebSocket(this.websocket_uri)
		this.websocket.onopen    = evt=>this.wsOpen(evt)
		this.websocket.onmessage = evt=>this.wsMessage(evt)
		this.websocket.onerror   = evt=>this.wsError(evt)
		this.websocket.onclose   = evt=>this.wsClose(evt)
	}//}}}
	wsOpen() {//{{{
		this.setState({ wsConnected: true })

		// A ping interval to implement a rudimentary keep-alive.
	}//}}}
	wsClose() {//{{{
		console.log("Lost connection to Notes server")
		this.websocket = null
	}//}}}
	wsError(evt) {//{{{
		console.log("websocket error", evt)
		this.websocket = null;
	}//}}}
	wsMessage(evt) {//{{{
		let msg = JSON.parse(evt.data)

		// Broadcast message
		if(msg.ID == '') {
			this.broadcastHandler(msg)
		} else {
			this.msgHandler(msg)
		}
	}//}}}

	responseError({comm, app, upload}) {//{{{
		if(comm !== undefined) {
			comm.text().then(body=>alert(body))
			return
		}

		if(app !== undefined && app.hasOwnProperty('Error')) {
			alert(app.Error)
			return
		}

		if(app !== undefined) {
			alert(JSON.stringify(app))
		}

		if(upload !== undefined) {
			alert(upload)
			return
		}
	}//}}}
	async request(url, params) {//{{{
		return new Promise((resolve, reject)=>{
			let headers = {
				'Content-Type': 'application/json',
			}

			if(this.session.UUID !== '')
				headers['X-Session-Id'] = this.session.UUID

			fetch(url, {
				method: 'POST',
				headers,
				body: JSON.stringify(params),
			})
			.then(response=>{
				// A HTTP communication level error occured
				if(!response.ok || response.status !=  200)
					return reject({comm: response})
				return response.json()
			})
			.then(json=>{
				// An application level error occured
				if(!json.OK) {
					return reject({app: json})
				}
				return resolve(json)
			})
			.catch(err=>reject({comm: err}))
		})
	}//}}}

	broadcastHandler(msg) {//{{{
		switch(msg.Op) {
			case 'css_reload':
				refreshCSS()
				break;
		}
	}//}}}
	setStartNode() {//{{{
		let urlParams = new URLSearchParams(window.location.search)
		let nodeID = urlParams.get('node')
		this.startNode = new Node(this, nodeID ? parseInt(nodeID) : 0)
	}//}}}
}

class Login extends Component {
	constructor() {//{{{
		super()
		this.authentication_failed = signal(false)
		this.state = {
			username: '',
			password: '',
		}
	}//}}}
	render({}, { username, password }) {//{{{
		let authentication_failed = html``;
		if(this.authentication_failed.value)
			authentication_failed = html`<div class="auth-failed">Authentication failed</div>`;

		return html`
		<div id="login">
			<h1>Notes</h1>
			<input id="username" type="text"     placeholder="Username" value=${username} oninput=${evt=>this.setState({ username: evt.target.value})} onkeydown=${evt=>{ if(evt.code == 'Enter') this.login() }} />
			<input id="password" type="password" placeholder="Password" value=${password} oninput=${evt=>this.setState({ password: evt.target.value})} onkeydown=${evt=>{ if(evt.code == 'Enter') this.login() }} />
			<button onclick=${()=>this.login()}>Login</button>
			${authentication_failed}
		</div>
		`
	}//}}}
	componentDidMount() {//{{{
		document.getElementById('username').focus()
	}//}}}

	login() {//{{{
		let username = document.getElementById('username').value
		let password = document.getElementById('password').value
		window._app.current.session.authenticate(username, password)
	}//}}}
}

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

		this.props.app.tree = this

		this.props.app.request('/node/tree', { StartNodeID: 0 })
		.then(res=>{
			//  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.
			res.Nodes.forEach(nodeData=>{
				let node = new Node(
					this,
					nodeData.ID,
				)
				node.Children = []
				node.Crumbs   = []
				node.Files    = []
				node.Level    = nodeData.Level
				node.Name     = nodeData.Name
				node.ParentID = nodeData.ParentID
				node.Updated  = nodeData.Updated
				node.UserID   = nodeData.UserID

				this.treeNodes[node.ID] = node

				if(node.ParentID == 0)
					this.treeTrunk.push(node)
				else if(this.treeNodes[node.ParentID] !== undefined)
					this.treeNodes[node.ParentID].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.
			this.crumbsUpdateNodes()
			this.forceUpdate()

		})
		.catch(this.responseError)
	}//}}}
	render({ app }) {//{{{
		let renderedTreeTrunk = this.treeTrunk.map(node=>{
			this.treeNodeComponents[node.ID] = createRef()
			return html`<${TreeNode} key=${"treenode_"+node.ID} tree=${this} node=${node} ref=${this.treeNodeComponents[node.ID]} selected=${node.ID == app.startNode.ID} />`
		})
		return html`<div id="tree">${renderedTreeTrunk}</div>`
	}//}}}

	setSelected(node) {//{{{
		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
	}//}}}
	crumbsUpdateNodes(node) {//{{{
		this.props.app.startNode.Crumbs.forEach(crumb=>{
			// Start node is loaded before the tree.
			let node = this.treeNodes[crumb.ID]
			if(node)
				node._expanded = true

			// Tree is done before the start node.
			let 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)
	}//}}}
}

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

		let children = node.Children.map(node=>{
			tree.treeNodeComponents[node.ID] = createRef()
			return html`<${TreeNode} key=${"treenode_"+node.ID} tree=${tree} node=${node} ref=${tree.treeNodeComponents[node.ID]} selected=${node.ID == tree.props.app.startNode.ID} />`
		})

		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" />`
		}


		let 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._app.current.nodeUI.current.goToNode(node.ID)}>${node.Name}</div>
				<div class="children ${node.Children.length > 0 && this.expanded.value ? 'expanded' : 'collapsed'}">${children}</div>
			</div>`
	}//}}}
}

// Init{{{
window._app = createRef()
window._resourceModels = []
render(html`<${App} ref=${window._app} />`, document.getElementById('app'))
//}}}

// vim: foldmethod=marker