import {LitElement, html, unsafeHTML} from './lit-all.min.js';
import * as tfutils from './tf-utils.js';
import * as tfrpc from '/static/tfrpc.js';
import {styles} from './tf-styles.js';
import Tribute from './tribute.esm.js';

class TfComposeElement extends LitElement {
	static get properties() {
		return {
			whoami: {type: String},
			users: {type: Object},
			root: {type: String},
			branch: {type: String},
			mentions: {type: Object},
			apps: {type: Object},
			drafts: {type: Object},
		}
	}

	static styles = styles;

	constructor() {
		super();
		this.users = {};
		this.root = undefined;
		this.branch = undefined;
		this.mentions = {};
		this.apps = undefined;
		this.drafts = {};
	}

	process_text(text) {
		if (!text) {
			return '';
		}
		/* Update mentions. */
		for (let match of text.matchAll(/\[([^\[]+)]\(([@&%][^\)]+)/g)) {
			let name = match[1];
			let link = match[2];
			let balance = 0;
			let bracket_end = match.index + match[1].length + '[]'.length - 1;
			for (let i = bracket_end; i >= 0; i--) {
				if (text.charAt(i) == ']') {
					balance++;
				} else if (text.charAt(i) == '[') {
					balance--;
				}
				if (balance <= 0) {
					name = text.substring(i + 1, bracket_end);
					break;
				}
			}
			if (!this.mentions[link]) {
				this.mentions[link] = {
					link: link,
				}
			}
			this.mentions[link].name = name.startsWith('@') ? name.substring(1) : name;
			this.mentions = Object.assign({}, this.mentions);
		}
		return tfutils.markdown(text);
	}

	input(event) {
		let edit = this.renderRoot.getElementById('edit');
		let preview = this.renderRoot.getElementById('preview');
		preview.innerHTML = this.process_text(edit.value);
	}

	change(event) {
		let edit = this.renderRoot.getElementById('edit');
		this.dispatchEvent(new CustomEvent('tf-draft', {bubbles: true, composed: true, detail: {id: this.branch, draft: edit.value}}));
	}

	convert_to_format(buffer, type, mime_type) {
		return new Promise(function(resolve, reject) {
			let img = new Image();
			img.onload = function() {
				let canvas = document.createElement('canvas');
				let width_scale = Math.min(img.width, 1024) / img.width;
				let height_scale = Math.min(img.height, 1024) / img.height;
				let scale = Math.min(width_scale, height_scale);
				canvas.width = img.width * scale;
				canvas.height = img.height * scale;
				let context = canvas.getContext('2d');
				context.drawImage(img, 0, 0, canvas.width, canvas.height);
				let data_url = canvas.toDataURL(mime_type);
				let result = atob(data_url.split(',')[1]).split('').map(x => x.charCodeAt(0));
				resolve(result);
			}
			img.onerror = function(event) {
				reject(new Error('Failed to load image.'));
			};
			let raw = Array.from(new Uint8Array(buffer)).map(b => String.fromCharCode(b)).join('');
			let original = `data:${type};base64,${btoa(raw)}`;
			img.src = original;
		});
	}

	async add_file(file) {
		try {
			let self = this;
			let buffer = await file.arrayBuffer();
			let type = file.type;
			if (type.startsWith('image/')) {
				let best_buffer;
				let best_type;
				for (let format of ['image/png', 'image/jpeg', 'image/webp']) {
					let test_buffer = await self.convert_to_format(buffer, file.type, format);
					if (!best_buffer || test_buffer.length < best_buffer.length) {
						best_buffer = test_buffer;
						best_type = format;
					}
				}
				buffer = best_buffer;
				type = best_type;
			} else {
				buffer = Array.from(new Uint8Array(buffer));
			}
			let id = await tfrpc.rpc.store_blob(buffer);
			let name = type.split('/')[0] + ':' + file.name;
			self.mentions[id] = {
				link: id,
				name: name,
				type: type,
				size: buffer.length ?? buffer.byteLength,
			};
			self.mentions = Object.assign({}, self.mentions);
			let edit = self.renderRoot.getElementById('edit');
			edit.value += `\n![${name}](${id})`;
			self.change();
		} catch(e) {
			alert(e?.message);
		}
	}

	paste(event) {
		let self = this;
		for (let item of event.clipboardData.items) {
			if (item.type?.startsWith('image/')) {
				let file = item.getAsFile();
				if (!file) {
					continue;
				}
				self.add_file(file);
				break;
			}
		}
	}

	submit() {
		let self = this;
		let edit = this.renderRoot.getElementById('edit');
		let message = {
			type: 'post',
			text: edit.value,
		};
		if (this.root || this.branch) {
			message.root = this.root;
			message.branch = this.branch;
		}
		if (Object.values(this.mentions).length) {
			message.mentions = Object.values(this.mentions);
		}
		console.log('Would post:', message);
		tfrpc.rpc.appendMessage(this.whoami, message).then(function() {
			edit.value = '';
			self.mentions = {};
			self.change();
			this.dispatchEvent(new CustomEvent('tf-draft', {detail: {id: this.branch, discard: undefined}}));
		}).catch(function(error) {
			alert(error.message);
		});
	}

	discard() {
		let edit = this.renderRoot.getElementById('edit');
		edit.value = '';
		this.change();
		this.dispatchEvent(new CustomEvent('tf-draft', {bubble: true, composed: true, detail: {id: this.branch, discard: undefined}}));
	}

	attach() {
		let self = this;
		let edit = this.renderRoot.getElementById('edit');
		let input = document.createElement('input');
		input.type = 'file';
		input.onchange = function(event) {
			let file = event.target.files[0];
			self.add_file(file);
		};
		input.click();
	}

	firstUpdated() {
		let tribute = new Tribute({
			values: Object.entries(this.users).map(x => ({key: x[1].name, value: x[0]})),
			selectTemplate: function(item) {
				return `[@${item.original.key}](${item.original.value})`;
			},
		});
		tribute.attach(this.renderRoot.getElementById('edit'));
	}

	remove_mention(id) {
		delete this.mentions[id];
		this.mentions = Object.assign({}, this.mentions);
	}

	render_mention(mention) {
		let self = this;
		return html`
			<div>
				<pre style="white-space: pre-wrap">${JSON.stringify(mention, null, 2)}</pre>
				<input type="button" value="x" @click=${() => self.remove_mention(mention.link)}></input>
			</div>`;
	}

	render_attach_app() {
		let self = this;

		async function attach_selected_app() {
			let name = self.renderRoot.getElementById('select').value;
			let id = self.apps[name];
			let mentions = {};
			mentions[id] = {
				name: name,
				link: id,
				type: 'application/tildefriends',
			};
			if (name && id) {
				let app = JSON.parse(await tfrpc.rpc.get_blob(id));
				for (let entry of Object.entries(app.files)) {
					mentions[entry[1]] = {
						name: entry[0],
						link: entry[1],
					};
				}
			}
			this.mentions = Object.assign(this.mentions || {}, mentions);
			this.apps = null;
		}

		if (this.apps) {
			return html`
				<div>
					<select id="select">
						${Object.keys(self.apps).map(app => html`<option value=${app}>${app}</option>`)}
					</select>
					<input type="button" value="Attach" @click=${attach_selected_app}></input>
					<input type="button" value="Cancel" @click=${() => this.apps = null}></input>
				</div>
				`;
		}
	}

	render_attach_app_button() {
		async function attach_app() {
			this.apps = await tfrpc.rpc.apps();
		}
		if (!this.apps) {
			return html`<input type="button" value="Attach App" @click=${attach_app}></input>`
		} else {
			return html`<input type="button" value="Discard App" @click=${() => this.apps = null}></input>`
		}
	}

	render() {
		let self = this;
		let result = html`
			<div style="display: flex; flex-direction: row; width: 100%">
				<textarea id="edit" @input=${this.input} @change=${this.change} @paste=${this.paste} style="flex: 1 0 50%">${this.drafts[this.branch || '']}</textarea>
				<div id="preview" style="flex: 1 0 50%"></div>
			</div>
			${Object.values(this.mentions).map(x => self.render_mention(x))}
			${this.render_attach_app()}
			<input type="button" value="Submit" @click=${this.submit}></input>
			<input type="button" value="Attach" @click=${this.attach}></input>
			${this.render_attach_app_button()}
			<input type="button" value="Discard" @click=${this.discard}></input>
		`;
		return result;
	}
}

customElements.define('tf-compose', TfComposeElement);