1 files changed, 149 insertions, 0 deletions
diff --git a/src/util/text.js b/src/util/text.js
new file mode 100644
index 000000000..f1b7f245a
--- /dev/null
+++ b/src/util/text.js
@@ -0,0 +1,149 @@
+/*
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import {curry} from 'ramda'
+import {fromString} from 'html-to-text'
+
+/**
+ * @type {Text}
+ */
+class Text {
+	constructor(format, value) {
+		this.format = format
+		this.value = value
+	}
+
+	/**
+	 * @param {Text} other
+	 * @return {Text}
+	 */
+	append(other) {
+		if (this.format !== other.format) {
+			throw new Error("can't append two different formats")
+		}
+
+		return new Text(this.format, this.value + other.value)
+	}
+}
+
+/**
+ * @param {string} format
+ * @param {string} value
+ *
+ * @return {object}
+ */
+const wrap = curry((format, value) => {
+	return new Text(format, value)
+})
+
+/**
+ * @param {string} value
+ * @return {Text}
+ */
+export const plain = wrap('plain')
+
+/**
+ * @function
+ * @param {string} value
+ * @return {Text}
+ */
+export const html = wrap('html')
+
+export const detect = (str) => {
+	if (!str.includes('>')) {
+		return plain(str)
+	} else {
+		return html(str)
+	}
+}
+
+/**
+ * @function
+ * @param {string} format
+ * @param {Text} text
+ */
+const isFormat = curry((format, text) => {
+	return text.format === format
+})
+
+/**
+ * @function
+ * @param {Text} text
+ * @return {bool}
+ */
+export const isPlain = isFormat('plain')
+
+/**
+ * @function
+ * @param {Text} text
+ * @return {bool}
+ */
+export const isHtml = isFormat('html')
+
+/**
+ * @param {Text} text
+ * @return {Text}
+ */
+export const toPlain = (text) => {
+	if (text.format === 'plain') {
+		return text
+	}
+	const withBlockBreaks = text.value.replace(/<\/div>/gi, '</div><br>')
+
+	const converted = fromString(withBlockBreaks, {
+		noLinkBrackets: true,
+		ignoreHref: true,
+		ignoreImage: true,
+		wordwrap: false,
+		format: {
+			blockquote: function (element, fn, options) {
+				return fn(element.children, options)
+					.replace(/\n\n\n/g, '\n\n') // remove triple line breaks
+					.replace(/^/gm, '> ') // add > quotation to each line
+			},
+			paragraph: function (element, fn, options) {
+				return fn(element.children, options) + '\n\n'
+			},
+		},
+	})
+
+	return plain(
+		converted
+			.replace(/\n\n\n/g, '\n\n') // remove triple line breaks
+			.replace(/^[\n\r]+/g, '') // trim line breaks at beginning and end
+			.replace(/ $/gm, '') // trim white space at end of each line
+	)
+}
+
+/**
+ * @param {Text} text
+ * @return {Text}
+ */
+export const toHtml = (text) => {
+	if (text.format === 'html') {
+		return text
+	}
+	if (text.format === 'plain') {
+		return html(text.value.replace(/([^>\r\n]?)(\r\n|\n\r|\r|\n)/g, '$1<br>$2'))
+	}
+
+	throw new Error(`Unknown format ${text.format}`)
+}