rte: fix history

src/ComposerHistoryManager.js

@@ -0,0 +1,63 @@
+//@flow
+
+import {ContentState} from 'draft-js';
+import * as RichText from './RichText';
+import Markdown from './Markdown';
+import _flow from 'lodash/flow';
+import _clamp from 'lodash/clamp';
+
+type MessageFormat = 'html' | 'markdown';
+
+class HistoryItem {
+    message: string = '';
+    format: MessageFormat = 'html';
+
+    constructor(message: string, format: MessageFormat) {
+        this.message = message;
+        this.format = format;
+    }
+
+    toContentState(format: MessageFormat): ContentState {
+        let {message} = this;
+        if (format === 'markdown') {
+            if (this.format === 'html') {
+                message = _flow([RichText.HTMLtoContentState, RichText.stateToMarkdown])(message);
+            }
+            return ContentState.createFromText(message);
+        } else {
+            if (this.format === 'markdown') {
+                message = new Markdown(message).toHTML();
+            }
+            return RichText.HTMLtoContentState(message);
+        }
+    }
+}
+
+export default class ComposerHistoryManager {
+    history: Array<HistoryItem> = [];
+    prefix: string;
+    lastIndex: number = 0;
+    currentIndex: number = -1;
+
+    constructor(roomId: string, prefix: string = 'mx_composer_history_') {
+        this.prefix = prefix + roomId;
+
+        // TODO: Performance issues?
+        for(; sessionStorage.getItem(`${this.prefix}[${this.lastIndex}]`); this.lastIndex++, this.currentIndex++) {
+            history.push(JSON.parse(sessionStorage.getItem(`${this.prefix}[${this.lastIndex}]`)));
+        }
+    }
+
+    addItem(message: string, format: MessageFormat) {
+        const item = new HistoryItem(message, format);
+        this.history.push(item);
+        this.currentIndex = this.lastIndex;
+        sessionStorage.setItem(`${this.prefix}[${this.lastIndex++}]`, JSON.stringify(item));
+    }
+
+    getItem(offset: number, format: MessageFormat): ?ContentState {
+        this.currentIndex = _clamp(this.currentIndex + offset, 0, this.lastIndex - 1);
+        const item = this.history[this.currentIndex];
+        return item ? item.toContentState(format) : null;
+    }
+}