Add annotation manager in rendition

src/annotations.js

@@ -0,0 +1,205 @@
+// Manage annotations for a book?
+
+/*
+let a = rendition.annotations.highlight(cfiRange, data)
+
+a.on("added", () => console.log("added"))
+a.on("removed", () => console.log("removed"))
+a.on("clicked", () => console.log("clicked"))
+
+a.update(data)
+a.remove();
+a.text();
+
+rendition.annotations.show()
+rendition.annotations.hide()
+
+rendition.annotations.highlights.show()
+rendition.annotations.highlights.hide()
+*/
+
+import EventEmitter from "event-emitter";
+import EpubCFI from "./epubcfi";
+
+/**
+	* Handles managing adding & removing Annotations
+	* @class
+	*/
+class Annotations {
+
+	constructor (rendition) {
+		this.rendition = rendition;
+		this.highlights = [];
+		this.underlines = [];
+		this.marks = [];
+		this._annotations = {};
+		this._annotationsBySectionIndex = {};
+
+		this.rendition.hooks.content.register(this.inject.bind(this));
+		this.rendition.hooks.unloaded.register(this.clear.bind(this));
+	}
+
+	add (type, cfiRange, data, cb) {
+		let hash = encodeURI(cfiRange);
+		let cfi = new EpubCFI(cfiRange);
+		let sectionIndex = cfi.spinePos;
+		let annotation = new Annotation({
+			type,
+			cfiRange,
+			data,
+			sectionIndex,
+			cb
+		});
+
+		this._annotations[hash] = annotation;
+
+		if (sectionIndex in this._annotationsBySectionIndex) {
+			this._annotationsBySectionIndex[sectionIndex].push(hash);
+		} else {
+			this._annotationsBySectionIndex[sectionIndex] = [hash];
+		}
+
+		let contents = this.rendition.getContents();
+		contents.forEach( (content) => {
+			if (annotation.sectionIndex === content.sectionIndex) {
+				annotation.attach(content);
+			}
+		});
+
+		return annotation;
+	}
+
+	remove (cfiRange) {
+		let hash = decodeURI(cfiRange);
+		let result;
+		if (hash in this._annotations) {
+			let annotation = this._annotations[hash];
+
+			let contents = this.rendition.getContents();
+			contents.forEach( (content) => {
+				if (annotation.sectionIndex === content.sectionIndex) {
+					annotation.detach(content);
+				}
+			});
+
+			delete this._annotations[hash];
+		}
+		return result;
+	}
+
+	highlight (cfiRange, data, cb) {
+		this.add("highlight", cfiRange, data, cb);
+	}
+
+	underline (cfiRange, data, cb) {
+		this.add("underline", cfiRange, data, cb);
+	}
+
+	mark (cfiRange, data, cb) {
+		this.add("mark", cfiRange, data, cb);
+	}
+
+	each () {
+		return this._annotations.forEach.apply(this._annotations, arguments);
+	}
+
+	inject (contents) {
+		let sectionIndex = contents.index;
+		if (sectionIndex in this._annotationsBySectionIndex) {
+			let annotations = this._annotationsBySectionIndex[sectionIndex];
+			annotations.forEach((hash) => {
+				let annotation = this._annotations[hash];
+				annotation.attach(contents);
+			});
+		}
+	}
+
+	clear (contents) {
+		let sectionIndex = contents.index;
+		if (sectionIndex in this._annotationsBySectionIndex) {
+			let annotations = this._annotationsBySectionIndex[sectionIndex];
+			annotations.forEach((hash) => {
+				let annotation = this._annotations[hash];
+				annotation.detach(contents);
+			});
+		}
+	}
+
+	show () {
+
+	}
+
+	hide () {
+
+	}
+
+}
+
+class Annotation {
+
+	constructor ({
+		type,
+		cfiRange,
+		data,
+		sectionIndex
+	}) {
+		this.type = type;
+		this.cfiRange = cfiRange;
+		this.data = data;
+		this.sectionIndex = sectionIndex;
+		this.mark = undefined;
+	}
+
+	update (data) {
+		this.data = data;
+	}
+
+	attach (contents) {
+		let {cfiRange, data, type, mark, cb} = this;
+		let result;
+		/*
+		if (mark) {
+			return; // already added
+		}
+		*/
+		if (type === "highlight") {
+			result = contents.highlight(cfiRange, data, cb);
+		} else if (type === "underline") {
+			result = contents.underline(cfiRange, data, cb);
+		} else if (type === "mark") {
+			result = contents.mark(cfiRange, data, cb);
+		}
+
+		this.mark = result;
+
+		return result;
+	}
+
+	detach (contents) {
+		let {cfiRange, type} = this;
+
+		if (contents) {
+			if (type === "highlight") {
+				result = contents.unhighlight(cfiRange);
+			} else if (type === "underline") {
+				result = contents.ununderline(cfiRange);
+			} else if (type === "mark") {
+				result = contents.unmark(cfiRange);
+			}
+		}
+
+		this.mark = undefined;
+
+		return result;
+	}
+
+	text () {
+		// TODO: needs implementation in contents
+	}
+
+}
+
+EventEmitter(Annotation.prototype);
+
+
+export default Annotations