Autocomplete Cross-Link

script

// Autocomplete [[cross-links]]
// by Matt Gemmell - @mattgemmell - https://mattgemmell.com/
// 
// Type "[[" then at least 2 characters (by default) before invoking this action.
// Requires Drafts 20.1 or later.


// ===========================


var chooseBestMatch = false; // If false, user is asked to choose between multiple matching titles.


var minimumQueryLength = 2; // Must type at least this number of characters after the "[[" opening delimiter or we won't search.


var excludeCurrentDraft = true; // If true, the draft currently being edited will be excluded as a candidate for autocompletion of cross-links. This avoids the situation where autocompleting a cross-link within the first line (i.e. the title) of a draft will always include the draft itself in the list of suggestions.


// ===========================


function minRange(theRange) {
	// Returns index of start of theRange.
	return theRange[0];
}

function maxRange(theRange) {
	// Returns index immediately AFTER end of theRange.
	return theRange[0] + theRange[1];
}

function editorTextInRange(editor, range) {
	// Returns editor's text in the given range.
	return editor.getTextInRange(range[0], range[1]);
}

function getTitle(theDraft) {
	return theDraft.displayTitle;
}

function getUUID(theDraft) {
	return theDraft.uuid;
}


// Grab entire line(s) of text which contain the selection.
var selectedLineRange = editor.getSelectedLineRange();
var selectedLines = editorTextInRange(editor, selectedLineRange);

// If selection spans more than one line, abort.
var newLineIndex = selectedLines.indexOf("\n");
if (newLineIndex !== -1 && newLineIndex!== selectedLines.length - 1) { // i.e. Just a trailing newline.
	app.displayInfoMessage("Doesn't work with multi-line selections.");
	
} else {
	var selRange = editor.getSelectedRange();
	selRange[0] -= selectedLineRange[0]; // Normalise to be line-relative.
	var partialTitle = null;
	var partialTitleRange = null;
	var openingDelimiter = "[[";
	
	if (selRange[1] > 0) {
		// There's a selection. Assume it's the partial title to be autocompleted.
		partialTitle = editorTextInRange(selRange);
		partialTitleRange = selRange;
		if (partialTitle.indexOf(openingDelimiter) == 0) {
			// Trim delimiter.
			partialTitle = partialTitle.slice(openingDelimiter.length);
			partialTitleRange[0] += openingDelimiter.length;
			partialTitleRange[1] -= openingDelimiter.length;
		}
		
	} else {
		// No selection. Try to find opening link-delimiters "[[" to left of insertion point.
	
		// Limit the amount of text we're searching for the closest match to a reasonable length.
		var searchRadius = 250; // Num chars around selection/insertion to search.
		
		var searchRange = [0, selectedLines.length]; // Entire line.
		if (minRange(selRange) > searchRadius) {
			// Move beginning of searchRange to within searchRadius of selRange's start.
			searchRange[0] = minRange(selRange) - searchRadius;
			searchRange[1] -= searchRange[0];
		}
		// Move end of searchRange to beginning of selRange (i.e. just behind the insertion point).
		var delta = maxRange(searchRange) - minRange(selRange);
		searchRange[1] -= delta;
		var searchText = selectedLines.substring(minRange(searchRange), maxRange(searchRange));
		
		// Find rightmost occurrence of openingDelimiter within searchText.
		var foundIndex = searchText.lastIndexOf(openingDelimiter);
		if (foundIndex != -1) {
			partialTitle = searchText.slice(foundIndex + openingDelimiter.length);
			partialTitleRange = selRange;
			partialTitleRange[0] -= partialTitle.length;
			partialTitleRange[1] = partialTitle.length;
		}
	}
	
	if (partialTitle != null) {
		// Check that partialTitle is long enough to be worth searching for.
		if (partialTitle.length < minimumQueryLength) {
			app.displayInfoMessage("Please type at least " + minimumQueryLength + " characters for autocompletion.");
			
		} else {
			// Search for matching drafts.
			partialTitle = partialTitle.trim();
			var chosenDraft = null;
			var foundDrafts = Draft.queryByTitle(partialTitle);
			
			// Eliminate current draft from results.
			if (excludeCurrentDraft && foundDrafts.length > 0) {
				var foundUUIDs = foundDrafts.map(getUUID);
				var index = foundUUIDs.indexOf(draft.uuid);
				if (index > -1) {
					foundDrafts.splice(index, 1); // modifies in place
				}
			}
			
			if (foundDrafts.length > 0) {
				// We found at least one match.
				if (foundDrafts.length == 1 || chooseBestMatch) {
					// Use the first/only match.
					chosenDraft = foundDrafts[0];
					
				} else {
					// Choose one of the matching drafts.
					var draftTitles = foundDrafts.map(getTitle);
					
					var prompt = Prompt.create();
					prompt.isCancellable = true;
					prompt.title = "Link to which draft?";
					prompt.addButton("Insert Link");
					prompt.addSelect("select", "", draftTitles, [draftTitles[0]], false);
					var didSelect = prompt.show();
					
					var chosenDraftTitle = prompt.fieldValues["select"][0];
					if (didSelect) {
						var draftIndex = draftTitles.indexOf(chosenDraftTitle);
						chosenDraft = foundDrafts[draftIndex];
						
					} else {
						if (!editor.isActive) {
							editor.activate();
						}
					}
				}
				
				if (chosenDraft != null) {
					// We don't insert the opening delimiter because it's already there.
					var linkToInsert = chosenDraft.displayTitle + "]]";
					
					// Insert link, either replacing selection or relevant text before insertion point.
					partialTitleRange[0] += selectedLineRange[0]; // make document-relative
					
					editor.setSelectedRange(partialTitleRange[0], partialTitleRange[1]);
					editor.setSelectedText(linkToInsert); // avoid the setTextInRange() scrolling bug
					//editor.setTextInRange(partialTitleRange[0], partialTitleRange[1], linkToInsert);
					
					editor.setSelectedRange(minRange(partialTitleRange) + linkToInsert.length, 0);
					
					editor.save();
					draft.update();
					if (!editor.isActive) {
						editor.activate();
					}
					
				}
			} else {
				app.displayInfoMessage("No matching drafts found.");
			}
		}
		
	} else {
		app.displayInfoMessage("Couldn't find start of link ( [[ ).");
	}
	
}