feat: better regex matching for trigger

src/trigger.ts

@@ -1,17 +1,93 @@
-const triggerRegex = /\((.*?)\)/g
+/**
+ * Matches single square bracket pair [] or parahtheses (), but not a double square bracket pair [[]]
+ * (?<!\[)     # Negative lookbehind to make sure there is no second [
+ * \[]         # Matches [] 
+ * (?![\]\(])  # Negative lookahead to make sure there is no second closing ] from wiki link or opening ( from a markdown link
+ * |           # OR
+ * (?<!\])     # Negative lookbehind to make sure there is no closing ] from a markdown link
+ * \(\)        # Matches ()
+ */
+const emptyRegex = /(?<!\[)\[](?![\]\(])|(?<!\])\(\)/g
 
+/**
+ * Maches single square brackets or parantheses with some text in them
+ * and captures the text
+ * If the brackets start a wiki link or markdown link, they are ignored
+ * but links inside another layer of brackets are returned:
+ * 
+ * (
+ *   (?<=^\(|\s\()   # Pattern for parantheses
+ *     .+?:{0,2}.*?
+ *   (?=\)$|\)\s)
+ *   |
+ *   (?<=^\[|\s\[)   # Pattern for square brackets
+ *     .+?:{0,2}.*?
+ *   (?=\]$|\]\s)
+ * )
+ */
+const filledRegex = /((?<=^\(|\s\().+?:{0,2}.*?(?=\)$|\)\s)|(?<=^\[|\s\[).+?:{0,2}.*?(?=\]$|\]\s))/g
+
+/**
+ * Finds the dataview metadata field the user is currently inside.
+ * It returns [text, start, end] where text is the text inside the field,
+ * and start and end are the cursor positions of the start and end of the field.
+ * If the user is not inside a field, it returns null.
+ */
 export function getTriggerText(line: string, cursorPos: number): [string, number, number] | null {
-    triggerRegex.lastIndex = 0  // resetting global regex
-    
-    let match = null
-    while ((match = triggerRegex.exec(line)) !== null) {
-        const cursorInMatch = cursorPos > match.index && cursorPos <= match.index + match[1].length + 1
-
-        if (cursorInMatch) {
-            return [match[1], match.index+1, match.index + match[1].length + 1]
-        }
+    // Check for empty [] or ().
+    // If the user starts typing with no text in the field, this is the fastest way to find it.
+    let match = getEmptyTrigger(line, cursorPos)
+    if (match) {
+        return match
+    }
 
+    // If the user types inside an existing field, this is the function to find it.
+    match = getTriggerTextFromRegex(line, cursorPos, filledRegex)
+    if (match !== null) {
+        return match
     }
     return null
+}
 
-}
+/**
+ * Matches an empty [] or empty (), but not [[]]
+ * Has its own function since there is no capture group resulting in a different index calculation
+ */
+function getEmptyTrigger(line: string, cursorPos: number): [string, number, number] | null {
+    let matches = Array.from(line.matchAll(emptyRegex))
+    for (const match of matches) {
+        if (match.index === undefined) {
+            continue
+        }
+
+        if (cursorPos === match.index+1) {
+            return ["", match.index+1, match.index+1]
+        }
+    }
+    return null
+}
+
+/**
+ * Given a regex with a capture group, a line of text, and the users cursor position,
+ * this function finds the match of the regex in the line that the user is currently inside.
+ * If the user is inside the capture group, returns [text, start, end] where text is the text inside the match,
+ * start is the position of the start of the match, and end is the position of the end of the match.
+ * Otherwise, returns null.
+ */
+function getTriggerTextFromRegex(line: string, cursorPos: number, regex: RegExp): [string, number, number] | null {
+    let matches = Array.from(line.matchAll(regex))
+    for (const match of matches) {
+        if (match.index === undefined) {
+            continue
+        }
+
+        const matchStart = match!.index
+        const matchEnd = matchStart + match[1].length
+        const cursorInMatch = cursorPos >= matchStart && cursorPos <= matchEnd
+
+        if (cursorInMatch) {
+            return [match[1], matchStart, matchEnd]
+        }
+    }
+    return null
+}