feat(hashline-edit): add anchor insert modes and strict insert validation

src/tools/hashline-edit/edit-text-normalization.ts

@@ -0,0 +1,109 @@
+const HASHLINE_PREFIX_RE = /^\s*(?:>>>|>>)?\s*\d+#[A-Z]{2}:/
+const DIFF_PLUS_RE = /^[+-](?![+-])/
+
+function equalsIgnoringWhitespace(a: string, b: string): boolean {
+  if (a === b) return true
+  return a.replace(/\s+/g, "") === b.replace(/\s+/g, "")
+}
+
+function leadingWhitespace(text: string): string {
+  const match = text.match(/^\s*/)
+  return match ? match[0] : ""
+}
+
+export function stripLinePrefixes(lines: string[]): string[] {
+  let hashPrefixCount = 0
+  let diffPlusCount = 0
+  let nonEmpty = 0
+
+  for (const line of lines) {
+    if (line.length === 0) continue
+    nonEmpty += 1
+    if (HASHLINE_PREFIX_RE.test(line)) hashPrefixCount += 1
+    if (DIFF_PLUS_RE.test(line)) diffPlusCount += 1
+  }
+
+  if (nonEmpty === 0) {
+    return lines
+  }
+
+  const stripHash = hashPrefixCount > 0 && hashPrefixCount >= nonEmpty * 0.5
+  const stripPlus = !stripHash && diffPlusCount > 0 && diffPlusCount >= nonEmpty * 0.5
+
+  if (!stripHash && !stripPlus) {
+    return lines
+  }
+
+  return lines.map((line) => {
+    if (stripHash) return line.replace(HASHLINE_PREFIX_RE, "")
+    if (stripPlus) return line.replace(DIFF_PLUS_RE, "")
+    return line
+  })
+}
+
+export function toNewLines(input: string | string[]): string[] {
+  if (Array.isArray(input)) {
+    return stripLinePrefixes(input)
+  }
+  return stripLinePrefixes(input.split("\n"))
+}
+
+export function restoreLeadingIndent(templateLine: string, line: string): string {
+  if (line.length === 0) return line
+  const templateIndent = leadingWhitespace(templateLine)
+  if (templateIndent.length === 0) return line
+  if (leadingWhitespace(line).length > 0) return line
+  return `${templateIndent}${line}`
+}
+
+export function stripInsertAnchorEcho(anchorLine: string, newLines: string[]): string[] {
+  if (newLines.length <= 1) return newLines
+  if (equalsIgnoringWhitespace(newLines[0], anchorLine)) {
+    return newLines.slice(1)
+  }
+  return newLines
+}
+
+export function stripInsertBeforeEcho(anchorLine: string, newLines: string[]): string[] {
+  if (newLines.length <= 1) return newLines
+  if (equalsIgnoringWhitespace(newLines[newLines.length - 1], anchorLine)) {
+    return newLines.slice(0, -1)
+  }
+  return newLines
+}
+
+export function stripInsertBoundaryEcho(afterLine: string, beforeLine: string, newLines: string[]): string[] {
+  let out = newLines
+  if (out.length > 1 && equalsIgnoringWhitespace(out[0], afterLine)) {
+    out = out.slice(1)
+  }
+  if (out.length > 1 && equalsIgnoringWhitespace(out[out.length - 1], beforeLine)) {
+    out = out.slice(0, -1)
+  }
+  return out
+}
+
+export function stripRangeBoundaryEcho(
+  lines: string[],
+  startLine: number,
+  endLine: number,
+  newLines: string[]
+): string[] {
+  const replacedCount = endLine - startLine + 1
+  if (newLines.length <= 1 || newLines.length <= replacedCount) {
+    return newLines
+  }
+
+  let out = newLines
+  const beforeIdx = startLine - 2
+  if (beforeIdx >= 0 && equalsIgnoringWhitespace(out[0], lines[beforeIdx])) {
+    out = out.slice(1)
+  }
+
+  const afterIdx = endLine
+  if (afterIdx < lines.length && out.length > 0 && equalsIgnoringWhitespace(out[out.length - 1], lines[afterIdx])) {
+    out = out.slice(0, -1)
+  }
+
+  return out
+}